Re: '65 GMC 1500 project. From the Netherlands
 

Yes, one in the same Prowbar.

Great work and thanks for posting your progress. :welldone:

Re: '65 GMC 1500 project. From the Netherlands
 

Went ahead and stripped the complete front end to prepare for paint. Will do the front suspension and steering at a later date. Don't want to keep the truck off the road for too long, or I'll start to miss driving it :)

Just been busy cleaning up all the parts, removing almost 60 years' worth of caked on grease.

Re: '65 GMC 1500 project. From the Netherlands
 

That grease removal was one of my least favorite parts. I bought a 5 gallon bucket of Super Clean (purple stuff) and it helped a lot. Still wasn't fun though.

You're making some great progress. How cold is it where you are right now?

Re: '65 GMC 1500 project. From the Netherlands
 

Thanks Fetch. the weather varies between 40 and 50 degrees Fahrenheit right now (converted it for you guys :))

For grease removal I use a product called Elbow Grease :D The best way I've found is a trip to the local car wash to spray the 'wet junk' off and then use an old flat-bladed screwdriver and a putty knife to scrape off the thick, dry layers. It is so caked on that no solvent really penetrates it. A variety of brass, steel and nylon brushes are used also. For the last bits and to clean the surface I use my parts washer with a degreaser. To prep for paint a silicone remover fully cleans the surface.

Parts such as the bell housing takes a couple of hours to fully clean, but in the end, it's all worth it.

Forgot to mention, but the previous owners in the USA must have driven over a very hot asphalt road as there is a nice thick layer of asphalt in the fenders, covering up all the bolts. Fun stuff to find them and get them all loose. No rust or stubborn bolts, nowhere. That is a blessing.

The only rust spots I have to fix are the typical front fender reinforcements, a small hole in the floor, and a spot in the radiator support because of a leaking battery.

Re: '65 GMC 1500 project. From the Netherlands
 

Could be that the tar coating you're talking about was applied as undercoating when the truck was new. A good idea that worked well until the coating aged and cracked then allowed road grime to get under it and cause rust. We have all experienced the outcome of salt/dirt that found pockets and seams to rest in over the years - some of us more in the "Rust Belt" compared to the sunny southern states.

Re: '65 GMC 1500 project. From the Netherlands
 

Pretty sure it is asphalt. I added a picture. Some layers are 3/4" thick. There's still lots of OEM undercoating on this truck, which is a very thin gray layer. It flakes off now. I have also found the original GM rustproofing in the doors. It also comes off in big chunks.

Anyway, this is a CA built truck and it had a Washington title on it when I bought it. It must have spent most of its life in very dry conditions as there is only very light surface rust on everything, except the usual rot in the fenders, rockers, doors, hood cab corners, windshield etc.

The picture is a shot of the right fender reinforcement, behind the front wheel. It has some damage and a piece of tin can along with lots of Bondo was used to 'fix' it.

Re: '65 GMC 1500 project. From the Netherlands
 

Busy on the front-end work. Originally I wanted to paint the truck in the 503 light green/turquoise color, but decided against it. There is still a lot of good original Flame Red paint left, and I've decided to bring the original color back as best as I can.

Right now I'm working on removing the layers of spray paint to reveal it. It is a tedious process, to say the least, but we're getting there. I'm using green ScotchBrite and nylon Dremel brushes to remove the paint.

I've cleaned up and painted the frame rails and part of the front end. These areas will not be easily accessible again when the 478 is in. The front end needs a total rebuild anyway, which is for a later stage. I could do it all at once, which is preferable from a restoration standpoint, but again I don't want to have it off the road for too long.

Once the firewall is completed, I can get back to the engine work and complete it. The engine can then be dropped back in.

I'm also working on rebuilding the starter motor and engine wiring harness. The engine harness was a fire hazard in the making. It will be redone with new cables while re-using the old connectors.

Re: '65 GMC 1500 project. From the Netherlands
 

Working away on the truck. Most of the firewall paint was removed. A caramel disc (usually used to remove stickers) is an effective method to remove old spray paint. A couple of spots need to be touched up to finalize the firewall.

I rebuilt the starter motor with a new Bendix, brushes, and bearings.

478 has the timing cover and top end installed. Need to make a slight dent in the 305 oil pan to clear for the governor; the 478 oil pan is deeper. Can't run the 478 pan due to the slope in the pan interfering with the front end.

Also, I wanted to run the original 4-groove pulley due to the external weight. Turns out I cannot, it hits the water pump pulley on the light-duty timing cover. Planning to make a fixture to balance the 305 pulley to the 478 pulley; I will make up an external weight, which can be easily bolted to the 305 pulley.

Also working on the engine wiring harness. Hope to install the 478 soon, when the firewall work is completed.

For reference I took a picture of the crank shaft keyway. It has a very odd shape to it, basically an extended Woodruff key.

Re: '65 GMC 1500 project. From the Netherlands
 

Completed the firewall paint strip. Wanted to touch up spots first but decided to re-paint as a whole. Primer was next, it also serves as the conversion layer between the old and new paint. New 2K epoxy paint was mixed in the correct color, using an old panel as a reference. The firewall was then painted Flame Red, the original color of the truck.

Now the 478 can be installed (finally!!)

Did a lot of preparation work also. for example, the throttle and clutch linkage are all steel-on-steel. All of the linkages and holes showed excessive wear. I welded up the worn parts and filed or turned them to original size. Bronze bushings were made up, the old holes bored out and the bushings are pressed in and further secured with Loctite. The throttle linkage is shown as an example here. I also added a washer on the clutch linkage rod, as it did not have a good surface for the axial reaction forces.

Parts such as the timing indicator on the front pulley and other small parts are sent off for zinc plating.

There is also a picture of the balancing fixture for the front pulley.

Lizziemeister made a good comment about the undercoating last time. I check other trucks and indeed, what you can see on the firewall is the original undercoating. However, some spots are so thick, I figured it to be asphalt. How thick is the undercoating on your trucks? In the nooks and crannies of the front fenders.

Re: '65 GMC 1500 project. From the Netherlands
 

Originally I had planned to also paint the front inner fenders and radiator support etc. That will have to wait for another time, as there is a car show coming up that I would like to attend, and the weather is getting better by the day. I'm getting the urge to drive it again. Have to keep the big jobs in sections to avoid having it off the road for too long.

Rust repairs are the next job when this is finished.

Anyway, the second post is to show off the added ported vacuum advance port.
Originally this engine had no ported vacuum advance port, and I prefer ported over full manifold vacuum for drivability. Therefore a small aluminum block was made with a hose fitting. A small hole was drilled in the carburetor to allow for ported vacuum.

I could have gone with the Holley 500 CFM 2 barrel, but the engine will be running on propane most of the time so there is no benefit from it really. Also, the Holley throttle blades are the same size as the Stromberg WWC, so I doubt it will be inferior in airflow.

Re: '65 GMC 1500 project. From the Netherlands
 

Installed the 478 today. Took the engine off the stand with the engine hoist, then installed the bell housing, flywheel, pressure plate, clutch, starter, engine wiring harness. Checked the bell housing runout, .003". Pilot bearing runout is less than .002". Used the same method of removing the rocker assemblies and using a head bolt with a piece of strip as a mount for the chain.
Very satisfied with the install. Then installed the transmission.
Had to take the SM420 top cover off to clear the firewall.
Used new motor mounts (Thanks for the Anchor part numbers, Funky61)

After installation, we pulled the engine as much forward as we could to give the right side exhaust manifold as much clearance as possible. There is about 7/16" clearance between the manifold and firewall now.

Now, onto reinstalling the rest...

Re: '65 GMC 1500 project. From the Netherlands
 

Been busy, but slowly building up the engine and hooking up everything.
Got most of the to-do list taken care of.
Hope to fire her up for the first time next week. I'll be sure to take a video.
We'll hook a manometer to the oil pressure sender, prime the engine beforehand, and then do a few rotations with the starter without the sparkplugs installed. Then add some gas to the carb and fire her up. Probably take her to 1000 RPM or so for 10 minutes and verify the lifters are rotating.

The carb fuel line is a temporary addition. It came with the carb and is easy for testing.

Re: '65 GMC 1500 project. From the Netherlands
 

What was supposed to be an easy start-up didn't turn out to be one. When we went to start the engine we quickly had coolant between the block and heads. Had some problems with poor starter performance as well. After a lot of attempts without any success, we gave up and drained the oil. Full of coolant...

Then made the decision to take off the heads. This went rather easily and soon was discovered that the coolant passages in the block do not line up with the head gasket. See pictures. This NOS head gasket (picture 5) only relies on crush rings to do the sealing. I never noticed this misalignment during assembly. This probably caused the leakage.
Also discovered that the cylinder crush rings seat inside the bore. Which is bad for detonation and gasket life.

Anyway, I have some Fel-pro 305/351 V6 head gaskets. They rely on gasket material instead of crush rings to provide the seal on the coolant passages. Fel-pro also turned these coolant passages into slots, which do line up, which is great. Even if they did not completely cover the bore, the gasket material would take care of the sealing. Now the bores still need to be opened up. I have tested one and it can be done, by moving the crush ring to a larger diameter. Now to make some specialized tooling to facilitate the process...

I was given the original GMC 478 head gaskets (that came off the engine, picture 3) as well. They line up properly. Which got me thinking... Maybe I've been given NOS 401 V6 head gaskets... which would explain the crush rings sticking into the bores...
And for the coolant passages, they probably moved them away from the bores to deal with the larger 478 bores... But this is speculation.

I'm glad we discovered it now instead of later... But it makes you feel like an idiot for not noticing.

Re: '65 GMC 1500 project. From the Netherlands
 

Picture of the 401 gasket (bottom) compared to the original 478 gasket (top). Notice the bore difference and the offset in coolant passages. What do you think?

Re: '65 GMC 1500 project. From the Netherlands
 

As talked about I made some tools to help form the gaskets from the 305/351 size to the 478. First off a plate with the locating dowels is made. In the center of each bore a hole is milled to hold a steel cup, which fits a bearing. This is the center is my bead roller setup.

The process starts by grinding down the old crush ring until they can be separated. This also separates the gasket. One bore is formed at a time, to keep the pieces properly located.

Then with a Dremel, the blue gasket layer is enlarged to 5.125" + some extra. A piece of plastic is stuck between the steel backing and blue gasket material to protect the steel backing from being cut.

Then with the roller and forming dies, the sheet metal backing is brought upwards and a new ring is formed. The length is then ground down to the right height and deburred. Then it is rolled over, forming a new crush ring. The sheet metal works easily and takes the shape well. The crush rings look good and smooth.

See the last picture for the finished modified gasket.

One head has already been installed with a new gasket. I also used some head gasket sealer as an added measure. So far it looks good. Tomorrow planning to reassemble the engine, then hopefully a first start without any troubles. I will be running straight water for the first start (without any calcium).

Of course, this is an experiment, maybe they blow out quickly, maybe not. We'll see. Some redneck engineering at its finest :ahhhh:

Re: '65 GMC 1500 project. From the Netherlands
 

Got this far today.

Re: '65 GMC 1500 project. From the Netherlands
 

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First start of the 478 V6!

Re: '65 GMC 1500 project. From the Netherlands
 

Here is a video of the second run:

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Runs much better, throttle at idle wasn't opened far enough and we retarded the time some. Two of the valve lifters are spinning slowly, and two aren't spinning at all, these will be replaced with new Melling lifters from Rockauto.
For the experiment, I switched two lifters around, a fast and slow turning lifter, and the lifter is at fault, with no proper crown. These are the OEM lifters.

Lifters are easy to change, back off the valve lash adjustment, remove the pushrod and use a stick magnet to retrieve the lifter.

The 305 starter doesn't have the oomph and drains the battery rather quickly, have to figure out what causes it.

The haze from the manifolds is the paint baking.

Re: '65 GMC 1500 project. From the Netherlands
 

Bought me some new Melling lifters from Rockauto to replace the slow-turning or stationary lifters. After replacing them with the Melling lifters nothing happens at all.

Pretty ticked off. Makes me wonder if the cam is still decent. I measured the lobe lift before assembly and all intake/exhaust lobes had about equal height, but I couldn't detect any noticeable taper then. Might have to pull the cam, and have it reground, along with the lifters... Not the news I was waiting for, to say the least :pullinghairout:

I am using oil with proper ZDDP content.

Re: '65 GMC 1500 project. From the Netherlands
 

Going to pull the camshaft out and have it reground according to Bigblock V6 (Pete) specs. Also, new lifters.

Need to wait a bit before I can get the cam ground, but in the meanwhile, I can finish most of the tasks that still need doing:

Remove the camshaft
Exhaust downpipes welding. Bought an air-fuel meter to install.
Propane mixer adapter
New battery cables
Leaking rear axle seal
All sorts of odd jobs that need to be done

Keeps one busy.

Traced the slow starting to the starter itself. Have to look it over. Seems like the new brushes aren't seating properly. When the switched them for the old brushes, it cranked over just fine.

Re: '65 GMC 1500 project. From the Netherlands
 

Did a couple of things last weeks:

1. Made some better battery cables. The old ones were junk and made out of old welding wire and battery terminals we had laying around. One of the reasons for poor starter performance. Bought some 50 mm2 wire (equal to 1 AWG) cable with fine strands, very flexible stuff. Proper fitting battery terminals were soldered in and heavy-duty connectors were crimped and soldered. Heat shrink with glue protects from moisture and corrosion. I've added an accessory wire to the positive cable to supply the new relay-operated headlights with direct battery voltage. A connector will be added to easily connect/disconnect them in case of repairs.
The engine turns over much better now.

2. There is a picture of the added bronze bushings to the clutch pedal. I've mentioned this before but did not show a picture. As you can see a washer welded on the lower clutch rod. This prevents the clutch linkage from wearing in to the corner of the rod. The clutch linkage was made from hardened material, and couldn't use a regular drill, endmill, or reamer to cut the material. However, a carbide burr and some patience made a nice 1/2" hole, and the made up bronze bushings were pressed in with LocTite.

3. Made a new adapter for the Impco mixer to go on top of the carburetor. Hood clearance is minimal but present due to the higher raised manifold on the earlier 478s.

4. Welded up one of the downpipes, in this case, the right side. Still need to weld in the O2 sensor bung.

5. Started tearing apart the engine to remove the camshaft. Been studying the original grind and seeing how one could extract a little better performance from one. I've considered Pete Chronis' grind, but it is more of a higher RPM camshaft. Another issue is the lack of CNC camshaft grinders - all of the companies use a copy camshaft machine with existing cam profiles to regrind camshafts.

Some thoughts:
All durations are based on advertised numbers since this is what the GMC book gives.

- Stock cam LSA (Lobe Separation Angle) is 110 degrees. I would have liked to go lower, for example, 108 or 106, to improve low-end torque. However, not possible without welding up the cam I would think. Still open for discussion. Pete's specs keep a 110 LSA as well.

- Keep the stock 63-degree overlap between intake and exhaust. Pete's cam has a 32.6 crank degree overlap, which is much less. I believe the book also gives all cam duration in crank degrees since advertised duration numbers comparable.
- Stock intake closes 61 degrees after BDC. I would like to close the intake earlier, for example, 50 degrees ABDC for an increased dynamic compression ratio. Since the static compression ratio is low as is, one could extract a little more compression out of one. However, cylinder filling might become a problem. Pete's cam closes intake 46 ABDC, which is even earlier.

-A bit more cam lift would be nice to compensate for later intake closure. Still need to measure the stock camshaft lift.

-Keep the same intake duration of 268 degrees, if possible. However, reduce exhaust duration from 298 degrees to about 275-280 degrees.
Pete's cam has an intake duration of 236 degrees and an exhaust duration of 268 degrees.

Seems like Pete's cam really 'sacrifices' on intake filling by closing the valve early, having less intake duration, and less valve overlap.

Your thoughts on the camshaft?

Re: '65 GMC 1500 project. From the Netherlands
 

As mentioned, I also converted the headlights to relay. I was given a universal relay conversion kit for headlights. I made my own harness, with the original colors. The box has relays and also 2 30 amp fuses to protect the circuit. It is nicely hidden.

Had to cut off the original connector from the OEM harness to supply the relay box. Not pictured, but I've also added the original clips to fix the harness to the grill. Power is supplied by the battery cable accessory wire.

This should take a huge load off of the headlight switch and the rest of the wiring while improving the headlights' brightness as well. From a fire hazard in the making to a win-win situation.

Re: '65 GMC 1500 project. From the Netherlands
 

Been working on a cam design.

I've added Pete Chronis custom cam specs. Note these specs close the intake much later, to up the dynamic compression ratio. Note the shorter duration figures (advertised) These specs also have a little improved lift.

Stock lift figures as measured by me, with the current camshaft, without any valve lash, are .415" for both intake and exhaust.

I also added the cam I want to have ground for my build. I have to decide on the lift, but the rest is pretty much final. Unless you have groundbreaking suggestions :)

It is a compromise between the stock camshaft and Pete's design.

Compared to stock, earlier valve intake closing to improve dynamic compression. A little less duration as a result. The exhaust is about the same as stock. I was concerned with cylinder filling at first, but don't think it matters as much due to the improved valve job and slight porting in the heads.

I've also decreased the valve overlap compared to stock, but not as much as Pete's design. The lobe separation angle comes out to 109 vs the stock cams 110.

Let me know what you think.

Re: '65 GMC 1500 project. From the Netherlands
 

I have done some flow testing on a stock magnum head (reference the link). I didn't show it on the graph but the head continue to flow more air when there is more lift.


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Also I have measure the maximum lift for both valves (reference the link).


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Hope this will help in your planning on the cam lift profile.

Re: '65 GMC 1500 project. From the Netherlands
 

Thanks, James. Forgot about those posts. Good job on the data.
Your cam lift measures a lot more than mine, didn't think mine was all that worn. Not sure now, maybe the cam lift was revised a couple of times. Have to measure my 305 now also to compare.

Seems like more lift definitely helps.
Will talk with the cam grinder about how much I can safely improve the lift.
More seems better but I would have to probably change/modify the valve springs also.

The stock ones are lousy on seat pressure, maybe 50 pounds, maybe shim them for improved pressure or change them for another spring.
They are good are break-in springs, though.

I left the stock exhaust duration as is, the exhaust port on non-Magnum heads is pretty restricted, not much can be done about it I think.

Re: '65 GMC 1500 project. From the Netherlands
 

Personally I would installed bronze valve guide sleeves first. Then I will be using valve springs from Comp Cams #972. I will also need to use spring seat cups Comp Cams #4704, guide will need to be machine to allow installation. While you are getting it machine I would also get machine for positive valve stem seals. And to top it off with Comp Cams retainers #743. The springs comes extremely close to the stock seat pressure base on the maintenance manual specs, I also double check a set just to be sure. The springs are good for .700" before coil bind.

Here is something I found on Motor Trend web site:


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Lobe Displacement Angle (LDA):
Although the installer can advance and retard the lobe centerlines, the displacement angle between the centerlines is ground into the cam at the time of manufacture and cannot be changed by the end-user. Narrow LDAs tend to increase midrange torque and result in faster revving engines, while wide LDAs result in wider power bands and more peak power at the price of somewhat lazier initial response.
A street engine with a wide LDA has higher vacuum and a smoother idle. On the street, LDA should be tailored to the induction system in use. According to Comp Cams, typical carbureted, dual-plane manifold applications like 110-112 LDAs, while fuel-injected combos want slightly wider 112- to 114-degree LDAs. Fuel-injection doesn’t require the signal during overlap that carburetors need to provide correct fuel atomization, and most computer controllers require the additional idle vacuum that results from decreased overlap.
Bracket racers with higher stall-speed converters, high compression, single-plane intakes, and large carbs usually want 106-110-degree LDAs.
Engines equipped with blowers or turbos, or used primarily with nitrous oxide, typically work best with wider 110- to 116-degree separations. Race engine speeds have increased over the years causing a corresponding upward creep in LDA and duration

Duration:
Duration has a marked effect on a cam’s power band and driveability. Higher durations increase the top-end at the expense of the low-end. A cam’s “advertised duration” has been a popular sales tool, but to compare two different cams using these numbers is dicey because there’s no set tappet rise for measuring advertised duration. Measuring duration at 0.050-inch tappet lift has become standard with most high-performance cams. Most engine builders feel that 0.050 duration is closely related to the rpm range where the engine makes its best power. Typical daily driven, under-10.25:1-compression ratio street machines with standard-size carbs, aftermarket intakes, headers, and recurved ignitions, like cams with 0.050-inch durations in the 215- to 230-degree range if using a hydraulic grind, or 230- to 240 degrees with a solid.
When comparing two different cams, if both profiles rate the advertised duration at the same lift, the cam with the shorter advertised duration in comparison to the 0.050 duration has more aggressive ramp. Providing it maintains stable valve motion, the aggressive profile yields better vacuum, increased responsiveness, a broader torque range, and other driveability improvements because it effectively has the opening and closing points of a smaller cam combined with the area under the lift curve of a larger cam.
Engines with significant airflow or compression restrictions like aggressive profiles. This is due to the increased signal that gets more of the charge through the restriction and/or the decreased seat timing that results in earlier intake closing and more cylinder pressure.

Big cams with more duration and overlap allow octane-limited engines to run higher compression without detonating in the low- to mid-range. Conversely, running too big a cam with too low a compression ratio leads to sluggish response below 3,000 rpm. Follow the cam grinder’s recommendations on proper cam profile-to-compression ratio match-up.

Lift:
Another method of improving cam performance is to increase the amount of lobe lift. Designing a cam profile with more lift results in increased duration in the high-lift regions where cylinder heads flow the most air. Short duration cams with relatively high valve lift can provide excellent responsiveness, great torque, and good power. But high lift cams are less dependable. You need the right valvesprings to handle the increased lift, and the heads must be set up to accommodate the extra lift. There are a few examples where increased lift won’t improve performance due to decreased velocity through the port; these typically occur in the race engine world (0.650-1.00-inch valve lift). Some late model engines with restrictive throttle-body, intake, cylinder head runner, and exhaust flow simply can’t flow enough air to support higher lift.
Besides grinding a lobe with more lift, you can increase the lift of an existing cam profile by going to a higher rocker arm ratio. For example, small-block Chevys where the cylinder head runners are not maxed out may benefit from moving up from the stock 1.5:1 ratio to 1.6:1 rockers. But going up more than one tenth in rocker ratio can lead to trouble; there’s a limit to how fast you can move and accelerate the valve before the valvespring can no longer control the system. If a profile was a good design with 1.6:1 rockers, it’ll probably be unstable with 1.8:1 rockers. The correct solution is to design the profile from the ground up for use with high-ratio rocker arms.

Hope this is not too much information ("Information Overload"). I just want you to make the best choice with the information you know.

Good luck.

Re: '65 GMC 1500 project. From the Netherlands
 

Not a problem at all. I used cast iron guides for the exhaust, with the positive valve stem seals. Bronze would have been better, couldn't find any in the size I wanted. The engine is assembled, last thing is the cam, because I had some issues with it.

I've read a lot about cam design in general. Tried to stay very mild on the cam, to increase torque and drivability, and get as much out of the engine as possible. No need to try high hp/high rpm tricks if the engine doesn't turn past 3200 rpm.

Those Comp springs are pretty stiff I think but could work. I would prefer 85 pounds of seat pressure. Pete Chronis talked about Ford FE390 springs. For a low RPM engine, this should be sufficient in my opinion. A 5.9 Cummins uses about the seat pressure.

I'd like to increase lift but it has to be doable.

One way to increase lift is to reduce base circle size, there is indeed a possibility of running into geometry trouble.

I am going to discuss with the cam grinder if they can weld up the lobe to increase the lift and accommodate the new profile.

Different rocker arms are also possible. But would need to be custom-made.

Hope it makes sense.

Re: '65 GMC 1500 project. From the Netherlands
 

Was wondering what changes you are thinking about that differ from Pete's grind specs. I run a Pete spec ground cam - it sounds nice which was one of mine goals and seems to do good at highway cruzin' speed. My truck clocks at 60 mph about 2600 rpm. I think this is about where the power band comes in due to the cam grind. My truck sees mostly highway speeds and most generally pulls a car trailer lightly loaded. You can relate my truck's usage to that of 379 Peterbilt pulling a chrome reefer - gets the job done with a little flair. Sure there's better builds and combos but hey - it's a little different that any run-of-the truck - and it gets more looks that any 2023 decked out $100,000 truck when you pull up to gas pump.
I guess it's all in what you want - but the truth is anything you do to a 60 yr. old GMC V6 motor will never be equal to what a truck engine of today's manufactured engineered marvels can do in performance. BUT when we raise our hoods we CAN see a motor and are ABLE to work on it. This is just my thoughts - give me and other GMC V6 caretakers your inputs - for now I think I go out and crank-up the 1960's Diamond T "Cat" powered road tractor and blow some smoke while dreaming about a V12 powered "Crackerbox". Have a good day!

Re: '65 GMC 1500 project. From the Netherlands
 

The reason for the changes is a comprimise between the stock cam and Pete's cam. A powerband of 2600 is a bit high for a 3200 rpm engine in my opinion. I like the low end torque and want to retain this. So a powerband around 1600-2000 or so. I hope to achieve this with the modified design.

Figured I added some info where I explain my reasons:
Most people agree that there are two key events in a camshaft: intake valve closing point and valve overlap. The others are important too, but not as much.
Generally speaking, intake valve closing determines the place where in the rpm range the torque is generated. Valve overlap has about the same effect. The intake can be timed later for higher rpm power. Valve overlap can be extended for higher rpm power.

Intake valve closing point:
The stock cam: 61-70 degrees ABDC, depending on the year.
Pete's cam: 46 degrees ABDC (After Bottom Dead Center)
Modifed design: 50 degrees ABDC - I agree with closing the valve earlier to up dynamic compression as much as possible.

Valve overlap:
Stock: 63 degrees, might vary with the year.
Pete: 33 degrees
Modified: 45 degrees - Searched the middle ground, as a compromise between the two.

I am thinking Pete's cam has a sweet spot at about 2600 rpm where the pulses act to charge the cylinders better. According to the 'books,' it should behave as a lower RPM cam.

Not trying to build a race monster, but hope to improve the usable power as much as possible.

Re: '65 GMC 1500 project. From the Netherlands
 

By the way, Lizziemeister, do you have any videos of your V6 running? Would love to hear what it sounds like.

Re: '65 GMC 1500 project. From the Netherlands
 

I don't have one at this time - but I have see/heard my truck on video - I think someone on this site may have it. They commented that it sure didn't sound like a V-6. Next time 1 of my computer savvy buddies with a smart phone stops I will post a video.:thumbsup:

Re: '65 GMC 1500 project. From the Netherlands
 

Asked a local company that specializes in spray welding for repair work to build up the camshaft by spray welding. They advise against it due to the poor bonding to hardened surfaces, and the risk of the new surface flaking off.

Too much work and trouble for added lift. Might make custom 1.6 rockers in the future, we'll see.

I've sent the camshaft to the cam grinder today together with my specs.

Also took a look at the valve lifters - measured the face surface with a dial indicator by sweeping the lifter on a flat surface. The originals are cupped in (concave) from the wear. They should have a crown. (convex)

I also bought new Melling lifters to test, they have a flat face :banghead:

But, I also measured hardness with a Vickers tester of the lifter faces. I wanted to check the new Melling lifters vs the OEM lifters for hardness. I tested 2 of each lifter:
OEM lifters:
No. 1: 629 HV (56 hRC)
No. 2: 690 HV (58 hRC)

Melling lifters:
No. 1: 750 HV (60.5 hRC)
No. 2: 748 HV (60.5 hRC)

Interesting results. I figured the Melling lifters were much softer, low-quality pieces. Properly refaced, they should last a long time.

Now to reface the lifters. Since no one refaces lifters anymore in the Netherlands, I'm going to think up something myself...

Re: '65 GMC 1500 project. From the Netherlands
 

Here is the quickest way to pull the camshaft without removing the radiator support - just loosen the front engine mounts and use a jack to tilt the engine.

Re: '65 GMC 1500 project. From the Netherlands
 

The flat lifters should work as design. The camshaft lobes has a front to rear ramp on them to make the lifters spin.

Placing a crown on them would reduce the spinning effects.

On a side note, roller lifters camshafts does not have a ramp on the lobes. You do not want those lifters to rotate.

Re: '65 GMC 1500 project. From the Netherlands
 

Yes, the camshaft lobes are ground on a slight taper, but the lifters should have a crown. Should they be flat, that would result in a line contact, which would wear rapidly. The crown helps break in and mating to the cam lobe. It does reduce spinning to an extent but helps distribute the load better due to increased surface area.

Take a look, this article explains it very well:

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Re: '65 GMC 1500 project. From the Netherlands
 

Thanks. That was a good read. I always though the lifter was flat on the bottom. Having the slight crown explains a few things.

Re: '65 GMC 1500 project. From the Netherlands
 

This is what is needed for lifter regrinding.


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Re: '65 GMC 1500 project. From the Netherlands
 

If you need lifters resurfaced, I deal with a well known cam grinder in my home town here called Delta Cams. I'm thinking it was $100 to resurface the 12 lifters. I have an extra set of these if you get into a pinch I send in to get resurfaced then sent to you.
Steve

Re: '65 GMC 1500 project. From the Netherlands
 

Thanks Steve, I'll keep that in mind. I've watched some videos of Delta Cam on Youtube, Jon seems like a good guy. Have also read good things about the company.

Re: '65 GMC 1500 project. From the Netherlands
 

They have been grinding my cams since back in the early 80's. When I was racing they built me a couple custom turbo cams for my 351 Windsor motor and I flew. Lots of experience there and they gotten a lot of people needs straightened out.