Priming a 351e v6 engine
 

Hello everybody, I am sure happy this site exists. A relative just gave me a 1967 GMC Dually that has not been started in 6 years. I am a novice mechanic at best and that's probably stretching things. But I am fascinated with this motor and don't want to damage it so I decided to "prime" the engine.
I first poured mystery oil down spark plug holes over a period of several days. and was able to turn motor by hand.
I changed oil and filter oil used is a 5w10 or 20 (the thinnest viscosity I could get hoping that it would seap through any dried up parts easier) I live in pa and it's in an unheated garage. As soon as I get it started I will put heavier oil in.
I removed the distributor and my first surprise was the type of oil pump shaft it had. It is a long hex shaped rod. I hooked up a drill extension drilled it a couple for at least a minute or 2 a few times waiting to see oil squirt from rockers but nothing has happend. The drill turns at 1200 rpm. I checked a couple times to be sure rod is turning pump. Turning with fingers And it feels like it has the type of resistance one would expect with an impeller spinning in oil. So I think it is making a connection.
I have watched dozens of youtube of people priming engines so Now my next thought is to connect an oil pressure gauge but I can't seem to find where it would connect. I have the gmc maintenance book and the engine overhaul book
but I don't see any noted places to do this. Can somebody tell me.. Where it can be connected or better yet do I even have to prime it at all. One reason I ask that is because I have read one feature of this motor is some type of pre-oiling it does when starting that saves wear and tear. One other thing. I put 5 quarts oil in but I did not pre-oil the filter. (Could not pre oiling the filter have caused an
air pocket that is preventing the oil from getting up to the rockers.)
Hope to hear from somebody. Ihave ordered the factory assembly manual which will arrive Monday hopefully that will be helpful in locating the place to connect oil pressure gauge. Opinions,ideas,tips greatly appreciated.

Re: Priming a 351e v6 engine
 

If there is a port on the filter housing, that will work for a gauge. Where ever the oil pressure sender goes is the place to install a gauge, right on the engine, for testing. In my opinion you do need to see oil moving somewhere. Keep the drill going longer. Have you had the pan off to inspect pickup screen? Sounds like you are on the right track. Take out all spark plugs and crank it some. Not too much, just to see if it will crank. Oil may blow out of holes. If it sounds OK and you got some oil to flow at rockers. Start her up. NOTE: there really is no way to tell for sure that you won't mess it up without some dis assembly, but these preliminary steps will help. If something is already broken inside, you may have trouble. If you know it ran good when parked, then these oil and gentle rebirth methods will work. You probably have a spin on filter. Take it off and fill it. Don't run more than a min or 2 max without water/air flow.

Re: Priming a 351e v6 engine
 

Thanks for your input.
When you say try to "crank it" do you mean using the electric starter? If that's what you mean should I re-install the Distributor or does that matter? I have marked where the tab was pointing and have not touched the crank by hand since I took the distributor off. (From what I have seen on you-tube doing so could make it difficult to get everything re-aligned again. I'm sure an experienced mechanic could do that with ease but I have to realize my limitations and I fear I could cause a situation that could create a new problem. I have seen where people re-position the crank by aligning it with some type of groove on one of the wheels that hold a belt. (I think it had a belt, I may have to go back and watch that one again if I can find it) with a certain point on the front of the engine. There are so many scenarios and some videos often leave out an important detail or new concept assuming one knows the other details already. It's all new to me and takes awhile to absorb. The maintenance and engine over haul books kind of help but the audience for them was obviously experienced, paid, professional GM mechanics.
Thanks again for your help I really appreciate it.

Re: Priming a 351e v6 engine
 

Put distributor back on after you run drill long enough to get oil. You can't hurt anything but the drill that way. You can reset distributor if you loose the position, but for you it would be better to reinstall before turning motor. Also you will be starting it after prelim cranking. Yes cranking means using starter. There are other issues here, points, condenser, wires, plugs, etc, involved in an actual start up. You can try however and see if it fires. It does not have to start but should fire. Then you know it's doable with more help. You should wait for other members to give their advice and you should find a friend that knows a little more about motors. The start up of this motor is no different than any other dormant motor restart. Keep checking your post for others to respond besides me. In the mean time report back if you are able to see oil flow with valve covers off as you run drill. You did not answer my question about screen and did not respond to filling filter. You need to answer questions from posters as they try to help. The more I read from you indicates less experience than first thought. Internet help may not be the best for you on this. You will learn a lot, some correct, some not. You need a good ol' boy to help in person. Carlisle used to be the heart of rodding and motor heads.

Re: Priming a 351e v6 engine
 

Thanks for input. I will take the filter and reinstall with oil. I will see if I can get at the oil pump next. Fortunately, I do have an older gentleman "local good ole boy" type mechanic who owns a small shop who I am quite certain prefers these older vehicles. He works on another older truck I have. In fact once I got it started I was planning on driving it down to his shop and having him look at other things that will need worked on. The truck only has 70,000 miles on it. It was a special factory order and then the owner had a frame attached mini motor home type camper on it. Like many campers, it had lots of early use and then sat around. I may just have to have it towed down there and leave this issue to him as well.
thanks.

Re: Priming a 351e v6 engine
 

This is probably supremely stupid, but I am afraid I can't see how the distributor drive would turn at all.
At some point it would have to be attached to a drive gear for both the dist and oil pump.

Re: Priming a 351e v6 engine
 

Jim, not sure what you are saying but: The distributor has a gear on it's stem which engages a gear in the motor. (cam shaft gear) The distributor also "engages" a pump rod which is turned by the distributor because the distributor is turned by the motor gear when motor is turning. When the distributor is removed, nothing will drive the pump rod, so a drill is used to circulate oil. I'm not sure what you mean by "distributor drive". The pump rod is a hex shape, in many engines it's a slotted shaft. If he turns the engine with distributor out, the cam gear will turn and that changes the position of the distributor vs timing when you put it back in. If someone has marked everything before removing dizzy, they usually don't want to rotate motor. As I said, it's not the end of the world, it can be pretty easily reset by finding TDC cyl 1.

Teddy: Taking it to him sounds like a good plan. At the very least explain what you have and what you are doing and see what he says. 70K mile? WOW, that's neat. Should start right up with the proper procedures. Do you know if it was running when parked? How did you attach a drill? Long shaft with hex socket? My motor started showing oil at rockers with turning with starter motor, so I didn't use drill. I did cover everything with oil and cleaned the screen and put some oil in plug holes before cranking. NOT WD40.

Re: Priming a 351e v6 engine
 

Aiken: By the way, since we're discussing this subject. I went to autozone looking for a primer shaft that would fit this hex rod and got into a conversation with a kid working behind the counter. ( Who was absolutely fascinated that a big block v6 ever even existed.)
He told me that he gets chewed out for doing this by coworkers and some mechanics but his method of priming a motor is he just takes the valve covers off and pours oil all over on top of the rockers and everything else and let's it seap down. At first I thought oh great now that I spend about a week or so learning all about distributor removal etc. etc. And building a small scaffolding set up so I could to see and work way back in the engine compartment he tells me this quick,cheap and easy engine prime method. I'm just curious is that an effective method to do this also?

Re: Priming a 351e v6 engine
 

Well it's not a bad idea but it's done just so that there is not a dry initial few seconds before a dormant motor primes up and starts delivering oil thru passages. It does NOT prevent a big problem from a bad pump or oil distribution to all the other critical parts. It is not a substitute for being sure the pump and passages are open and working. You are not wasting any time and he is playing with fire. He gets chewed out by mechanics and co-workers and pays no attention? Does that tell you anything? You can't pour oil on the "everything else" he is talking about. You should, by all means, see oil moving up there either by drill or no start cranking, period. And that is not even fool proof. But that ,with an oil pressure gauge (reading 30-50 lbs +/- while running) would be as safe as possible for a dormant startup. Knowing the history of the motor when it was parked, if possible, is also important. A known noise or freeze up is a big warning.

Re: Priming a 351e v6 engine
 

Minor point, but you need to add one more quart of oil. The oil pan should have 6 quarts in it for the light duty application V6. Heavy duty applications used an 8 quart oil pan.

Although they're pricey, an alternative to spinning your oil pump shaft with a drill is to install a pre-lubricator like MasterLube http://www.masterlube.net/classic.htm sells. They're good for protecting engines that sit for long times between start-ups. I've got one on my 401.

Re: Priming a 351e v6 engine
 

I guess I had in mind that he only had the rotor off and not the whole distributor.
I assume the hex drive for the oil pump fits inside the distributor drive, taking its spin to turn the pump.
A further probably dumb observation is that the direction (cw or ccw) the oil drive is turned makes a difference.

Re: Priming a 351e v6 engine
 

Yes distributor has female hex. Not sure if both directions will work (probably not) but it's CW. There are no dumb questions here just sometimes dumb answers. (from me). Forums are for all levels of experience and knowledge. No one knows everything. Every one of us started with no knowledge. I try to be right, but sometimes slip up with bad memory, not thinking properly or wrong assessment. I change my posts allot until it reads what I wanted to say. I can't tell what it says until I see it posted and sometimes rethink it.(brain lock)
I hate to be wrong. But I love answering because I learn by it. Look it up, study it, check to see if my experience/memory is correct...and in the end read the correct answer from another member. :)

Re: Priming a 351e v6 engine
 

I need to correct that. I did put in 6 quarts. For some reason the larger containers of oil I had contained 5 quarts and my mind was automatically and lazily, subconsciously recalling most other things in bigger containers usually come in 4 quart/gallon sizes. I recall 1 container plus a quart from another, sorry.

I did look at that masterlube site which is interesting but no prices listed which throws up the "so overpriced salesman has to tell you how much" red flag signal.
About how much (ballpark) are they?

Re: Priming a 351e v6 engine
 

With options (chrome plating, larger size, longer hoses) I paid about $400 for mine.

Re: Priming a 351e v6 engine
 

When priming my 478 I experienced the same situation of not getting oil in the rockers, the solution to that was just hand cranking the engine with a breaker bar in small increments and continuing the priming process and yes oil did come out of the rockers. It was that simple, otherwise I've got to say this whole issue on priming is getting blown out of proportion!!!

Re: Priming a 351e v6 engine
 

It may seem blown out of proportion. It may seem like it's not rocket surgery. It is over explained, by me especially. When someone asks for help and they say they are inexperienced, I don't want them to damage their motor. I want to explain, suggest, advise, if they care. Experienced members can just ignore the repetitive, boring aspect, so that others can get help. Starting at a basic level of explanation. Let me know if I am right or wrong. I am new here also and don't want to cause headaches.
Priming is one thing but walking a possibly inexperienced person thru a 6 year dormant motor startup is another. Ed's post on primer was interesting. Had never heard of that. At this point, I would not advise that to the poster. That's for an already good runner as added protection. It costs more than a good running 305!.... (joke)...... (maybe).

Re: Priming a 351e v6 engine
 

Aren't there holes in the rocker arm shafts that have to be lined up with holes in the mounts before oil will flow? That won't happen with just spinning the oil pump.

Re: Priming a 351e v6 engine
 

Thanks everybody for advice. 1.

1. It never occurred to me that the rocker arm shafts had holes in them that should be lined up with holes in the mounts I will look at that.
2. I see the top of the oil filter housing has a small metal line (Probably about 1/3 the diameter of a air pressure nozzle on a tire) that works its way up into the dashboard. I am guessing it's the oil temperature sensor maybe? That's where I guess I will install an oil pressure gauge. (I certainly have a new and improved appreciation for mechanics because the small confines they have to work in is baffling.) But first I want to look into the rocker arm shaft suggestion.

I hope I am not causing anybody frustration do to Ignorance but a big part of the reason I am doing this myself is an exercise raising my mechanical IQ. And I do appreciate everybody's input.

Re: Priming a 351e v6 engine
 

No frustration on my part. I'm learning from Ed like you are. Don't turn motor to check passage holes until you put the Dizzy back on or we will be explaining another procedure. When I did mine I did turn motor over with starter and I did see oil moving. Did not do the drill thing. I thought I remembered doing it on other motors with a drill and seeing oil. But as ED has pointed out, the drill on pump rod would be to prime pump and pressurize the system as seen by having a gauge hooked up. To see oil, I guess you need to rotate motor with hand or starter after priming. You probably already did prime. Seeing movement up in the rockers, you should be ready to start for a min or two. Use fresh gas from a fresh container, NOT from old tank. Or starter fluid only, to get a second or two of running. Wear safety glasses and keep an extinguisher handy. I would do it outside for safety and exhaust fumes.
You are correct, you have a mechanical oil gauge. The oil goes thru the line and the pressure is read by the dash gauge. On an electric oil gauge, there is a sensor on the motor. You can hook up gauge as I did in my pic above or if your dash gauge works, voila!

Re: Priming a 351e v6 engine
 

When I managed a hi-performance automotive machine in the 70's we primed every engine that left the shop. On that note while priming whether by an auxiliary pressurized oil tank or spinning the oil pump, on certain engines you have to also rotate the engine by hand. The reason being, some engines feed oil to certain parts of the engine occasionally, so the camshaft might have a flat in a cam bearing journal, this is just one of several ways oil is fed to the top end of an engine.

Re: Priming a 351e v6 engine
 

I just looked at the dash and it does have a factory installed oil pressure gauge. So I may see if that shows any pressure. Now All I got to do is figure out how to HOT WIRE the truck. ( I guess that's under another thread subject maybe.) I mentioned earlier truck was given to me. It was my cousins and he has been sick last several years which is why the truck sat. It did run good before. He has only a few weeks or months left. He's is not in good enough health to locate key. So I will have to solve that problem. I seen ignitions on internet. And about the gas tank it's all rusted up. I started cleaning it up but may just get a new one. I built a special contraption with an old trailer axel mounted on 2 posts and attached the tank Like one would do at pig roast. I dumped 300 1/4" nuts inside and rotated it. When I opened the Gas Fill Inlet brown powder flowed out like water. So I have no choice other than to rig up an alternate quick mini tank with fresh gas.
Anyhow I will keep you all updated. Thanks.

Re: Priming a 351e v6 engine
 

Drop the key switch down on it's pigtail so that you can see it/access it. Don't unplug connector yet. You can be the switch, by connecting two terminals and temporarily touching another. You can do it under the hood also, that takes some jumper wires too. A cheap 2 gal Walmart plastic gas can ($5 ) is good to have around the yard anyway. That's what I use. Run rubber fuel hose from fuel pump inlet to down inside can spout, can sitting on the ground. You don't need a filter in that line. Take off or replace any filter between pump outlet and carb. You don't need any filters for this test. New gas, new can, new hose. I don't think the carb will operate correctly but it should at least start. May have to cup your hand over carb and work the throttle. A helper would be nice. If you have a working hand choke, you can close it 90%-100%. Now that you know it was running, don't worry, it will be OK to start. The oil in plug holes should be blown out or leaked down by now. Don't add any more when putting plugs in tight. (damage can occur) I will check schematic for wire colors/position to jump on switch or describe under hood . Others here may help. Good battery? If your dizzy is off on the bench, you can set points easy. You need to do that. The rotor is keyed and the cap is keyed. You are still going to rotate motor with starter and no plugs before actual start. I understand you will be watching oil pressure gage and watching rocker area. You should continue to report your progress. Maybe someday this post will help someone else. Good job so far. It is good you want to do it yourself, that's what old trucks are all about. When you hear it fire off you will want a cheeseburger and fries. I think a lot of guys think a 351E is cool. Make sure you read everything, at least about motors and specs, on the Jolly legacy site.

Re: Priming a 351e v6 engine
 

Depending on what position the camshaft is in there are holes in the camshaft bearings that feed the heads with oil that travels up to the rocker arm shafts. That's why turning the engine over in small increments will allow you to reach the right position so oil will flow up into the heads.

Re: Priming a 351e v6 engine
 

Thanks for straightening me out, Pete. I must have had my thinking cap on too tight, blocking blood flow to my brain. Of course you're right -- it's the turning of the camshaft that sends oil to the rocker arm shafts. The rocker arm shafts don't turn.

Re: Priming a 351e v6 engine
 

The cams are not cross drilled the bearings are grooved the oil travels around the cam in the groove. Then it travels to the rocker arm shafts. There is no need to turn the engine at all. Here is a oil flow chart.

Re: Priming a 351e v6 engine
 

Grooved bearings? Well just to confirm my suspicions I checked out the old 305E out of my 68 that's getting scrapped and there are no grooves in the cam bearings. The GMC Truck Unit Overhaul Manual as a very good illustration of the cam bearings with their oval shaped oil holes. From first hand experience it is necessary to turn the engine over to get the oil up into the rockers, when Azken brought up his issue it took me back when I was priming my 478 almost two years ago having the same situation and remembering a professional engine builder telling me you need to turn the engine over to see the oil flow through the rockers. The oil chart only shows where and which direction the oil flows and that's about it.

Re: Priming a 351e v6 engine
 

Ok Mr. GMC Advisor! I just looked at it again and there are no grooved cam bearings anywhere on this factory original 305E V6.

Re: Priming a 351e v6 engine
 

Included in this post is a pic of a factory rear cam bearing on a 305E V6 I just took, yes it is smooth and no grooves. To the moderator I hope you take note that such personal attacks using profanity from other people on this site are uncalled for.

Re: Priming a 351e v6 engine
 

Last post. Pull the bearing and look.

Re: Priming a 351e v6 engine
 

When I posted about turning some engines over, I was re-affirming a previous comment, I did not mention the GMC V6, as it does not have to be turned over. When priming an engine it does help it to turn it over a few times by hand. If memory serves me correctly the block is grooved behind the cam bearings on the GMC V6, not the cam bearings them self.

Re: Priming a 351e v6 engine
 

Thread cleaned up. Let's keep it civil, gentlemen. To the right of every post is a little exclamation point that allows you to report inappropriate activity. Anyone may use it if they see something that would break the rules.

Barry will return in 10 days.

-Jeannie

6066 GMC Club

Re: Priming a 351e v6 engine
 

Clyde you are absolutely right the cam bearing has no grooves, the grooved area is at the very back of where the rear cam bearing mounts. These bearings are so thin that the idea of being grooved is ludicrous. I've posted pics of the cam bearing and the grooved area at the back of the engine block.

Re: Priming a 351e v6 engine
 

Are those slots in cam bearing for oil? Are the slots what is meant by grooves in bearings? If oil travels from grooves thru slots, does that mean you don't have to turn motor to get oil in there when spinning with drill?

Re: Priming a 351e v6 engine
 

The slots feed oil into the passages like the grooved area in back of the block in the second pic, one passage goes to the lower part of the engine block and the other leads up to the right cylinder head.

Re: Priming a 351e v6 engine
 

What I'm trying to determine while helping this poster and trying to learn is: Does the oil get to the cam shaft from the grooves and thru the slots? Doesn't the cam shaft go into/thru that bearing? I'm trying to determine if there is flow with the drill pump method no matter where the cam shaft ends up when motor shuts off.

Re: Priming a 351e v6 engine
 

What you need is to look at is an oil flow chart on these engines, oil does flow up from the filter to the grooved are on the back of the block through the slotted holes to the cam and another passage below the cam that goes to the front of the block for starters.

Re: Priming a 351e v6 engine
 

OK Teddy, Thanksgiving is over so start your motor.

Re: Priming a 351e v6 engine
 

I'm baaaak! I took a break for couple days from truck project. I guess I missed some good engine engineering intellectualizing from the more experienced members. So where do I go next. Do I put the distributor back in and turn engine by hand and wait to see oil rise through the rockers? Or do I continue and see if I can get the rise from drilling the oil pump.
Or do I just connect battery and try turning the motor with distributor in and spark plugs out.
Thanks.

Re: Priming a 351e v6 engine
 

Do the drill for one full minute or oil flow, whichever is sooner. No oil? Turn over with starter, dizzy in/plugs out/oil squirted on rockers. 7 seconds at a time. no oil? Punt. Oil at any test? start it per previous caveats. (including gauge monitoring)