How to service the heads with no parts??

[GVDobler]

From what I can see of my water leak, I am going on the theory that a head gasket has blown.

Now, since I have to take the one head off and everything except the other head, I may as well try to make lemonade out of the lemons, and do both heads. I ordered the head gasket set that has all the gaskets that are needed to service both of the heads.

My question is, what method would be best since about all I can find are exhaust valves and listings for valve seats (didn't notice intake or exhaust) and push rods. But springs, intake valves and anything else is a no-find. I'm also not equipped or skilled for valve seats.

If I took them to a shop, what could they do without all the parts?

Is it neccessary to have all new stuff or can you work with the existing parts? If so, what would you do?

Also, would you put in new lifters (from IL6) if so, what do you order?
and pushrods?

This oughtta be a hoot!

[BarryGMC]

I do all my own head work, and here is what I do. I grind the valves and seats and stems. I check the guides and if they are only a little out I knurl the guides. If they are way out I check another head. If thats no good I put in new guides. If I have a bad valve or 2 I go to the parts pile and find another valve to grind. same with the springs, check the tension. On the v6 I check the rocker shaft and rockers. I put it all together with new seals on the intake valves, Same as chevy smallblock. There are no seals on the exhaust. These are the little O rings in a head set. Here is were I will dissagree with most shops I have never seen seat erosion on a gmc v6 so I dont put in hardened seats if the heads dont have them. The incredible cooling around the valves and high nickle fine grain cast iron seem to go a long way in preventing erosion. Finally dont touch the lifters unless the cam is bad, and only replace the pushrods if there is galling or any unusual wear on the ends.

[George Bongert]

Hello Jon!

Any reputable automotive machine shop can tell you what you will need, and that having been said, I highly doubt that you will need new valve springs, seats, or valves, since these engines were not noted for burning valves, and the valve faces and seats likely are not worn to the point where they cannot be resurfaced. As to the need for new lifters, again, not necessary unless the bottom of the lifter is cupped in shape. Please be mindful to place the lifters in the same bore(s) that they came out of, since each one has it's own wear pattern, and matches the lobe that it was riding on. Putting the lifters in bores other than the one(s) they came out of can result in premature camshaft wear/failure. If you have already removed them and not kept track of which one(s) went where, have them resurfaced, then you can put them back in any bore. The push rods can be re-used unless one or more is bent, and in that case only replace those that are bent. you very likely will not have to break your bank account to have your heads checked out. Good luck, and keep us posted!

[jimjaz]

Hey Jon,

I definitely would follow along the advice of Barry. Don't mess with the cam or lifters if you don't see anything WRONG. Sure, take them out of their bores (ONE AT A TIME AND PUT IT BACK IN THE SAME HOLE) so you can get a "feel" for how the cam and bottom side of the lifters look. You could take them all out, but put them in order so they go back into where each one came from. Pushrods? Like Barry says, if they are not damaged on the ends, then leave them alone. I believe these need to go back where they came from also, but I could be dead-wrong on this point.
Chances are you did just blow a head gasket, but doing both heads is a great idea. Just have a shop that you can trust do the heads for you, don't spend any money on something that you don't need, and see about checking the block deck for being FLAT, otherwise your rebuilt heads (which will be machined flat) won't help you in your plight to put Humpty-Dumpty back together again without an issue of leak and possibility of blowing it out all over again. Your block should be OK- these beasts are tough! Where else can you get an 800 pound engine?

Good luck and good fortune (may you keep most of what you have)...

[GVDobler]

Thanks for the info guys.

I have not taken it apart yet so I will follow advice and keep track of where stuff goes.

How would I have the block checked for flatness if still in the vehicle?

Also, what should I expect to pay since they are not going to be able to supply any parts other than intake seals?

Got the head service set of gaskets from Summit. Wouldn't it be nice to just order any v6 parts we need and have them ship?

[jimjaz]

"How would I have the block checked for flatness if still in the vehicle?"

A good old-school mechanic might have a better answer here, but....
A good solid straight-edge laid on the block face with some thin feeler gauges and a good light source may prove fruitful in this endeavor.
This kind of special tool a good should have- it has to be flat and rigid- we're not talking about a steel ruler here.

[Rockdriller]

Jon,

All these answers are correct....
But, fer the record, the only blown head gskt I've ever had on a BBV6 was on my original 305E which I was happy to find out was just the rear block-off plate on the right hand head....a one hour repair.
I spent a few of my younger years as a "Mr Goodwrench", GM mechanic.
Any time we did in-frame work on an iron block engine, we would prep the block for head gskts by using a regular body shop flat board (manual, not pneumatic...) with 80 grit paper and just ran it over the head deck until all traces of the old gskt and any other impurities were removed...and then checked it like jimjaz explained.
A few shots of brake cleaner and a blast from the air hose and she's ready to go back together.
Back in the late seventies and early eighties, when I was turning wrenches for GM, this was the 'scientific' method recommended by the factory.
I guess they figured it wasn't rocket surgery.
BTW....I love the "Burbs"....we need to see some more pic's, I'm thinkin'.