I was tlaking to thirdgen chas (one of the 3,4 pioneers) about how I'm stepping down form the engine swap and getting a blower. We also talked about higher performance head building, and he highly recomended after I get all the parts together, I should hand them ovr and let someone else have the fun of actually putting all of my expensive parts together.

Anyone ever assembled a head, or have any advice?

-Reno

 

I don't think there's much to it. I think new valves need to be "lapped" in by hand... and the machine shop would take care of any decking or valve guide repair. Rocker arm lash is set when the head's installed on the car.. otherwise, they just flop around when you put the head together. Seems like a valve spring compressor's the only "special" tool you need.


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

 

If you are planning to have the heads rebuilt or just have new valves put in you will want to have the seats ground (3 angle) and at least have the heads magnafluxed and surfaced.

Also if you need new seats/guides the shop will be able to do all this at once.

If they are off I would definately have a shop work them over.

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ASE Mechanic/Machinist/Smog Tech

1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R

GO #3

 

Engineboy, I just read last night that the V6/60 heads got a 3-angle job from the factory! Is that true? The same book said that hand-lapping the valves destroys the 3-angle job- so everyone please ignore what I wrote originally!

Oh the book is "Rebuilding the GM 60-degree V6" by Tom Currao...


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

 

I don't know for sure Tom but it could be.

Most stock engines are nowadays.

I've heard of some pro engine builders doing 5 angle jobs.

Lapping them widens the center angle (the one the valve seats against) and it can eliminate the other 2 angles if the valve has sunken into the seat a little.
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ASE Mechanic/Machinist/Smog Tech

1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R

GO #3

[This message has been edited by Engineboy (edited December 07, 2000).]

[This message has been edited by Engineboy (edited December 08, 2000).]

 

Cool, thanks for that info. Why do books & magazines still mention valve lapping, then? Is that for heads without valve jobs?

One more question I take it new valves should be installed when a 3-angle job's done (or redone)?


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!

 

Lapping would be OK if the heads were in good shape and you just wanted a quick clean up. This just smooths out the surface of the seat/valve contact and cleans any "hard" deposits that can effect the seal.

You don't always need new valves when you get a valve job. (3 angle or not)

When I used to do heads the first thing I did was to cut the old valve and see if it had enough "meat" on it.(a good air gap between the head and the seat contact area). If it doesn't than it needs new valves.

New valves are usually done by choice, you don't need them for a 3 angle job.

If you want to go more performance than you can get lighter/stronger/thinner stemmed valves that will help you out in the flow department.

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ASE Mechanic/Machinist/Smog Tech

1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R

GO #3

[This message has been edited by Engineboy (edited December 08, 2000).]

 

Okay, I get it now.. checking the valves has to do with looking at the thickness on the valve end, right? Is it cheaper to cut old valves than to replace them with new?

I have two sets of heads in the basement; I assume I can mix & match to get a good set. Oh, er, unless I can't put a used valve in a guide/seat it's not meant for, like mixing up used lifters with a used camshaft...


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards
---Think your car could be pic of the week? Visit http://www.f-body.net for details!