I'm replacing my heads on my '86 2.8L, don't ask why. I got new bolts, I was told to put on 'blue' permatex on the threads and torque them to 40lbs. then 90 degrees more. Is this right? Any other tips would be appreciated.

 

Don't use blue permatex! The head bolts go through coolant passageways! You need a non-hardening sealant on the head bolts... and I don't think blue RTV will do the job well.

Loctite's (or Permatex's) "PST" (pipe sealant w/teflon) is good for this... but it's hard to find. You might find it thru a plumbing store. GM also carries their own brand, but it's more expensive. You can also use Permatex's "#2 gasket maker", the brown stuff in a thin tube. Apply the sealant to the lower 1/2 of the head bolt threads.... these are the threads that go into the coolant areas. Otherwise, you might end up with leaks.

As to the torque spec, yeah, that's the final torque- 40 ft/lbs, then 90 degrees (1/4 turn) additional rotation. But, torque the bolts down in three steps. Following the torque sequence (inside of head to outside, in a clockwise circle):

6...2...3...7
5...1...4...8

Do the first pass to 20 ft/lbs. Do the next pass to 30 ft/lbs, then do the final pass of 40 ft/lbs + 90 degrees. The shorter bolts go on the outside of the head, near the exhaust ports.

Also, make sure the threaded holes of the engine are clean of any old sealer, and make sure no old gasket material's in the coolant passageways of the engine block and head... but you probably already knew this.


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-Tom P (Hot rodded 1986 Firebird 2.8l)

 

Tom thanks. 1 more question...what is the best way adjust my vavle lash. Do I soak the lifters, then push down on them with the pushrod in a cup to load. Then what is the best way to adjust them, I've been told different ways, snuge then a 1/4 turn tight. I'm not sure.

 

How I do mine with 100% accuracy, first time.
I get a compression guage & a fixture for fitting in the spark plug hole. I have the starter under the hood hooked up for my engagement.
I adjust the valve until the highest compression reading. I adjust one more time, to make sure I do not get to NO COMPRESSION (valve opened, never closing to build compression), I reset to highest compression, then I'm done.
This is a guaranteed 100% foolproof way you do this. I've done three engines this way so far.
I've tried the small block chevy method. Rotate the push rod trick never works as right on the V-6 engines, as it does on a small block chevy engine. I have both engines & I know! And I have done both ways!! I always resort to a compression valve adjustment. 100% guaranteed!! Always.

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Chat Soon,
KED85
Karl
1985 Firebird 2.8 to 3.4 swap project for Smog Happy LA, CA

 

On the heads I did, we jiggled the push rod up and down as we tightened the rocker arm nut. We stopped tightening the nut when the pushrod wouldn't wiggle up/down anymore. This is supposed to be "zero lash". The spin-the-push-rod method doesn't give as accurate "zero lash" setting, since if I'm stronger than you, I might continue to spin the pushrod whereas you might've stopped. As soon as the pushrod has no more "up/down" play, stop tightening the rocker arm nut; that's zero lash. Then, you give the rocker arm nut it's final "1/4 rotation" turn- that sets the preload for the lifter. This is supposed to set the pushrod in the middle of the lifter's adjustable plunger.

There's a certain sequence that you're supposed to go in; I forget which it is right now. You get the #1 piston at TDC, and adjust some lifters... then you put another piston at TDC (5?), and do the other lifters. I'm not near my books now; I'll look tonight when I get home.

I think you can squeeze some oil into the lifter hole with a squirt can; we didn't need to do this, since the lifters still had oil in them.


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-Tom P (Hot rodded 1986 Firebird 2.8l)

 

Tom & KED85, thanks again. I've done my share of small chevys, but Not any V6's. I went Chevy to ask them, they said to bottom out the nut, as long as the lifter is down. I have the sequence order. I may try it all 3 ways, see which 1 gives the most compression. Also I'm going to Home Depot to get the teflon thread sealer. Chevy wants $17.00 for a tube.

 

Damn, $17?! I bet it's a small tube, too! I couldn't find the stuff at Home Depot; let me know if you do, I might have to try another store. We used the Permatex #2 on one head; then my friend's father gave us his tube of Loctite PST. We used the PST on the other head. I should've had his dad buy me a tube!

And yeah, let us know about the compression on all three. We never checked the compression after doing valve lash. Seems to me that bottoming out the nut would yank all the "self-adjustability" out of the hydrualic lifters...


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-Tom P (Hot rodded 1986 Firebird 2.8l)

 

Home Depot has a 1.75 oz. tube of thread sealant w/teflon for $3.00, plus bigger sizes.

 

White goopy stuff, right?
I used that stuff from GM & it's great!!!

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Chat Soon,
KED85
Karl
1985 Firebird 2.8 to 3.4 swap project for Smog Happy LA, CA