1986 4.3 to vortec heads. valve adjustment help.

[fourwinnsdook]

i'm going to start out by saying that i expect everyone to call me an idiot for asking this but i want to double check. I put 98 vortec heads on my 86 block. will i need to adjust the valves? my compression numbers are all messed up and that's all i can figure that could be wrong since the boat ran fine with the old heads on it. Please don't make me sound like to much of a dumb *****

 

[Don S]

Re: 1986 4.3 to vortec heads. valve adjustment help.

Just answered it on your other post. No adjustment on those heads, just torque the nut down to 20 ft. lbs.

One problem you will have, is you probably don't have roller lifters or balance shaft on the old block. And I highly doubt that the above torque value will work with your flat lifters.

 

[Bondo]

Re: 1986 4.3 to vortec heads. valve adjustment help.

I put 98 vortec heads on my 86 block.
my compression numbers are all messed up

Ayuh,...

And using What hardware,..?? ei: Lifters, rockers, pushrods, etc,..??

What are the #s,..??

 

[iang]

Re: 1986 4.3 to vortec heads. valve adjustment help.

Loosen off all the rockers and leave overnight so the lifters relax back to zero .Then start on no 1 ,thighten rockers until there is zero clearnce,do this by gently shaking the pushrod up and down until all the clearance has gone and then tighten the nut another half a turn,do this on all cylinders by following the firing order and you should be good to go.

 

[Don S]

Re: 1986 4.3 to vortec heads. valve adjustment help.

No need to wait overnight, there is a sping inside the lifter that pushes it up as soon as you back off the rocker.
The problem is, you can't adjust that type head. There are steps in the rocker arm studs that can, and may, stop the insides of the lifter from being in the right place for it to work. Can see the difference in the rocker studs in these 2 pictues.

<<<<<<<<<<<<<<<<<<<<< >>>>>>>>>>>>>>>>>>>>>>>>

 

[fourwinnsdook]

Re: 1986 4.3 to vortec heads. valve adjustment help.

I am using the vortec heads. everything else is stock from the 86 block. So if there's no adjustment for the valves why else would my compression numbers be so far off? both engines were running when taken apart. Has anyone else ever had this problem or was it plug and play? The comp. numbers are ...

1- 65psi
2-150psi
3-70psi
4-30psi
5-65psi
6-130psi

 

[iang]

Re: 1986 4.3 to vortec heads. valve adjustment help.

Soprry Don,I have only seen the stepped studs on the big blocks,all the small block vortecs I have worked on have all be adjustable as I described in my previous post.Bondo,have a look at the studs and let me know if they are stepped,I would be very interested to know.

 

[Bondo]

Re: 1986 4.3 to vortec heads. valve adjustment help.

Bondo,have a look at the studs and let me know if they are stepped,I would be very interested to know.

Ayuh,... Sure,.. I'd love too...

I just don't know Where fourwinnsdook keeps his boat....

 

[chiefalen]

Re: 1986 4.3 to vortec heads. valve adjustment help.

What i don't see is the compression test numbers before the heads were swapped.

Maybe got nothing to do with the heads. Maybe the rings are shot in the 23 year old motor?

Maybe this maybe that ? Why you switch them out to begin with ? The heads i mean.

 

[fourwinnsdook]

Re: 1986 4.3 to vortec heads. valve adjustment help.

I don't remember exactly what they were before but i did check it about 3 months ago when i adjusted the valves on the old heads. they were all i believe between 135 and 140 and the #1 was about 95psi. The reason i changed them out is because the old heads were tapping real bad and nomatter how much i adjusted they kept doing it. I thought the springs were really shot and it was cheaper or atleast close enough to the price to swap. Not to mention the performance gains.

 

[fourwinnsdook]

Re: 1986 4.3 to vortec heads. valve adjustment help.

Bond-O the boat is outside of my house in Daytona,fl. if your coming this way anytime soon feel free to come work on it!

 

[Don S]

Re: 1986 4.3 to vortec heads. valve adjustment help.

The reason i changed them out is because the old heads were tapping real bad and nomatter how much i adjusted they kept doing it.

Hate to tell you this, but your lifters were the problem, not the head. Probably still your problem. They aren't adjusting hydraulicly anymore.

 

[JustJason]

Re: 1986 4.3 to vortec heads. valve adjustment help.

Hate to tell you this, but your lifters were the problem, not the head. Probably still your problem. They aren't adjusting hydraulicly anymore

I'll agree with that. You can try pulling the lifters out and soaking them in solvent for a few days then prime them by hand and see if you can get it going that way (doing it on the cheap)
But id pull the valve covers and start the motor up (make sure you lay down alot of rags first) and make sure your getting a good spurt of oil out of the top of the pushrods. If your not getting a good spurt you may have some clogged/dirty oil galleys..... especially if the boat had neglectfull oil changes.

 

[fourwinnsdook]

Re: 1986 4.3 to vortec heads. valve adjustment help.

is there a way to see if the lifters arent working? i am not very familliar with the american stuff. i can work on import motors but this is really the first american motor i've done any work too.not used to push rods and lifters. I'm used to DOHC where ther's no such thing as all that stuff. how do i prime them manually? etc? is there a manual that shows it?

 

[JustJason]

Re: 1986 4.3 to vortec heads. valve adjustment help.

you prime them with a drill press and a pot of oil. But I'd go to the Adults Only section and download the manual for your engine. Try to commit it to memory if ya can.

 

[Don S]

Re: 1986 4.3 to vortec heads. valve adjustment help.

you prime them with a drill press and a pot of oil.

Actually, all you have to do after putting the engine together, is to prime the oil system with a real oil priming tool thru the distributor hole while turning the engine by hand (Not with the starter). Once you see oil coming out of the rocker arm holes, you know you have oil in the lifter.