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Posted

Took the '95 Olds Cutlass Supreme 3.1 to the shop...they said I had no compression on Cyl. 6, didn't change w/oil. Probably a burned valve. I pulled the rear head off and confirmed it was burned.

 

The shop told me I'd be a fool not to pull the other head off and have it re-done. I say if it ain't broke, don't fix it. Of course, I've tore it apart this deep...wouldn't be too hard to pull the other one off now.

 

Should I spend the extra money and give both heads a valve job? Bought the car for $500 and it has 203,000 on the ticker. Otherwise seems to be a strong engine...barely any ridge at the top of the cylinder (just catches your fingernail).

 

Frankly, I thought we could just replace the *one* single burned exhaust valve and be on our way.

 

Any thoughts?

Posted

If #6 was burned, then why did you pull the rear head? Even number cylinders are the front head, odds on the rear. But, I would rebuild both heads. I mean, its not that much more work to pull the other one.

Posted

If it were me I would, sure they are trying to make some extra money but it's alot easier to do it now rather than later when it is all back together. Ask them how much to put some bigger intake valves in it while they have it apart. Would be a good time for an upgrade.

Posted

or how about doing the 3400 pushord motor head and intake swap, and discard the bad parts you have?????

in fact, You might be better off getting heads off a lower mileage car with a bad motor, (such as one that looks like it went to the boneyard with a LIM leak)

Posted

Hmm... It's the rear right cylinder. He told me it was on the back head when he did the compression test. Perhaps it's number 5...either way, I got the right head off.

 

I don't want to drop a bunch of money on this car 'cuz we only bought it for $500, front end has some damage and is going to be used as a beater until it dies. I'm not a big fan of spending money on performance mods for a vehicle with 200K on it...I mean, if a lower bearing is starting to go why add more stress now? It'll just shorten it's life that much quicker.

 

My thought is...if the other valves are sealing well enough now what's the point in re-doing them?

Posted

burnt valve, is the head where the valve goes damaged?

 

I suggest buying a used head. Again, one that has had an intake gasket failure damage the engine would be a good donor part source.

Posted

with 200k just get a used head, fix that one, whatever is cheepest and run the car into the ground if its just a beater.

Posted

Precicely my thought. There's a remote possibility that it burned the valve seat, but the seat is made of pretty durable stuff...will have to wait until they pull the valve out to make sure.

 

I'm curious what condition caused the valve to burn in the first place. The location of the valve makes it closest to the exhaust pipe...perhaps there's a bad seal there?

Posted

i have seen valves burn when the Cat gets plugged. Basically a possible exhuast system restriction.

p.s. you can remove the valve yourslef with a valve spring compressor availible from autozone (loaner tool)

Posted

Yea. I know valve removal is relatively easy...but, I've been known to screw up relativley easy things. I figger if I take it to a shop, they can test the valve spring pressures, check the head for warpage, clean up the deck area, etc. Just so I don't have to do this again soon.

 

How would one check if the cat was plugged? It *has* been running on 5 cylinders so it's possible it's all uggy inside. Will whacking on it with a fine adjustment hammer help?

Posted

How would one check if the cat was plugged? It *has* been running on 5 cylinders so it's possible it's all uggy inside. Will whacking on it with a fine adjustment hammer help?

 

After driving it for a while, if the cat is clogged, it'll glow red. Or, hit it with a hammer and if it rattles, its usually bad.

Posted

Go with a used head,

 

I am sure if you do a valve job on one head, the compression wont match and will be higher than the old head. I dont think this will be good in the long run. So go used or do a valve job on both heads.

Posted

check to be sure the exhaust manifold isn't cracked near where the downpipe bolts onto it. That particular right side manifold is known for that.

Posted

I didn't notice it when I pulled the head off but when I got it to the machinist he called me and told me it wasn't a burned valve. Turns out the dufus before me switched the intake and exhaust pushrods (DOH!) and the intake valve hit the piston and bent the valve and pushrod. He went back, switched the pushrod but didn't mess with the valve. All better now, though. I'm waiting for the loc-tite to cure on the LIM bolts...going to the garage today to bolt up the alt, psp, spark coil & battery. I'm 99% sure it's going to spin like a top. Everybody cross your fingers...I want this heap out of my garage!

Posted
I didn't notice it when I pulled the head off but when I got it to the machinist he called me and told me it wasn't a burned valve. Turns out the dufus before me switched the intake and exhaust pushrods (DOH!) and the intake valve hit the piston and bent the valve and pushrod. He went back, switched the pushrod but didn't mess with the valve. All better now, though. I'm waiting for the loc-tite to cure on the LIM bolts...going to the garage today to bolt up the alt, psp, spark coil & battery. I'm 99% sure it's going to spin like a top. Everybody cross your fingers...I want this heap out of my garage!

 

What?

 

I understand that the valve would get bent if it got hit by the piston...

 

But to my knowledge, the pushrods in the motor are all the same length!!!! More likely the timing chain failed or jumped at some point in the cars life, or the valve spring failed....

 

Any thoughts on this???

Can/could you see a mark on the piston?

Posted
I didn't notice it when I pulled the head off but when I got it to the machinist he called me and told me it wasn't a burned valve. Turns out the dufus before me switched the intake and exhaust pushrods (DOH!) and the intake valve hit the piston and bent the valve and pushrod. He went back, switched the pushrod but didn't mess with the valve. All better now, though. I'm waiting for the loc-tite to cure on the LIM bolts...going to the garage today to bolt up the alt, psp, spark coil & battery. I'm 99% sure it's going to spin like a top. Everybody cross your fingers...I want this heap out of my garage!

 

What?

 

I understand that the valve would get bent if it got hit by the piston...

 

But to my knowledge, the pushrods in the motor are all the same length!!!! More likely the timing chain failed or jumped at some point in the cars life, or the valve spring failed....

 

Any thoughts on this???

Can/could you see a mark on the piston?

 

The Exhaust and intake pushrods are different sizes, the Exhaust ones are longer...at least thats what iv read and learned

Posted
The Exhaust and intake pushrods are different sizes, the Exhaust ones are longer

 

x2

Posted
The Exhaust and intake pushrods are different sizes, the Exhaust ones are longer

 

x2

 

3

Posted

ok.... is this true all years? including 3.1 and 3100 w or w/o the roller lifters?

I always was careful to reinsert them in the right spot, but I have to ask.

Posted

I think it's for all of 'em. Intake pushrods are about 1/4" shorter. Yea, there was a crescent on the piston.

 

I fired it up and it ran very smooth...much to my relief.

 

One problem, though...there seems to be an abnormally loud ticking from the front valve cover... My '93 ticks but it's much quieter than this. I don't think it did this before I had that head milled .017. Might this head need a shim?

Posted
ok.... is this true all years? including 3.1 and 3100 w or w/o the roller lifters?

I always was careful to reinsert them in the right spot, but I have to ask.

 

Yeah, all of them. Anything with an aluminum head has different length pushrods. The old iron head versions of these engines have equal length pushrods, since they have in line valves. The aluminum heads have splayed valves.

Posted
One problem, though...there seems to be an abnormally loud ticking from the front valve cover... My '93 ticks but it's much quieter than this. I don't think it did this before I had that head milled .017. Might this head need a shim?

Could it be a dry lifter from having sat??? let it run and keep an eye on it, I guess.

 

I never noticed the different length pushrods before!!! I swear!!! But I know not to switch them!!!

Posted

i know most autoparts stores sell a product called "reslone" or something to that effect, it comes in a yellow quart bottle. your supposed to add it at a oil change, its essentially a detergent that clears up varnish and deposits. it does seem to work rather well in clearing up a noisy valvetrain. it always seemed to work wonders on noisy GMs when i was working at the shop.

Posted
One problem, though...there seems to be an abnormally loud ticking from the front valve cover... My '93 ticks but it's much quieter than this. I don't think it did this before I had that head milled .017. Might this head need a shim?

Could it be a dry lifter from having sat??? let it run and keep an eye on it, I guess.

 

I never noticed the different length pushrods before!!! I swear!!! But I know not to switch them!!!

 

:werd: on the lifter causing the ticking. Did you check the pushrods for straightness??

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