[Mike S]

First outing with the high ports didn't go well. First trans brake didn't hold and car rolled forward. Decided to run it out and see how it felt. Floored it from a roll and was surprised it pulled the wheels. Felt real good till 1000', started missing so got out of it. Really bad valve tap on the return road. No, 1 cylinder exhaust valve hung open and hit the piston. Looks like it seized in the guide. Thought a few seemed tight putting the exhaust valves back in after bowl cleanup. I bought them complete from Kaffman so figure that's how he set them up. I even numbered them and put them back in the same spots. I posted pic;s .You can see bronze from the guide on the stem. Had to use a hammer and punch to get the valve out.

[Dragncar]

Well, when I bought my High Ports I got them with no seats, seats cut or valve guides at all.
Whitmore told me he had a KRE set up and ported E heads though his shop and he checked the seat fit with a small flashlight. He could see light under the seat.
So..... I had Dave at SD do the seat and guide work and all is well.
Sorry to hear this happened to you. The incident I was referring to was over 25 years ago.

[steve25]

Sorry to hear this, but on the bright side if an intake valve had been the one to hang up, the harm would have been far worse!

With an intake the valve that is in the opening phase you have the piston is rising .

Hopefully you will just need to check that rod for straightness and big end roundness, replace that rod bearing and maybe polish that rod jurnal.

Next replace that valve have a guide liner put in that exh guide and sized and then touch up all the valve seats and then vacuum test the valve job.

Properly sized guides and valve stems that are free of oil should allow the valve to just slide out on its own even when the head is just rotated over 45 degrees on the work bench.

Seeing that this whole mess should not have taken place with new heads I would look for a different shop to do this work at this point.

You gave them one chance to get it all right and they blew it!

[Mike S]

These heads where bought complete from Kaffman, so he did all the work on them. All i did was remove the valves to clean up the bowls.

[PAUL K]

Well that's a bummer! ..... Things could have gotten a lot worse, but still sucks.

[Dragncar]

Yeah, a dropped valve is one of my worst nightmares. Could have been much, much worse. At least you can get her back up and running without too much time and expense.
I was stressing just about the 2 valves on # 1 that were removed for the light springs checking piston to valve.
But, pulling the wheels from a roll off the line is pretty sweet too.
In the end I think you will be happy with your new heads.

[R 70 Judge]

Man that sucks!

[Mike S]

Bottom end is good. everything checks out. Took the heads apart and a few exhaust valves are tighter than the intakes just doing the wiggle test. Ex valves have almost no play.

[PAUL K]

I think sometimes these "big" Pontiac vendors get intake and exhaust confused. I'm fixing a pair of top shelf heads that they used a radius cutter on the intake and a three angle cutter for the exhaust.

[steve25]

Radius cutters help intake or exh flow real nice, but on the intake side they don’t help shred the wet flow up at all that takes place and that cost power.

[ponjohn]

What is the ideal guide clearance?

[steve25]

That depends on the guide material.

[Mike S]

Had 4 exhaust valves that where very tight in the guides. 2 with 0 clearance. The valve seat was not damaged one bit. Guess because the valve was seized open. Don't know how this can happen. Wouldn't this show up when you cut the seats? They are good now. They fall out when you flip the head over.

Set Jeff an e-mail with pictures and explained what happened. His reply was "Dam that's really odd".

Going to get back to the track Saturday with fingers crossed.

Going to just live with a war scar on the piston.

[AG]

Did you have the tight exhaust guides opened up for proper clearance?

[Mike S]

yes, everything was gone over and good to go.

[Dragncar]

How did they let the heads go out of the shop like that ? "0" clearance !!! what the ....................................
At any rate, you are working your butt off on that thing. Getting it back up ang running in a short period of time.
Good luck on your next outing.
I think you will be happy.

[Mike S]

I can't believe they would send them out that way. I was thinking detonation but no sighs of it on plugs or pistons. running 11-1 on 94 octane and 32 deg timing. I richened carb up 4 jet sizes as a starting point. Have no audible pinging even lugging engine but the car is somewhat loud.
Double checked all the valve train geometry and everything it good.

When I cleaned up the bowels when I first got them, I do know the exhaust valve had to be pushed it the guides with a little force whereas the intakes didn't. Honestly, I thought it was the valve seals.

Crossing my fingers when I take it to the track this Saturday. That's if my new lifters show up tomorrow. A couple came out tight at the roller end (where good once they got to the cam) but i knew this because they went in that way. After 20 years I got my money worth out of them. I am running more lift and more aggressive cam now.

[AG]

Sorry to hear you have this issue. Your situation should never have happened regardless of who you got the heads from. I had a titanium retainer break (top separated from the bottom and I looked under a microscope and there was a defect) and dropped an exhaust valve going across the line which destroyed the piston and the chamber of the head. Had the head welded and had to buy 4 new custom pistons for a total cost of $2900.

[ChiefCrazyCanuck]

Originally Posted by Mike S

These heads where bought complete from Kaffman, so he did all the work on them. All i did was remove the valves to clean up the bowls.

How thorough was the cleanup after the bowl cleanup? It doesn't take much debris in a guide to end up like this.

[Dragncar]

Originally Posted by Mike S

I can't believe they would send them out that way. I was thinking detonation but no sighs of it on plugs or pistons. running 11-1 on 94 octane and 32 deg timing. I richened carb up 4 jet sizes as a starting point. Have no audible pinging even lugging engine but the car is somewhat loud.
Double checked all the valve train geometry and everything it good.

When I cleaned up the bowels when I first got them, I do know the exhaust valve had to be pushed it the guides with a little force whereas the intakes didn't. Honestly, I thought it was the valve seals.

Crossing my fingers when I take it to the track this Saturday. That's if my new lifters show up tomorrow. A couple came out tight at the roller end (where good once they got to the cam) but i knew this because they went in that way. After 20 years I got my money worth out of them. I am running more lift and more aggressive cam now.

My High Port 461 with just a little more CR (11.4) and 94.5 octane fuel really took off when I went from 32 deg to 36. .08 is a lot from a lot from 4 deg timing.