325 hp 330 CYLINDER HEADS ADVICE

[Guest]

I've been going through an extra-long, drawn-out restoration on my 1967 cutlass. I guess they're all that way, come to think about it. It seems that every time I finish fixing one problem, a new one crops up.

For example, while changing the leaking valve cover gaskets, I noticed hard, black pieces of something or other lying around the springs. I thought they were valve keepers, turns out they were the brittle and shattered valve stem seals. No big deal, I thought, burn a little (a lot) of oil, so what.

As the weeks go by, the car idles worse and worse. I replaced the carb, replaced the HEI module (parts I had on hand already). But it wouldn't idle without kicking out a big cloud of unburnt gas. I finally broke out the vacuum testor and discovered a rapidly fluttering needle around a low and slowly rolling vacuum reading. The needle smoothed out at high revs.

So it is a big deal to have no valve stem seals.

So here come the questions:

How hard is it/Is it worth it to replace only the seals? Or, at 96K miles, should the guides be done as well? If the guides should be done, that means the heads should be gone through completely. Which leads to the next question:

What should I know before I take these particular heads into a shop and having them rebuilt and perhaps mildly "opened up"?

Or, at 96K miles (but with around 170 psi on all cylinders) should it be time to rebuild the whole thing? I'll bore it out to a 350, of course. But an early 400 would be nice...

All suggestions are appreciated, even if to just point me to the right web sites, people, etc. I'm in Burbank, So. California, so if anyone knows any good shops down around here, I would like very much to hear about them! Thanks.

--Brendan

[Guest]

Brendan, I think you maybe looking at rebuilding the heads and possibly re-ring the pistons and worse case rebuild the whole engine. Rebuilding the heads is pretty easy to do. I would try that first before getting into a full blown rebuild that will cost you alot money. But if you rebuild the engine you shouldn't have any issues then.

[Guest]

Monster:

Thanks for the advice. I basically did what you said: pulled the heads, then decarbonized the piston heads, and checked the hone on the cylinder walls. I have put rebuilt heads on 289s and 302 with walls so smooth you could see your whikers in them, but luckily mine still had a dull sheen. You could barely feel the cross-hatch with a fingernail. i figure I'll have to do the bottom end in 10-20K miles after my rings are pushed all out of shape.

The heads needed 2 new exhuast valves because the tips were chewed up. I lightly filed and polished the rockers on those valves and replaced those lifters, just to be safe. The guy who did my heads (Dave at Burbank Speed & Machine) seemed to really know his stuff, lost of NHRA and IHRA guys up on his walls, engines he had done.

He remarked that the valves and seats looked incredible for a 60s motor with 100K, but that the guides had been knurled and would need bronze guides, which i wanted anyway. That surprised me that they had been knurled, because the engine has never been pulled apart (I know the original owner and have all the service records). Was that something done at the factory?

He just grazed the heads at 5 thuosandths to clean them up. My valve train all seemed fine. But one thing puzzled me--the original lifters appear to be hydraulic, but they have no "spring" to them. You can't depress the plunger part, wheeras the replacement lifter "pumped" easily with a pushrod. Can anyone explain that to me? It really had me nervous for a while, because if the lifters had no "pump," or give, there was nothing to adjust in the rest of the valvetrain (Except shimming, and where the heck am I going to get those).

Since Dave only took off 5 thou, and the new gaskets were considerably thicker, I din't worry too much. He checked the installed hieght of the valves and had to shim all the valves to get them up to around 80 pounds or so closed.

I went with an edelbrock performer rpm intake manifold, figuring that it was planned overkill for a future rebuild. i kept the edelbrock 600. I might try the 750 i originally had on the car to see if that makes a big difference. To me, the car feels about as fast as before, but with much more low-end throttle response.

Thh edelbrock is a beautiful piece, with some drawbacks. Like anything from the aftermarket, you have to expect that there will be grinding and hammering, no matter what the car magazines may be paid to say. My stock brackets needed to be hacked and ground, something that caused me much pain because I swore I would not hack on this car, and i have until now held fast to that rule.

The a/c bracket mounting bass was off by 3/16", so I had to drill out the hole on the bracket. On the other side, the front coolant passage on the manifold is way too high, and interferes with the alterntor bracket. That is a definite no-no in my book if a stock alt. can't fit. I could almost understand the A/C thing happening.

Starting up the car produced billowing clouds of white smoke, which reminded me the one thing i forgot to do: add stop-leak before firing it up. So I added it and the smoke went away and now I am happy. The End.

--Brendan