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Old 09-29-2002, 07:15 PM
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Post Valve job questions

When I pulled the heads I see marks in the tops of a few of the pistons where the valves have made contact. This probably happened when the timing chain when south. Should I try to clean them up or leave them alone? Worried about detonation due to the edges of the marks.

A compression check before the tear down showed ~165psi on all but one cylinder (150psi). all of the cylinder bores look great. No scars or gouges. The bores are all between 4.001" & 4.002". Is there a good way to check ring seals at this stage?

Is it OK to clean and re-use the head bolts or should they be replaced?

What else should I check while I'm at it?

Thanks for the pointers

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Old 09-29-2002, 07:27 PM
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Im sorry i cant answer your question but i have one
? Maybe you could help when i take my heads off is there anyway of telling if your valve seats are ok?
any type of test. also will changing out an old head gasket increase your pressure on a compression test?
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Old 09-29-2002, 07:28 PM
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You could smooth the valve marks with a little crocus cloth, it probably wouldn't make that much of a difference if you just left them alone, I would inspect the pistons closely with a magnifying glass to make sure it didn't fracture anything. The best way to check ring seal is with a leakdown test, but you need your engine assembled to do this.
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Old 09-29-2002, 07:51 PM
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If you have removed the heads from the engine, then you have a few options, you can pull a vacuum on the intake and exhaust ports with the head assembled and check for vacuum leaks, this is a band-aid check in my book, but it does work to an extent.
You can physically disassemble the heads, and check the seats and valve faces, and look for cracks while you're at it.
Also, you can have a leakdown test done on the head, which is what I use. I have a plate I use that is o'ringed to seal off the combustion chambers, I then bolt the head to the plate, and screw a leakdown tester into the spark plug holes and check for leakage that way.
But, if you have the heads off anyway, I would just spend the 80-100 bucks for a valve job.
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Old 09-29-2002, 09:34 PM
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A simple method I use is this, flip the heads chamber up with plugs installed and surface level. Then pour gasoline into each chamber, if they have a good seal they will hold the gas for some time. See wich ones (if any) are leaking, and look into the intake and exhaust ports of the leaking chambers to see wich valve is leaking.
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Old 09-30-2002, 02:10 AM
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[ [quote]Then pour gasoline into each chamber...<hr></blockquote>

Hope you don't smoke...
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Old 09-30-2002, 07:13 AM
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If you have any gouges you'll need to smooth them down, they'll leave areas for hot spots on the pistons.
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Old 09-30-2002, 12:38 PM
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If this is a stock '54 engine, the compression is pretty low. It wouldn't hurt to touch up the piston tops but I doubtl that the motor is going to be subject to pre-detonation if timed properly. If it ran well after you correct the timing chain problem, and has good compression, I would only be worried about bent valves and it seems you have eliminated that concern alredy.
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Old 09-30-2002, 07:42 PM
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The engine is a 1967 327sbc. The heads are double hump 64cc 1.94" 462 castings.

I also noticed that 2 exhaust ports were soaked in oil. The others looked good. Could a problem in the head like worn valve guides cause this or should I be looking somewhere else???

I think I'll smooth out the piston tops. Compression will be between 9.7 and 10.25 to 1.

What about the head bolts? Is it OK to use the old ones or is it always best to replace them. I'm on a budget. (aren't we all)

Thanks
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Old 09-30-2002, 10:33 PM
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yes you can re use your head bolts smooth out any sharp edges wherethe valves hit, you have good compression so the ring lands are o.k. you may have some bad valve guides especially on the center two exhaust try to wiggle or move the valve spring and retainer if any side movement at all the guides are bad. unless you can eyeball .001-.002 inches. also check that all the valve heads are the same height in the chamber just look for exhaust valve being lower in head -good indicater that seat and guide are bad.
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Old 10-01-2002, 06:53 AM
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Reusing your head bolts depend on what brand they are. I'm sorry but I cant remember the brand that is recommended for one use only.

I would think if an engine is bought through Auto Zone or some place like that than I would be careful about reusing the head bolts.
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Old 10-01-2002, 07:53 AM
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I would be carfull of those autozone and pepboys engines. my buddy got one and it had 6 5.7" rods and 2 6.0" rods and yes it knocked. for head bolts use them your not doing a 9 sec. run down the track. just check for obvious rust eating at the treads. just my thought. 6-71sbc
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Old 10-01-2002, 11:42 AM
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Generally speaking most Chev V-8 head bolts can be reused, if they are in good condition. Best preparation is to use thread CHASING dies and taps to clean the bolts and the threads in the block and heads. Don't use rethreading taps and ties, as they will actually remove material, making the bolts less affective. Put a light oil (such as 10 weight) on the threads. Be careful not to put oil into a blind (taped) hole as it will cause a hydraulic lock and the bolt will not torque down to the proper spec.
With all this said it is still very important to replace "torque to yield" type head bolts. Some guys reuse them, saying that they can be reused once, but who knows for sure what the history of the engine is. Best bet is to replace them each time. FYI - torque to yield bolts are only used in later model engine, approximately mid 1990's and later.
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