Engine evaluation

[David H.]

I spent yesterday afternoon with my machine shop evaluating the condition of my engine.
Here is what we found.
The block is in good condition. No cracks or problems.
The heads are ok, however had two of the head bolt shoulders cracked. These were repaired. Most of the other head bolt shoulders are missing some material but are not cracked.
A valve job will be necessary and he has recommended hardened valve seats. They are very aware of the issue of breaking into the water jacket but apparently a stock rebuild such as this is not an issue.
The crankshaft is the original one and after magnifluxing it one hairline crack was found. They will be checking it to see if it is a deep crack or not and will let me know.
The camshaft is a Melling CCS 8 for solid lifters. It is in good condition and has not been run much. One option would be to replace it and the lifters with a hydraulic set. This would eliminate the need to adjust the lifters every so often.
The pistons are original and in good condition. The concern here is how worn they are and what clearance there will be after honing the cylinders. They will be doing that and letting me know. Too much clearance and we will have to replace the pistons.
THey will be working up an estimate with options for me as our next step and we will go from there.
Any and all comments are more than welcome on this.

[Duke W.]

Re: Engine evaluation

Engine option? Already modified? What's your objective?

Duke

[Gene M.]

Re: Engine evaluation

They can repair the bolt boss shoulders. I had this done, may need to send them out to a shop that specialize in that. Once painted can't see repair if done right.

Do not suggest harden seats in those old heads, casting will be too thin.

Get another crank, and have rods checked.

Yes, mild hydraulic cam is better choice for driving.

[Jim L.]

Re: Engine evaluation

A valve job will be necessary and he has recommended hardened valve seats. They are very aware of the issue of breaking into the water jacket but apparently a stock rebuild such as this is not an issue.

I don't get their logic. Because it's a stock rebuild that minimizes the risk of ruining a perfectly good set of heads by punching through to the water jackets?

Toro poo.

Don't install hardened valve seats. The risk of ruining the heads is very real and you just don't need the hardened seats.

Jim

[David H.]

Re: Engine evaluation

Here is what I would like to be able to do with this car.
I want to go out to the garage, get in and turn the key, and drive it locally. (Say within an hour of home) I dont want to have to perform maintanence on it every time I want to drive it. I am on the fence about the solid lifters. From what I have read it is necessary to adjust them fairly often, say every other oil change or around every 6k miles. My plan is that it wont be driven over 3k miles per year if that. So, are solid lifters really a problem. Well, I dont really like the idea of taking the valve covers off every year and having oil go all over under the hood. Hydraulics are easier but do I loose lots of performance by changing them? I am not worried about smokin' the tires or racing anyone. I like to just go out and cruise and maybe put her thru her paces once in a while. I got over wanting to go really fast long ago.
The engine is the original 340hp with the original crank, pistons, and a correct replacement cam with solid lifters and the correct AFB Carter 4bbl. The machine shop is recommending to drop the 11.25 compression down to 9-10 so that I can pull up to the pump and just go. I realize this will drop the hp but like I said, I'm no hot rod anymore. As long as she jumps when I say jump, I'm ok with that. The engine as far as I can tell has not been modified. It still has a bore of 4.0 and I am being told that this can be cleaned up with a good hone. No overbore should be necessary. Pistons may have to be replaced if there is too much clearance after honing. This would be one way to drop the compression. I hope this answers the questions that have come up about the car.
Let me know what you think.
~Save the wave~

[Jim L.]

Re: Engine evaluation

I am on the fence about the solid lifters. From what I have read it is necessary to adjust them fairly often, say every other oil change or around every 6k miles. My plan is that it wont be driven over 3k miles per year if that. So, are solid lifters really a problem.

I don't know where that 6K mile claim originates but it sure doesn't match my experience with solids. On my FI '60, last time I remember adjusting the clearances was 20 years and about 22K miles ago. Could have been longer.

Jim

[Duke W.]

Re: Engine evaluation

Here is what I would like to be able to do with this car.
I want to go out to the garage, get in and turn the key, and drive it locally. (Say within an hour of home) I dont want to have to perform maintanence on it every time I want to drive it. I am on the fence about the solid lifters. From what I have read it is necessary to adjust them fairly often, say every other oil change or around every 6k miles. My plan is that it wont be driven over 3k miles per year if that. So, are solid lifters really a problem. Well, I dont really like the idea of taking the valve covers off every year and having oil go all over under the hood. Hydraulics are easier but do I loose lots of performance by changing them? I am not worried about smokin' the tires or racing anyone. I like to just go out and cruise and maybe put her thru her paces once in a while. I got over wanting to go really fast long ago.
The engine is the original 340hp with the original crank, pistons, and a correct replacement cam with solid lifters and the correct AFB Carter 4bbl. The machine shop is recommending to drop the 11.25 compression down to 9-10 so that I can pull up to the pump and just go. I realize this will drop the hp but like I said, I'm no hot rod anymore. As long as she jumps when I say jump, I'm ok with that. The engine as far as I can tell has not been modified. It still has a bore of 4.0 and I am being told that this can be cleaned up with a good hone. No overbore should be necessary. Pistons may have to be replaced if there is too much clearance after honing. This would be one way to drop the compression. I hope this answers the questions that have come up about the car.
Let me know what you think.
~Save the wave~

This is the typical standard line of machine shop BS. They're walking you down the primrose path. Search "327 LT-1" and get the facts.

As far as overbore is concerned it's a matter of how much taper there is in the tops of the cylinders. Any reputable machine shop should measure and record this data. It's what you need to make a decision.

So...

Once you've done the research in the archives you should be able to put together a decent game plan. Pay particular attention to what you read about connecting rods and pistons.

Do you have a service manual? Look under engine tuneup. What does it say about vavle adjustment frequency?

You can spend some time learning about these early 327s or you can give the machine shop your credit card and overpay for a stone. It's up to you.

Duke

[Bruce B.]

Re: Engine evaluation

My 62 340 HP solid lifter gets a valve adjustment when I get unusual lifter noise or every 10 years whichever comes first.
Lifter adjustment is no problem. Do it using the static method and no oil anywhere.
I like to adjust with the engine running. Use an old steel valve cover with the center cut out and there is no mess at all.
As far as the 11.25 compression, no problem with 92 or 93 pump gas.
Also, I have original heads, no hard seats and not a problem over the last 20,000 miles or so.
Good luck.

[Patrick T.]

Re: Engine evaluation

Don't install hardened valve seats. The risk of ruining the heads is very real and you just don't need the hardened seats.Jim

I saw a post here a few years ago about a guy who had hardened valve seats installed and while driving the car, one of the seats let go and the head suffered a catastrophic mechanical failure. FWIW. PT

[Joe C.]

Re: Engine evaluation

It's too late now. From the way you are talking, you should have never taken the engine apart in the first place. Why did you start this engine project, anyway?

You have a well designed high performance engine, which should rebuilt as good as, or better than original. If you listen to your "engine builder" and lower the compression, you will emasculate the engine.

You have 2 choices:

1. If it is the original engine, put all the pieces in boxes, and save them for the next owner. Buy yourself a nice, mild GMPP crate motor, such as a 350/290 horsepower.

2. If it is not the original engine, get yourself another engine builder. Have him hone the cylinders using torque plates. He will very likely have to use new pistons, despite what your "engine builder" is telling you now. Use Speed Pro L2166NF-30 pistons. Use the FM Speed Pro CS113R cam, which is a replacement for the original 3736097. There are others who reproduce the "Duntov" cam. Here is another:

http://www.flatlanderracing.com/musclecams.html

the camshaft you want is "cam 1-1".

[Timothy B.]

Re: Engine evaluation

I agree with others, keep the compression up there where it's supposed to be and be very careful with choice of head gaskets. Use the solid cam that belongs in the engine with the stock valve springs. If the bore can be cleaned with honing and torque plate the piston skirts may be knurled and used.

Pay attention to the condition of the rocker arms/studs for wear as that may be a good thing to replace if you go with solids.

If the machine shop will not listen go and get your engine back.

[Robert S.]

Re: Engine evaluation

Also, if this is the original engine, do NOT let the engine builder machine the deck on the engine. The original machine markings and numbers will be gone forever.
BIG value loss.

[Edward B.]

Re: Engine evaluation

What caused you to open up the engine in the first place - it sounds as if it would have been just fine as it was. Remember, the enemy of "good" is "better." I don't particularly like the way the machine shop is dispensing advice piecemeal since each revelation adds to the cost incrementally and soon you will be much deeper into the project than you ever intended to be with no turning back.

[Dan D.]

Re: Engine evaluation

For what its worth, this is what I did - right or wrong?

I had my 870 engine rebuilt last year (1962 - 340HP). This is what my machine shop recommended - and what I did: The way I intend to use the car is EXACTLY the way David said in this thread.

1. Heads: No hardened valve seats. The water jacket problem and I don't need them for my intended usage.
2. Bore cylinders to +.030. New flat pistons with very close (.001 to .002) skirt clearance. New pistons are much improved over original ones, and the tighter clearance results in less blow by, less oil consumption, and quieter running.
3. Pistons are 10:1. Some HP loss, but much less stress on 50 year old parts.
4. Stock rods okay, but new rod bolts. Taking a chance with old ones (11/32).
5. Crank: Superfinish and re-balance for use with new pistons. Don't know if it was magnafluxed or not - I doubt if it was and I am going to ask this question. Stock grind - was not turned.
6. New hydralic cam, lifters: Quieter running - new cams experience less wear than old ones.
7. The cam and pistons are not the Speed Pro ones Joe recommends.
8. Timing gear and chain are the double link type. Not sure this was a good choice. Anyone?
9. Heads milled .010. Block was NOT decked.
10. Block and heads were pressure tested, hot tanked and cleaned.
11. I could have probably bought a crate engine for what this cost me, but I did not want to go that route. I want the 870 engine.
-Dan-

[Duke W.]

Re: Engine evaluation

You basically detuned it to a 327/300.

Without a mechanical lifter camshaft and the loose fit forged pistons a 327/340 completely looses it unique Special High Performance characterer that was unique to these Corvette-only engine options.

It's your car, but it's sad!

Duke