Rebuild Project

[W K.]

I'm preparing to have my motor rebuilt. Any advice, does or don'ts would be greatly appreciated. 1966 L79, numbers matching.

Thanks

Patrick

[William G.]

Re: Rebuild Project

With today's fuels the temptation is to lower the compression ratio. I would try real hard to resist doing that as in my opinion the camshaft needs the compression or the horsepower will suffer......and you can't have an L79 without that somewhat lumpy idle. It would appear if you dial back on the compression and soften the cam all you have is a 300 horse engine dressed up with that nice looking aluminum on top of the engine (all dressed up with no place to go). Maybe you weren't asking about this issue, but there is my two cents worth.
Bill

[W K.]

Re: Rebuild Project

That's exactly the kind of thing I'm asking!

[Joel T.]

Re: Rebuild Project

I'm preparing to have my motor rebuilt. Any advice, does or don'ts would be greatly appreciated. 1966 L79, numbers matching.

Thanks

Patrick

Patrick;

I would make sure that who ever you choose has experience with vintage motors... There are some things for which experience in this space is a must. In my case, for my 1963, I used a race engine builder who installed the wrong valve seals with a new solid lifter cam and lifters... Was a real horror show.. took me almost a year, including three motor pulls, to get it corrected. While the race motor guys did not know about this, the issue was common knowledge with a vintage motor guy....

Good luck, and have fun!

Joel

[W K.]

Re: Rebuild Project

What kind of issues?

[W K.]

Re: Rebuild Project

My idea is to keep the motor as original as possible, 11-1 forged pistions etc. But if there are things that I need to specifical aviod please help.

[Jim T.]

Re: Rebuild Project

Do not let the machine shop grind the numbers pad. You do not need the heads rebuilt with hardened valve seats.
Document your parts by casting dates and any other numbers before you turn them lose.

[Jack H.]

Re: Rebuild Project

The weak link of a small journal ('62-'67) 327 is the rod bolts (11/32"), followed by the rods themselves. I went the route of having my original rods fully reconditioned and new high strength ARP bolts (11/32") installed. Duke has since convinced me that simply buying a set of brand new aftermarket Eagle brand rods complete with 3/8" (not 11/32") ARP bolts is better and cheaper. There's a set on a popular auction site for $242 (buy-it-now w/ free shipping). This is money well spent in my opinion and is cheaper than what I have in my reconditioned set.

If you need pistons, you can still get Speed Pro L2166NF forged 11:1 (domed) replacements. I believe you can find duplicates/replicas of the 151 cam if needed also. I also agree with others recommending you stay with original L79 configuration. I've run this config with premium pump gas without any pinging or problems.

[Joel T.]

Re: Rebuild Project

What kind of issues?

Patrick;

The issue I was referring to had to do with valve seals. When I rebuilt my '63 I went with a new solid lifter cam and new lifters. The new lifters pump more oil up into the heads than did the originals. When the rebuilder did his work, he installed vintage style seals which did not seal effectively due to the increased oil in the heads... The result was smoke at idle. Drove me nuts! We wound up trying different things to solve the problem... One school of thought was that the intake was not sealing properly and therefore pulling oil in from the cam chamber... I wound up pulling the motor again and had to argue with them as to the source of the problem... A quick look into any exhaust port told the tale. The rebuilder actually had to call the cam manufacturer who confirmed what needed to be done.. In any event once they installed positive valve seals, the problem went away and has never returned. I relayed this story to a well known Corvette restorer and he knew immediately what the issue was and told me that positive valve seals were a must with new solid lifter cams/lifters.

The point of all this is that while my rebuilder had turned out hundreds of very successful race motors there were things which he did not know about rebuilding vintage engines which wound up costing me considerable time and money...

Joel

[Joe R.]

Re: Rebuild Project

Patrick,

Don't let them deck the right side of the block. That will wipe out the broach marks and / or numbers on the pad. Manage the compression ratio. Does it detonate prior to rebuild? On what octane gas? The first step is to take measurements before any machine work is done. Ask them to notify you with what machine work they recommend before cutting any metal. Post it here, see if the fine folks on the board agree.

By the way, what are your goals for the engine restoration and the car in general?

Joe

[Duke W.]

Re: Rebuild Project

The most important thing is to plan and manage your project. Have a written plan including manufacturer and part number of all replacement parts, which should be OE or OE equivalent with the exception of the connecting rods.

You start with a "forensic teardown", which includes measuring deck clearance on all eight cylinders so you can manage the compression ratio. Target no more than 10.3:1, which is easily achieveable with the OE pistons (see the Fall 2009 Corvette Restorer) Most blocks will need nothing more than boring.

My current opinion on the OE rods (and yours should be the second design) is "all or nothing". Do nothing to them and use them as is or buy the Eagles.

The machinist is nothing more than a vendor who should do only the work you specifiy. Make sure that specific operations are written on the work order - no more, no less.

If you plan on just handing your engine to some "engine builder" my bet is that is will turn into a disaster as so many engine projects have when the owner trusted the managment of the project to some machine shop.

This subject has been extensively discussed, so do some research in the archives.

Duke

[W K.]

Re: Rebuild Project

Patrick;

The issue I was referring to had to do with valve seals. When I rebuilt my '63 I went with a new solid lifter cam and new lifters. The new lifters pump more oil up into the heads than did the originals. When the rebuilder did his work, he installed vintage style seals which did not seal effectively due to the increased oil in the heads... The result was smoke at idle. Drove me nuts! We wound up trying different things to solve the problem... One school of thought was that the intake was not sealing properly and therefore pulling oil in from the cam chamber... I wound up pulling the motor again and had to argue with them as to the source of the problem... A quick look into any exhaust port told the tale. The rebuilder actually had to call the cam manufacturer who confirmed what needed to be done.. In any event once they installed positive valve seals, the problem went away and has never returned. I relayed this story to a well known Corvette restorer and he knew immediately what the issue was and told me that positive valve seals were a must with new solid lifter cams/lifters.

The point of all this is that while my rebuilder had turned out hundreds of very successful race motors there were things which he did not know about rebuilding vintage engines which wound up costing me considerable time and money...

Joel

I get the point and appreciate the warning because I'm considering using a friend who builds race motors for boats to save money. He does what he does very well, but may not undersatand vintage motors.

[Duke W.]

Re: Rebuild Project

Beware of guys who build "racing engines". Road (and restoration engines) are completely different animals.

Ask him how many restoration engines he has built. Chances are the answer will be a blank stare.

A few years ago I consulted with a Cosworth Vega owner who was having his engine rebuilt by a guy who builds "killer small blocks". I didn't like what I heard and warned him that it didn't sound like the guy understood the CV's linerless aluminum block technology, but he went ahead full bore.

The engine seized up after 100 miles!

Duke

[W K.]

Re: Rebuild Project

You guys are scaring me.

I have started my inventory by cast numbers. The block, intake manifold, cylinder heads, exhaust manifolds and carburetor are all correct and when applicable date stamped. I'm not sure what is internal, pistons, rods, cam, etc. The motor runs well considering. No pings or detonation, but she smokes after warming up. The spark plugs show signs of burning oil. After talking with several mechanics they all come to the same conclusion that the rings are done and valve guilds are probably not much better. Here in Henderson, NV octane is no problem, I can purchase street legal unleaded 100 octane at the pump. Currently I am using 91 octane.

I truely appreciate all of your input. I can go with a local vintage car company and they do great work, but they are expenses. That's why I'm talking with you all. I want to make the right discision.