BB Chevy Rebuild Books

[John M.]

I'm planning some winter work on my 69 L71. I used Vizards books for my 67 SB and they were very useful. Is there similar literature out there for BB Chevy? Not hot rod stuff just good advice and techniques.
Thanks,
JB McRae30025

[Joe R.]

Re: BB Chevy Rebuild Books

John,

I've been putting a 66 427 back together. I have two books on rebuilding big block Chevys. The best one is:

"How to Rebuild Your Big Block Chevy" by Tom Wilson

It's available from Amazon.com and probably other places.

The second one is:

"Haynes Chevrolet Engine Overhaul Manual"

It's also good, I got it at AutoZone.

Per a recommendation from this board, I rented the following DVD from SmartFlix:

How To Build Your "Big Block" Chevy Like A Pro

I would highly recommend the DVD. I'm a visual person, the DVD was easier for me to follow than the books.

I hope this helps.

Joe

[John M.]

Re: BB Chevy Rebuild Books

Thank you Joe.
John

[Joe R.]

Re: BB Chevy Rebuild Books

John,

You're welcome. It sounds like you are getting ready to rebuild your engine. Have you researched weak points and the unique aspects of your engine? I posted a question here about my engine. I heard back that the original valve springs were prone to breakage. I was given a recommendation on what springs to use. I also found out that for 65 / 66 only big blocks the rear portion of the camshaft has a groove in it and the rear cam bearing has three holes instead of one for 67.

Good luck,
Joe

[John M.]

Re: BB Chevy Rebuild Books

Joe,
Here's the short version. The engine in this car, a 69 L71, was rebuilt by a professional shop abot 15,000 miles ago, 10 years ago. It has run well and very strong since then with only one problem. It will not run on 93 or 94 octane without pinging. I've tried all sorts of remedies but none are very friendly and most don't work. What works well is higher octane gas but that is a real PIA because there's no place around here where you can get it at a pump. So, the engine is out of the car for other reasons and the first thing on the list is find out what the compression ration is and change it to something useable. While I'm at it I thought I might look at porting and that sort of thing to increase "efficiency". I took one of the heads off last night and everything looks great, so the measurements will probably tell the story. Then I'll need to make the corrections.
Thanks for your interest.
John

[Duke W.]

Re: BB Chevy Rebuild Books

"How to Hot Rod SB Chevys" is an excellent reference, and there is a companion book for BBs. (The old Chevrolet Power Manuals are also very useful, but they are long out of print.) Don't let the "hot rod" in the titlle fool you. It covers mostly engine blueprinting and cylinder head massaging, and as with the SB version, the the BB book should be an excellent reference for restoring an OE engine to "massaged, blueprint" specs. Both these books were written in the seventies, so they cover all the vintage engine parts (heads, cams, etc.) that we love to use.

I think both are still in print, and can probably be found new and used from the normal online sources.

It sounds to me like the CR of this engine is too high. Take the requistie measurements, run them through the calculator, and let us know the results. Was this L-71 rebuilt with the OE SHP cam and pistons?

Duke

[John M.]

Re: BB Chevy Rebuild Books

Duke,
What I know so far. It has the correct cam, I put it in shortly after I bought the car. The valve springs could be the wrong ones. I took a head off last night and it looks good and the pistons look fine. The bore is .030 over, the pistons are domed. I can measure deck clearance and chamber volume but what about the dome? I guess I could do someting with clay or plaster?
I'll post the numbers as they are measured. This is the 69 with the 327-300 transplant. My buddie calls the car a mule.
John

[Duke W.]

Re: BB Chevy Rebuild Books

From my old Speed Pro catalog the OE replacement SHP forged piston for closed chamber heads is L2268F-30. The dome volume is speced at 35.5 cc, and the dome height is 0.266", and compression height is 1.765"

Maybe someone else can confirm.

I don't know the thickness of the OE head gasket. Does anyone know?

What is the thickness of the gasket under the head you removed, and what is the nominal deck clearance and actuals you measure.

Nominal deck clearance = nom. deck ht. - (crank throw rad. + rod length + piston compression ht.)

Based on memory I think the nominal deck height is 9.800, but I don't remember the rod length. Maybe someone can provide the data to complete the calculation.

Duke

[John M.]

Re: BB Chevy Rebuild Books

Duke,
The gasket, compressed, is 0.040". It has an odd shape but maybe it matches combustion chamber, I'll check and take photos. The other measurements will be made soon. A photo of a standard L71 piston would be helpful, too.
John

[John H.]

Re: BB Chevy Rebuild Books

John -

Here's an L-71 piston.

[Joe T.]

Re: BB Chevy Rebuild Books

"How to Hot Rod SB Chevys" is an excellent reference, and there is a companion book for BBs. (The old Chevrolet Power Manuals are also very useful, but they are long out of print.) Don't let the "hot rod" in the titlle fool you. It covers mostly engine blueprinting and cylinder head massaging, and as with the SB version, the the BB book should be an excellent reference for restoring an OE engine to "massaged, blueprint" specs. Both these books were written in the seventies, so they cover all the vintage engine parts (heads, cams, etc.) that we love to use.

I think both are still in print, and can probably be found new and used from the normal online sources.

It sounds to me like the CR of this engine is too high. Take the requistie measurements, run them through the calculator, and let us know the results. Was this L-71 rebuilt with the OE SHP cam and pistons?

Duke

I also have the big block book Duke refers to. It is also a wealth of part numbers and interchangeability info, as well as parts identification, both standard and heavy duty. Clutches and transmissions are also touched upon If you can find one, get it and cherish it!

good luck...Joe

PS: if you need some info that might be in it, email or PM me?

[John M.]

Re: BB Chevy Rebuild Books

Thanks John,
That's what's in there. I think the answer to the problem is a simple one. I now have the heads off and it looks like the deck clearance is close to zero. I'll measure tonight. The block has been decked and the heads have been milled so if it's the standard piston the compression ratio has definitely gone up. After I CC the chambers I'll plug the numbers into the calculator and see what it is. Then, what to do? I dont want to take the pistons out but it looks like that may have to happen. Can I simply take the necessary amount off the domes?
John

[John H.]

Re: BB Chevy Rebuild Books

John -

I'm not a big-block guy - don't know much you can safely mill off the dome, if any; a better approach might be to manage it with thicker head gaskets. Once you measure deck clearance and chamber volume, Clem can probably advise you what your options are.

[John M.]

Re: BB Chevy Rebuild Books

I made the measurements of deck clearance and combustion chamber volumes last night on the 69 L71.
The deck clearance was about 0.003 on the two cylinders that I checked and the combustion chamber volumes were 111.7 and 112.8CC; only one measurement on each one so +/- 0.5cc. So if the dome volumes are 35.5CC and the gasket is 0.040' compressed, I get CRs of 11.13 and 11.2. I think this would mean that the builder did CC the chambers and open them up to get the 11 to 1 ratio. I think the standard chamber is 104.9. It seems to me that this is right on the edge of being able to use 93 octane so I'll experiment with different head gaskets thicknesses first. Can anyone confirm the dome volume for a 69 L71 piston.
Thanks for the help.

[John M.]

Re: BB Chevy Rebuild Books

Instead of working the job that pays for the car I spent time calculating the CR using a 0.080" compressed gasket thickness and got 10.2. If this is possible it would be a nice solution. Any comments?
Thanks,
John