To Sleeve or not to sleeve
 

I was just informed that my block (numbers correct) was bored .060 over. It is a 64 870 block. The machine shop suggested going .065 over as a cost cutting measure. I am concerned about doing this and having the cylinder walls too thin. Another option is to sleeve every cylinder and deck the works less the pad area. Thoughts?

no question here about it sleeve all eight!.......better ring seal, better metallurgy....go for it with an original block.......:thumbs:

If those cylinders will clean up at .005 over whatever the bore is now, you don't need to bore it unless you plan on driving it 100k miles or so.

Somebody is yanking your ying-yang.:D

:iagree:

Original only once ...Resleeve it 100k from now !

it's already 60 over.....it is the most valuable piece on the car...im assuming it is a 65 fi....why not protect what he has and assure a super block, i gather there are no cracks that's why the machinist is suggesting another .005.....no problem with water leakage here ....darton or keith black are great names and it will put a 40+ year old casting in the 21 century for clearances and metallurgy..pricey but well wotrh it...jmho....;);)

Because it's perfectly okay to have .005 taper on the cylinders for a re-ring job, that's why. And if it will clean at .005, that means it doesn't even have .005 taper.

Why in the world would you spend that large amount of money, take a chance on the machinist screwing something up and for what tiny, tiny benefit?

I'd like to know why the engine was torn down to start with??????????

:iagree:

Take a dingleberry hone to it and put it back together. You don't bore .005 over, you hone it. Just like when you do an overbore you should leave .007 and hone that to size for finish.

Now, you need +.065 pistons made. Hmmm, that wouldn't be costly; would it? And now you need to fit rings to the morphodite oversize.

If, however, you want to sleeve back to standard it is not rocket science and a competent machine shop can do it for you. If you go this direction and want to be assured of thick cylinder walls tell them to use a 5/32 wall sleeve instead of the standard 1/8 wall sleeve.

Rich:cheers:

dingleberry hone...i love it!!..LOL.....does it give a dingleberry crosshatch too???

I guess it depends on what you plan on doing.

If it was me, I'd get another motor. Keep the original for the next owner to deal with. That's just me though, I drive our 'vette as much as I can. Not worrying about ruining the original motor would give me peace of mind.

If you barely drive it and it will for sure clean up and you are judging it, then that's different.


How much to sleeve all eight cylinders?

:cheers:
Gerry

Wow! Thank you all for your opinions. I haven't received the cost for the overbore nor the sleeving yet. My intent is to show the car, get it Top Flighted, and see what makes sense then. I do have another 327 that appears to be pretty fresh (hone marks are still in the cylinders. The car was not purchased with the original engine. It was a fluck to find the engine but the engine has a double stamp (the first stamp is my VIN). This car is extremely early and per some very respected sources this engine may well have been the original engine installed in this pilot car. The engine was sold under the pretext of having had a recent rebuild (20 miles ago which was found to be totally false. the engine was not a recent rebuild at all). To tear it down was done to confirm the information provided from the previous owner of that engine. Too much money going into this to take a chance.
So, at this point, I guess the thing to do is sleeve it and should it turn into a driver, put the other engine in.

If the block was just bored and rebuilt, and the cylinders are straight, I would just put it back together. The .060 overbore should not be a problem from a durability standpoint. Back in the day, we used to wail the tar out of .060 over 327s. They used to bore 283 engines .125 over to make 301 inch engines. (Z28s, before Z28s were made by Chevy.) The book "How to hot rod small block chevys" says .060 is not a problem but it is as far as you should go. Chevy used to race 327s bored and stroked to 377 cubic inches. so yours should be OK. I assume, since you are showing the car, you wil not be wailing the tar out of it, so don't worry.

To be extra safe, have the block sonic tested to check for core shift. That way you can tell if the cylinder walls are uniform, or thinner in any area.

Rich

Here's minimum V8 wall thickness specs from Jeff Smith at Car Craft:

0.200-0.300 inboard wall, driver's side, outboard wall, pass. side
0.090-0.120 opposite wall

The thicker walls are on the thrust side of the cylinder.

O.K., its already bored .060 over, but nowhere do we hear anything about the condition of the cylinder walls. Why are we talking about sleeving an engine that seems to be destined for a show car life. Freshen the walls with a hone (dingleberry preferred), reassemble and move on.

the so called dingleberry hone that is lovingly referred to is actually called a "glaze buster", that came on the scene in the mid sixties and its intended use is just that..knock the glaze from cylinder walls on a cheap re build.....after that you are supposed to follow up with a regular hone to achieve a crosshatch.....if we were talking a briggs and stratton here that would be another deal, but a classic fulie 65 vette?? i dont think so....jmho.....:cheers:

Absolutely correct. You would be better off not touching the cylinders, than using a dingleberry, unless you are using cast iron rings. Modern rings require a hone with a 400-500, or finer, grit finish. Any coarser, and you wipe the moly right off the rings. Most diggleberry glaze breakers are about 200 grit. The smoother the finish on the walls, the better for the rings. Modern rings seat almost instantly on a finely finished cylinder.

Good point. All I know at this point (I am not close by to see the engine currently) is that there is no evidence of a recent hone.

IMO: My approach based on attempting to save the block in my 57 RPO 684 car. Have the block sonic checked, find the best machinist in the area with restoration motor experience, make sure he has the hone machine which sets up the block off the main webs, have him determine minimine bore size to clean the cylinders up, work with him to determine if there are rings available for that bore size, order custom forged pistons from JE (order high silicone)(send one original domed piston to them for dome configuration). Have the block honed to fit the pistons.
The block came in second at Bridgehampton in !957 and I wanted to save it. The original which won Montgomery and Lime Rock was lost at Watkins Glen two weeks prior.
Regards

to each his own; but only you can make the final decision... not knowing the true condition of the bores, but assuming that they are unmarred, then i agree with the majority: hone it, ring it, run it....

it can be sleeved and/or bored some other day
Bill

I just went to check the engine today. The cylinders have ridges and are, definitely, overbored .060 over. There is also a taper milled at the top of the cylinder around the circumference. I am not sure what the purpose of that taper was but the end result is very little clearance between cylinders. The rebuilder has suggest use of figure eight o-rings and copper gaskets. He feels going an additional .005 over and not sleeving may be more sensable. He, also, suggest not use hardened valve seats on the original 202 heads. He is concerned about the thickness of metal between the combustion chamber and water jacket.

Concerns are the need to always have to use a lead additive and the diminished amount of metal between cylinders. Thoughts?

A ridge means a worn cylinder. Are you sure .005 will clean it up? Do those O rings require machining grooves in the deck?

They used to knurl pistons for worn cylinders. They don't last as well as new ones, but how many miles is that thing going to see?

Knurled pistons, file fit rings, and good head gaskets, would be the cheapest route. Sleeves would be the most durable, and expensive route, but hey, how much is that car worth?

I agree with your builder on the valve seats. You are probably not going to put enough miles on the car to create an issue, unless you plan on adding 80,000 to the odometer. Rich