Potential problem!??

Nebraska Kirk · May 29, 2009

I am working on this "52 Case DC for a fellow. I took my "35 CC block to the machine shop to have the worn 3 7/8" sleeves bored to 4 1/16" to use in the DC with the new 4 1/16" pistons that I found. I got the block back and pressed the sleeves out. Then I discovered that they had been bored OFF CENTER!! It was not very noticeable from the top, but from the bottom where the sleeve walls are thinner, it is more noticeable. I got out my calipers and measured the sleeve walls at several points to find the thinnest and thickest points and compare.

It might not be so bad if they were all the same and only .005 to .010 off center but no.... all 4 are different. This is what I came up with as far as how much each sleeve has been bored off center.

.010"
.015"
.020"
.025"

What do you all think?

petetx · May 29, 2009

hard to explain but i will try in my old machinist talk. are the bores centered to the crank throws remember you are looking at a casting and the wall thickness will tell you very little it's hard for me to fathom that if the machinist that bored it centered up on each cylinder it would be hard to bore off center in other words he would have machined a equal amount all the way around keeping it concentric hope you can understand what this old man's trying to say

Anonymous-0 · May 29, 2009

I wouldn't think it was a problem. You are measuring the thickness of the bottom of the cylinder from the machined inside to the casting on the edge, if I understand you. The more important check would be if the cylinders are perpendicular to the top of the deck.

Nebraska Kirk · May 29, 2009

Well, it is obvious that the machinist did not center up on the sleeve bores, therefore they ended up being bored off center.

RobMD · May 29, 2009

Put it together. It's not a racing engine.

Anonymous-0 · May 29, 2009

Once it is bored [which maybe was indexed to the deck] the sleeves should remain in the block They have to be put back as they were removed.The wall thickness varies and is irrelevent.Perpendicular to the centerline of the crank is what matters.It may be the machinst had some crud of leftover gasket to cause some inaccuracy tilting block on boring bar table, Ive seen that, but you should not have removed them.

Nebraska Kirk · May 29, 2009

Well, these are wet sleeves and are not pressed in the block like a dry sleeve. The reason I had to press them out of the block was because of 70 years of rust and crud and also the O-ring was adhered to the sleeve. Once I got the sleeve loose, it came the rest of the way fairly easily. Also, I measured the sleeve walls at the very top to see how far off center they were bored.

petetx · May 29, 2009

what i was trying to say is they may not be off center it's hard to tell from a casting i agree with rob.

Nebraska Kirk · May 30, 2009

The sleeve is not a rough casting, the outside is machined too, granted not as smooth or as accurate as the inside but decent enough to get a pretty good measurement with my calipers. Also, I measured the sleeve wall thickness at the very top when I was determineing how far off center it had been bored.

37 chief · May 30, 2009

A good test will be to install a rod and piston, and check the rist pin in the piston to see if is equal clearance on both sides of the rod top in the piston. Stan

Gun guru · May 30, 2009

The only way to check the perpendicularity of the sleeve to the block is to have the block mounted on a boring mill or other inspection type of equipment and then have the face where the head mounts trammed in true and then run an indicator down the bores to see if the piston bore runs out compared to the face.

I will assume that as the boring bar was cutting the deflection of the bar caused the eccentric cut.

I think the way to have it fixed is to have a scim cut made on each bore to true it up.
I have never machined engine blocks before.

El Toro · May 30, 2009

I would go back to the machine shop that did the work and ask them what happened. Hal

TomTex · May 30, 2009

I am not an expert, but I agree with Dr Sportster. You should have pulled the sleeves, had a professional cleaning of the block, re-installed the sleeves with new seals, then had the sleeves bored. Now that you have removed them after boring, I think you better start over by sooking for some new sleeves. Tom

Anonymous-0 · May 30, 2009

Lucky it was not 6 cylinders,
take it back and get them to explain it.

teddy52food · May 30, 2009

How bad were they wore? The boring bar centers on the inside of the bore. If it is worn off center, the result will be off center also.

Nebraska Kirk · May 30, 2009

How could it possibly get worn off center .010" to .025"? Even if it was, since the top 3/8" of the sleeve was unworn that should not effect it.

Spook · May 30, 2009

I don't think it is very important at all. What is important is the perpendicularity to to the CL of crank. On a wet sleeve engine, usually you mark the liners so that they go back in as machined. If you were gonna do something with the o rigs, the time to do that is before it's bored.

MIKE FRENCH · May 30, 2009

Kirk, put it together, I put a set of 4020 jd sleeves in a DC case block, they were off a little, remember it doent run that fast, good luck. PS got another M&W hand clutch in on a MD might be taking it off, later Mike

JOCCO · May 30, 2009

I have seen engines borred of center and crooked too.. My concern is stressing the crank and block. Why did we not put in new sleeves with pistons and do it properly?? Next i have seen remanned sleves one guy put them in a 425 cat they did not last long. Some shops can line bore and also check to see if the bores are out from centerline from the crank.

Ray · May 30, 2009

The only problem i see is the work you've already done is worth more than the tractor.

Potential problem!??

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