Line Honing Q

Want some more? I went round-N-round for 8 years at various dirt tracks before I decided I had enough.. Still have my picture of my entrance into the "river club" at Fonda...

Forged would likely have done the same. I ran a 358 one year that decided to drop the oil pump drive in turn one, made it through 2 and went to turn onto pit lane and she locked up TIGHT. Pulled the pan and found the crank had snapped and took #2 main with it, snapped the webbing. OOPS!

Reply to
Steve W.
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Yep there are a few engines that had the matched bearings. Most of them were imports though. Suzuki, Mazda and Mitsubishi are the ones I can remember up front. The reasoning went that it was faster and cheaper to have the different bearings on hand to fit the journals than it was to check the grind on every crank and regrind if it was out. Instead you mic'd the journal and selected the correct combination to fit. .001-.005 under were the sizes on the Suzi., in .0005 increments IIRC.

Reply to
Steve W.

You're talking about turning a JOURNAL on a crank, which affects the inside diameter of the bearing that rides on that journal (and accounts for the need for undersize bearings). Line boring affects the block which determines the OUTSIDE diameter of the bearing shells, and there are NO over/under sizes for that. You come back to the exact same diameter, no other options exist.

Reply to
Steve

I have a really nice Australian Rollmaster timing chain in my 351 Cleveland, and on the box it came in they state "line bored sets available", which I assume is for this precise reason.

This link also state that:

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Reply to
Thomas Tornblom

Yup, I have a Rollmaster in my 340. When I ordered it, I had to give them the center to center distance between the cam and the crankshaft. Nice tight fit!

Reply to
aarcuda69062

fwiw, my timing set was just stretched - I replaced it and it's nice and tight. Now, about the bent rocker stud... Race Cars... It's like crack, only more expensive.

Ray

Reply to
news

Fun ain't it. What track do you run at?

Reply to
Steve W.

Geese guys.

It 'clearly' states the 'cylinder block' outer main journal diameter can vary 0.010" and you buy stock bearings to fit.

These bearings come in sizes from 2.4901" up to an outer diameter of

2.5001".

It also states the stock 'crankshaft' main journal diameter is 2.2988".

This gives a whole bunch of 'honing' or reaming room without having to change or dick with the centerline seeing as even being out a hair is bad news for most engines.

Mike

Steve W. wrote:

Reply to
Mike Romain

Geese guys.

It 'clearly' states the 'cylinder block' outer main journal diameter can vary 0.010" and you buy stock bearings to fit.

These bearings come in sizes from 2.4901" up to an outer diameter of

2.5001".

It also states the stock 'crankshaft' main journal diameter is 2.2988"

This gives a whole bunch of 'honing' or reaming room without having to change or dick with the centerline seeing as even being out a hair is bad news for most engines.

I can see where a bad one might need the centerline changed by cutting the journal, but...

Mike

Reply to
Mike Romain

Not on a Jeep engine.

It 'clearly' states the 'cylinder block' outer main journal diameter can vary 0.010" and you buy stock bearings to fit.

These bearings come in sizes from 2.4901" up to an outer diameter of

2.5001".

It also states the stock 'crankshaft' main journal diameter is 2.2988".

I can see where a shoddy shop might get the center off or there might be too much damage, but that isn't what I was going on about.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's - Gone to the rust pile... Canadian Off Road Trips Photos: Non members can still view! Jan/06
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Reply to
Mike Romain

Red River Co-Op Speedway up in Winnipeg, Manitoba. The Camaro is what used to be called Enduros, but now is the "Stock Car Challenge" - 200 laps around a 4/10 mile oval. In 4 years, I think I've managed to bust everything on the car at least once. When I'm not crying over my Visa statement, it's fun. My buddy was over last night and we replaced a smushed in control arm and a lower balljoint...

Ray

Reply to
ray

OK, then on virtually every other mass-produced engine out there....

Granted I've never built a Jeep inline 6, but I've NEVER heard of bearing shells with different outside diameters. Ever. Doesn't mean that they don't exist, but it means they're not the norm.

Screw the crankshaft journal, that's irrelevant to this discussion. The journal passes through the middle of the bearing, we're talking about the backside of the bearing shells. Talking about the journal just confuses the issue.

No, its the ONLY way to line-bore most engines. And it doesn't hurt a thing! You gotta remember:

a) its ONLY done in a way that removes block material when absolutely necessary (eg, bearing saddle damage due to a spun bearing, block warpage due to overheating, etc.). It is also done whenever you areinstalling new main caps, but in that case the boring bar just "kisses" the block material and doesn't remove any material from the block at all, it JUST cuts the caps to match the half-circle formed by the block.

b) If you have to move the crank more than a few thousandths, the block is junk. Line boring NEVER moves the crank enough to affect anything but the timing chain tightness.

Reply to
Steve

fwiw, my replacement chain is nice and tight, I only got an align hone, so I don't know how much they took off, but it couldn't have been much.

Comp Cams sells timing sets for align bored blocks.

Ray

Reply to
ray

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