Re: how "tight" should the crankshaft be with new bearings?

Yup, here's a picture of the front of a 4.0 showing the timing gears:

That tensioner stands right out, doesn't it? And this guy works for a Jeep stealership???

Chris

Yeah they do, but you are dead wrong as to why they do it. It has nothing to do with a small fillet increasing strength, it has to do with providing clearance for the sides of the bearings. It is common sense (maybe this is why you don't get it?) that a larger fillet increases strength. 'nuff said.

Chris

in

wrote

The fillet radius doesn't so much increase strength as it spreads out the stresses on the crank. Without it, all of those stresses would concentrate at the sharp corner leading to eventual fatigue failure. This is why aircraft engine crankshafts have radiused journals.

---------------------------------------------------- Del Rawlins- del@_kills_spammers_rawlinsbrothers.org Remove _kills_spammers_ to reply via email. Unofficial Bearhawk FAQ website:

Are you claiming the 4.0 does use a tensioner ?

Dave Milne, Scotland '91 Grand Wagoneer, '99 TJ

No SHIT!

A regrind, is not a performance crank, and the OP said he was looking for narrower bearings to clear the filler.

So put that in your pipe and smoke it.

He wasn't building a nitro funny car engine.

Next time, learn to read context, and not hammer your one sided point to make yourself deeman, kid!

Refinish King

manufacturers

This is the world according to C:

news group. He wanted his point known, disregarding the original post saying he required narrower bearings. But, there would have to have been some submerge arc welding on that crank to make the fillet narrower?

Grinding makes the fillet area wider, does it not?

Refinish King

Ok, let me put you out of your obvious misery.....

There is a bumper for the chain in the 4.0 and in the 4.2, but it is just the rattle noise when things finally stretch. Even new, the 4.2 has over 10 deg of back slop, no tensioner, haven't checked the 4.0, but bet it's close, same block.

I even phoned my local Jeep dealer to make sure I wasn't mistaken.

I was also making a fool out of you, my apologies.

You do have some decent knowledge on some things but on others you are 'way' off base.

When you send a block in for refinishing and get a main crank and cam turn/grind, they turn the block 10 thousands over to make it perfectly straight.

At the same time you are likely getting the crank turned 10 under to make it like new.

The machine shop then gives you a bearing 'with plastigauge' that is ten over 'and' ten under.

This keeps the crankshaft 'exactly' centered where it was new.

You come home and plastigauge it to verify their work, then you assemble it. 'With the 'same' bearings Eh!'

On the Jeep 4.0 and 4.2 block, the oil boss has codes stamped. You can have a block already turned 10 over from the factory. Still no chain tensioner....

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

mic canic wrote: