Had the cam cone de-chromed. Despite the given advice it would be OK, of course the acid ate out all the zinc in the bronze cam and pinion shaft bushings.

Fitted two new ones and sent it out with the right hand side case to be line reamed as I don't have the tools.

Got it back and discovered straight away the dick had not drilling out the oil feed line. I'm thinking that's not exactly an optional choice.

But by question is, is this scoring really acceptable? I would have thought a light cross hatch was good enough, and that a spiral will pull at the cam (BTW, which direction does the cam turn, CW?).

I've never seen this before, has anyone else? The grooves are as deep or deeper than on K-liners. It's sized well, but this looks like the tool is damager or had some swarf stuck it in.

A second opinion appreciated.

Frankly, if I was going to be pedantic, the oil line should have been drilled out before it was reamed.

What's the recommended finish? I cannot see any mention of it in the manual or JIMS instructions.

 

Unless this is some "trick" way to get/keep oil into the bushing ( never seen it before ) and the fact that there's groves would indicate that cam is riding on only the "high" points hence accelerated wear. That's my perspective from years as an ASE mechanic, but what do I know. A properly used ream should leave no grooves.

 

Appreciated, neither have I.

Needless to say, I've not actually used it as yet.

I'd rather go with fine tolerances keeping up good oil pressure.

 

It's funny because the manual and fitting instructions for camshafts actually say, "inspect for grooving".

As an aside, does anyone know the part number for a non-chrome cover for a 1996?

 

Should be 25254-93b which means that they are the same for 93-98. Easy to find on fleabay.

 

That's f'ed up. I think I'd start over on that. And find a different machine shop.

 

My cam bushing with 100,000 miles on it looks better than that! I'd never go near that machine shop again except to give that machinist a kick in the pants!


There's supposed to be a smooth finish on the cam bushing. The cam and pinion bushings and the tappets are the only two places in an Evo engine that generate the resistance to the oil flow that generates oil pressure. That bearing won't do that.

 

It's hard to imagine what the machinist was thinking when he let that thing out of his shop.

 

Wow. I have never seen one that bad. It should be waaaay smooth. I don't think you could even make marks like those with the teaming tool

 

Damn thing looks like he threaded it!!!
Or at least tried to!