Evo X upgrades

[mlomker]

Cam cap has a boo-boo:



I like how the engine bay is going to look.

[Matt D.]

Originally Posted by mlomker

Cam cap has a boo-boo:

That's seriously fucked up. I don't follow EvoX news, but has anyone anywhere reported a problem like this, even a dealer doing something on the head and having this happen?

[mlomker]

Originally Posted by Matt D.

That's seriously fucked up. I don't follow EvoX news, but has anyone anywhere reported a problem like this, even a dealer doing something on the head and having this happen?

I'm so not a mechanic but the guys at DB said they immediately searched the Internet and found 2 or 3 similar instances. My bit of research suggests that the cam caps are custom machined for each head. It is to compensate for machining tolerances in the head itself. If the cap is torqued down even the slightest bit out of alignment then the cam will bind and break the cap.

I posted a thread on EvoXforums and I've gotten some feedback already. The immediate comment was that you have to use dowels to hold the cap in place while torquing it down and that the specs on those bolts are in in/lbs and you have to use a very good torque wrench. I obviously wasn't there when Shane did that work so I'm not going to speculate.

It's an "upgrade opportunity" as far as I'm concerned. There are a number of people on the EvoX forum that want to buy the head from DB and have a machine shop fix it. They seem to think that'll be fine. The tolerances sound rather tight to me. I dunno.

[Matt D.]

Originally Posted by mlomker

I'm so not a mechanic but the guys at DB said they immediately searched the Internet and found 2 or 3 similar instances. My bit of research suggests that the cam caps are custom machined for each head. It is to compensate for machining tolerances in the head itself. If the cap is torqued down even the slightest bit out of alignment then the cam will bind and break the cap.

I posted a thread on EvoXforums and I've gotten some feedback already. The immediate comment was that you have to use dowels to hold the cap in place while torquing it down and that the specs on those bolts are in in/lbs and you have to use a very good torque wrench. I obviously wasn't there when Shane did that work so I'm not going to speculate.

It's an "upgrade opportunity" as far as I'm concerned. There are a number of people on the EvoX forum that want to buy the head from DB and have a machine shop fix it. They seem to think that'll be fine. The tolerances sound rather tight to me. I dunno.

That is the first head I've seen having a cap that goes over both cams. Other Mitsubishi heads (4G63) have separate caps for each cam.



I can see where if the cap isn't seated correctly before tightening, or if the cam puts pressure upward on the cap when it gets tightened, that the cap could break like that. Though how it would break when the engine is turned over doesn't make sense.

Best of luck, we'll be looking forward to seeing what you end up doing.

[mlomker]

Originally Posted by Matt D.

That is the first head I've seen having a cap that goes over both cams. Other Mitsubishi heads (4G63) have separate caps for each cam.

Totally. This is new with the 4B11T.

I got a bit of good news tonight. A guy that does R&D work for Cosworth saw my post and offered me a head for $3800. I seriously doubt that I could beat that--it looks like $4200 is the going price.

Originally Posted by Matt D.

Though how it would break when the engine is turned over doesn't make sense.

It may very well have broke while he was torquing it down. I am smart enough to not ask a lot of questions after someone offers to fix an expensive problem. I could tell he was kicking himself enough already.