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Re: Evo X upgrades
It happened while taking off/putting on that double cam cap, while working on setting up his valve clearances. The Evo X doesn't have hydraulic lifters, it uses non-adjustable valve tappets that need to checked/measured/bought/etc that go between the cam and valve. I had 3 that weren't within the specs with his new cams in there.
There is a bearing on the cam cap where it broke. Only 1 cam journal in the head uses a bearing and it was the one that broke. I am sure not if a dowel wasn't seated correctly or the bearing was a little out of alignment/high/rotated and it caught an edge. It took very little force for it to break. I didn't realize it was such a potential risk for breakage until after I did it and found other people on EvoM who had done it also and heard from Brookdale Mitsu that they have had other customers in town do it also. Since there is a bearing in the one that did break, I have a solution for fixing it, that I would do if it was my car, but it's a customer car and I didn't want to do that on his head or fix in that without telling him. The look of the casting and thickness of cap in that area doesn't scream strong, it looks like something you could tap on the ground and expect it to snap off. |
Re: Evo X upgrades
Well I guess more research for when you pull my head;)
You didn't have to deal with this when doing my cams did you? I am guessing because you didn't have to pull my head...i am no mechanic. |
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Toyota uses this type of design on some of those heads too, but they are more robust and better designed then these are.
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Re: Evo X upgrades
I had that piece off your head to do the cams, but I didn't have to mess around with yours as much taking things on and off, because all of your valve clearances seemed to be within spec. All of his clearances that were out of spec were on the exhaust cam, 2 were barely out of spec and 1 was a bit farther out. You won't have any rockers popping off or lifters collapsing with these heads, but dealing with shim buckets is sometimes a pain and can get expensive. I have done Subaru and Supra heads with BC cams that required every shim bucket to either be moved from another valve or replacement ones bought. Buying the cheaper cams ends up costing more than just buying some HKS cams that are ground right in the first place, but a lot of guys will also just drop whatever in without ever measuring anything.
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I HATE doing the shims on those buckets!! Luckily the dealerships paid us a few hours book time to do them!
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Regardless, your car is in good hands. This is why DB rocks and Shane is the man.
Thanks for the info, Shane. |
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That's freaking crazy that there's a bearing on one of the cam caps...what on earth is the reason for this one random bearing? What a PITA. That thing does look thin as hell too, no wonder it broke. :( |
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Kracka, you are good:)
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twss
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Nice!! |
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I have a PM in to AMS on this. Shane says he has a good machinist in town.
The question now is how many weeks will it take AMS to make a batch. We waited quite a few weeks just for CBRD's wheels to be anodized in blue, so I'm not holding my breath. Looks like I'll be doing auto-x novice school in a `94 plymouth acclaim. hell yeah! |
Re: Evo X upgrades
There are some instructors who say you'll learn more as a driver in a shitty car on bad tires so that may not actually be a bad thing. Although I personally like practicing/learning in my actual car.
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I did some research today. Fixing the head doesn't look like such a great idea to me.
1) AMS says "2 to 3 weeks" to get a $225 cam cap. I've seen that turn into 4-6 weeks too many times. Then machining time...then shop time. I probably wouldn't see the car until June. Not sure what machining costs but I'm assuming hundreds. That's a lot to sink into a $1k head not to mention the time. 2) Stock head. About a $1k and comes totally bare. I'm guessing these are readily available but I haven't checked. They come bare so I'm not sure how many little parts or labor is required to move the valves, springs, seals, etc over to the new one. http://tinyurl.com/yckyjt9 3) Cosworth built head. Found a guy who can get it for under $4k and doesn't require a core. Supposedly good to 10.5k rpms (not that I'd even think about it). These are on the shelf and ready to ship. They come fully assembled so it doesn't look like there'd be any extra labor other than installing the cams. I'm obviously going to need new gaskets for everything and need to ask Shane about re-using the head studs. I'm trying to get some details from the guy that offered me those great prices so we'll see how that goes. Hope to make a decision and get something ordered this week. |
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I might be better off driving a POS. That way I can pretend it's the car that sucks. haha. |
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Go big or go home. I'm ordering the Cosworth head tomorrow.
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