Hey, I am looking for some help. I brought my evo to my friend who said he could swap my cams out. Long story short he ended up breaking a cam bearing cap in half. Can I just order a new set? Or would I have to buy a used one? Any input would be helpful. Thank you!

 

The cam cap bearings are line honed to their mating partners. You will have to buy a new one and take the whole head to a machine shop.

 

This^^^^^^^^^^^ no short cuts

 

Even then you have a lot of work ahead. Whole thing gets cut down and honed fresh. Not cheap or easy. I usually throw away a head without all Cam caps accounted for.

 

Appox cost in my area to have a head aligned honed is appox $100 per cam

 

while this goes against what most people will tell you, you can just get a used cam cap from an engine with close to similar miles. the line hone from engine to engine should not be that far off at all. i have done it on northstar engines and have had no problems

 

Terrible advice. When the Cam seizes and destroys everything then you will have lost tons more money because of bad advice. Also finding Cam caps for EVO's is very difficult since the heads are very expensive.

 

Im not machinest but I agree with this. All the heads are lined honed from the factory by the same machine using the same specs......so why would they be different? also drop in aftermarket camshafts would mean you would need to measure them and then measure your cam caps to make sure there in spec, I know for a fact I have done it with my old dsm and had no issues at all useing cam cap on my spare head since I broke one like you. Havent done it on my evo

 

By that advice we should just be able to swap rods caps at will too. Hahaha. If you have done it and not killed your engine you got lucky. It isn't that the holes aren't the same size it is that they could be a thousandth or two off center in any direction. This is why the head is line bored with the caps in place.

 

wouldnt this affect any camshaft you put in it then? meaning every cam would need to be specific to that head? Also once the cam caps are line honed if you were to use them off a different head, wouldnt this affect the camshaft to? wouldnt you need to turn down the cam to match the line hones? Im just trying to understand this. I just dont see why a cast head from the factory machined by a machine that has all the same specs as it machines all the heads the same. If Im wrong thats fine, im not saying dont check the line hones,if you got the money, hell with it. Im just trying to understand it

Rod caps are easy to line hone and match up though at any machine shop, and that also goes by the crankshaft being if its been turned or cut down

 

It would not effect the cam. The reason it gets line honed is so they are perfectly centered. Before the head and caps go to be honed they are undersized quite a bit. They are then bored and then honed. Mitsu may even torque the head on to flat surface to account for distortion. If you put a cam cap on from another the head, the center of the imaginary circle for that cap may not be in the same location as the center of the imaginary circle for the head. If a cap off of another head is too far off, it may not even be useable.

Just like rod caps are honed with the rod, and new main caps get honed with the block. The small block fords I've put together have always gotten billet main caps, and the caps come about 1/8" under sized. The machine shop bores them with the block, and then line home them. This also raises the crank center line, and a shorter timing chain is used to compensate.

If the crank gets turned down, you simply get oversized bearings for the now undersized crank, it's a little different. Then honing caps to their mating component..

 

Pull your head, get a new cap and take it to a machine shop

 

Ok, I understand that. I can also understand if he were to get cap 3 off a different head and use it on cap 2 spot on his head, that could be off, but use cap 3 onto cap 3 spot then maybe not so much. I wouldnt do a 8 cap on a ix or vise versa. I would like to hear from machine shops that actually do this how often there "off" and need to be lined honed when this happens.

To the OP, good luck finding cap or caps, you cant buy them from the dealer seperate. You need to find someone with a already bad head. Also the machine shops I checked before charged a good amount. I dont know but you might be better off gettting another complete head depending on the machine work price and finding a cap/caps

 

lol, a machine shop will tell you the same thing.

The reason you would line hone a a new cap, or a cap from a different head, is the same exact reason you reinstall the caps you took off your head in the same location that they came from on your head (and pointing in the same direction). And in engines that don't use a one piece main cap/girdle like the 4g63, you install the main caps in the same location they came from (and pointing in the same direction), and why you don't mix and match rods and rod caps (and you don't install them "backwards").

It's also something you can't check by measuring it with a mic, or caliper, or anything. You know it was off when you run tooling through and you can see where half a thou came off from the fresh tool marks. If it's bad enough, you might feel a lip in the bore where the cap meets the head, but it would have to be way off for that.

I've taken apart enough engines that blew up with very low miles because of other people's mistakes, to know that you don't **** around and cut corners when it comes to engine internals. Especially when it comes to parts that control oil clearance on vital rotating components.

I cut corners on one engine, I left ptw a little loose (.0045 instead .0015 on a n/a ford v6) because I already had pistons, and the block needed more honing then expected to make the cylinders round again, and I didn't want to wait. That engine broke a piston skirt in 5k miles. I wasn't happy, and it was my fault. I learned from that though, there is a reason there are specifications and procedures for building engines. That's the only failure I've had, it was the first time I cut corners, and it will be the last. I attached a picture of the broken piston, I'm luck I didn't lose the whole engine.

Right now, the OP has a good short block, a good head, and a good cam. If he takes the chance with a random cam cap, it could work fine. Or, he could end up with a junk cam, a junk head, and depending on how long it runs before locking up or making amazing sounds, a junk short block from all the **** that will be in the oil from the cam self clearancing the head.

Disregard the suspension picture, the app for browsing this forum is a pos, I can't delete the extra pic.

 

Spend the extra money. Rake The Extra Step. I came from a long line of Hondas. I had a 768 hp evo that got head lift and ended up needing tons of work. This would be a quick head gasket job and drill hone if it were one of my older Honda engines. Since evos have cast iron blocks, antifreeze got in the cylinders and rusted them so that needed to be bored. My head got grooves cut in it from the coolant escaping out the side. I could have half assed is and Slapped another head on it and just "cleaned" the cylinders. Instead this was a 10,000$ engine rebuild that I felt was needed because I wasn't dealing with a Honda. I was dealing with an evo. From experience man just sick it up and do it right. I also had a fully build single cam Jap engine in an old Honda. Bought a brand new cam and it was warped and I had no clue. Not even a couple miles down the road the cam siezed, broke my true time cam gear. Ripped my gates timing belt. And sent the gear through my mishimoto radiator. That cost a lot of money to fix. I couldn't imagine doing that with an evo. Hopefully you will make the right choice.