Depending on the extent of what happened to the cap, you could bolt it in place, weld it and then line hone it. This way you are still using the correct cap that was originally part of the head. Either route you take, you are pulling the head and getting it line honed. If it cannot be repaired, see if you can order one from a dealer and have it line honed.

 

There is both good and bad info in this thread.

From a machinist point of view, get a cap and have it line honed, and be done.

Yes there are some "shade tree ways" that this can be repaired

As far as just grabbing another cap and putting it on and going, I would not do that, a good chance you will end up with more or not enough clearance. You would be better with too much than not enough.

With the followers out of the head, and the cam in place, with the cam caps torqued, the cam needs to turn by fingers only, and feel smooth, not sticky.

If you have to use a tool to spin the cam, then it is too tight and you stand a chance to grab the cam, and really junk the head.

Now in the past, with having to make a head work for the Buy here, Pay here car lots, that want to patch everything. I have done a "back yard line hone" to fit a single cap.

This is NOT the best method!!!!!!!

But you use a 1 inch Dia flapper wheel, and a 12 inch long drill bit extension on a die grinder.
You will also need a wide tip sharpie marker.

First is to torque the cap in place with no cam, and polish the parting line area of any overhang is gone.

color the inside of the cap with the marker.

Torque cap down and try to spin the cam.

Where the marker is wore off polish with the flapper.

Color and torque the cap again.

Keep working it till the cam spins by finger.

Once the cam spins, clean the casting and oil ports of grit and metal flake.

This should NOT be done on the short block, but the head off and on a bench.

BY using this method , you do so at your own risk and gaining "moron" status if it fails!!

I still recommend that the head is pulled and taken to a machine shop that is equipped with proper cam boring machine.

 

Nice information +1


Professionally : remove and take it to your machinist not a "engine builder" ( your a evo owner now you may as well get to know them) I use a diamond shaft to line hone fixed size it's mint

Personally: see if the cam turns by hand with the replacement cap then use the above method provided you will see contact if there isn't enough clearance , if there is rubbing use the flapper wheel , You can do this in place but it's dodgy, flappers will create very fine dust that WILL contaminate your oil system.

I've had to do this once but we were in the jungle trying to get to the next stage .
Just don't sit there all day taking out material , I would never let any of our apprentices do this EVER !

Lol broke a cam cap while installing ...... how ?!?!?!

 

Not to be off topic out I took my head off to replace headstuds and install new cams etc and saw one of my camshaft cap bolts was broken in half! The car had been running like this for thousands of miles fine.

I had the broken one drilled out so it's all fixed now bit jeez that could have been VERY BAD

 

I'm also going to through in my question instead of starting a new thread, all of my cam caps are waded from soaking them in a degreaser to clean them....it literally corroded the top part of the inside bearing a little on all of them. It's the smallest amount and I'm stumped on my next move

 

Post pictures. You could probably get away with polishing them up, unless they're badly pitted...

 

Go buy some plastigauge and measure them out before you do anything, a few thousands makes a big difference-- you may not have to do anything if they spec out.

 

Thanks for the replies I'll check that tomorrow, the head is at a shop right now and he's checking to see if there's anything he can do. I'll know more tomorrow

 

I too am curious how he broke the cam cap. What is the long version of that story?