Cam caps

[Lil Dee]

Okay I have read what is here. Now here is my problem. I have a friend who bent his valves after his dowel pin snapped. He needed a new head.

Because I was waiting on a combo of 264/272 Crowers to arrive I gave him the cam caps off my head (his new head didn't have any) not knowing there would be a problem. I picked up some more cam caps from a 1g automatic turbo head at the junkyard. I installed my new cams with the caps from the car from the junkyard and now when I set the timing the cam sprocket / cams are hard to turn.

I have not started the engine in fear of bending valves. Is it the caps or Cam sprocket?

Just wondering why it won't turn. It turned just fine before. I have set timing over a dozen times on DSM's with no problem.

 

[greenydsm]

Never ever switch cam caps, If you ever swap caps you should always get a line bore on the cam caps.

 

[gofer]

100% certain its your cam caps. Mixing Cam Caps

I bought a used 7 bolt head that was missing just one cam cap, to get the clearance on the cams thats required I had to get it line honed by a machine shop.

 

[Lil Dee]

Wow, never knew this. So what if I get them back from the guy. Do you think it will turn then? UGH. DSM's man. Well do you think I could have bent my valves by manually turning the cam sprocket when setting the timing?

 

[gofer]

Valves won't bend from the cams rotating unless somethings not timed correctly, using incorrect cam caps will just wear grooves in your cams.

!!!DO THIS WITH THE HEAD REMOVED FROM THE MOTOR, IF ITS NOT YOU WILL BEND EVERY VALVE!!!
The "redneck racing" way of line honing cam caps to fit a head are to install a trash cam in the head (using assembly lube) and torque the cam caps down. Install the cam gear and then, with an impact wrench, rotate the cam CW until the cam turns freely. This method will trash your cam but in your situation it might be better than dropping over $200 to get ALL the cam caps line honed by a shop, especially if you have a spare set of 1g/2g cams somewhere.

Use the above technique at your own risk, you didn't hear it from me.

Personally I'd get the cam caps back from you buddy if he hasn't used them yet.

 

[Lil Dee]

Thanks will try him in the AM. Otherwise will try to do it on some trash cams. Will let you know how it turns out.

 

[motozachl]

Also make sure the cam caps are in the correct order

 

[Lil Dee]

I did do that. That's what made me so frustrated and surprised at the same time. I actually took time to make sure that they remained in the same order. Just didn't know that you couldn't switch them on different heads. By the way if the guy used them I do better just to redo the ones I have right? Or should I redo the ones I gave away?

 

[gofer]

If your buddy has already ran his motor then those cam caps have been "line honed" for his head just from the cams rotating through them, I guarantee his cams have grooves in them and metal shaving don't pass through motors very well.

Your probably better off getting the ones you have now to work, tell you buddy he owes you. If worse comes to worse you should be able to find a 6 bolt head with all its cam caps for $50 to $80.

 

[BogusSVO]

cam caps can not be swapped from one head to another just like others have staed above, just like main caps and rod caps

get you caps back from your buddy

 

[turboglenn]

LIke most have said, try your best to get your original caps back as long as your friend hasn't installed them and ran the engine yet... if he has forget it, they're trashed along with his head and possible rotating assembly too from the shavings.

If you can't get them back then you can find a shop in your area that does racing motorcycles and have them do the fly-cut and align boring on the new caps on your existing head

I say find a motorcycle shop because here in omaha the bike shop that does drag bikes was more familiar with the process, not to mention he is one of 2 in the whole local area that even has the machine to do the work.

If nothing else this will be a good lesson to keep an engine/head's parts with that engine/head unless you absolutely have no choice