Cams tight after head rebuild

[razza]

Hi all,
I am in the process of putting the engine of my Lancer Evo 2 (similar to a 2G) back together. The head was stripped down and recondition by the local machine shop. We have gone about putting the head back together which has gone pretty straight foward. However now the head has been bolted down to the block the cams are difficult to turn. The cam caps have been torqued to the correct amount (15 ft lb's) and we prelubed where required. The cams etc have been timed up correctly. It seems sometimes the cams are very tight on 180degs and then are OK for the other 180degs. The cam caps have been put back in the correct order (marked with I&E) so dont believe its anything to do with this. Possibly the head has been warped during rebuild. Does anyone else have any ideas?

Many thanks in advance.

Regards,

Ryan

 

[delta448]

Was the block deck cleaned well or shaved before you torqued it down? The head may no longer match the deck surface and when torqued it may have twisted a little. Any chance of gasket remnants on the deck? Please tell me you at least used a new headgasket. Don't turn the cams over any more if they are hard to turn. Take the head back off and double check everything. See if the cams turn with the head off. I'm assuming that this is without the valvetrain completely reinstalled. The cams will have resistance when they act on the rockers to move the valves.

 

[->PrOjEcTGS<-]

I don't quite fully understand how far you are to having a complete head.

If you have the head fully assembled with the valves, valve springs, retainers, lifters, and rockers. Then when you put the cams in, and try to rotate them, you are going to have resistance from the valve springs when you turn them. Do you already have the timing belt on there? You said they are timed up and everything. DO NOT turn the cams with the timing belt off if the pistons are at TDC you will bend some valves since your pistons will not be going down when your valves are trying to open. Then again if you do not have any of the lifters or rockers in your cams should be easy to turn.

 

[razza]

Was the block deck cleaned well or shaved before you torqued it down? The head may no longer match the deck surface and when torqued it may have twisted a little. Any chance of gasket remnants on the deck? Please tell me you at least used a new headgasket. Don't turn the cams over any more if they are hard to turn. Take the head back off and double check everything. See if the cams turn with the head off. I'm assuming that this is without the valvetrain completely reinstalled. The cams will have resistance when they act on the rockers to move the valves.

Yes was all cleaned down and, of course, a new head gasket used. Yes the head is fully back together with valves, springs, rockers etc etc.

 

[razza]

I don't quite fully understand how far you are to having a complete head.

If you have the head fully assembled with the valves, valve springs, retainers, lifters, and rockers. Then when you put the cams in, and try to rotate them, you are going to have resistance from the valve springs when you turn them. Do you already have the timing belt on there? You said they are timed up and everything. DO NOT turn the cams with the timing belt off if the pistons are at TDC you will bend some valves since your pistons will not be going down when your valves are trying to open. Then again if you do not have any of the lifters or rockers in your cams should be easy to turn.

Yes the head is complete. It is tighter than the resistance provided by the valve springs.

 

[delta448]

Pry out the rocker arms and see if the cams are still difficult to turn.

Lifter VFAQ

If they still are, I think you should pull the cams, check them thoroughly for imperfections, ensure that the journals are still round and then reinstall them. If that doesn't work, pull the head and have the cam bores checked and deck surface checked.

 

[AndrewD5418]

Cams should be tough to turn when everything is in the head and they're bolted down...

 

[SnowBird]

when the head is off the car you should be able to turn the cams pretty easy with a wrench and they should "clank" or spring into every turn. If it doesnt trun smooth and doesnt seem right, DONT run it. Ive had 2 sets of cams that didnt pass this inspection and they ate away ate the head until it got so hot they locked up forcing the engine to stall and jump time. Im no guru, but the cams shouldnt be tight.

 

[freeman 188]

this happened to me because I had one of the cam caps put on the wrong way very important to have them all in the right place ,just somewhere to start before getting into the bigger job

 

[1992awdlaser]

this happened to me because I had one of the cam caps put on the wrong way very important to have them all in the right place ,just somewhere to start before getting into the bigger job

That's my guess.

 

[Defiant]

Remove the rockers, check for resistance. If any "unusual" binding is felt, pull the caps one at a time until you find the tight one.