Roller cam valve spring question..

[Steve V]

I have Mike's austemper cam kit. Everything is at the machine shop. He called tonite and says the cam card calls for 1.8 installed spring height. He can only get 1.725. He wants to cut the heads where the springs sit .075. Is this okay. Anybody had this issue with Mike kits.

There's nothing fancy about these heads other than they don't have any EGR passages. They've probably had 2 valve jobs in there lifetime.

I also sent Mike a PM,it was too late to call tonite.

Please advise

 

[blown okie]

the cam card should give pressures requirement, they can only assume an installed height you should be able to find springs that will give you the desired/required pressure within your installed height, i deal with this all the time, cutting the heads that much seems excessive, but shouldn't hurt anything, is this a hyd. roller?

 

[Steve V]

Yes it a hyd roller. Thanks for the reply.

 

[blown okie]

what are the lift/ duration specs. you'll prolly need a spring with about 125-140 lbs on the seat and around 300+ lbs open, this is a typical requirement for hyd. roller cams, start getting crazy w/ pressure like if it was a solid roller, and the lifters won't "keep up". hyd. cams are a beautiful thing but are ultimately limited by the fact that they are hyd. when they start to get BIG, ( and by that i mean bigger than what you're going to find in the typical turbo car), then its time to expensive lifters or just go solid.

 

[bison]

I used comp 941 springs with an installed height of 1.700. I think the seat pressure was around 145 lbs. The installed height is dependant on the spring for the most part.

 

[blown okie]

I used comp 941 springs with an installed height of 1.700. I think the seat pressure was around 145 lbs. The installed height is dependant on the spring for the most part.

one should get a spring that matches their installed height per the requirements of the engine/cam, one can adjust the installed height some by getting + & - height keepers, altering valve length, and if you cant find spring that will work by doing that then start cutting the head, trust me a book could be written on setting up head( wait i think several already have been), but dealing with it on a day to day basis it opens a whole world of understanding & complication of this subject.

 

[Mike Licht]

Put them in at the 1.725 and you will be fine.
Mike

 

[V6RACER]

Listen to Mike... My cam seems to work well.

 

[bison]

one should get a spring that matches their installed height per the requirements of the engine/cam, one can adjust the installed height some by getting + & - height keepers, altering valve length, and if you cant find spring that will work by doing that then start cutting the head, trust me a book could be written on setting up head( wait i think several already have been), but dealing with it on a day to day basis it opens a whole world of understanding & complication of this subject.

Yes. Had to use differnet keepers and a combnation of shims to get the correct installed heights at different times myself. The 941's rev to 6200 with no problem at the installed heights mentioned.