Cam Installation Sanity Check
Thread Starter
Racer
Joined: Jul 2007
Posts: 444
Likes: 0
From: Roselle IL
Cam Installation Sanity Check
I installed my Lunati camshaft this evening and it appears that it is offset by about .100" I assumed that the cam lobes should be centered on the lifters. Instead, the lobes are at the edge of the lifters. Can someone help me confirm that this is incorrect? Here is a picture with the cam pushed back with the gear fully against the block. I tested this with both the new and the old timing gear to be sure that wasn't the problem.
Thanks for your assistance.
Thanks for your assistance.
Thread Starter
Racer
Joined: Jul 2007
Posts: 444
Likes: 0
From: Roselle IL
No, but I confirmed that the timing gear is inline with the crank gear when the cam gear is just a few thousands from touching the block. I was under impression that the cam gear would spend most of it's time touching the block, as the .002 taper and the oil pump resistance pull it back that way. Is that correct?
EDIT: Ok, I put the timing chain on and it still looks lined up when the gear is against the block. However, when I pull forward on the cam, it will slide out almost until the lobe reaches the opposite side of the lifter. I guess this explains why it is lined up like this.
Please advise here.
EDIT: Ok, I put the timing chain on and it still looks lined up when the gear is against the block. However, when I pull forward on the cam, it will slide out almost until the lobe reaches the opposite side of the lifter. I guess this explains why it is lined up like this.
Please advise here.
Last edited by lr172; Apr 15, 2008 at 10:57 PM.
Le Mans Master
Joined: Mar 2004
Posts: 7,493
Likes: 1,502
From: Little Rock AR
Flat tappet lobes are not flat, they have a pitch from front to back. This helps to keep the cam pushing back when running. The valvespring force pushes the lifters down and the pitch on the lobes will push the cam to the rear of the engine. The timing gear/chain will stop it from going back too far and helpd to locate it. The lifters have a 1 degree convex surface that rides on the pitched lobes. This is what causes the lifters to rotate in the bores as the cam turns.
Lobes on a roller cam are totaly different. They need to line up with the lifter bores perfectly. They have no pitch from front to back. The roller cam also requires some method to locate the cam and prevent it from moving forward in the block so you need to add a button spacer or a bearing to the front of the timing gear area to prevent the cam from walking forward. These are also a good idea if you run a gear drive rather than a timing chain setup.
Sorry if this was too long.
-Mark.
Lobes on a roller cam are totaly different. They need to line up with the lifter bores perfectly. They have no pitch from front to back. The roller cam also requires some method to locate the cam and prevent it from moving forward in the block so you need to add a button spacer or a bearing to the front of the timing gear area to prevent the cam from walking forward. These are also a good idea if you run a gear drive rather than a timing chain setup.
Sorry if this was too long.
-Mark.
