mr slow

I just got my 408 short block back from the machine shop and started putting it together and started having an issue with the cam gear. The motor turns freely before instaling the timing set but after I install the timing set and torque it to spec the motor will not turn over. (I have the comp double roller set) Just wondering if anyone else has had a simular issue, and what you did to correct it, any help would be greatly appreciated, thanks guys.

mr slow

I think have come to the conclusion that one of two things are happening, 1)the inside shoulder of the cam gear where the torrington bearing sits is rubing on the cam retaining plate or 2)the cam is sucked up against the back of the retaining plate not allowing it to turn.

S10xGN

iTrader: (11)

Can't remember exactly, but there was a thread a year or so back about certain bolts being too long and causing interference when tightened, if the correct bolts were mistakenly used somewhere else... Have you tried just the gear w/o the chain? Or turning the cam with just the retainer plate installed?

mr slow

I have thought of the head of the stock bolts on the retaining plate sticking out too far and rubing the back of the cam gear but there are no marks on the back of the gear and I can see through the holes on the cam hear and can see that the bolts are not touching close but not touching. Yes sir I have tried without the chain and the cam will not turn.

S10xGN

iTrader: (11)

Just the bare cam without lifters and pushrods? Can you turn the cam without the retainer plate? If so, it would have to be something in the retainer plate area. If not, the cam bearings...

01 blue ss

iTrader: (2)

I had a 416 built and my engine builder had tried to use clevite cam bearings and the cam would seize up trying to go in. I swapped in durabond cam bearings and it slipped in like butter.

LS1MCSS

iTrader: (18)

Just to be sure, you might wannt to get the new style retainer plate. It uses flat head bolts, that come with the plate.

willyfastz

http://www.progearweb.com/4000/pg4210.htm

87silverbullet

iTrader: (11)

^^^ What is that supposed to do. His cam is seizing up, nothing is wrong with the timing chain itself.

willyfastz

My bad I read all but the last sentence. Looks like cam bearings.

willyfastz

I also read his first two post and he thought it was something with the dual roller timing set.

willyfastz

Pull the cam out, then start putting it back it. Turn it each time it goes in a cam bearing. You should be able to tell which bearing is bad when you get to the one that doesn't allow it to turn freely anymore.

mr slow

Sorry guys I have been working my a** off, thanks for the help. I didn't have any issues putting the cam in and then after the cam is in it has no problem turning freely, only until I tighten down the cam gear to the cam and then the cam will it not turn, is there any difference between retaining plates from different year motors?

mr slow

Its prolly just operator error lol

3rdCoastPowerSports

iTrader: (5)

the older retaining plates used non counter sunk bolts, the new retaining plates are countersunk and use countersunk bolts.

blacknyellow

iTrader: (3)

If the cam is in and turns freely and smoothly without the chain installed then the cam bearings aren't the problem. I would say you have the wrong retainer plate and cam gear setup. If it does not turn freely with the cam gear and retainer installed and the chain off the gear then there is simply something not right with your cam gear and retainer.

mr slow

Yes I have narrowed it down to the cam gear and the retaining plate, nothing is wrong with the cam bearings, I was worried about the bearing on the back of the cam gear getting in a bind against the retaining plate not allowing it to move. I was just seeing if anyone had a simular issue, I will have to tryusing a retaining plate from a newer motor with countersuck bolts, because right now I'm using a plate from a 5.3 I had laying around.

mr slow

I figured it out, thanks for all your help guys

G Engines

I have had this issue mine turned out the cam gear was milled to deep. I have had this more than once.

blacknyellow

iTrader: (3)

Good job, what was the solution? different cam gear? retainer plate?