heres my question.


i have a solid roller cam with the necked down nose, ment to be a replacement cam for a roller block. it has the necked down nose for the retaining plate.

im putting into a 400 small block chevy. now i know i need a roller timing chain because the cam gear bolt pattern is diffrent.
and i know i need my thrust button to keep it from walking forward.


reading online, i see some people mention a "spacer" that covers where the old retaining plate goes.

why would this be needed? as i see it, the thrust button keeps the cam from going forward, and the rear of the block keeps it from going backward... if i put a spacer there what would it do??

 

There is no "rear of the block". If the can gear wasn't on the cam, the cam would be able to go all the way right through the block, knock the plug out of the back of its bore, and continue on through the transmission.

The thing that retains the cam from going rearward is the thrust surface on the rear of the cam gear running into the thrust surface on the front of the block. Or, in the case of the stupid factory roller system, it's the modified rear surface of the cam gear, running into the extra added retainer plate piece, which is bolted onto the modified block.

The problem with the factory's stupid design, is that the cam gear is a different thickness (thinner) to make up for that extra piece they put in their roller system. So, if you use that gear but don't use the retainer plate, the cam will sit too far back in the block, by the thickness of the retainer plate.

So you need a spacer of the same thickness as the retainer when assembling that combo of parts.

AFAIK, both of the factory's retainer plates (as if using a redesigning the whole thing to use a retainer plate wasn't stupid enough in the first place, they actually redesigned both the block and the retainer plate at some point to change the spacing between the 2 screws that hold the retainer plate to the block) are the same thickness.

 

ahhhhhhhhhh. gotcha.

well ****.

id have to look at my motor to see, but i guess im going to have to find someone with a lathe and get a piece of steel turned down to the proper size...
or perhaps i'll just get a retainer plate, and have that turned so the "ears are cut off... that way when it spins, its round, and therefore, somewhat balanced.


if i just slip my retainer plate spacer in before i put the cam gear on, will that work?

 

edit: double post.

 

actually, should i make the spacer the same as the stock plate, or do i need to take some kind of measurement and make a custom thickness spacer?

 

It looks to me like if you took a stock spacer plate and ground the ears off, it might be OK. I'm not real sure whether its rear surface is set up to be a moving part, rubbing against the block, though.

Another possibility, if you have access to machine tools, is to measure the thickness of the stock plate, and measure a Torrington thrust bearing for it ("block protector"), such as you can get from Comp or Crower and elsewhere, and cut the difference out of the cam gear. Seems like you could come up with something superior that way.

 

im kinda wondering if theres enough meat in the block of that area to drill and tap some kind of hole and make my own plate.

it may not have the ears where the stock one is, but it wont spin..

then i can see about putting a thrust bearing on the surface....


main problems being, the bottom end is already assmbled.. so no major machine work is possible, and i dont have direct access to shop tools, so any custom machine work is pricy at the moment