Hi...i realy want to know what is the difference between a two pieces real main seal and a one piece...is this only on 350 or on 305 too?? and...is it on roller bloc only??

Other question...Roller bloc mean that GM made stock roller lifter en rocker??? so many question to ask!!

Thnx alot

Patrick

 

The rear seals are just those. 1 and 2 pieces. THe 2 piece you put the top half in the block, install the crank and whatnot, and the lower half rests on that. Its just another place for oil to leak out of.

The 1 piece forms a complete ring around the rear of the crank. it is one less place for oil to leak out of.

As for the "roller block" designate, no it does not refer to the rockers being of roller design. It refers to the lifter type. roller means that there are little rollers on the end of the lifter that act as a bearing point and greatly reduce friction.

The roller tappet is on the left, flat tappet on the right. You can see the roller design of the lifter and how that "rolls" on the lobe.

As for your questons...just ask or do a search. or do a search, then ask

 

Thnx Stekman!! now i'm less stupid and i know about the roller lifter but...the block change if its roller??? or just the lifter..because i heard people say that he want a roller block....???

Thnx

 

The block needs to be made for the factory lifter retainer to use the factory roller lifters, hence "roller block".

 

The lifters on the left are roller and the ones on the right are flat tappet. You had that switched. Good pic.

 

Indeed i did mix those up, my error. Thanks for the correction shifty.



That is what was meant when he said the lifter valley was tapped in 3 places. As you can see the 3 places that are raised and tapped. Thats where the lifter retainer plate gest bolted down.


That is the other thing that designates a roller block. The cam retainer plate. That catches the little step on the nose of the cam and acts as a catch to prevent the cam from walking forward and thrusting against the timing cover. Obviously, the block would need to have 2 holes drilled and tapped in the front of it in order for that to be present.


Thats the 'roller cam' nose. Notice the stepped nose profile. That just centers itself inside the cam retainer plate. That retainer plate catches the step and prevents any forward motion that a roller cam may have. The other way that cam walk is prevented is with a cam button.

 

A BIG thanks to you guys that's the best answer that i can have!!!

Thnx

Patrick

 

you can however retrofit an older non-roller block to roller.

 

Yup. People do it all the time. The 400 block is very popular with modern stuff on it.

 

But if you do, be sure to ask yourself:

Does the price justify the performance gains? (everyone has their own answers to that)

 

It goes way beyond performace. Smooth idles, tons of cam selections for muit port set-ups, self allinging valve train, not having to adjust lash every other day, etc etc are just a few of the many advantages.

 

True. I have a solid roller setup. I dont have the luxury of all that lash stuff. But yes, generally the gains can offset the costs. But to some that are on a budget, they arent first upgrade on the list.

 

Now that I agree with.