Performance Boats Forum banner

stantard size roller lifters vs the .904

10K views 21 replies 10 participants last post by  1QuickCP 
#1 ·
is it worth the extra money to have the block bored?
 
#4 ·
My machinist charges me 275.00 to bore lifter bores if I already have the block in the machine.
A few things come to mind:
Pro's
In any situation, the .904 lifter is going to be more stable.
The larger wheel and axle are going to last longer.
The fresh mchine work gives you the opportunity to regain proper lifter/bore clearance if the block is worn.
Con's:
A set of Pro series .904 GS or Morels are 800.00. I think Crowers run about the same.
If you already have a cam, you'll change the cam profile with the larger wheel. The cam should match the lifter.
You might also need new pushrods.
 
#6 ·
800" lift, yes a .904" would be in your best interest. With the spring pressure required for that the larger lifter just gives you more load baring capability. You take a spring that is 750# open and multiply that by the rocker ratio you are seeing 1275#.
 
#7 ·
TX, is this a race piece?
.904 ceretainly are an advantage. The question is are they enough of an advantage for your application.

If it is a race piece... drag especially, .843 stuff is fine. I agree with CS on what he said. But is it necessary?

How many rpm will you be turning?

One advantage is you can step up on lobe profile, less roller speed, more stable, etc. Just like CS said.

Is it worth the money is the real question. If your budget has no limits, hell yes. Or save the extra cash and get a better block. Etc.
Give us info about your plan.

Oh, don't go put in a piece of crap .904 just cause they are bigger. Excellent .843's will be better than run of the mill .904's.

Why do you need an .800 lift cam?


Wags
 
#8 ·
i am building a 584 bbc.i just purchased a set of the brodix 18* pb1800.the block is a tall deck bowtie block with a kryptonight 4.375 stroke.im going to be getting oliver rods and maybe custom pistons unless i can find a off self piston.hoping to spin 7k out of it.
 
#21 ·
.903 are surely the way to go with the bigger body you have more surface area in the bore and the engines we have seen come back to be refreashened the lifter bores look great with no bushings.

With the bigger wheel on high pressure spring applications you won't see any tracking on the lobes compared to a .750 wheel.

The bigger wheel and axel make for a much more dependable lifter and won't milage out as fast as a smaller .842 or a .875 roller lifter.

On the blocks we machine for other companies and engine builders we like to have the lifter in hand to measure and fit and we have seen Crower, Isky, Jesel, Morel and PBM which is Morel.

One note on lifters there seems to be no standard size for the .903 lifters the Morels seem to run bery close to the flat tappet size and the Crowers and Isky's are appox .001 to .0015 smaller for some reason.

I love the ISKY lifters but is seems like we have to buy 2 sets to make up on set and there seems to a big differance in size from one lifter to another lifter.

One set varied from .9019 to .903 which is .0011 and they want .0016 to .002 clearance and we don't selective fit lifters. They should all be the same size and they should be checked for taper as well as one lifter had .0005 taper.

Lifter bores should have a honed finish only and not a reamed finish. And lifters have to be sized and fitted to the bores as there is to much of a variance between lifter companies on roller lifters.

Its funny on flat tappet lifters there seems to be a standard on sizing between companies.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top