Originally Posted by CNC BLOCKS (Post 4511128)

I machine alot of lifter bores for lifter up grades to .904 and .937 rather then go to an .842 with bushing I would go to a .904 or .937.

I have seen about every lifter out there to size for lifter bores and to date ISKY .842 lifter are not .842 more like .8405 to .841 to put them in a .844 lifter bore and end up with .003 to .0035 oil clearance in not going make for a happy lifter. Same with Crower. There seems to be a lot of sizing issues that have never been addressed. The last set of bushed lifters had sizing issues and the Customer was not happy with their 1400.00 lifters.

Don't get me wrong ISKY makes a good lifter but having to buy 2 if not 3 sets to make up one set is not very cost effective.

Do a search on Yellow Bullet forum there is a lot threads about lifter sizing.

Comp Cams, ISKY and Crower and Jesel .841 lifters I have had to bush the lifter bores back and fit them to .0014 to .0019

Roller lifters like a controlled environment have oil clearance .003 to .0035 is not good.

Having alot of oil clearance with cost good HP because of extra unwanted bleed off.

Oil control is key to making HP
https://www.youtube.com/watch?v=SpfOKr3B3FA

There Does not seem to a standard when it comes to lifter sizing compared to OEM sizes

Originally Posted by getrdunn (Post 4511214)

I read .0020 for iron or brass and .0010 on aluminum and recommend to heat the block before use. Thought this came right off there site unless I misinterpreted it. So yes I'd say your right in there. Splitting hairs.

Originally Posted by Black Baja (Post 4511281)

It may seem like splitting hairs. But remember we are dealing with 16 lifters. So when you start looking at .0001x16= .0016 or .0002x16= .0032 or .0005x16= .008 The numbers start looking a little more interesting. Now let's say .001x16= .016 When you look at it like that and think of the leakage in the motor it really makes you think that it's worth splitting hairs in the lifter department. It's probably one of the most important clearances in the motor. Jesel recommends .0018-.0022 as I stated. We run them in the middle at .002. And we have found this works very well in the Marine environment. We have one motor that has 4 World Championships on it with the same Jesel lifters. Over .800" lift 6500rpm and every time the lifters are pulled for inspection they look like they have never been run... Should they be tighter? Based on our track record with them we will continue to run them where Jesel Rocomends. Now with that said we don't run everyone's lifters at those clearances.

Originally Posted by CNC BLOCKS (Post 4511320)

On the .904 lifters and the .937 I run them on the low side as with the bigger bore more bleed off.

I did this build years ago for Kjell Adams Drag boat set National and World records ran for four years and it was called the Swiss watch. That had the Morel .904 roller lifters, Machined the cam tunnel to 55MM.
http://www.performanceboats.com/gn7-...is-straub.html

Using .904 lifters with an .810 wheel and .937 lifters with a .850 wheel keeps the wheel speed down and less revolutions around the lobe compare to a lifter using a .750 wheel.

Jesel Roller lifters are my first choice second would be Morel. Morel and Jesel there sizing seems to be a lot better then other companies selling roller lifters.

Originally Posted by mike tkach (Post 4511331)

since we are splitting hairs,jessel wants .00188 to .00220.just saying.

Originally Posted by MILD THUNDER (Post 4511332)

Whats your thoughts on a .700 wheel in a .842 body

Originally Posted by Black Baja (Post 4511281)

It may seem like splitting hairs. But remember we are dealing with 16 lifters. So when you start looking at .0001x16= .0016 or .0002x16= .0032 or .0005x16= .008 The numbers start looking a little more interesting. Now let's say .001x16= .016 When you look at it like that and think of the leakage in the motor it really makes you think that it's worth splitting hairs in the lifter department. It's probably one of the most important clearances in the motor. Jesel recommends .0018-.0022 as I stated. We run them in the middle at .002. And we have found this works very well in the Marine environment. We have one motor that has 4 World Championships on it with the same Jesel lifters. Over .800" lift 6500rpm and every time the lifters are pulled for inspection they look like they have never been run... Should they be tighter? Based on our track record with them we will continue to run them where Jesel Rocomends. Now with that said we don't run everyone's lifters at those clearances.

Originally Posted by CNC BLOCKS (Post 4511360)

Going to bigger cam cores and bigger rollers effects pressure angle in a good way. Less pressure angle happier lifters!!

http://performancetechnician.com/pdf...a-Lifter-2.pdf


Here is an interesting article about lifter bore truing, Look on page 52 Also having the cam tunnel to blue print should be considered.

http://digital.enginebuildermag.com/...1-ae5dfcff4c38