A true S60 roller cam-now available-regrind or new billet!

[John B]

With the stock base circle you would use the same ammount of shim with the PT lifters as for a stock cam. To use less shim you would need to have a larger than stock base circle. For me, I would prefer a stock base circle to maintain the original valve train geometry. I wouldn't let the PT lifter be a show stopper; I've used PTs and stock and see no difference in performance.

[moparzrule]

I understand that, I was asking simon if his billets will be stock base circle. And I was also wondering how many shims stock lifters require with these regrind cams.

[John B]

We can kinda sorta guesstimate (yeah, I'm from the south...). A .450" lift (S1)takes a .041" shim, .467" lift (F2)takes .050" shim, so .499" (S60) should take somewhere around .060" shim. I guess. Sorta. I'm not sure how this works. An alternative is lash caps which I used to keep the PT lifters with my S1. The thinnest I found were .050", but due to the 1.66/1 rocker ratio, they had the effect of about .085" under the lifter, so I ended up with about .035" shim under the lifter. Whew! My head hurts. Lash caps add weight so I don't really like that approach (and they are not cheap!).

Before the subject drifts away, how much preload should there be between the cam lobe and the follower with the valve closed?

[turbovanman²]

Why can't you run PT lifters with a regrind???

The PT lifter is shorter, so with a stock cam, you need to run 2 shims to maintain some geometery. Regrinds, IE Tafts, require one more shim and they will work, but thats it. I have done it and 3 shims is doable.

This really sucks. Now I'm not sure about this cam, I really want to run PT lifters, and I don't have the money right now for a billet. How many shims do I need with the stock lifters?
Just out of curiosity, Simon would the billets here go off the stock base circle and be able to run with no shims or PT lifters with the normal shims?

The billets are the same as a stock cam so they not undersized so to speak. You would need 2 shims, the same as a stock cam.

Before the subject drifts away, how much preload should there be between the cam lobe and the follower with the valve closed?

Not sure, my rule of thumb, which hasn't let me down, is I lay the cam on top of the valve train, if the cam sits aprox a .25cent thickness of room between the cam and bearing journals, your fine. This is what stock is.

[moparzrule]

The PT lifter is shorter, so with a stock cam, you need to run 2 shims to maintain some geometery. Regrinds, IE Tafts, require one more shim and they will work, but thats it. I have done it and 3 shims is doable.
.

So 3 shims will work with your cams simon?

[turbovanman²]

So 3 shims will work with your cams simon?

I will double check with him and ask how many shims it will take if using stock lifters.

[Turbodave]

We can kinda sorta guesstimate (yeah, I'm from the south...). A .450" lift (S1)takes a .041" shim, .467" lift (F2)takes .050" shim, so .499" (S60) should take somewhere around .060" shim. I guess. Sorta. I'm not sure how this works. An alternative is lash caps which I used to keep the PT lifters with my S1. The thinnest I found were .050", but due to the 1.66/1 rocker ratio, they had the effect of about .085" under the lifter, so I ended up with about .035" shim under the lifter. Whew! My head hurts. Lash caps add weight so I don't really like that approach (and they are not cheap!).

Before the subject drifts away, how much preload should there be between the cam lobe and the follower with the valve closed?

John, what about a taller valve? I've got a set of MP big valves that are +1mm longer.

1mm is approx .039" x 1.66 = .065" So maybe a PT lifter with no shim and my taller valves would work in this situation?

[turbovanman²]

John, what about a taller valve? I've got a set of MP big valves that are +1mm longer.

1mm is approx .039" x 1.66 = .065" So maybe a PT lifter with no shim and my taller valves would work in this situation?

I've posted that before. I used swirl valves in a G-head and needed no shims,

[moparzrule]

Or what about Swirl valves in a G head? They are about 2mm longer, you would have to shim the valve springs though to get proper seat pressure.

[moparzrule]

Haha simon you beat me to it LOL.

[moparzrule]

So with the regrind, and swirl valves in a G head, you would still need 1 shim under the PT lifter correct?

[turbovanman²]

Ok, he won't know until he's ground one but he's sure it will be only one shim.

So, if using a PT lifters, a regrind cam, swirl valves in a G-head, worse case is 2 shims, and remember, 3 will work.

[moparzrule]

At this point I'm not sure whether I'll be using my G head or Swirl. I'm porting my own swirl head, depending on how well it comes out is whether I'll run it or not. But I do have a set of really nice turbo swirl valves I just took out of a low mileage head, doesn't even look like they need cut.
But as long as 3 shims is still good with the PT's, looks like it doesn't matter.

[John B]

Or what about Swirl valves in a G head? They are about 2mm longer, you would have to shim the valve springs though to get proper seat pressure.

Great idea! I wouldn't have thought of that. I have a swirl though, so I'll go with billet.

[glhs727]

we are currently testing a new lifter. These are almost identical to the stock lifter but are approx. 1mm longer so if you are using a regrind that requires shims, this will go in without having to use a shim. it has a large bleed hole on the top, and can withstand a lot more abuse and rpm than our other lifters. We have tried them on our drag car, w/o issue, but before we release them for sale, I'd like to try them in a couple of road race applications. If you know anyone running one of our regrinds and they have a motor that easily spins past 7K, we would like to talk to them.
Later,
Cindy

[turbovanman²]

we are currently testing a new lifter. These are almost identical to the stock lifter but are approx. 1mm longer so if you are using a regrind that requires shims, this will go in without having to use a shim. it has a large bleed hole on the top, and can withstand a lot more abuse and rpm than our other lifters. We have tried them on our drag car, w/o issue, but before we release them for sale, I'd like to try them in a couple of road race applications. If you know anyone running one of our regrinds and they have a motor that easily spins past 7K, we would like to talk to them.
Later,
Cindy

Way to go Cindy,

[turbovanman²]

Ok guys, last call, I want this cleaned up in a few weeks as I am leaving the TM scene.

[87glhs232]

WTF???

[turbovanman²]

WTF???

Nevermind, long story but I won't be around much anymore, need to refocus my life,

[87glhs232]

Nevermind, long story but I won't be around much anymore, need to refocus my life,

Well that's too bad for us.....good for you I hope.