atb

Greg,

Is the 944 Turbo spring the same as the 944S2 spring?

Do you have any input on what kind of seat pressures you would like to see with the bigger cams (more than stock GT lift) in a 928 for a street application?

FlyingDog

subscribing...

BC

Other than the fact that this cam has larger bearings, its almost exactly like a Chevy cam. Simple, no sprockets, etc. Would would any cam shop not be able to grind it, with, as Jim morton has been nice enough to inform, specific understanding of the ramping nunbers, etc?

BC

The 944 turbo spring is the dual spring for the 2V heads. Its larger than the dual spring for the 4V 944S2 heads.

largecar379

I had made several calls to cam shops, and they all referred me to WebCam.






--Russ

BC

The Cam shop that Adam has graciously suggested is indeed viable. I called them today, just now.

The gentleman I spoke to seemed to be familiar with what I was asking for, and the price is as Adam suggested, as long as I can provide him information about how much "wiggle room" I actually can take up in these lifters. It was suggested that there is almost 2mm in the smaller more compact lifters in the 32V engines to add lift to the cam, and not have to change anything drastic in the lifter.

I want to find and confirm this same information for the 2V lifters. He said that as long as we know that, there should be some realistic room for improvement from grinding some base circle away and leveling this removal into the rest of the profile (just as Jim suggested).

So: Anyone know how much room we have in the lifters? I will see what Mike Ford knows since he just had some big bumpsticks made. I just want some more lift to possibly unshroud the larger valves in a euro head a bit more.

atb

Thanks for the clarification.

Glad that the call into Delta Camshaft went well. If you need someone local to to do any running around to help out with your cams, let me know.

RicerSchnitzzle

Question is the benefit of just reducing the base circle with out adding weld on a 16v Euro S cam? About $700 cheaper than a weld and grind giving close to same results. Changing the base on a Euro S 1mm, lift should go from .471" lift to .512", 1.5mm would net a .531 lift. I understand a straight grind, even with some profile blending, will result in greater lifter acceleration and decelleration and not be the most ideal solution. But for a couple hundred bucks I can have a couple extra sets lying around for rainy days.

Is my math wrong? Base circle reduction is added directly to lift as lobe pivot point is effectively moved, while cam center point is unchanged, right?

Over simplified, Over-exagerated version of what I'm thinking...

BC

The second pic is actually more like the original. Our cams are very very pointy. We don't have that smooth bull nose on the cam like the Chevy cams do. I think Hammer said why not, but I forgot.

Dennis Wilson

If you increase the lift without decreasing the base circle, you may not be able to get the cam into the cam housing.

Dennis

BC

The bearings are not affected Dennis.

Dennis Wilson

Brendan,

It isn't the bearings but the opening size for the bearings. If the lift is too high and the cam radius is larger than the radius of the bearing housing the cam can't be installed in the housing.

Dennis

BC

That would indeed be true if I was wanting to get some grinding done on the nose of the lobe, as Mike Ford did on the pelican forums (pics there). He reduced base circle AND had the cam welded, but had to remove the tip of the cam in the calculations because it was close or at the bearing diameter as you suggest.

If what I want works, it will only remove base circle, MAYBE with some work to the ramp area, and nothing to the nose of the cam, thereby not affecting the way it fits in the housing.

******

But I did have a thought - its expensive, but so is everything else in a Porsche - all that needs to be done to REALLY get a big stick in there is some longer valves with *more* (edit) installed height, stock or solid lifters, and boring new, larger bearings in the housing itself (like enlarging main holes in a block) and then adding diameter to each of the bearings. Or making a cam with every profil you want and bearings large enough to be larger in diameter than the cam lobes.

Is that cheaper than putting on a 4V head with super cams? Probably not, but its a cool idea.

Dennis Wilson

Brendan,

Agree about reducing the base circle to increase the lift. My comment was in reference to the second picture that showed the lift increased above the current radius. I should have been more explicit.

Concerning your thought, why not source thinner bearings and open up the bearing housing ports? That would give you more wiggle room and would be less likely to weaken the housing.

Dennis

BC

The bearings in all of my housings have BEEN the housings. So I was not aware of actual bearings, replaceable type, in the cam housings?