Cam and Cap??

[6togo]

Well my hunt for a Stg2 off-center block is not doing well so i'm thinking about a 4.1 prod stroker build i hear good things about them on the street and track plus they seem to be able to dip in the 9's and stay together which is where i want to be!
Cam question is it worth messing with a billet roller or will a ductile do just fine?
Billet caps or a girdle seems most i chat with are doing just the caps but i want to make it a solid as possible?
What size cam would be nice in a 4.1 street motor in the 218/218 area? or a tad bigger due to the extra cubes?

 

[9SECV6]

Billet roller and a girdle others will chime in on cam selection but 9's you will have to push it a little now high 9's low ten it should last ( its in the tune ) and common sense

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[6togo]

High 9's are about the most i would push it and for the most part i will keep it turned down on the street!

 

[6togo]

Bump!

 

[Mike Licht]

With the new Ductile roller blanks the billet is a wastes of time and money. They can handle solid roller spring pressures and you never see them fail. With a billet you have all the expensive nose gear and the machine work
Mike

 

[bison]

With the new Ductile roller blanks the billet is a wastes of time and money. They can handle solid roller spring pressures and you never see them fail. With a billet you have all the expensive nose gear and the machine work
Mike

They may take the pressures of the springs and not have mechanical failure but the results of the analysis speaks for itself. Weve analyzed the same lobe on both billet and ductile cores many times and the results were not the same. This doenst mean that a ductile cam core is not the correct choice either. I sell both and i know the machine work to correctly setup a billet is a pain in the ass but in some instances its worth it.

 

[CGASTON]

They may take the pressures of the springs and not have mechanical failure but the results of the analysis speaks for itself. Weve analyzed the same lobe on both billet and ductile cores many times and the results were not the same. This doenst mean that a ductile cam core is not the correct choice either. I sell both and i know the machine work to correctly setup a billet is a pain in the ass but in some instances its worth it.

What were the results?

 

[Mike Licht]

Bison, I will not disagree with you as I have also plotted some of both. I will still say that for 99% of the guys here a ductile cam is a better way to go. There is a couple all out race applications where a billet would be a better choice but they a few and far between.

 

[bison]

What were the results?

The results were that the lobes ground on the billet cores had more intensity and were closer to actual catalog spec given a certain master compared to a ductile core. More intensity means less overlap and faster open/close. This is typically done by taking two lift points and looking at the number of crankshaft degrees of rotation between them. The less the number of degrees the more intense the cam is. When i look at the analysis i can tell right away which cam will have better drivability and potentially make more power. Ive seen some ductile cores that were very good and Ive actually had to send a couple back for re-grinding since the lobes wer a flat as a pancake compared to what it should be. Once i ordered an aggressive 214/214 (catalog spec) on a ductile core and the actual duration @.050 was 217.5 degrees and the open/close events were stretched quite a bit. On the same cam the duration at .200" was about 4 degrees less than catalog. That is a lot of variance on a cam. Comp was not able to explain why this variation occurs and why the consistency varies so much. But the cam analysis was much better on the re-grind. Commonly the duration at .050" is about the catalog spec and the loss @ .200" is a couple degrees when S master lobes are ground on Buick cam cores. As the open/close events spread out a few degrees its noticeable. Its unfortunate that almost everywhere the cams are referred to by their catalog duration @.050. Much more info is needed to get an accurate picture of what the lobe is capable of. The ones that are capable of making more power and having less overlap are going to require a lot more spring pressure because of the aggressive ramps.

 

[Mike Licht]

the 214/214 I put in my car is about the most aggressive they have, it is done on a ductile core it was a little over at .050 but less than one degree. it was about 1 1/2 degrees under at .200 from the catalog so your measurements are close to mine. We adjusted the grind accordingly and the results were more than acceptable. FYI A billet version measured about the same. There are limitations in the Buick lobe as you know. Comp knows perfectly well about this a why it happens, I have talked to them in depth about it, it happens to many different makes as the lobes are different sizes. They also know how to minimize it but it is a fact of life

 

[6togo]

How would a Billet hyd. roller with these specs work in a stroked 4.1 another member has it .519/.511 224/218 LS 112 probably be running around a 70mm turbo with ported aluminums?

 

[bison]

How would a Billet hyd. roller with these specs work in a stroked 4.1 another member has it .519/.511 224/218 LS 112 probably be running around a 70mm turbo with ported aluminums?

It would be a waste to grind that on a billet blank and the ex duration could be increased a lot more and show power if you had a large turbine. It could easily be re-ground but in another thread youre asking about heads and are wanting to use stock rocker arrangement on a ported aluminum head? You should re-think the weak stock rocker arm arrangement in favor of the 14 bolt head setup and run some aggressive springs and a cam that can give you some advantage.

 

[6togo]

No I did not say I planned on stock rockers I said those other heads were not setup for stock rockers. I plan to use a nice roller rocker setup when that time comes!

 

[bison]

No I did not say I planned on stock rockers I said those other heads were not setup for stock rockers. I plan to use a nice roller rocker setup when that time comes!

You are still limited if you run the factory style shaft. There is only 3 fasteners holding the shaft to the heads and the pedestals are failure prone with aggressive valvetrains. Ive seen many break. Ive machined them off and drilled/tapped for stronger rockers.

 

[6togo]

I understand and I will be using non shaft mounted rockers when that time comes I was just stating that about the ebay heads if anyone else was looking at them. I was never crazy about 3 Bolts holding the shaft not to mention In a alum. Tower!