Custom Ground Cams

[SappySE107]

6 deg adv on intake and 6 ret on exh rocks. It should have been stock. Idle is smooth...perfectly smooth, maybe smoother than stock (how it felt on teh test car). Power is much better, especially lower in the powerband. Im going to try it on my 5 speed car next.

[your_I.D.]

6 deg adv on intake and 6 ret on exh rocks. It should have been stock. Idle is smooth...perfectly smooth, maybe smoother than stock (how it felt on teh test car). Power is much better, especially lower in the powerband. Im going to try it on my 5 speed car next.

Right on!

Ben have you ever plugged in the exhaust cam numbers for the intake in Desktop Dyno?

[SappySE107]

Yeah, it hurts low end a little and helps out about 6 hp at 5000 RPM. 14 hp at 7000. Thats according to DD2k. Its only a few hp lost to 4000, then at 4k its 1 hp up. You can scale it from there.

[JJ77]

6 deg adv on intake and 6 ret on exh rocks. It should have been stock. Idle is smooth...perfectly smooth, maybe smoother than stock (how it felt on teh test car). Power is much better, especially lower in the powerband. Im going to try it on my 5 speed car next.

HELL YES, but should I still invest in the high stall

[SappySE107]

I don't really know. I didnt think there was any problem with the stocker with that cam timing, but I have no comparison with a higher stall being used either.

[fieromadman]

well we just timed my motor for the Fiero application with a manual and went half way between the 6 and 6 and the 13. We did a 1.5 degree advance on the intake and a 5 degree retard on the exhaust. It favors a little more on the exhaust because its in a lighter car with manual, but i still wanted a smoother idle and a little more bottom end than with the 13*. Im doing a gasket matched lower intake, new belt, ffp pulley, lower temp thermostat, and changing my exhaust drastically all at the same time, so i wont be able to tell you the exact results of it, but i should be able to get a good idea after i drive it some. Its still 13 crank degrees of overlap, so no matter what i should be gaining top end since im within the 6*&6* and the 13* settings.

[SappySE107]

Ok, the 1.5 and 5 are degreed at the cams, not the crank. Don't want anyone getting confused on this

[BlueShift]

Sappy - on the CHRFab regrind, they just grind and you need lash caps, correct? I snagged a set of cams from a 94' Cutlass yesterday at the JY and wanted to know what the deal is with getting ahold of the caps, how much it will cost, etc? Will the valve springs bind at W41 spec lift?

I'm thinking that down the road, I'm gonna pull my cam carriers and swap cams to CHRFab regrinds and put in a set of those light lifters while I'm at it. Now that would be cool.

[SappySE107]

stock springs will allow .430 lift, and thats all I know. I have ran .060 shims on stock cams which is how i know .430 is ok. Coil bind is obviously going to get close with that which is why I want to try out another set of springs on my car to see how they work out.

Lash caps, most likely though until you get them ground and check for lobe to lifter clearance. Ill have to look for some 7mm valve stem caps though as they would be what is needed to make up the difference, unless you want to shave the entire cam carrier and try it that way.

[your_I.D.]

Ben, i downloaded your 34DOHC...xls file. I was wondering if you ever tried those numbers with -6exh and +6int cam timing.

[SappySE107]

In desktop dyno? Yeah, ive tried a lot of stuff with that program and ill tell you right now its all crap. Its fun to play with but I don't take any of it too seriously.

[your_I.D.]

In desktop dyno? Yeah, ive tried a lot of stuff with that program and ill tell you right now its all crap. Its fun to play with but I don't take any of it too seriously.

I total understand. There is only one way to find out for sure. Thats on an engine or chassis dyno. The first way being the most accurate.

Will the w41 profile or Ben's lobe #'s fit are camshafts? How much lobe base has to be ground down?

[SappySE107]

have to talk to the regrinder as for how much material would have to be removed. We can go .480 without modifying the valve stem and seal, but finding springs to do that is another story. Probably looking at machining the seats on the heads to make something like that work. .430 is as far as I would go on stock springs, .450 might be possible with these other springs I have found though .430 is still what I would go with.

On a 97, no idea.

[Fierobsessed]

My personal opinion, and its just that, an opinion. .410" and no more. If you are getting close to coil bind, and the gains are already dropping off, and you are putting more stress on the valvetrain then usual, it might be time to call it quits due to diminishing returns. .410 isn't far from HUGE numbers like .5 or so that we usually leave to pushrod motors. Also with smaller valves like what this engine has, there is less lift required to reach the point where flow is dropping off. I still hold fast to my hypothesis that Quad 4 cam specs can give this engine a real kick in the ass. I suspect that there would be some low end loss though, but the high end would really be out there. I've been tossing around an idea to make my own cams for the 3.4 DOHC that will use old Quad 4 HO lobes, Cut them off bore them out, slip them over a hollow shaft, weld them in place... its a far fetched idea, but if it works would be an alternative to having to go crazy with the weld up regrinds, or the reduced base circle cams with lash caps.

Your id: .040" to hit W41 specs (thats the .410" Im talking about)

[Kohburn]

a lot of production cars are now using a similar method of cam production
they machine just the lobes then press them onto a tube then run a mandel through the tube to pinch it all together solid..

hollow cam

don't see any reason why someone could weld lobs onto a tube or rod to make custom cams..

maybe I should look into the cost of having a lobe profile extruded

then i could just chop lobes off the extruded stock, weld em onto a shaft and case harden them..