the new cam got here today. niiiice, prettty!
aHere is a list of the valve events, watcha think,Doug?
Intake opens: 34 BTDC
Intake closes: 66 ABDC
Intake centerline: 106
Exhaust opens: 76 BBDC
Exhaust closes: 28 ATDC
Exhaust centerline: 114
Lobe centers: 110 @ cam
duration: int-280, exh-284 (248/253 at .050)
overlap: 62
lobe lift: .339/.339
valve lift .508/.508 (with 1.5 rockers)
lash: .018/.020
seat pressure: 130-150 lbs.
open pressure: 330-350 lbs.
that is all i have, hope this helps you come to a conclusion! cant wait to install the thing.
the bad news is the weld on the pump drive neck on my convertor started to leak, i had to install my old stocker till i can get it fixed. can i just have a shop weld it, or does it need to come apart so nothing internal is damaged? i really dont want to ship it back to transmission specialties in pensylvania to have them fix it.
........chad

beardliz@msn.com

Good luck with da cam Putzie! I know ya donwanna here dis but ya better send the converter back to the builder. Just my opinion. Goomba


aschumers@aol.com

Well, Reminds me a little of the origional Hyper-Pak grind but with a lot more lift. (276º / 268º .430 lift, 44º overlap)

All that overlap is going to make for a lumpy idle but it should pull real strong from 3,000 RPM on up. I need to "plot-out" the different lobe centerlines and think about that a bit, 106 & 114 on the same cam...Uhmmm....
Well, the proof is in the running. How are you planning to install the unit, any advance or per the events above?? (or just split the overlap over TDCEx)?

CHECK THIS: Tell me if this cam has a .312 dia. hole drilled through the rear bearing journal, front to back. (Not the "cross-hole" used to get oil up to the rockers but one you can see looking at the back "face" of the rear journal. Any ideas on what that hole is for? (look at a "factory" cam)
DD

Yes, it has the hole drilled throught the rear journal, i have to double check, but i think i remember seeing the cross oil holes running into it. the grinder recomended setting it up at 106.(+4*) i may be wrong, will look closer after work.
i have a guy here (local) that is an excellent welder, says he can patch up the vertor real nice.???

beardliz@msn.com

Doug,
I would say that front to back hole in the cam shaft is to prevent oil pressure build up behind the end of the cam shaft. Think about it. If oil pressure were to build up there it would push the camshaft forward causing misalignment of timing chain, gears, and lobes. Plus oil pressure would blow out that plug in the back of the block causing you-know-what. Also I hope that hole does not intersect the other cross hole or the head / rocker shaft will never recieve any oil.


cfield@ll.net

no, the oil holes do not intersect, had to doublecheck. there is a small hole that runs across the cam from the "mystery hole" after looking at the "motor side" of the hole, methinks it is there for machining purposes (to hold or turn while grinding) there is also another "half hole" that is a bit larger in diameter, directly across from the smaller one. again, methinks for machining reasons. maybee someone call their grinder and get the facts?

beardliz@msn.com

Chad,

I'm with Goomba. Send the converter back and have an "alloy" or "CroMo" or high strength pump drive hub welded on. I have cracked two of the lower-buck hubs and I'll never go back. Spend the dough and it'll save you a buncha work.

Hope the cam really screams...

Lou

madsenl@caltech.edu

the pump drive neck itself is fine,(looks to be cromo;) ) it is the weld that was leaking. i e mailed and called transmission specialties (the "maker") and they are more than willing to fix or replace it, they are gona up the stall speed about 600 rpm while they are at it! the 90 day warranty includes one stall speed adjustment, and repair/replace any defect. sent the vertor off today. should be back by next weekend. gona hold off on installing the cam till then. from what i hear, the pump drive neck failure on chryslers is a common thing, and related to flex plate/runout in crank/vibration problems. the tranny guy is gona show me a trick to modify the flex plate and not have any more problems. let ya know what happens.....chad

beardliz@msn.com

You got it, we have been working on solving the cam / oil pump gear failure issue and this has come up on some of the surveys we sent out to racers. Everyone look at their aftermarket cams to be sure this "pressure relief" hole is there and large. (I have one cam with a pretty small hole).
Some front timing chain cam gears also have a second hole in them, I am now drilling ones that do not.
If anyone out there has ever had a SL6 oil pump / cam gear failure and did not get our data collection questionair, let me know and I will send you one.
DD

Cam Gear Failure Data Collection Sheet

Who's cam grind is this and what are their cam grind numbers? Are the valve events at 0.050" or at 0.020"? Was this grind based on a 0.904" lifter size? Looks very close to the COMP cam I ordered. The "cam card" had this info on it:
Lash: 0.018" both intake and exhaust
Duration @ 0.020": 274°I/284°E
Duration @ 0.050": 247°I/251°E
Timing @ 0.050":
Intake:opens: 15 BTDC closes: 51 ABDC
Exhaust:opens: 53 BBDC closes: 17 ATDC
Events based on 108° intake centerline with 108° lobe separation
Lobe Lift @ .345I/.355E (valve lift @ .5175I/.5325E @ zero lash)
Grind # CR6274-MP/284-MP @ 108° separation
Cam has been installed in the engine @ 108° centerline, and has no piston interference at all. Could maybe even go up on the rocker ratio to 1.6 and still have 0.85-0.90" clearance on the exhaust.

Based on what I have found, the cam grinders tend to use F### and GM# lifter diameter cam grinds on the Mopar cams even though the 0.904" lifter size allows us to use more aggressive timing events without incurring damage to the lifters and lobes. The COMP cam shown above is based on the Mopar lifter size, and it looks like the cam Chad's using was too. Any idea on how a mushroom lifter cam would work in a slant 6? Has anyone tried this yet? You could get some real fast lift rates yet keep the overall duration down with a big mushroom cam. Am I wrong, but would this make a better RV/Off-road type cam for torque?


sgw041454@aol.com

Doug I have two different brands of aftermarket cams that stripped oil pump gears. I just checked them both and they have large passages drilled thru the rear. So I am afraid that may not be the reason for the failures.
Thanks,
Ron

slantsixdart@aol.com

Thanks Ron,

We keep collecting data and Burnie has contacted some of his engineering friends to see if they have any ideas. I have a few gears we want to run some hardness tests on.

The thing that "stuck" with me is when you told us you could see your front cover / cam button move when you reved your engine.....even with a strap across it!?! We will keep working on this issue so anyone with info, send it in. (A link to the survey is in my last post).
DD