Thoughts From Stipe .290 Grind Cam Users

[ModelTWoods]

I'm looking for thoughts from Stipe .290 grind cam users. I have a new Stipe .290 cam and bought it to use in a 27 engine with a Scat stock stroke, undrilled crank, a Prus head, and improved carburetion. I have not decided on the carburetion, yet. I can go with a Model A intake and exhaust with either a Stromberg OE-1 or a Zenith Model B carb, OR a Model T standard or high volume intake with any one of several side draft accessory carburetors. The comments that I think I remember reading before, are: a slightly rough idle and a loss of torque at lower, usable engine RPM. I'm debating whether to 'back off' on the cam lift, as this engine is not going into a speedster, so if you are running, or have run a Stipe .290 cam, what's your experience.

[Joe Bell]

They do not do well in a Heavy sedan, much better in touring or roadster.

[BRENT in 10-uh-C]

They do not do well in a Heavy sedan, much better in touring or roadster.

Joe, I wonder if that 290 cam could be advanced some (-7½° +/-??) using the timing gear which theoretically should bring in more low end torque.

[ModelTWoods]

They do not do well in a Heavy sedan, much better in touring or roadster.

Joe, I wonder if that 290 cam could be advanced some (-7½° +/-??) using the timing gear which theoretically should bring in more low end torque.

Brent, I'd be interested in knowing that, also. The motor would be going in a coupe weighing 1851 (A roadster weighs 1645 and a fordor weighs 1994, by comparison, according to Ford)

[Mark Gregush]

That would be a good question to ask re the advance. Pretty sure Chaffins had that built in on thiers. With my huckster, stock engine/cam, that 7-1/2 really seemed to help overall.

[Mark Nunn]

I just need clarification. Does the 7 1/2 degree advance actually increase torque on the low end, not high RPM? I just installed a .280 reground cam and I'm concerned about low-RPM losses. I don't drive over 35 mph so I don't rev too high. I have not driven the car yet (maybe I'll have it back together by the weekend) and I don't know what to expect.

I also don't know who reground the cam or if a stock cam could have been ground with an advance. Dave confirmed that it was not one of Chaffin's regrinds. The cam came to me from a friend who got it from someone else so the origin is a mystery. If low-end losses are present in the hills that I drive in, I would install an advanced gear if you all believe it would help.

Sorry for the thread drift.

[George Mills]

Mark,

Others who have done it can provide numbers...but advancing the cam by that amount should move the peak torque down to about 22MPH (standard rear) from the factory claimed 25 MPH. In the process crunch all of the torque points at the lower RPM towards the lower speeds...so...the torque for acceleration occurs faster but I'm not all that sure it is a lot...but its a T, and it always seems a little helps a lot.

While there is a rob Peter to pay Paul on the over 22...it's not like gearing with its give and get being almost equal...you don't need a lot of torque at the 'cruising speeds' and the HP pretty much goes near flat at 35 mph and above, with torque falling off while it stays flat.

As to the other questions? The real secret is getting the darned thing to breathe better! The stock model T engine is only like 22-25% efficient on a thermo analysis. Get it to breathe better, by any means, is where the juice comes in across the board!

[ModelTWoods]

That would be a good question to ask re the advance. Pretty sure Chaffins had that built in on thiers. With my huckster, stock engine/cam, that 7-1/2 really seemed to help overall.

Mark, Both Chaffin's and Bill Stipe told me that advance was built in. I bought the Stipe cam, very soon after they introduced it, several years ago, and specifically asked Bill about advancing it. He said NO.

[Joe Bell]

Jack Putnam used the 290 in his Fordor and it fell on it's face in the hill climb, flat out it was great, but then there was not a high compression head on it?

[Jack Putnam, in Ohio]

Yes I HAD a 290 cam in my fordoor. Waukesha head, OF carb. Ruckstell rear end.
Put four people in the car and forget climbing any hills. Absolutely no low end. Great on the flat country, worthless in hill country. Ymmv

[BRENT in 10-uh-C]

Terry, while Bill and Mark likely designed the lobe's centerline by tightening it which affects the duration by allowing more fuel to enter, and it sometimes fools the engine into thinking it has more 'low end' compression than it actually does, but most of the aftermarket T cams are so much better so Volumetric Efficiency rarely is affected. An engine is just an air pump, and generally speaking for wherever there is a gain, there will be a trade-off somewhere else. By advancing the camshaft, all that is happening is affecting the RPM range that cam will work in. In your situation with your 290, advancing the camshaft will likely still provide a performance advantage over timing it straight up because it will move the optimum RPM efficiency range into a lower level. (i.e.: more pulling or lugging power).


Joe/Jack, do you feel like that 290 cam was affected by the low(er) compression ratio of the Ricardo head, and exacerbated by the slower airflow caused by the larger OF which potentially was causing the fuel to fall out of suspension at low-end speeds? My suspicions are that if Jack's engine would have been using a higher compression Reeder or Prus head where the VE would have increased at those slower RPMs, I suspect the sluggishness would not have been as noticeable on hills. I have always viewed the Ricardo heads as more of a 'power adder' head and not necessarily a performance head. The difference being that one is used singularly whereas performance is generally a group of components used together in conjunction to increase the engine's efficiency exponentially.

[CamMan]

I designed the 290 cam and run one in my Tudor. Forget lift. It's not nearly as important as valve timing. If you look at the timing you will see the intake duration is the same as stock but the intake is advanced about 5 degrees. Good lord, don't advance it another 7.5 degrees. The exhaust lobe timing is about the same as the Stipe 280. The net effect is better low end. If anything it may suffer a little on the high end. My sedan will still easily do over 50 mph and it is stock except for cam and high compression head. The problem with advancing a stock cam or the other Stipe cams is that it helps the intake but screws up the exhaust.

There is a lot of misinformation on this cam. Here is an earlier post - http://www.mtfca.com/discus/messages/82 ... 1538957294

[Tmooreheadf]

I messed up and put a 7.5 cam gear on an already advanced 280 cam. Had to use Ruckstell at every traffic light. Once it got wound up, it purred at 45 with a 3 to 1 rear end. Took the gear off and it ran pretty good with a z head, straight thru with distributor. Ran that way for 8 years before selling the car.