MTFCA Forum

I would like very much to talk to any one who is running a Prus high compression
head in combination with a Stipe cam.

Thanks,

Craig Bothwell
bothwell.craig@gmail.com

I have a Stipe 280, a 7 1/2 degree advanced cam gear and a Waukesha head (vastly improved combustion chamber but little additional compression...easy to crank)

My Impression: WOO HOO!

Whatever you do to increase the power, be sure not to lug the engine at low speeds. Remember that high speed torque does not put extra strain on the crank, however, low end torque puts the most strain on it. You didn't mention what you did to the crankshaft, but I would recommend a SCAT crank.
Norm

Kevin Prus’s heads are hard to beat, excellent balance in the chambers and get going and cruising very well.

Hank

I've run Pru, Z, and Reeder heads and the Prus gives the best performance of the three as well as better head gasket sealing surface area over the Z head. All run with a stock cam however.

Bruce,
Not trying to pick on anyone, just looking for information. Many model t owners who have a .280 cam in their engine claim the engine is stock. I just wondering if your cams are really .25 standard.
Art Mirtes

Does a 280 cam require stiffer valve springs?

Pat...no, they don't, but some blocks will require a quick countersink inside the block on the lifter bore to allow the lifter enough clearance to make the extra distance it will now travel.

I have run a.320 lift cam and I like stock T springs as the valves will float at about 4200 rpm. This way you have a built in “rev limiter”!
Yes the engine has a counterbalanced pressure oiled A crank and a high compression Sherman head.

Art,yes, my cams are bone stock and previously used. I'm really thinking about getting a new one, either stock , .270 or .280. Any recommendations? Bruce

Have Prus head and Stipe 280 cam in professionally rebuilt engine with a SCAT crank. Also and Ideal Timer(Kossor). Starts easy, runs like a dream in my '26 Touring. I like the combination so well I am building up another engine just like it for my '26 Tudor.

Perfect combination Kevin, built a few like that.

Hank

I have that same combo. Prus head, Scat crank but Chafin 280 cam and I timer. Great combo for sure. Good power, starts very well. I only have one issue. I rebuilt the coils using an ECCT and the magneto he’s putting out about 30 volts, but it runs way better on battery. It seems like you cannot get the proper timing on magneto. It wants to be between notches per se. if there’s a solution for that I am all ears.

I always joke with my friends that they should not call them a high performance cam. They should be considered a more performance cam. That’s always good for a laugh.

I wonder if your magneto has a poor internal ground or a poor connection somewhere in the system...

Brian,
Your problem could be the timer. On battery, you begin to build up the current in the coils when the rotor makes first contact and continues to spark until it ends contact with that segment. However on magneto, the peak voltage and current occurs when the magneto reaches the peak of the sine wave. So if your timer is not making good contact at that point you will misfire. And it is even possible that if the timer is set in certain positions, you could one coil firing more advanced than another.
Norm

I would check the ignition switch first.

Then try a non electronic timer.

Then a different set of coils known to be good. You might have a friend who could loan a set.

From there it could be the magneto.

Was the cam timing changed by 7 degrees like some people do?

Keep us informed on your progress. Wish you lived closer,
I like working on challenges that this. Except it reminds me of working, which was more than 21 years ago.

Art Mirtes

I am surprised by the I Timer being run off of the magneto. I thought they were only meant to be used powdered by the battery. Learn something new every day!

I have been driving T's all of my adult life. I would love to have one of Kevin's heads, but not until they are made of cast iron. I also run a Stipe cam. but wish he would make BOTH designs as Ford did. I now have an early cam in my '25, and a late cam in my '13. I don't feel like tearing the engines down just to have the correct looking cam in my cars!

RE: I-TIMER: Does the I-Timer run on Magneto?//////////////

Yes! Start on battery, Run on battery OR Magneto just like the stock timer

Can I get free starts using the I-Timer?

Yes! Same as a stock timer

Can I start on magneto using the I-Timer?

No, the I-Timer will not start on magneto ////////////// (Kosser I-Timer Website)

Larry
The first production run of Prus heads were cast iron. I bought then and have one. No it’s not for sale!