Swift DB ring and pinion

[Ted and Nancy]

just finished installing a FT200 ring and pinion in the Staffs gear box. Should make for more reliable gear box. Also for club racing removed the oil pump and cooler. This same basic gear box ran in club racing for years as MK5 without oil pumps.

[Stan Clayton]

Hey Ted,

We have got to get together. As I am sure you know, Ren and I run a Staffs box in our Ralt, and I am interested in why you deleted the oil pump and cooler. Also, we are 2000+ miles into our current r&p, which is making our friend Craig Taylor nervous (though not us, as it is polished to a mirror with no signs of pitting).

Cheers, Stan

[Ted and Nancy]

Stan, the FT200, Mk5, MK8-9 and Staffs all use about the same size ring and pinion. I installed a FT200 ring and pinion in the staffs with out major changes. In our RT4 and March 77b CSR we used a FT 200 without pump and had no problems. Also in all the MK 5 series we did not use a pump. The problem with a gearbox driven pump is that even when the oil is cold it is sent to the cooler so warms up slower. In the transam cars that I have worked we did not tell the driver to turn on the pump until about 1/3 of the race. I think that if you really want a pump use an electric pump with a thermo switch. I don't think the pump is a lubrication issue but a temp issue for longer races. In the larger gearboxes for longer races a pump is necessary and gearbox driven is most reliable.

[Ted and Nancy]

Stan, I think that the surface condition of the gears in your box is not the issue but the number of times the the tooth has been flexed. I supect that the failure mode will be broken tooth that is eaten by the box. I spent 40 years at United Airlines as a maintinance controller so know that it is not the surface condition that counts but cycle time. With your background I am sure you know this also.

[Stan Clayton]

Yeah, I definitely hear ya about the cycles. OTOH, I have repeatedly read of folks going twice our distance on a Staffs r&p without any problems, claiming that there isn't enough torque in these engines to hurt the r&p gears. I honestly don't know the answer to that one.

Also, Craig has looked at ours (though the oil fill hole) periodically, and pronounced it good-to-go. He seems to be concentrating on its surface condition. Even so, I'd hate to find out the hard way... ;-(

Actually, we don't use a gearbox cooler. I retained the pump to run the oil though the filter mounted off the rear of the box. It also pressure-sprays oil onto the r&p mating surfaces.

Also, thanks for the tips about substitute parts. Maybe some of the r&p's from other boxes are cheaper than those specifically for the Staffs.

Stan

[Ted and Nancy]

Not much cheaper but more ratios. We use a very low 7-31 to the first gear small gear is bigger and more reliable. We also have a problem with getting a low enough 1st as our BD makes peak power at 11500+. I built a new layshaft for the FT200 and used top gears in 1st and 2nd. Planning to do the same with the staff's. The lay shaft is the same diameter and spline as the FT box!

[Charles Warner]

Hi Ted,

Wanna sell the oil pump unit from the FT? Which style is it? Also, I believe I have a new 7:31 F3A CWP (same as NST). That be of any use to you?

Thanks,

[Ted and Nancy]

The only pump I have is the one out of the Staff's sorry.

[Charles Warner]

Thanks, Ted. I must have misunderstood. By the way, if you are using the 7:31 with FT gears I have a ton of extremely high ratio FT upper gears for sale. If you need any let me know and I'll check exactly what I have.

[Craig Taylor]

Dear Stan, Charlie, Ted and all,

I just discovered the new Atlantic website. What a pleasant surprise! Great new way to share ideas.

On ring and pinion life: Generally a ring and pinion will pit before a tooth breaks, this being a property of 9310 steel. Howeve, with the newer finishing techniques (REM isotropic finsihing) the surface wear is reduced signifigantly, increasing the time to pitting. This might result in core failure prior to pitting. Ahsen Yelkin actually made 10,000 miles on his NST gearbox before failure. Of course, it failed in the morning warmup prior to thr Runoffs race!

We still recommend that the Staffs or NST ring and pinions be replaced at 2000 miles in a pro car, or 3000 miles in a National club car.

Renne drives Stan's car like a pro, so that's why I am nervous after 2000 miles.

[Stan Clayton]

Originally posted by Craig Taylor:
Renne drives Stan's car like a pro, so that's why I am nervous after 2000 miles.

Okay, Ren, you hear da man...start saving your pocket change.