tkg

My Feedback: (1)

The Bowman rings are made from a very fine grained iron. They have a very low expansion rate and require a very small gap, but there is a gap needed.

closetguy

My Feedback: (13)

can someone tell me how to get a hold of Bowman rings.for future rebuilds. also Tired Old Man you and i have more than one thing in common.i still have my 1969 shovelhead and a 1955 panhead.
one more thing i have never been able to get any ring in any type of cylinder to seal with out deglazing the bore first.

arobatx

505-327-0696

[email protected]

[email protected]

karolh

That 17x8 might be just a tad too much prop for the engine, I would try a 16x8 or a 17x6 and see how it goes.

Karol

Tired Old Man

My Feedback: (1)

Mine was a custom '68. Last of the pre-AMF Shovels... That Pan made me start drooling

pe reivers

If you have a chance, just kind of sneakingly fit an engine with a zero end gap ring and give it a carefull initial 5 minutes before you turn it loose.

As an apprentice, I did something like that once with a faulty injection fuel pump (the pump stuck up high in the bore when using light fuel because of too little plunger play) in our ships diesel when I was denied the experience I had gained at the engine factory. I was ordered to send the pump back to the shipyard for replacement. However, I corrected the pump, refitted it, and after 1000 hours of problemless operation on the seven seas I pointed their attention toward the "bad" pump number, and asked how it had performed, and who on earth had dared to put it in service again. [&:] No comment was given, and that was the last I heard of it.

closetguy

My Feedback: (13)

arobatx,THANK YOU!

hamman

My Feedback: (61)

I had Frank made me a couple of rings for engines that he had never done. I just give him the measurements of the cylinder and piston but I had to file the end gaps and his recommendation for the for the gap was .001 to .002. I made them .002 and they worked fine. Larry

togatoga

My Feedback: (42)

Take a look at the pic of the spe ring on the right and bowman on the left.Thats the gap difference. I think there's a little gap when the ring is fitted to the piston but definitely not as big as the original ring. Compression seems better. Its hard to change the gap as the ring ends are slotted for the notch in the piston.I think if frank designed it that way, it should be fine.
Material used seems to be different. I am happy so far with the results and if it takes another 3hrs to seat the ring , then I can expect improved performance!
Another thing i noticed is that the original ring was uneven in thickness- don't know if its because the cylinder is uneven?

pe reivers

This is not the gap we talk about. When relaxed, a smaller gap means that the ring has slightly less pressure against the cylinder wall in the lower part of the bore, and probably stays round better when compressed into the bore.
The gap we talk about here, is the end gap with the ring fitted into the bore.
Thickness can be radial (width) and/or axial (height). Radial thickness difference can be designed in to get the ring into contact with the bore better. Most of our model engines however would not have this feature.

Oilsands

So what are the benefits one can see or expect from changing to Bowman rings? I mean if both the original and Bowman rings are seated to the cylinder wall, what are the benefits on will notice between the two?