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-   -   Custom Piston Rings (http://www.rcuniverse.com/forum/engine-conversions-92/9107979-custom-piston-rings.html)

Frank C. Bowman 09-19-2009 02:08 PM

Custom Piston Rings
I was asked by a customer to leave information in this section of RCU Forums. I have been a machinest all my working life and making Custon Piston Rings for approx. 12+ years for Gas, Glow and diesel engines, some motorcycles too. With my custom rings, performance will improve over nearly all factory rings because of the material I use, machining method I use and Ring gap I recomend with my rings. I use fine grained cast iron machined from solid round bar stock rough cut on OD to .010 oversized and finished with a .002 finish cut on OD for accuracy. OD of ring is cylinder bore to assure ring fit is correct and round rather than making ring larger than bore and shinking oversized ring after saw cut into smaller bore. Rings are then hand lapped to .001 smaller than piston ring land. I don't saw cut ring, I have a special tool that snaps ring before heat treat at 850+ degrees F. After heat treating on mandrels I gap ring to .001 to .002 end gap. Rule of thumb in machinest world on cast iron rings is .001 to .0015 ring gap per 1" bore diameter. I make bore gage to .0001 of cylinder bore to gap rings & ship all over the world. I make over 300+ rings and to date made thousands with a lot of happy customers. There is a lot more involved in my manufacturing process along with a lot of tooling involved, too much to discuss here. If I don't currently have dimensions to make rings for certain engines a lot of customers send the piston & cylinder to me to measure for rings & I install rings for no extra charge. I make special rings for 30 CC Homelite & 31 CC Ryobi engines that require a slight mod. of cutting anti rotation pin in ring groove down 1/2 way so my custom rings will overlap pin for much improved performance. Most rings for Gase engines $10 ea. shipped to most countries & US at $14 for 1 & $24 for 2 shipped. Discounts of $1 off per ring on orders of 10 or more mixed sizes & Brands fine. I have been endorsed many times by engine builders like Clarence Lee, Joe Wagner in magazines, etc. Email me if you have additional questions and a list of custom rings that I currently have in stock. Thanks & God Bless all. Frank Bowman at Bowman Rings. Email: ringmaster46@msn.com

balsa brain 09-19-2009 03:36 PM

RE: Custom Piston Rings
Just sent you an email Frank.



Ralphbf 09-19-2009 03:39 PM

RE: Custom Piston Rings
I'm so glad I asked.

I know that Bowman rings make a big difference over perfectly good stock rings.

He even made a set of rings for me that fit a Tamper.
That's a engine powered pogo stick with a big foot for compacting the earth.
It was so old parts were no longer available.
I sent him the cylinder and piston and he did the rest.

Frank; There was a discussion about your rings in a Stihl 066.
How would your rings compare to the stock rings?

Would they be able to with stand the large exhaust port?

As you know that is the trouble spot on most 2 stroke engines.

Frank C. Bowman 09-19-2009 03:55 PM

RE: Custom Piston Rings
Hello Ralph, My rings should be better than original factory because when I make them I heattreat rings with lower tension. This is because my rings are round and I don't need to put a lot of tension to seat ring because it is round. Factory rings have more tension to seat ring, but also wears them out sooner and heats engine more. Where I'm going is with less tension larger port not much of a problem as long as rings are pinned so ring gap doesn't go into open port window. Remember less tension, less heat & ring lasts longer with less chance of over heating. At present time I have rings for Stihl: 028 44CC, 25.4 CC, Super 045, 57CC, MS 440. Great engines with lots of power. Hope that answers question. Hope you got my Piston Ring List Bill, if not email me again as computer returned some of you emails. Thanks Frank

balsa brain 09-19-2009 04:05 PM

RE: Custom Piston Rings
Will do Frank. I may have to adjust my settings.


Ralphbf 09-19-2009 04:31 PM

RE: Custom Piston Rings

Is there a link you could post so people who wanted it could just go there and view it?

I know I'd like a list.

Thank you


w8ye 09-19-2009 04:37 PM

RE: Custom Piston Rings
Frank Bowman's stock list. You can order these as stock without sending him cylinder and piston

Ace Twin .64

Aircom M61 (pin)

Anderson Spitfire .65

Air-O .45

Asp .52 4C, .61, .80 4/C, .91 4/C

Atomic 60

Atwood .49, .51, .63

Avistar .60 (pin)

Bantam .16

Bat .19

Berilli 36 CC (Pin)

BME 3.5 (Pin)

Brison 2.4 (pin), 3.2 (pin)

Brown Jr. .60 cylinder sizes vary (send Piston & cylinder for proper fit & correct ring)

Brownie .29

Bushwacker 37.7 CC (pin) Sears

Bunch .45, .49

Cameron .15, .19

Cave Cobra

Cleveland Tom Thumb .45

Como .29 (pin), .40, .51 (pin), .90 (pin)

Contestor D.60

CRRC Pro 45 CC (pin)

Cub Cadet 25CC (pin)

DL 50 CC (pin)

DME 100 Twin (pin)

Dooling .29, .61, Yellow Jacket

DZY 48 CC Twin (Pin)

Echo 16CC (pin), 21CC (pin), 21.2 CC (pin), 23.6 (pin), 24.4 CC (pin), 30 CC (pin), CS-3000 (pin), 50 CC (pin)

Edco Sky Devil .64 Old or New (RJL) state which one?

Enya 3.5 (pin), .30 SS (pin), .35 X (pin), .40 X Dykes (pin), .40 Dykes model 6002, .45, .45SS (pin), .46 4C,.49 X (pin), 50SS (pin), .53 4/C, .60 4C, .60 X (pin), .60 standard, .80 X (pin), .80 4C, .90 4C, 120 R 4C, 1.55 4C, 240 4C Twin

ETA .29

Forster .29, .31, .88, .99

Fox 36 Sand Cast (pin), .40 Sch., .45, .50, .59 .047 thick ring only, .59 long shaft Ign., .60 Blue Head, .60 Eagle, Fox Hawk

Red Head .60 (pin), .74, .78, 120 Twin (pin)

GMS .61 (pin), .76 Dykes (pin)

Hassad Blue Streak .64

HB .21 Dykes, .40 PDP Dykes, .50 Dykes, .61 (pin), .61 Dykes

Hiller (Car)

Hirobo 36 (pin)

Homelite 25 CC, 30 CC (pin) old .060 thick , 30 CC newer .030 thick, 33 CC (pin), 38 CC (pin), 40.6 CC Super EZ Chain Saw, 45 CC (pin), 50 CC (pin)

Horner 3.7 Twin (pin)

Hornet .19, .60

Howler .60 (pin)

HP .21 4/C Dykes ,.40 (pin) ,.61 R.I. Silver Star (pin), .61 Dykes (pin) Blk Case Gold Hd.

Irvine .40 Pylon Dykes & Standard, .61 Dykes, .25 Dykes.

Kavan MK 50

KDC Kioritz 21.2 CC (pin), 23.6, 25 CC (pin), 30 CC (pin), 58 CC (pin)

K&B .35 Dykes, .40 Dykes, .40 S Dykes (pin), .61, .61 Dykes (Lee Custom), 1.35 (pin), 1.5 (pin)

Kometa 29

Kraft .61 (pin)

Kratmo 10 CC, 4A Ignition

Laser 61 4/C

Lewis 60

Magnum .53 XL 4C, .61 XL (pin), .91 XL 4C

Maloney 100 (pin), 125 (pin)

McCoy .09, .19, .19 Dykes B.H., .21 Dykes Car, .29 all versions, .29 Dykes B.H., .35 Dykes B.H., .36, .40 Dykes B.H., .49, .55, .60

McCulloch 21 CC (pin), 25 CC (pin) MDB 90 Leaf Blower, 28 CC, 32 CC (pin),

MDL 28 CC (pin)

MDS .78 (pin), 1.48 (pin), 2.18 (pin)

Merco .40, .49, .49 Dykes, .50, .61, .61 Dykes

Moki M .51 (pin), .61 (pin), 1.20 (pin), 1.35 (pin), 1.50 (pin), 1.80 (pin), 2.10 (pin)

O&R Industrial Motor 1 HP

OPS Maxi .30 (pin)

OS .20 FS 4C, .26 4C, .28 FH Dykes (pin), .32 (pin), .37 H (pin), .40 H Dykes & Standard, .40 H (P) Pylon, .40 FS 4C, .40 SR (pin), .807 bore, .40 FSR .835 Bore, .40SR Dykes, .45 (pin), .45 Dykes (pin),

.45 RSR Dykes, .46 Dykes (pin), .46FX (pin), .46SF (pin), .48 Surpass, Max .50 old, .50 FSR Dykes (pin) ,.50 H (pin), .50 SX & SXH (pin), Surpass .52 4C, .58, Max-H .60 FGR .60 4C, .60FSR (pin) .9445 Bore - older or SF .9055 Bore, .61 FS 4C, .61 SX & SXH (pin), .65 (pin), .70 & .75 Surpass, .80 H,.80 Dykes (pin), .90 & .91 4C, .90 & .91 Glow, .91 FX (pin), .91 SX H (pin), 1.08 (pin), 120 4C, 160 FX (pin), BGX-1 3500 (pin)

Poulan 42 CC (pin), 42 CC Wildthing (pin), 46 CC (pin), 54 CC (pin), 60 CC (pin)

Profi .40 (pin), .61 (pin), .76 (pin)

Quadra 35 CC , 40 CC (pin), 42 CC (pin), 50 CC (pin), 150 Twin (pin)

RSC 1.40 (pin)

Ross .60 Dykes (pin), .60 opposed twin Dykes (pin), .61 (pin)

Rossi Speed .60 old, .60 (pin) .021, .61 (pin) .023, .65 (pin) .0235

Ryobi 26 mm Bore EJ 100 (pin), 31CC (pin) older .064 thick, 31 CC (pin) newer .047 thick

Saito .40 4C, FA .45 4C, FA .50 4C, FA .60 T 4C Twin, FA .65 4C, 72 4/C, FA .80, .91 4C, 120 4C,130 TD 4C Twin, 150 4C, 300 4C Twin

Sachs 2.0 (pin)

Scott Thunderbird

Shindiawa 33 CC (pin)

Skil chainsaw (pin)

Sky Chief .53

Spe 25.4 (pin), 40CC (pin), 45CC (pin)

Stihl 25.4 (pin), 028 Chain Saw 44 CC (pin), Super 45 (pin), 57 CC (pin), MS 440 Chainsaw 70 CC (pin)

Super Tigre .19, X.25, S .29 (pin), G21.29 old, .34 (pin), .40 Bullring, S.40 (pin), G21.40 std., G21 .40 Dykes, G21.46 std. ,S.45 (pin), V.45, X.45 (Pin), G21 .46 wide Dykes, .46 Bullring, G.46, G .46 Bullring, V 51, G51 (pin) Italian, G51 (pin) China, V.56, V.56 Dykes, V 60 light case .044 or .047 top to bottom measurement, G24 60 Old, G 60 Bluehead, X60 (pin), V.60 wide & narrow Dykes, S.61 (pin), G.71, S.75 (pin), .90 (pin), 2000 (pin), 2300 (pin), 2500 (pin), 3000 (pin) Italian, 3000 (pin) China, 3250 (pin), 4500 (pin)

Syncro B-30, Syncro ACE, Syncro ACE Special

Tartan 1.34 (pin), Twin .77 (pin)

Technipower 7 Cylinder radial

3MM 53 TOC (pin)

3W 80 CC Boxer Twin (pin)

Thunder Tiger .39 (pin), Pro .50 H (pin), .54 4C, .91 FS 4C, 120 Pro (pin)

Ueda .45, .61

US 25 CC (pin)

Vlvatam 5 CC

Veco .50 Dykes, .61, .61 Dykes

Vega 10CC

Webra 10 ccm, 6.5 (pin), .40, .40 (pin), .40 Dykes (pin), .50 Dykes (pin), .61, .61 (pin),

Speed .61 FS (pin), Speed .61 F Dykes (pin), T480 4C, .91 (pin), .120 Dykes (pin), T 4.90

Weedeater (pin) 1.380 Bore, 22 CC (pin)

Weedwacker (pin)

Westbury Atom III

YS .61 Long Stroke (pin), .63 4/C, .80 H (pin) 2C, F.91 AC 4C, .91 2C (pin), F120 4C

YW 24CC single & 48CC Twin (pin)

Zenoah G20 (Pin), G23 (pin), G26 (pin), G38 (pin), G45 (pin), G62 (pin)

aerowoof 09-19-2009 05:36 PM

RE: Custom Piston Rings
Do you have any recomendations on removing stuck/seized rings so as not to damage piston and groove?

Nosedragger 09-19-2009 05:50 PM

RE: Custom Piston Rings
What about chrome?
Barrel faced and dykes?

Frank C. Bowman 09-19-2009 06:26 PM

RE: Custom Piston Rings
Heat Piston with propane torch & find ring gap to pry on ring halves. Once ring starts to pry out put oil under ring and repete process. Light oil works best, be careful if piston gets too hot oil will ignite and catch on fire. If ring is stuck and gap is over .003 replace ring as power is slipping past wide ring gap.

Frank C. Bowman 09-19-2009 06:29 PM

RE: Custom Piston Rings
My rings work fine in chromed cylinders if that is what you are asking. I make dykes rings for pistons machined for dykes. Again low tension and they last longer than conventional rings.

Nosedragger 09-19-2009 06:50 PM

RE: Custom Piston Rings
No,not chrome bore, chrome faced piston ring.

nitro joe 09-19-2009 07:50 PM

RE: Custom Piston Rings
Mr. Bowman
It's nice to see a true artisan posting in the forum.
It would be nice to read your thoughts in here more often!
Oh,and please don't feed the trolls...:eek:

av8tor1977 09-19-2009 08:40 PM

RE: Custom Piston Rings
I've been using Frank's rings in all my engines for several years now. They flat work and work well. It is now a normal step in the conversion of any engine I do to install one of Frank's rings.

BTW= His service is first class as well.


Flathead 09-19-2009 09:07 PM

RE: Custom Piston Rings
Thanks Frank for making yourself known. If Frank can't help you, you just as well forget your project. I talked to him today because he called me to check on what I needed for sure. He ships fast and gets you back running soon. I use nothing else but "BOWMAN RINGS"
Give him a try, you wont be sorry! Flathead 4

Ralphbf 09-19-2009 09:09 PM

RE: Custom Piston Rings

ORIGINAL: nitro joe

Mr. Bowman
It's nice to see a true artisan posting in the forum.
It would be nice to read your thoughts in here more often!
Oh,and please don't feed the trolls...:eek:

For some reason the "Oh,and please don't feed the trolls..." was pretty funny.

I would think chrome-moly on chrome may not be the best thing.

Cast iron rings that fit properly would give a much better and faster seal plus they would not really wear on the cylinder.

$12.00 rings verses $200.00 OEM cylinder.

But I am interested in hearing from the Master.

Nosedragger 09-19-2009 10:15 PM

RE: Custom Piston Rings

I would think chrome-moly on chrome may not be the best thing.

Cast iron rings that fit properly would give a much better and faster seal plus they would not really wear on the cylinder.

You don't know the details of the application, making assumptions like that causes confusion. I am asking a simply question about what is available.

"$12.00 rings verses $200.00 OEM cylinder. " Yes thats a real concern, it is a real issue with rings dropping into wide exhaust ports.


Ralphbf 09-19-2009 11:36 PM

RE: Custom Piston Rings

Frank C. Bowman 09-20-2009 07:49 AM

RE: Custom Piston Rings
Thank you asking, I only make Precision low tension fine grained Cast Iron compression Piston Rings. My standard rings are $10 ea, not $12 up to 2" diameter bore. The shipping, padded envelope, etc is $4 per order. I do not have chrome faced or chrome rings. The chrome is for wear factors but my low tension rings don't wear or heat engines as high tension cast or chrome rings would do. Normally I don't have much time to sit at this computer to post on different sites as I'm always working & find little extra time outside of making rings, working at my church, & some fishing & flying. Thank you very much RCU for your great site and all my customers for your patronage, God Bless all. Frank

Nosedragger 09-20-2009 09:04 AM

RE: Custom Piston Rings
Thanks for the info.I'm sure we will find a supplier who make rings to our specifications.

tony0707 09-20-2009 03:41 PM

RE: Custom Piston Rings

captinjohn 09-21-2009 09:14 AM

RE: Custom Piston Rings
Franks piston rings worked great for us. My friend bought a few Webra 1.20 engines, new. They use the dykes type of ring. One of his engines never did develop the compression the others did. We installed one of Franks rings and wow did it make a big difference. It had more compression even before we started it. That engine will hand start now real good, and has very good power. How many Webras 1.20 engine will hand start good??? If you know how to tune a engine right....you will have less problems with rings in the first place...just a general observation! Capt,n;)

Ralphbf 09-25-2009 04:17 PM

RE: Custom Piston Rings
Hi Frank

One last question .... well maybe.

With 2 ring pistons, someone stated that they run your ring on top and the factory ring on the bottom groove.

Is there a down side to running your rings in both grooves.

There is such a thing as too much of a good thing.

Thanks Again

Frank C. Bowman 09-25-2009 06:42 PM

RE: Custom Piston Rings
Hello Ralph, With my tighter ring gap that is the norm if you just want to buy 1 of my rings put it in the top groove. For almost no other advantage except possibly slightly less heat just use my ring in top groove & eliminate bottom ring. My low tension rings in both grooves best and will probably take a little longer before rings need replacing. Take care & God Bless, Frank

lewdfinger 09-29-2009 11:59 AM

RE: Custom Piston Rings
Great Info. This should be a sticky...

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