View Poll Results: Vote FSR VF Exhaust Timing
FSR 146 VF 146 2 14.29%
FSR 146 VF 150 3 21.43%
FSR 150 VF 150 9 64.29%
Voters: 14. You may not vote on this poll

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Jan 01, 2021, 02:47 PM
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Discussion

OS 61 FSR, VF ABC Replacement Piston Liner Sets


There are thousands of the OS 61 FSR/VF ABC short stroke motors around (1979-1986) but they suffer from the well known OS peeling liner problem.
OS used an electroless nickel process, as did YS earlier on, but the OS liners have a bad habit of peeling.

There is a lot of interest in these motors because of classic pattern, and I see new F3A models being built with still new FSR/VF's, over 30 years since they were discontinued.

How many of these engines are sitting unused in boxes and drawers in bits because of the lack of spare parts.
I have a couple of 61 VF's that are in good condition but need new liners, and one spare P/L set, but that will also start peeling after a few runs as well.
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This thread is to see how much interest there is in new sets of FSR and VF ABC P/L sets, and whether it is worth seeing if we can get them made up.
Please leave yours comments below.
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Jan 01, 2021, 02:54 PM
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Thread OP
List for P/L/rod/pin requests. Brian will do a minimum 50 sets of each.

MrM20 - 4VF 2FSR
Roguedog - 2VF 2FSR
RC YEAGER - 2FSR
hook57 - 2VF 2FSR
Alphonsog - 1VF
flyonenow - 3VF 2FSR
TonyF - 2FSR
gregg jacobson 3VF 4FSR
RCpilot7974 - 1FSR
djfuzzy - 2FSR
kablake - 1FSR
imodel - 2FSR
rabbid fly - 1FSR
KellyJ - 2VF 2FSR
toddblose - 3VF 3FSR
Mercura - 1FSR
Mike Denest - 1FSR
David Press - 2VF
nichda - 2FSR
Damarri - 1VF
ofremmi - 1VF 1FSR
ofirby 1FSR
Johnkpap 1VF
Ernie Smith 1VF 1FSR
Anders Johansson 1VF
Stuntflyr Chris McMillin 2VF 4FSR
Andy Green 1FSR
roary m 1VF 1FSR
kdunlap 2VF
mike3976 1VF
Glenn-Arne Jakobsen (Norway) 1FSR
Seth Krammer 1FSR
Ronnie Weaver 3VF 2FSR
billtulsa 4VF 6FSR
Kevin C 1FSR
ArnStein Solberg 1FSR
Orlando Amado Mateus 1VF
Tim-Janet Pritchett 1FSR (SE)
Imotv1 1VF
Hamish Galloway 1VF
Mike Marcsisak 1FSR
carnero69 2FSR
Joels55 4FSR
JCLARKE 2 FSR
nxtdoor 1VF 1 FSR
peazump 1VF 2 FSR
jengel 2FSR
ARNIE G 2VF
HCrackers 1VF
BOB ___ 2VF
b.bixel 2FSR
turbo.gst 1VF 1 FSR
jbudd 1VF
E_Richard 2VF
Jim Johns 1FSR
carr200 2VF 3FSR
_Jas 2VF
Yogi1 1FSR
helipatt2 1VF
308jockey Rick 2FSR
Schmeg 2FSR
Dave Swanson 2FSR
apereira 1VF

Total: 60VF, 82FSR
Last edited by MrM20; Sep 18, 2021 at 07:52 AM.
Jan 01, 2021, 04:38 PM
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Roguedog's Avatar
I'd like to see a run of these.

I have 8 or9 OS 61 FSR's VF's

One has what appears to be an old Performance Specialties P&L set for a 61VF see pic.

Some food for thought ---
The Hanno's exhaust port has the v notches which is supposed give it a torque boost. The liner I have doesn't have that but does have the center post removed. see pics

Would be interesting to know it putting the v-notches in a FSR or VF liner would have the same effect e.g produce higher torque.

The fandom of the long stroke crowd claims the long stroke porting produces more power.

But Don Lowe published an article in the June 1987 RCM Magazine where he did an an experiment with a 61FSR and a 61SF where he used the same tuned pipe setup for the long stroke OS61 SF on the Short stroke OS61FSR and guess what the short stroke, when tuned like a long stroke produced the same power. see attached article.

I built my own V8 car engines in my youth and the when it came to bore vs stroke, bore was always preferred. The only reason mfg's went to short stroke was due to noise requirements of the day but really to sell the idea that long stroke engines where better to sell more engines.

The Lowe article clearly indicates that you could tune a short stroke to swing higher pitched props like the long strokes. So much for the difference in porting.

I made up a spreadsheet of the porting of a std FSR, RF(same as SF), Hanno, and Performance Specialties P&L set and theres not much difference in the stock port timings from OS Max but the PS is quite different from what i could measure using simple methods.

So looking at that data it's clear that the tuning of the header and tuned pipe is more a determining factor then the actual porting of the engines as well as the size of the carbs throttle bore.

One really interesting feature of the porting is between the 61 FSR and 61 Hanno. Both engines have very similar porting charateristics.

I have 2 short stroke OS 61 VF's and 2 OS 61SFN short strokes that I installed the PA 102 pumps systems on. This is the combination of the OS engines that the large bore butterfly type carb and pump that came on the 61RF-P or 61SF-P engines. Have not ran them yet so specs will have to wait til I get time.

But I suspect that this would have been the best combination of OS Max 61 engines if they didnt want to sell everyone the gimmic of long stroke engines.
Jan 01, 2021, 06:58 PM
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hook57's Avatar
Very neat info Rogue. I also have several VFs and quite a few FSRs, but not the level of knowledge you and others possess. In any case I’d be interested in a few replacement P&Ls for these engines as well.
Jan 01, 2021, 08:39 PM
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Roguedog's Avatar
So I'd be in for 1 vf and 1 fsr in ABC would be fine for me.

Would also like 1 each of the ringed versions with steel liners. So 4 in all. If not in steel then one more each of the VF and FSR.

The piston is the only difference on the steel versions. The steel liners are same.

I also have a YS-60FR that could use a spare.
Jan 02, 2021, 12:40 AM
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Uh... I knew that the peeling problem was something that the SF and RF suffered from, but didn't know it went all the way back to the FSR/VF series. Did all O.S. ABC (Chrome or... żNickel?) engines suffered from this malady? Could it be possible that there were a few "good ones" that didn't peel? I'm asking because back in 1980, I flew a T2-A with an FSR in it (no pipe) and never had that problem. Put about 340-360 flight on it and sold it after finished a new Webra powered Arrow.

More recently (2013-14) had one on a Super Sporster that I put together to get my thumbs/brain back in form after a long hiatus from the hobby. Don't know exactly how many flights I put on that one before it too got sold (didn't want to include the engine, but the buyer insisted and I regretably relented), but I'm sure it was more than two hundred 9 to 10 minutes flights. No peeling was encountered there either. Was I lucky? Could maybe the fact that neither had a pipe helped? Do more hours have to be put on the engine for the peeling to manifest itself?

I have 4 new FSR-ABC's slated for pending pattern projects. Should I be worried that they are going to peel??
Last edited by RC YEAGER; Jan 02, 2021 at 12:59 AM. Reason: Typo
Jan 02, 2021, 02:38 AM
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Roguedog's Avatar
I've been messing around learning about chrome plating over the last several years for the purposes of rechroming liners.

Learned a bunch.

Apparently the first batch of electroless nickle plated liner when introduced by OS where good. But electroless plating requires precise mixing and gets dirty fast. I'd say the reason for the bad Hanno, SF, and RF liners was the either they didn't prep and clean the liners correctly or they were using old plating solution. After so many liners are plated using this method the nickle ions in the plating solution get used up. It's better to mix up a new batch then try to rehab the old solution by adding more nickle ions to the used mixed solution.

For hard chrome it's not really the best chrome to use for liners. Yes it's hard. but it's also, believe it or not, it's porous. Hard chrome is good for relining bearings or for hydraulic rams as for the most part they're immersed in lubricant when in use.

I called Dave Brown products about 10 years ago looking for a specific motor mount that i needed that wasn't in stock anywhere and he actually answered the phone. Was great to talk with him. I told him i was rebuilding several OS 61's I had and that we had got together a group of people and where getting a bunch of Hanno liners made at that time.

He started to tell me that back when the Hanno's and SF/RF's were new that not only where the liners pealing but that the rear bearings were also rusting out too fast. He said that him and other pattern flyers at the time investigated the cause and it turns out the main reason for this was the leftover burned synthetic lubricants were acidic and were basically removing steal bearing material on the steal in a form of electroless plating moving it to the crankshaft. He said that they were also having they same issue on the FSR's and VF's.

He then asked if any of my 61 VF's had a thin brass washer between the crankshaft counter weight and the bearing. In fact I did have one out of the 3 I had at the time with it. He told me that Him and several competition pattern flyers went to the OS Reps and asked if they could install this anti corrosion brass plate when that manufactured the next run of OS Max 61 VF's and they did.

Later when OS came out whit the Hanno he told me they incorporated the anti corrosion plate into the Hannos crankshaft to help the steel bearings last longer for those using synthetic oil. I was pretty much speechless as he went on and told this anecdote.

Totally amazing to be having a conversation with Dave brown about some history most would never know about. I was stoked.
See pics

I was able to purchase the motormounts over the phone and had them 2 days later. Really nice guy.


For hot rod buffs nothing looks better the hard chrome as it has a blue hue to it. Nickle Plating has a yellow hue so is less desirable for show cars. But, nickle chrome, yes is not as hard as hexavalent (hard) chrome, is not porous like hard chrome.

If you've ever seen car bumpers from the 40's, 50's, and 60's sitting in a field or junk yard covered in rust, for the most part that's hard chrome applied over steel. The water goes right through it rusting the steel behind it.

Custom chrome for hot rods is what is know as Triple Chrome. It consists of three layers. A base copper layer, then a nickle layer to seal out the water form getting to the steel, then finally the hexavalent (hard) chrome to give that very desirable blue hue.

Hexavalent chrome, or at least it's ions is what the movie Erin Brockovich is about. Really toxic stuff. It also requires 1 amp of current per sq in to apply to steel.

Nickle (edit not Trivalent) chrome does not have this huge current requirement and ins't nearly as toxic. Plus since it's not porous the water and for us or those that use synthetic lubes, the burnt acidic leftovers from the synthetic lubricants can't undermine the bond of the chrome which is what Dave Brown was telling me.

All i can say about that conversation is it was surreal.
Last edited by Roguedog; Jan 06, 2021 at 04:08 AM. Reason: Meant to say nckle hrome
Jan 02, 2021, 02:48 AM
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Roguedog's Avatar
Quote:
Originally Posted by RC YEAGER
Uh... I knew that the peeling problem was something that the SF and RF suffered from, but didn't know it went all the way back to the FSR/VF series. Did all O.S. ABC (Chrome or... żNickel?) engines suffered from this malady? Could it be possible that there were a few "good ones" that didn't peel? I'm asking because back in 1980, I flew a T2-A with an FSR in it (no pipe) and never had that problem. Put about 340-360 flight on it and sold it after finished a new Webra powered Arrow.

More recently (2013-14) had one on a Super Sporster that I put together to get my thumbs/brain back in form after a long hiatus from the hobby. Don't know exactly how many flights I put on that one before it too got sold (didn't want to include the engine, but the buyer insisted and I regretably relented), but I'm sure it was more than two hundred 9 to 10 minutes flights. No peeling was encountered there either. Was I lucky? Could maybe the fact that neither had a pipe helped? Do more hours have to be put on the engine for the peeling to manifest itself?

I have 4 new FSR-ABC's slated for pending pattern projects. Should I be worried that they are going to peel??

Sorry I forgot to answer your question. I have some peeled FSR and VF liners. Most are still good with no peeling at all. So i think yours will be fine.


The use of castor oil is apparently the best protection for peeling liners in the conversations I've read here on RCG and RCU over the last 10 years. It continues too have some lubricating ability if the engine runs lean and gets hot. Synthetic lubes apparently don't do as well in alean running engine.
Last edited by Roguedog; Jan 02, 2021 at 02:57 AM.
Jan 02, 2021, 08:40 PM
Registered User
Hi guys,
I assume you are hoping to get Brian Gardner to produce the parts. He'll need a minimum order of 50 sets of each (50 VF and 50 FSR). Another run of Hanno piston/sleeve sets is more likely at the moment as there are requests for an additional 29. Brian is currently about 6 months behind in current orders/projects; so I'd guess it would probably be a year or more before the parts were finished. We are almost 18 months out from the initial post for the OS RF & SF parts.
I will suggest contacting Bob Oge ([email protected]) to get piston/sleeve assemblies refurbished as an alternative, if the numbers for a production run don't materialize. He does excellent work.
Lastly, getting liners, pistons and rings produced may be a challenge. Bowman rings are still in production as he was able to pass the business on to his apprentice whose name escapes me at the moment. If Brian was willing to produce the pistons and sleeves (I doubt he makes rings, but will inquire), he will then want the rings for fit and assembly or maybe just ship the raw parts.
Good luck, I'll be watching.
-Will
Jan 02, 2021, 08:43 PM
Registered User
Ok... well... Assuming I get a 50% attrition rate from my four engines, I'd be in for at least 2 FSR piston/liner combos
Last edited by RC YEAGER; Jan 03, 2021 at 01:21 AM.
Jan 02, 2021, 09:37 PM
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hook57's Avatar
Well, at the risk of the “money talks, bs walks litany”, I’d be in for two of each. Holding my breath now....
Jan 03, 2021, 02:31 PM
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I need one 61VF set.
Jan 03, 2021, 04:06 PM
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Thread OP
Quote:
Originally Posted by Roguedog
I'd like to see a run of these.

I have 8 or9 OS 61 FSR's VF's

One has what appears to be an old Performance Specialties P&L set for a 61VF see pic.

Some food for thought ---
The Hanno's exhaust port has the v notches which is supposed give it a torque boost. The liner I have doesn't have that but does have the center post removed. see pics
Great info, thanks very much for posting.

Despite their high performance look, the VFs actually had fairly moderate exhaust timing (146°), similar to the RF (144°). Motors like Rossi and Webra had much longer exhaust duration to get more from the pipe.
There is almost no power difference between the 61VF and 61RF, but the RF produces about 10% more torque at lower RPM, which was needed for the switch to turnaround and bigger props. The massive bore 86 carb and pump made the real difference in power.

Lots of info here:
http://sceptreflight.com/Model%20Eng...ax%2061VF.html
http://sceptreflight.com/Model%20Eng...1RF%20ABC.html

If we could get sets of these liners made up, it would be worth seeing what sort of benefits come from the Performance Specialities liner, by removing the exhaust bridge and possibly increasing the exhaust duration.
Jan 03, 2021, 04:26 PM
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Thread OP
Quote:
Originally Posted by RC YEAGER
Uh... I knew that the peeling problem was something that the SF and RF suffered from, but didn't know it went all the way back to the FSR/VF series. Did all O.S. ABC (Chrome or... żNickel?) engines suffered from this malady?
These motors were before the days of synthetic lubricants, the VF in 1979 and the FSR ABC in about 82. The conventional wisdom says use lots (20%) of castor oil, clean fuel, and don't let them run lean. After tuning for peak RPM, back off the main needle about 3-4 turns, and make sure it doesn't lean out in the air.

But having said that, my one liner has peeled nickel on the outside, which points to a manufacturing problem, and nothing to do with oil/fuel/mixture/pipe etc.
Chrome liners were only plated on the inside, and you could see the brass.
Many of the FSR's were ringed sport motors, so the problems never seemed as evident.
Jan 03, 2021, 06:21 PM
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If I were to make these for you guys I wouldn't have the web across the exh port, and could do whatever exh duration you want. True ABC - piston/liner/rod/pin sets.


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