OS xm to RG piston & liner how to do this mod?H

[Hayden Bright]

Hi guys just wondering how to do this mod and if it's worth doing, My OS XM hasen't done much work but has lost a lot of pinch and thinking about doing this mod because a RG p/l can be had for $55 bucks on ebay any advice would be great cheers.

 

[camaroboy383]

hayden.,, the rg sleeve o.d needs to be turned down in a lathe to fit the xm case...thats it my man...then either raise the timing by cutting the ports or slap it in if will be running the muffler...

alden

 

[Hayden Bright]

hayden.,, the rg sleeve o.d needs to be turned down in a lathe to fit the xm case...thats it my man...then either raise the timing by cutting the ports or slap it in if will be running the muffler...

alden

Just the outside dia turned down ok, so does the RG sleeve have identical timing numbers as the XM then? Yeah I was just going with the stock muffler. I just seem to always be questioning this engine & why it has bugger all pinch maybe this is normal with ABN engines. I use a 22% full synthetic oil fuel so i don't have all that castor oil in there helping build compression either, maybe Im just being paranoid :blink: and should stop comparing it with the TT lol.

 

[RodneyPierce]

Hayden, its pretty normal *from my experience* that the OS seems to "lose" its pinch rather quickly. But the important part of that equation is the fit of the piston and liner. My OS doesnt feel like it has a whole lot of compression, but you can do the "bump" test back and fourth over TDC well over 20 times and still not have lost the trapped compression.

 

[camaroboy383]

rodney has a great point.... while the pinch seems to be nowhere near what you think it should be.seems to be a trait of the abn liners...... it well,,, means nothing.. do the compression test as rodney described and see how many times you can compress the same air..... dont compare the tt liner with the os liner... there is no comparison..... the abn will lose all of that pich and still be good if broken in properly....your oil content is fine... has nothing to do with it......timings on the rg sleeve are the same hyaden..... turn the outside down and she will slide right in..... one thing ive been trying to remember is if the sleeve land needs to be raised...kris flynn would know best,, hes done a bunch of them....

 

[RodneyPierce]

 

[Tim_Duggan]

one thing ive been trying to remember is if the sleeve land needs to be raised...

It needs to be adjusted if using an XM head because the XM head does not step into the sleeve, which makes the P&L fit even tighter, they Are VERY hard to start and run in!

My nickel sleeve has no nip at all with the plug out. Put the plug in and it seals up just fine. It's all about breaking the nickel sleeve in patiently, and not overpropping the OS and resorting to leaning it out to make it rev. Hot plugs work too, because even at 0.003" head clearance the engines are under compressed.

 

[Hayden Bright]

Hayden, its pretty normal *from my experience* that the OS seems to "lose" its pinch rather quickly. But the important part of that equation is the fit of the piston and liner. My OS doesnt feel like it has a whole lot of compression, but you can do the "bump" test back and fourth over TDC well over 20 times and still not have lost the trapped compression.

Thats the answer I was Hoping for makes perfect sense cause when the engine gets up to running temp the sleeve expands to fit piston pefectly so you would imagine, that at say room temp the pinch would'nt be all that relevent to running temp piston liner fit.... Thanks Rodney appreciated

Alden thanks for your help to man I'll just keep running her till she stops running I guess then do the RG when it needs a rebuild.

 

[Hayden Bright]

one thing ive been trying to remember is if the sleeve land needs to be raised...

It needs to be adjusted if using an XM head because the XM head does not step into the sleeve, which makes the P&L fit even tighter, they Are VERY hard to start and run in! My nickel sleeve has no nip at all with the plug out. Put the plug in and it seals up just fine. It's all about breaking the nickel sleeve in patiently, and not overpropping the OS and resorting to leaning it out to make it rev. Hot plugs work too, because even at 0.003" head clearance the engines are under compressed.

Tim thanks, yes my engine is the same with plug out can just feel a grab through tdc put plug back in and pops ok, so you personally don't think it's at all nessasery to do the RG p/l, well this is good news cause the engine has maybe 3 ltrs on it so I should stop worrying about the pinch and just drive it lol. Tim you say don't over prop it yes ,would you consider 38mm with 1.6p in a safe range from your exp and I'm not sure are you saying you need to lean on it to make it rev or leaning is bad?? Because i've been leaning on her alright I think I'm at 1 turn out with with reduced water cooling and she seems to like this... Any Os speed secrets you'd like to share I'm all ears.... thanks again

 

[RodneyPierce]

dont over lean the motor. And Im currently running 39mm 40/53 at 2.6 cup. back cut with tongues removed. Mine seems to like it well. I havnt settled on the diameter yet though, as Im still reducing a little at a time, and testing between trimmings. I have to thank Mark Sholund for the prop help.

 

[Hayden Bright]

dont over lean the motor. And Im currently running 39mm 40/53 at 2.6 cup. back cut with tongues removed. Mine seems to like it well. I havnt settled on the diameter yet though, as Im still reducing a little at a time, and testing between trimmings.

Rodney I just refured to it as lean cause at 1 turn out "sounds" lean but shows no signs of lean running, dosen't lose power or hesitate & can hold if full throttle through a full tank without any issues... and while breaking her in 2 turns out was blubbering rich so. Sorry about that I like to keep running on the rich side for sure I just couldn't get this thing to come alive with this prop and ended up at about 1 turn out before the magic happened. I should do a lot more prop and trim testing by the sounds of it

 

[RodneyPierce]

If the water is decent this weekend (which it appears its going to be windy again by the forcast) but Ill try and get some video of mine. It runs OK. Nothing spectacular, but runs pretty decent none the less.

 

[Hayden Bright]

If the water is decent this weekend (which it appears its going to be windy again by the forcast) but Ill try and get some video of mine. It runs OK. Nothing spectacular, but runs pretty decent none the less.

Awesome like to watch the vids helps a lot, na I just love watching tunnels flying across the water with not a lot of boat in the water Yeah weather turned bad on us to 35mph winds + rain might go fly a kite.....

 

[Tim_Duggan]

Any Os speed secrets you'd like to share I'm all ears.... thanks again

No secrets here. Yes, I like the nickel sleeve but you really have to be kind to them. Avoid running lean and don't get them hot. I don't use any cooling restriction on my OS - it's the only engine I don't restrict cooling on - because of the nickel plated sleeve.

Take out the head shim and then measure the head clearance. It should be about 0.003" IF IT IS IN THAT RANGE, leave the shim out. If it's less, use a shim.

Use an MC59 Mccoy or K&B 1L glow plug.

Wind out the low end needle (the one inside the carb arm end of the carb barrell) so that it's flush with the part of the barrell around the screw head. if it won't idle or kicks back on itself and starts running backwards, set the idle position of the carb a bit faster via your radio trim.

If you have to lean the motor down to where it sounds snappy on the shore to get it to sing out on the water, it's overpropped. ABC / Grimracer 40/53 with a backcut and decupped as RP has suggested is a good choice.

On a Villain or VS1 it should run mid 40's mph all day long and slow right down to a crawl without fueling up and stopping. If you can get a good start and hold a good line, someone has to go a lot faster to get around you and they'll probably DNF trying.

 

[Jim Mamaril]

If I remember correctly you also need to trim a little off the underside of the RG sleeve, I think it puts the transfers up a little high if you dont. Been awhile since I worked on one so correct me if I'm wrong.

Jim

 

[Hayden Bright]

Thanks to everyone for the info, IW is a great boating family with a wealth of knowledge and support it's great to be apart of. As for the OSxm I think I'll stick with the stock parts maybe try out some v2 components. I really like that they went to aircooled on the v2, I could bring my boat in after full speed runs and the engine would be barely warm!!!!!! Thats when I started experimenting with reducing the water outlet hole allowing the engine to get some heat, this produced a much more powerful and consistent running engine. I know the ABN liner can't be overheated but barely warm is a bad running temp in my books also. ABN engines still need to get up around 200 degrees F' to produce optimum performance. I'd love to hear points of view on NITRO MARINE ENGINE RUNNING TEMPS. In particular ABN engines......

 

[camaroboy383]

i typically dont launch my boats till my engines are up on temp anywhere from 180-240 degrees F. temp is for sure your friend...good temps will produce an excellent break in of the p/l set...somtimes it can be a pain to make them temps with an outboard....the lower is just a huge heat sink...which can play games with u when the water temps are lower....ideally id love my engines (both abn and abc) to run in the 200-220 range...temps taken at the center of the plug....

 

[Hayden Bright]

i typically dont launch my boats till my engines are up on temp anywhere from 180-240 degrees F. temp is for sure your friend...good temps will produce an excellent break in of the p/l set...somtimes it can be a pain to make them temps with an outboard....the lower is just a huge heat sink...which can play games with u when the water temps are lower....ideally id love my engines (both abn and abc) to run in the 200-220 range...temps taken at the center of the plug....

Temp is your friend for sure I did a blubbering rich cold engine break in once, ended not long after break in with piston pin connecting rod failure. Never again I'm a big fan of heat cycling it just makes complete sense, thought I might be stirring up a hornets nest with that post. Glad to see were on the same page camaroboy. OS went to aircooled for good reason...

 

[SayMikey]

Dont want horn in on your thread but isnt the abn better than the rg? Other than wear issues,the abn have a modded piston that has to be better than a stock rg piston?

 

[Tim_Duggan]

The RG sleeve is good if you want to change the port timing. While it is possible to alter the port timing on a Nickel sleeve, they are more prone to flaking off the plating. Not an issue with chrome plated brass.

I can't say for sure, but I think there are two different types of pistons that came with the XM's. Cast or billet.