Please Help, I've been trying to find Flywheel Clutch and Gear assembly for weeks.

[Ray]

Hi All, I have 2 old LOSI XXX NT's both still run and play great! However, I keep spinning collets on one, here is the set up:
Adam Drake XXX NT
O.S. Max 18TZ engine

I've been using the stock Flywheel from the xxx nt. I think thats the problem. I've been trying to figure out the correct Flywheel, Clutch, and Gear Assembly. I've only been able to find the correct out drive washer, Part # O.S. Drive Washer: 12TR (I think this it what it needs). However, I'm going nuts trying to find the correct Flywheel, Clutch and Gear Assembly.

The O.S. engine has a crankshaft that is notched on 2 sides, unlike the LOSI XX NT, and most set ups I've been able to find. The O.S. engine was bought new by a friend of mine that I inherited it from. Trying to get it running to remember the fun my friend and I had before he passed. Any help would be greatly appreciated. Thank You.

 

[Ray]

Here are some pics of my AD XXX NT, yes I know its old and discontinued, however there are still parts out there, and you can always mod or build your own. Believe it or not, the exhaust pipe I made from copper pipe fittings I got from Home Depot, about $10.00 and some glue. The front Suspension arms were cut and drilled from 1/4" sheet aluminum. The Shock tower brace and servo arms were made from .064 x 4 x 10" Aluminum sheet. Yes I have just as much fun working on it as I do driving it. And after breaking 10 or so Suspension arms and shock towers(probably more, and lots of $$$), I finally made those, no more broken arms. And yes, the parts I made are heavy, but I don't race, I just like to find some dirt and play. I just made this Template and brace for the rear shock shock tower, I think it looks a lot better then the first one and should be lighter. And for the pipe, its tuning sounds great, but it does weigh like 4x more then the original one I lost somewhere.

 

[Ray]

Oh, and the exhaust manifold, was made from a fender washer and a 90 copper pipe fitting(Home Depot).

 

[WVNed]

It appears there are 2 versions of this engine and I think you have the wrong one.

The second one has a round crank on the end for a collet

 

[Ray]

WVNed, Thanks for the reply! Thats one option I've been considering, I could get a new Crank like the one in pic 2, but my head bolts a striped, so taking the engine apart has not been going well, I got one outa three bolts off. going to try some heat next, wish me luck,lol

Any ideas where you can get a bolt extractor small enough and long enough to remove striped head bolts?

 

[WVNed]

Nope, never done that

I did see cranks on eBay. I think you have to change the backplate too.
I am no expert on nitro engine workings though. I just run them.

 

[cbaker65]

I think that threaded shaft takes a pilot that threads on to it ,but people cut some of the threads off
on what they call a cut crankshaft ,then you thread a pilot shaft on it ,you dont have to buy a whole
new crankshaft ,all yuo need is the pilot shaft!..

 

[Ray]

cbaker65, Thanks for the reply! I'm looking at that now, just wondering the diameter and length of the shaft, will my LOSI stuff now fit? Do I still need a different Flywheel Clutch and Gear assembly? And how does the flywheel and stuff hold on? Questions, Questions, Questions?

 

[D3MON]

that drive washer is not used on the XXXNT trucks, having that will push the flywheel further from the engine so the clutchbell will not line up properly.
as far as spinning over the collets, are you getting the pilot shaft really tight? when you replaced the collet did you also replace the flywheel? if not does the inside of the flywheel where it sits over the collet sit damaged?
the xxxnt is kind of different than most other as it was designed (in stock configuration) to use a long threaded style crankshaft but without the use of a "drive washer"/"prop washer"/"mini flywheel" etc, as the pilot shaft was threaded deeper and didnt use a hex on the inside of the pilot shaft, instead was cylinder all the way down.
http://www.losi.com/ProdInfo/Files/LOSA0887-manual.pdf
page 35 shows the assembly in stock configuration
when you were spinning the collets also, was the pilot shaft loose? or was still tight when you spun them?

 

[Ray]

More funny, there is a "OS Engines Pilot Shaft GT60" & "OS Engines Pilot Shaft GT55" & "#A805 HPI PILOT SHAFT M5 (HPI & OS MAX) SUPER NITRO RS4/ NITRO RS4 MT/" Crazy, which one to choose?

 

[D3MON]

More funny, there is a "OS Engines Pilot Shaft GT60" & "OS Engines Pilot Shaft GT55" & "#A805 HPI PILOT SHAFT M5 (HPI & OS MAX) SUPER NITRO RS4/ NITRO RS4 MT/" Crazy, which one to choose?

the O.S. ones you listed fit the O.S. line for aircraft, i am unsure if it would work correctly on the XXXNT or even on the small block engines it takes.
you also might have to replace the flywheel/collet if you get a different pilot shaft, as it will have the hex on the end and will protrude too far out.

 

[cbaker65]

It has been years since I messed with my OScvr 18 ,I have to look at it an see what it has ,
but I am quite sure that it has the ground crankshaft an the one piece that goes against
the bearing of the engine is removed ,I think that is called a drive washer ,then the brass
collet goes there an then the flywheel ,an then use the pilot shaft style clutch nut ,but the
a portion of the threads have to be cut off!
A trick is to use loc-tite on the brass collet!

Pilot shaft would look like this ,but you would need to find the right size thread to fit yours!

 

[WVNed]

there seem to be 4 versions of that engine

18TZ SERIES INSTRUCTIONS​

MAX-
This manual handles the following four versions.
18TZ-T with 11L carburetor
MAX-
18TZ(S)-T with 11L carburetor
MAX-
18TZ-TX with 11L carburetor
MAX-
18TZ(P)-T with 11K carburetor
exploded diagrams with part numbers are here for all 4 starting on page 16
https://www.manualslib.com/manual/1117006/O-S-Engine-Max-18tz-Series.html?page=16#manual

 

[Ray]

D3MON Thanks for the reply! Yes shaft always very tight! Thanks for the manual link, that was cool( I still have my original hard copy that came with the truck), the problem, I think, is that on the o.s. engine, I have to put to many shims between the flywheel and the outer crank bearing. The pin screws on the back of the flywheel bind on the bearing if I don't add the extra shims. This makes the collet only partially fit on the rounded/slotted part of the crankshaft, do to the fact that the LOSI pilot shaft nut is what presses the flywheel onto the collet, so the collet has space inside where the crank threads are. On the LOSI motor, the rounded not threaded part of the crank is just enough longer so that the flywheel pin screws don't bind on the outer bearing and the collet seats perfectly on the crank. As for the shaft length and not lining up with the spur gear, I can make new engine mounts to compensate for the change, theres enough room to move the motor over a little. Also, I've tried 3 different flywheels, all with the same results. Hopefully these pics show enough detail. Thanks again for the help!

 

[cbaker65]

D3MON Thanks for the reply! Yes shaft always very tight! Thanks for the manual link, that was cool( I still have my original hard copy that came with the truck), the problem, I think, is that on the o.s. engine, I have to put to many shims between the flywheel and the outer crank bearing. The pin screws on the back of the flywheel bind on the bearing if I don't add the extra shims. This makes the collet only partially fit on the rounded/slotted part of the crankshaft, do to the fact that the LOSI pilot shaft nut is what presses the flywheel onto the collet, so the collet has space inside where the crank threads are. On the LOSI motor, the rounded not threaded part of the crank is just enough longer so that the flywheel pin screws don't bind on the outer bearing and the collet seats perfectly on the crank. As for the shaft length and not lining up with the spur gear, I can make new engine mounts to compensate for the change, theres enough room to move the motor over a little. Also, I've tried 3 different flywheels, all with the same results. Hopefully these pics show enough detail. Thanks again for the help!

That was the purpose of a cut crankshaft ,once you shim too much ,there is no more surface area for the collet to bite
to ,so therefore ,you have to cut part of those threads off!..

 

[Ray]

cbaker65, Thanks for the reply! That one looks like it could work, any idea how to tell from the package what the thread is?

 

[Ray]

cbaker65, and the outer diameter of the pilot shaft?

 

[cbaker65]

cbaker65, Thanks for the reply! That one looks like it could work, any idea how to tell from the package what the thread is?

Not sure the thread size ,I only showed the pic so you know what the part is!

Cutting crankshaft threads is old technology ,people had to do it years ago!..

 

[Ray]

WVNed, Thank you, I've been threw so many o.s. engine manuals, even for other engines and cars, they don't show this set up.

 

[cbaker65]

WVNed, Thank you, I've been threw so many o.s. engine manuals, even for other engines and cars, they don't show this set up.

LOL...OS parts are way too expensive just to change over ,you may as well buy a new engine!..

All you need is part of those threads cut off so the collet has enough space to bite on ,that is why
you can't put shims there ,once you cut part of the threads off ,there is no shims needed ,only the
collet goes there that rides up against the bearing!...