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Repairing a FS12-LT Engine (MRE TA01 Nitro Conversion Build Thread)

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Hi, I've got a used Tamiya FS12-LT (and missing parts) engine that I'm using for a restoration project, so want to get the metal casing looking as good as possible. Any good tips as to what cloning agents work best? And when it comes to dismantling and cleaning the moving parts, what works best as a lubricant when putting it back together?

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I use for cleaning, automotive brake cleaner. Great stuff, but disappears really fast if used on large brakes :D

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If it's dirty, I'd scrub it with WD40.  Everybody has a can and it's cheap.  Things like Simple Green can discolor. (Was it @Saito2 who had that happen?)

But be careful not to use it with plastic and rubber parts. As with any oil, WD40 can warp or crack them. 

After wiping clean, I would use after-run oil for inside moving parts.  It protects parts from rusting for years.  Also it works as a lubricant when you fire it up.  You don't have to worry about lube while running because nitro fuel has lubricant mixed in it.  But the alcohol in the fuel attracts moisture, that's real reason why you'd need after-run oil.  

 

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2 hours ago, futureworks said:

Hi, I've got a used Tamiya FS12-LT (and missing parts, but that's another story) engine that I'm using for a restoration project, so want to get the metal casing looking as good as possible. Any good tips as to what cloning agents work best? And when it comes to dismantling and cleaning the moving parts, what works best as a lubricant when putting it back together?

There are some top-notch engine spripping down topics from member @acprc describing exactly how to restore old nitros. go for them...

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I use for cleaning, automotive brake cleaner. Great stuff, but disappears really fast if used on large brakes :D

Use nonchlorinated brake cleaner as chlorinated will damage plastic and always test before use. Plastic and rubber parts can be adversely effected with strong cleaners.  

 

use synthetic motor oil, castor oil, or after run oil for a reassembly lubricant. Dont forget to put a little after run oil on the screw threads if you ever want to take it apart again. Steel screws can seize in aluminum. 

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Boiling water and Baking Powder. Scrub, rinse in clean water and then dry (I sometimes put in oven at 100 degress for 30m) then I use light machine oil to lubricate.

If the casing has serious marks left after oxidation then i use a very fine metal brush and micromesh polishing sticks or if very serious I media blast the casing.

 

My Tamiya TGS build/restoration thread shows the process 

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OK so the next step was dismantling, the first obstacle being two remaining screws securing the heatsink in place having no thread. I have spent some time this morning carefully drilling off the screw heads. Now I can dismantle it fully and start the clean up job.

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Looking great. Looks like you may need some new exhaust gaskets or at least the one at the end. Nice set of bearings in the clutch bell will help as well. Screws will be in the post Monday, if I have a gasket I will put it in.

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@acprc that's great, thanks. I'm going to upgrade the brass bearings to proper ones, and need also to find the 4 bolts (hexagonal section with philips head) and spring washers to install the motor on mounts when done.

On gaskets, I also discovered that there's no head gasket once I'd taken the heatsink off, and the gasket between engine and exhaust is there but tired.  

Next step is the baking powder etc, though 2 things: 1) not sure if I'm supposed to try and remove the two bearings in the crankshaft first, i.e. are they OK to get the washing treatment as well because looking at the main case as a spare part they seem to come factory installed so perhaps not meant to be removed..?; 2) I've discovered a slight dent in the top cooling fin/heatsink as pictured, with a hairline crack on top across part of the corner - how to get the fin looking as it should without unduly risking breaking that part off - any advice? Gently tease up with a flat head screwdriver and see what happens?

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You can wash the engine with the bearings in place, dry the whole thing in an oven at 100 degress for 30mins afterwards. Then oil the bearings well with a little machine oil. When the casing comes out the oven try with the screwdriver then to bend it up whilst hot. Sometimes they break so be very careful. If you have something that is flat and fills the whole head slot that helps.

Check the head well sometimes its not obvious there is a gasket in it.

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So, first I removed as much dirt and grime as I could by scraping with an implement and wiping with a cloth, then two cycles of the baking powder and boiling water with brushing, 30 mins at 100 degrees to dry out in the oven, and all looking good! Ready now to reassemble, but definitely no head gasket so I need to source that to complete. A very satisfying process to have gone through for the first time, and a few lessons learned along the way  :-)

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Looks good, baking powder worked well. Head gasket is the same as the FS-15LT and the NDF FS-15 engines. I have added a used one to you screws with the muffler end fibre washer.

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Just done! Partially reassembled along with the muffler (lwhich also came out well - left one is the cleaned up one, right hand one is a brand new one I have spare).

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And most of the  missing parts also arrived today, so will get this finished next week and then move onto the TA01 MRE conversion chassis on which this will sit.

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Since it's taken apart, you've got a chance to port the sleeve.  

Expensive engines have porting done well, while inexpensive ones have gone through a much simpler machining process. 

And a tuned pipe!  That will also improve the performance.  

Just a thought...

 

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Almost completed the engine, having received some screws and small parts from @acprc and purchased some of the main missing parts on eBay. There was I thinking I was doing quite well with this engine refurb, only to realise I've missed a crucial part needed - a 7684015 one-way clutch to connect the recoil starter to the starer shaft...Doh!

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Easy enough to get, the NDF-01 cars have the same bearing.

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One of the challenges with this project turns out to be muffler choice. Having unboxed the TA01/MRE chassis a week or two ago to strip down, clean and do a parts-check ready for re-assembly, I took the opportunity to see how the FS12-LT engine and TM-4 muffler combo would actually fit. Turns out that whilst the engine will be fine, the muffler won't work - sits too low so snags the drive shaft as you can see in the picture and sits too far forward also.

I was wondering if I need a different motor perhaps with a muffler outlet on the other side. However, having found a very old image online of the MRE/TA01 built up from when these MRE TA01 Gas conversion kits were originally marketed, it definitely shows a Tamiya FS12 or 15 engine (I think), BUT with a different muffler to what I have. I can't make out what it might be. Any ideas? Alternatively, any thoughts on alternative mufflers that are smaller, sit further back, and will definitely fit the FS12-LT?

[Edit 17 March: I think in fact it’s a TM-3 muffler in the old advertisement given you can just make out horizontal ridges on the muffler,, and the TM-3 was typically paired with the FS15-LT].

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Isn't there a spacer in the MRE kit to extend the exhaust out?

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1 hour ago, acprc said:

Isn't there a spacer in the MRE kit to extend the exhaust out?

Maybe so, but I don't have it - the rolling chassis above is what I purchased from a Japanese auction site, i.e. new built, so the part you refer to, which I assume must be the bottom right piece on the parts page from the build instructions, is missing :-(

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8 minutes ago, futureworks said:

What..?!?!?

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  • Haha 1

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