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Discussion Starter · #1 ·
Guys,


For all of those Savage 25 owners, how is your backplate. Mine came from Tower and is therefore a North American model, and therefore had the red cross on the bottom of the box. It is bloody hot in Brisbane, and I am not happy with my current running temps and am about to pull the engine down and seal the backplate and carb.


Has anyone else done this? How did you find it when you pulled it down? Did HPI do a decent job when they "fixed" the issue and crossed the box, or did it still require a going over?


Irrespective of the answers, I am doing mine or the next couple of days, and will post a full pictorial overview of the process.


Regards,


AUSRCEdited by: AUSRC
 

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I did it before i broke it in, there was no red x on the box but i read on the hpi site that whether or not theres a x it is done. i straight away pulled it out, and locktighted it... no locktight on the backplate at all. when i put the pullstart on i locktighted and screwed it in really tight but i know not to now since it actually splits the plastic screw holes so i have no locktight and just snug for those 3 screws. it is easy to do and takes under 10 minutes.
 

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Discussion Starter · #3 ·
OK, after pulling the engine down I can confirm the following....


The 4 screws holding the engine backplate had no loctite - the 3 holding the rotostart did. That said, the engine backplate was still fairly firmly in place, and the 4 backplate screws were very tight.


In many posts I have read about sealing your engine, people talk about a product called Permatex Ultra Copper. This is a silicon based gasket maker used in 1:1 scale car engines. What is it? It is a high temp, "sensor safe", low odor, non corrosive gasket maker. You use a small bead around the back if the engine, as well as around the base of the carb. I thought - Hell - why not....





This picture is off of the RC Car Action Website from an article titled "How to: Start Your Engine on the First Pull". You can find it at:


RC Car Action


I could not find Permatex in Australia (not in my local area any way). Good news is Loctite make an identical product. (I might be wrong but I thinkthat Loctite and Permatex are the same thing - under licence or something). It is called Loctite Copper Maxx Hi-Temp RTV Silicone Gasket.


After stripping the engine down, I applied a small bead of this to the backplate and base of the carb, applied Loctite 262 to the backplate screws and put it all back together again. The proof of the pudding will hopefully come later today. The engine has to sit for 24 hours to allow the gasket maker to cure.


Some general comments on the S-25 engine:
<UL>
<LI>The rear backplate is fitted with an o-ring as opposed to a gasket - from what I have read, this should already provide a more efficient seal.</LI>
<LI>The base of the carb has a dual o-ring setup.</LI>
<LI>The setup of the backplate to accomodate the rotostart seems very solid. Using the Terra Crusher as an example of a bad design, the starter shaft came through the backplate and was supported by a bush. This bush leaked badly and filled the oneway in the starter with unburnt fuel and oil. Consequently stopping the oneway from slipping when trying to start the engine was a nightmare. The S-25 has no bush and is sealed with an o-ring, the oneway was therefore suprisingly dry. Also, the starter pin on the crankshaft is spring loaded, and the base of the starter shaft is designed in such a way that once the engine is running, the entire starter assembly stops rotating. In doing so, leaking would be greatly reduced and the oneway would stay in much better shape. Again compared to the Terra Crusher this seems far more robust.</LI>[/list]


As I say, the proof will be in the test run later today, and I will see if those temps come under control. I apologise for the lack photos, but my digital camera has "issues".


Regards,


AUSRC
 

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Hmm...


Good article, i think that deserves a sticky since i know theres a few members who are waiting for their savages to come so this would be good for them to read up on and use the information when their engines come and the time comes to locktight/seal the backplate.
 
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i have experience withh 1:1 cars and i am here to say that all gasket sealant will seal the back plate withh no worries, they are used in real engines afterall. a tube retails for around AUD$6 in repco or the like
 
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