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dual head gaskets

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tmaxxdout

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  1. Bashing
I've heard the 3.3's are easier to tune if u put 2 head gaskets on. i know u lose a little power but if its easier to to i can deal with it. has anyone heard of this or done it and info would b great
 
I've never heard of using 2 head gaskets. Sounds like it would just make the header more leak prone. If you can't get your engine tuned, your probably either adjusting the needles too much at a time or you have an air leak. If you haven't sealed your engine, now is the time.
 
It's necessary to add an additional shim when raising the nitro percentage, but the purpose is to lower the compression for the faster burning fuel.
 
in an effort to detune my 3.3 i put 3 of the thickest gaskets on. it worked good on 15% i could tell it lost some power but not a lot. i still tuned by smoke and temp, was happy about how it ran. effort
 
detune up date: found some hpi carbs, for $13. ea, that are 5.5 mm inside dia. i think the stock 3.3 carb is 6 mm. dont know yet if they are bolt on. as i broke the servo ears on the throttle servo, and the steering servo is loose so got to get that fixed first, on my jato. also the fuel i left out in the sunlight, is not hurt, it runs fine.
 
so none of the hobby shops around me have the 3.3 head gasket could i just use two glow plug gaskets to get the same ease of tuning:headscratch:
 
I think you should make sure your engine is sealed and practice tuning. Cheaters never win.;) Learning to tune a 3.3 is great nitro experience. Just remember; small adjustments and a couple of minutes of running in between adjustments to let them take. And as always, watch those temps.
 
the carbs i got from hpi are no 66727 5.5mm. venturi. the outsite dia of the hpi is 9.93mm, this is the part that goes into the crankcase, 12.98 mm is the stock size. so you would need a sleeve with a wall thickness of 1.5 mm. the inlet size that the air filter fits over. is 11.0 mm for the hpi, 15.97 for the o.s. or the stock traxxas inlet. the venturi for the stock 3.3 is about 6.48 mm. havent got a hpi mounted yet, it may reduce power to much. going to have to spend more time in the thinking mode.
 
Rolex - when you wrote about the need "to add an additional shim when raising the nitro percentage", were you implying that it's OK to stack shims or were you simply saying that a thicker shim is needed for higher nitro content fuels?
I personally don't like stacking shims, but have seen it done by others.
Having said that, if I was to stack, both shims would be virgin shims.

Traxxas part 5292 contains 3 shims of different thicknesses. (.2, .3, and .4mm) and I'll guess that the stock shim that comes with the engine is .3mm.
I don't have a 3.3 engine to verify that statement, but since the 2.5 comes stock with a .26 shim and that's the middle shim in the replacement pack - I'll assume that Traxxas stays true to form and provides us with the option of going up or down in thickness.

Tmaxxdout - No, don't go stacking glo-plug gaskets. You're asking for a compression leak. Hit an online site like A-Main or Tower Hobbies and get a cooling head gasket set or two.

Moe - Why are you looking to detune your engine?
Isn't running 15% nitro detuned enough?
I see you mentioned your Jato - are you looking to detune because it's wheely happy?
If that's the case, detune your index finger (don't mash on the accelerator)... lol
If you've added three of the thickest gaskets, that's 1.2mm of gasket.
Just seems excessive to me.
 
No problem using 2 shims when raising the percentage of nitro.
I believe some engines even come with 2 gaskets, and you remove one after the break in.

NEVER add another gasket to the glow plug. You're also very likely to strip the threads in the head button. Use one of these, instead:

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iam detuning for two reasons. 1. just to see if it can be done. 2. to see if its a good idea to get it to last longer. just think a 3.3 that runs for 10 years with out blowing up.
 
You don't really need to add additional shims when changing nitro percentage.
When you buy the crush washer kit from Traxxas it comes with three of them, they arnt just extras if you have a micrometer or even by hand/eye you can tell theres a difference in thicknesses.

I say dont run two shims, they weren't designed to be ran like that and shouldnt require it for tuning.
 
rolex what kind of gasket is that and where can i order on what is the difference between these gaskets
 
Moe - I think it’s commendable that you’re experimenting with different options - which is part of the fun of this hobby - as well as trying to look after your equipment, which will help extend its longevity.
Personally, I like to try to make my stuff go faster while retaining reliability. Having said that, I’ve had a couple of engines “blow up” on me when (for example) a con-rod snapped. One of these was purely an experimental endeavor.
Concerning engine life, my experience is that more often than not the piston/cylinder wears out and compression is lost. This is a result of friction / extended use etc., which is in direct correlation to the revolutions that the engine’s piston/cylinder have seen, and unless you’re running the engine excessively lean and hot, not the power output that you’re trying to extract from it.
 
"optically diluted bronze" i like that a lot, it sounds good enough that you could probably sell those to some unsuspecting people! :hehe:
 
to: TGL i tryed the going faster thing and yes it went fast enough, and not to much part breakage. so i thought make it milder. i was thinking what if i put a smaller carb on and the low rpm power went up more than i lost high end power. how ever back in the stone ages i knew some chevy guys that would do the math to get the carb size, then they would put a carb on the that was a good 150 cfm higher, go to the track and go very fast. then put the carb on that matched what the math said, and loose a good .500 sec.
 

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