Should this have a gasket ..gx12

[Lampwick]

Hi
I'm taking this kyosho gx12 engine apart and I've noticed it has no gasket between the head and the block ...is this correct or is it missing a gasket ???
Cheers

 

[D3MON]

it should have 1-3 head shims in there depending on that engines prefference and fuel % you are using. pretty much a really thin copper gasket that squishes to seal better and spaces the head further up off the piston to give correct compression.

can't get over how goofy that head pipe looks lol

 

[Lampwick]

Thanks for the info I don't suppose you know where to get them from? I've tried looking on eBay but parts for gx12 seem to be hard to find now ...I know the not prettiest of pipes is it lol

 

[D3MON]

Thanks for the info I don't suppose you know where to get them from? I've tried looking on eBay but parts for gx12 seem to be hard to find now ...I know the not prettiest of pipes is it lol

Just a strange pipe setup, should be able to find any .12 head shim .15 may work but I'd use that last resort.

 

[Lampwick]

Brilliant thanks for that .off shopping I go ........lol

 

[olds97_lss]

Quick google search suggests they are part number 74521-15:
http://rc.kyosho.com/en/74521-15.html

The 2 round/shiny ones are head shims, which are typically made of copper/brass/aluminum which are soft and malleable so that when you tighten the head down, they seal any imperfections while also making the combustion chamber the proper size for the fuel you run.

 

[Lampwick]

I can find the original kyosho head shims as they're discontinued every place I find on line ....so my next question is ....if I just use generic .12 head shims , how many should I use??

I'm using 16% fuel if that makes a difference lol

Cheers

 

[D3MON]

I can find the original kyosho head shims as they're discontinued every place I find on line ....so my next question is ....if I just use generic .12 head shims , how many should I use??

I'm using 16% fuel if that makes a difference lol

Cheers

16% would probably be 1 or 2, should probably experiment with how each run.

 

[olds97_lss]

The lower the nitro, the less shims you use, in general. But I think you should always have at least one, just for the sealing purposes. I'm with @D3MON on how many. Higher nitro (26%+) usually requires the combustion chamber to be larger or it detonates early vs combusts when it's supposed to. Usually see it also with cooler plugs.

For 20% on down, a medium-hot plug is usually ok and at least one head shim.

 

[Lampwick]

Cheers for helping out ?

 

[Arrmajunk]

Hi
I'm taking this kyosho gx12 engine apart and I've noticed it has no gasket between the head and the block ...is this correct or is it missing a gasket ???
Cheers

It should have at least one Shim yes!
I wouldn’t run much higher than 16% Nitro and I’d suggest an Oilly blend rather than a Race orientated mix if you do go 20% 25% then you need more shims

 

[Lampwick]

Cheers I went with one shim in the end with 16% and it's been running ok last couple of days ,apart from keep getting little air pockets in my fuel line , but I think trimming the ends so its a fresh bit should help it seal round the tank and carb or some stupidly small jubilee clips

 

[D3MON]

Cheers I went with one shim in the end with 16% and it's been running ok last couple of days ,apart from keep getting little air pockets in my fuel line , but I think trimming the ends so its a fresh bit should help it seal round the tank and carb or some stupidly small jubilee clips

it could also be the tank leaking itself, ususally can seal it up with some silicone sealant or use O-Rings to make things seat tighter. glad its running for ya though!
what body you settle on?
any more pics?

 

[Arrmajunk]

Cheers I went with one shim in the end with 16% and it's been running ok last couple of days ,apart from keep getting little air pockets in my fuel line , but I think trimming the ends so its a fresh bit should help it seal round the tank and carb or some stupidly small jubilee clips

Your welcome, & New tubing isn’t overly expensive ? And always handy to keep half a metre or so spare . Failing that Have a look at the rubber Gromit under the filler cap make sure that’s closing and making a tight seal.
If nothing wrong with the tank no leaks or anything Have alook around the nipple Of the main needle there’s a rubber seal under that too. There’s aso a rubber seal under the carb.
They could have perished if it’s an old engine if not move on , keep looking there has to be a reason your getting air into the fuel .

 

[Lampwick]

Hi ,Not picked a body yet it came with an rx7 shell but it doesn't quite look right , not to sure what body to get yet but when I see it I'll know lol .ill put some pics up over the weekend of it so far it runs and drives but is not finished ... would like new wheels and the bit the diff cup sits in on the front wheels/shaft as they are quite worn and wobbly but the parts are hard to come by but I'll find something that does the job lol

 

[Lampwick]

Also the front drive shafts keep popping out under full lock I've adjusted the end point on the tx but it left me with next to no steering, so I had a little look and it seems to me that they are to short ? (48mm) eye to eye (50mm) total ,they have quite a lot of travel a good 5-7mm ...could I (A) pack them out diff side? or (B) try some longer dog bones ?

Any body know what length of the front dog bones should be on a kyosho pureten alpha?
Cheers

 

[Lampwick]

Some random pics I took the other day before taking it to bits and giving it a little tidy up
.better pics to follow, can't wait for the new air filter to turn up , that thing just looks nasty lol going to try and take it for a spin Sunday evening so I'll try and a little video of it running as would like your lots input on how it's running etc .......but for now it's beer o'clock lol

 

[D3MON]

Also the front drive shafts keep popping out under full lock I've adjusted the end point on the tx but it left me with next to no steering, so I had a little look and it seems to me that they are to short ? (48mm) eye to eye (50mm) total ,they have quite a lot of travel a good 5-7mm ...could I (A) pack them out diff side? or (B) try some longer dog bones ?

Any body know what length of the front dog bones should be on a kyosho pureten alpha?
Cheers

i know one company used to sell cup springs awhile back, dont remember the company, may be able to use a cut up pen spring to stick in each side or maybe some fuel tubing?
i think RCMonster still does custom dogbones, i found a set of 52mm dogbones for HPI but i dont know the sizing for the dogbones to fit in the diff cups.

 

[D3MON]

Some random pics I took the other day before taking it to bits and giving it a little tidy up
.better pics to follow, can't wait for the new air filter to turn up , that thing just looks nasty lol going to try and take it for a spin Sunday evening so I'll try and a little video of it running as would like your lots input on how it's running etc .......but for now it's beer o'clock lol

looks good! wow that thing is pretty clean especially considering its age! man that head is tiny!!! is that the glow plug sitting above the top cooling fin!?!
is that a single needle carb? or is there a Low Speed on the carb? should be right where the linkage connects to the Carb slide.

 

[Lampwick]

Hi , new air filter arrived today so I've fitted that now (looks much better) I.m.o ....Also chopped up a pen spring and put half in each dogbone cup to stop them from popping out on full lock (Cheers whoever mentioned that little tip)....and solved the air bubbles in fuel line/leak by slipping a extra bit of fuel tube over the fuel line at connection points to squeeze the tube tight over the nipples etc and problem solved.
Still not decided on a body yet but put some leds in rx7 shell just to cheer it up a bit until I find a shell I like lol.
Runs quite well at the moment,Cheers for all the help .
Sorry for the crap video and driving , took it for quick blast on Sunday just for shits and giggles ,hard to hold the phone and TX,, film and control at the same time .