Super Jet Ada head question...with pics

[jetx]

All the Ada heads I’ve owned and seen have the spark plugs screw in and be flush with the head shell..this head has a recessed spot in the dome and the spark plug sits deeper. This appears to be an older Ada head...is this how the older domes/heads were or is there something special going on here. Searched and just couldnt find anything that looked like these. All I know about the motor is it is TLR ported.

Any insight is appreciated

 

[Aidan Burns]

I never noticed that buddy. Not sure what’s going on there either...


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[Aidan Burns]

I bet it has to do with plug length. I bet you can run brh8s which are stock Superjet plugs. The br8es are normally used with ADA Head because it is thicker.


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[jetx]

It uses the br8es just fine...just never seen the recess before and just curious what I have here. Tend to like tomknow all the details of my setup lol

 

[Aidan Burns]

The plug doesn’t stick too far into the cylinder though, does it?


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[Aidan Burns]

I guess no way to know unless you pop the head off. Easy enough to do since it’s o-ring head for some double verification....


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[jetx]

No it doesn’t, thread lengths are same size as br8es

 

[Jr.]

They are normal. Probably 31-33cc? Higher cc plug will sit flush

 

[jetx]

Will have to check size but that makes sense...thanks!

 

[JetManiac]

701/33cc still sits flush so those domes are something smaller.

 

[jetx]

Looks like I better check them

 

[Aidan Burns]

That’s weird. When I bought that motor I was told they were 35cc for around 180-185 psi


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[augustaf]

Yak! The op seems to have flat top domes- picture shows a 26 cc 86mm flat top dome I bought and then machined to suit my 5 mm stroker needs. They require the long reach plugs, just like the others. you might look at page 136 of the HP catalogue: http://www.hotproductsusa.com/Flip_Cats/2017/index.html#136

 

[jetx]

Well now I definitely need to check them...are flat top pistons perfectly flat? Pistons in it look pretty typical to me me and have a concave to them

 

[jetx]

I pulled the head and found 33cc 760 domes...I cant find my caliper but the pistons are marked 1.5 so I’m thinking this is actually a 771 61x bigbore. Still have to measure to confirm but guess I can’t be upset since I was told it’s a 718.

I did find some play in the lower connecting road bearing on the stator side, I can move it side to side a bit by reaching through the intake opening, the coupler side doesn’t seem to move at all, so I’m thinking the crank needs replaced. Or anyone think this is ok to run?

 

[Aidan Burns]

I pulled the head and found 33cc 760 domes...I cant find my caliper but the pistons are marked 1.5 so I’m thinking this is actually a 771 61x bigbore. Still have to measure to confirm but guess I can’t be upset since I was told it’s a 718.

I did find some play in the lower connecting road bearing on the stator side, I can move it side to side a bit by reaching through the intake opening, the coupler side doesn’t seem to move at all, so I’m thinking the crank needs replaced. Or anyone think this is ok to run?

I believe side to side is fine to an extent. It’s up and down that would be an issue. Also, if that’s a 771, good on you lol. Wish I knew it.


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[jetx]

Lol yeah definitely surprised me seeing those domes

 

[Aidan Burns]

If they are +1.5, I believe that would make it a 727. I was told they were 1 over but never had the head off to look myself.


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[tomski]

82.5mm looks like.

 

[jetx]

I have to confirm the bore size still...so it’s either a big bore or has the wrong size domes in it?