JPM cylinders

[spoolin70]

Good ?

Bad ?

Certainly not ugly 

Anybody using them in either 94mm or 4" ?

Thanks
Darren

[WPS]

Definately good!!....I've used the 94mm ones on a 400+hp nitros motor.....as with everything JPM makes...none of it is for show...it's all very well researched and tested using the best materials known to man....!!   

Use 8mm heavy duty studs (Raceware etc) as 10mm are too tight and machining the cylinder for clearance defeats the object...they're deliberately thicker in that area to avoid distortion when torqued/abused...

Speak to Johannes...you won't be disappointed!!

[Jeff68]

I was wondering the same thing about these cylinders. I read the ad on the JPM site that gives the details on the cylinders and it seems these are very high quality with a much thicker wall than other 94mm cylinders that are available from other manufacturers. I don't think they come with pistons so I'm guessing that you have to have some custom made for these cylinders probably based on JPM's recommendation  after you discuss the application with him - naturally aspirated, turbo, nitrous ect.  I'm considering these as well they look like they will cool well and last / live long in a street application. Nice....

[Airspeed]

I was wondering the same thing about these cylinders. I read the ad on the JPM site that gives the details on the cylinders and it seems these are very high quality with a much thicker wall than other 94mm cylinders t

.. I'm considering these as well they look like they will cool well and last / live long in a street application. Nice....

How does that work? The thicker the wall, the better?

Does a thicker iron cast wall really cool better?
 

[WPS]

Johannes can sell you a set of his custom pistons and hone the cylinders to suit...or you can use an off the shelf 94 piston and get the compression honing done yourself.....usually best to call him late in the day. 

I used them on a street motor in a bus with type 1 cooling....he drove it home from here (150 miles) ....with NOS it ran a mid 11....bigger (greedier) NOS jets being added this season so we'll see what happens but I expect the head to fail before the cylinder......they're built from truck iron!! 

The thicker the better......that way it stays round and true when hot ....the cooling comes from the fins!

[Jeff68]

WPS - Thanks for the information on the JPM pistons and cylinders. I think historically / what people have said about 94mm pistons and cylinders was that the cylinder wall was not thick enough and as a result when / if the pistons and cylinders got too hot the cylinders didn't keep their shape and then blowby would be a result. I know many people have used the Mahle 94's and not had problems so as always everyone should draw their own conclusions / decisions. I can't say as I've never used any 94's - yet.  From what I can see (in my opinion) the JPM 94 pistons and cylinders are the best that I've seen, are made from top quality materials and I'm sure are made to Johannes exacting specifications. I would really like to use a set of 94's that could last as long as good quality 90.5's and I think the JPM ones will.

This is a perfect reason to increase my engine from 2110 to 2276 and get some more head work done while the heads are being bored for the new Pistons and cylinders!

[spoolin70]

Appreciate the information Ian 

Interesting about the head stud sizes, I've already got 10mm Raceware studs so may have to open the holes out a little - although I am talking about the 4" cylinders more specifically. I've also just received my JE pistons so it sounds like I'm ordering parts a bit backwards.

Email sent to Johannes this morning - no prices on his site for 4" cylinders.

Thanks
Darren   

[WPS]

Hey Darren

I've not used the 4" ones but did use 10mm Raceware studs on a 94 set. I machined the studs rather than the cylinders....leave the material on the cylinders there if at all possible....especially with those big ol' slugs!! 

Good luck.

Ian