I understand and agree with you, and the OP can make his own decision on what Cr he chooses. So as I asked you before, did your melted pistons happen because of Pinging or what caused it? Could have been ran too lean, could have been sitting in city traffic over heating or maybe any combination of neglect. Hi compression engines are not for everybody because they have special needs and special tuning and a lot of people wont keep up with it, hence the problems. It's really not rocket science to make a 10-1 work correctly and without problems, but then again it seem to be for some.

 

what we had as issues is the loss of power after high speed driving - then when cold it seem to run better but the customers always had the same thing - never seem to run the same day in and day out or a running pull you recognize as the same

somtimes it goes like all - and sometimes its just not on its game

what we found AS you know the Evo cylinders grow and have a memory as well as having an alloy wrapped cast iron sleeve who's design was 8 to 1 compression, the cylinder was not coming back to the original shape that it was honed at with torque plates

having said that - some cylinders never did go way off it's torque plate's roundness but some do and no way we have found to tell what one will and what one wont stay round, SoOOO we dont go to that edge and we have had to eliminate that comeback issue and that is a big one -

BTW - the pistons we had talked about earlier were from other shops after all the storys they showed up and they recieved the best reliable performance available as we see it

again i am glad yours is great - jz

 

Johnjzjz--I bought the Axtell cylinders and Wiseco pistons as a set--both are brand new, but I got an unbelievably good deal. What would you do? I can afford to spring for new pistons. I just had most of the other parts on hand and want to know if they would work together. Its just a shame to have everything just laying around as parts and difficult to sell because of my location. I have a small budget left over from my bike, but my wife is going to poop a cinder block if I get carried away though.

 

i hope that does not happen to the wife - you will pay for that if she does

you need to have a shop put the torque plates on the axtell cylinders

than measure the lower section of your piston to get its size

than you transfer that measurement ( the pistons ) to the bore gage before installing it into the cylinder

and from that you can tell if they are a match --- if not maybe a little honing and they become a set at the correct clearance - i would say off hand .003 to .0035 in inches

remember to keep the front and rear as sets dont mix the pieces after they have been fitted - good luck

 

The 10.5:1 pistons were fitted and are marked for the Axtell cylinders. I am just curious as to what you would do, run this combo or buy new pistons.

 

I think you said you had a stroker so I would get some 9.5 weiscos forged pistons.

 

Some just mill the top off the pistons to reduce the compression. Johnjzjz could probably tell you how much to mill off.

 

i missed that too much reading to do every time --

you can shave the tops of the pistons in some cases to reduce the ratio - you need to find out if the pistons you have are ( solid dome ) or are they ( hollow dome ) if they are solid than you can adjust the compression to what ever number you want - hollow dome you need to be able to measure the inside hollow pocket to the dome top so as not to make it too thin when cutting the shelf area on top - a real shop needs to look at that for you

But you could contact wiseco and ask them about removing material for reduced compression

 

I have a ? what's the part number is on those pistons. if there 3.625 pistons wiseco doesn't make 10.5:1 they only offer 9.25:1 in that bore. if there 3.498 they only offer 10.5:1 for the screaming eagle heads. I tried to get 10.5:1 from them for my build
they told me they would make them for me if I ordered 500 sets. so how did you get so lucky.

 

D , he has a 4 1/2" stroke so they have different CR's available then they have for 4 1/4". At least that's the case with my 4.625 stroke.