CP piston and cilynder trick

[jr59]

So,
We ordered piston & liner kit from Shawn Geer in 96.7 and 101.6mm.Both ome with non finned cylinder (for race only engine).The piston are beautiful and very light.
But when we look at the Cylinder it seems that honning inside look s very light...And we don"t have any paper shit togive us the needed clearance for the parts.Needless to say that we tried to get the info from him (shawn).. with no answer!.
So we want to make a fixture to hone them correctly (2 pressure plates tighting the cylinder at good the torque thus having the right ID value).But before any kind of work We would need the clearance info
hope that someone would give us those
cheer
 JR

[Allen Wiess]

The honing sounds correct for the rings Shawn supplies.  Did you try emailing Shawn or calling?

[pig1200]

Yes I have the same question and the same problem as JR.
I try to have more information to fit finned cylinder in an aluminum case with STD head stud pattern.
I asked Shawn if  I need to check the clearance between the barrel and the piston, and I received no reply. What ring tensions do I need to apply for high or low CR. If my engine is N/A or turbo, nitrous. What is the max RPM with this brand piston.
The hone is very fine and we want to understand why it's very fine. This is to find the best settings fore each  engine.
If all is ok we bolt all like this, if we need to modify clearance or deep honing is not a problem, I know this type of product is a "Blank"
Thanks for your advice.

Cédric

[Allen Wiess]

What piston clearance do you have now?

What is the application? (NA, turbo, nitrous) Then I can get the ring gap clearances for you.

[pig1200]

Hi Allen
For the 96.7
Barrel: 96.80 and piston 95.90, clearance is at 0.9mm
For the 101.6
Barrel: 101.60 and piston 100.10, clearance is at 1.5mm
Strange difference between two cylinder kit.
The diameter of the pistons is taken between the top of the piston and the first ring.
The honning is the same for both kits.
The 96.7 is for a 86mm crank, NA, and high CR
The 101.6 is for a 88mm crank, NA and high CR.

Has Someone had a good result of machining the honning of the barrel between two big aluminum plates with 4 or 6 studs and the same tightening torque as the final assembly of the engine??

thx

Cédric

[Allen Wiess]

Cédric,

You need the measure the pistons on the skirt 12mm from the bottom.

The honing on the cylinders is correct for the application, the same as I use.

Allen

[richie]

Hi Allen
For the 96.7
Barrel: 96.80 and piston 95.90, clearance is at 0.9mm
For the 101.6
Barrel: 101.60 and piston 100.10, clearance is at 1.5mm
Strange difference between two cylinder kit.
The diameter of the pistons is taken between the top of the piston and the first ring.
The honning is the same for both kits.
The 96.7 is for a 86mm crank, NA, and high CR
The 101.6 is for a 88mm crank, NA and high CR.

Has Someone had a good result of machining the honning of the barrel between two big aluminum plates with 4 or 6 studs and the same tightening torque as the final assembly of the engine??

thx

Cédric

Where are you measuring to get those numbers?
I usually look for 0.005 tp 0.008thou  and Shawn honed my cylinders as you describe and they work excellently,the rings sealed up really quick and I ave virtually zero leakdown still after a season of abuse

cheers richie,uk

[Roman]

If it is a race engine you should use stress plates before you measure them and hone them.

[fish]

leave them alone and re-measure Shawn's stuff works "out of the box".

[jr59]

Ok Guys,
yes we exepcted to trust in geer parts,but as we're so far from him and as he don't take time to answer us we became quite dis

[jr59]

oops,misatake..
so back to answer:
Ok Guys,
yes we exepcted to trust in GEER parts,but as we're so far from him (in France) and as he don't take time to answer us we became quite disapointed .So cedric did't take the good measument.I will chek them  today,hoping that everything is fine.
The other point is that they were no paper shit to give us minimal or max clearance between piston & cylinder (when I purchased my wiseco there was the shit with value...).
As far the honing seems very light for us .. this is the first time we have non finned "pure race" cylinder !! so comparing to other the honing very light! but if it's OK for race... well OK
thus sometimes  a little explanation may clear most of the problem and brain storming...
cheer
 JR

[Allen Wiess]

CP Piston ring gap sheet   http://www.cppistons.com/LinkClick.aspx?fileticket=eBVGqvQcWj8%3d&tabid=75

Honing information    http://www.cppistons.com/LinkClick.aspx?fileticket=tGrcf6sUdOY%3d&tabid=107

I will wait to hear about the piston to cylinder clearance, but I am sure it will be correct.

[Marty]

Run them - they will be fine. I use them all of the time with that hone.