As a few of you know ive been rebuilding the bottom end in my impreza, i got the bits last friday but then realised ive been sent oversized piton rings. i emailed the seller (advanced automotive performance) and heres what was said:
i sent this:
----- Original Message -----
From: stuart jackson
To: enquiries@advancedautomotives.com
Sent: Saturday, May 09, 2009 8:20 PM
Subject: Problem with order
hello again,
just a quicky, i received the items on friday morning, around 11.30am and got to work straight away. when i got to the point of installing the pistons and rings i took the engine block a place in norwich ive been using for a few years now, to get the rings gapped.
while there, we suddenly realised that ive actally been sent 92mm pistons but 92.50mm piston rings (as it says on the box they came in)
unfortately, these rings will not fit my standard 92mm bore block and conciquently has put my completion date back even further. even if i could get these oversized rings gapped and fited, since the circumference is oversized, this would put too much stress on them and could seriously damage my block.
can you please ring me ASAP on 0777*****63 or just send out a new set 92mm rings to my address.
many thanks, Stuart.
and i got this reply:
Hello Stuart,
The Mahle forged piston kits have a file to fit piston ring system just like most other top end piston manufacturers. The 92.5mm ring set is used in the standard bore kit and 92.5mm kit as both bore sizes still require the rings to be gapped, even when the 92.5mm rings are fitted to the 92.5mm bore, the gap is still too small. The reason for the file to fit system is too allow engine builders to set their own gap depending on the bhp, fuel and road/track. This is why one gap will not suite all. The stress that you mention is not the case at all. Perhaps your guys in Norwich should know this but may be they have never used top end forged pistons before. We have used countless Mahle pistons in our engines and besides this who are we to argue with Mahle on their ring system.
I hope this clears it up.
Regards Cath
does this seem right??
has anyone else ever used Mahle pistons/rings and had a similar experience? :? :?
cheers, Jacko
Mahle Piston Ring Question.....
Mahle Piston Ring Question.....
JDM Blobeye STi
ive just read the spec sheet given with the rings reguarding the gaps and i cant make much sence of it 
it says:
top ring needs to be Bore x 0.0045"
second ring needs to be Bore x 0.0055"
oil rings need to be minimum of 0.015"
i calculated it with an online convertor (mm to inches)
and for the top ring i got:
bore = 92mm
0.0045" = 0.11mm
92mm x 0.11mm = 10.12mm
this doesnt make sence to have a ring gap of over a cm!!
ive done the same calculations to get:
top ring gap = 10.12mm
second ring gap = 12.88mm
oil ring gap = minimum of 0.38mm
does having a ring gap of over a cm really make sence??
it says:
top ring needs to be Bore x 0.0045"
second ring needs to be Bore x 0.0055"
oil rings need to be minimum of 0.015"
i calculated it with an online convertor (mm to inches)
and for the top ring i got:
bore = 92mm
0.0045" = 0.11mm
92mm x 0.11mm = 10.12mm
this doesnt make sence to have a ring gap of over a cm!!
ive done the same calculations to get:
top ring gap = 10.12mm
second ring gap = 12.88mm
oil ring gap = minimum of 0.38mm
does having a ring gap of over a cm really make sence??
JDM Blobeye STi
You need to convert to inches to get a sensible figure.jacko-sti wrote:ive just read the spec sheet given with the rings reguarding the gaps and i cant make much sence of it
it says:
top ring needs to be Bore x 0.0045"
second ring needs to be Bore x 0.0055"
oil rings need to be minimum of 0.015"
i calculated it with an online convertor (mm to inches)
and for the top ring i got:
bore = 92mm
0.0045" = 0.11mm
92mm x 0.11mm = 10.12mm
this doesnt make sence to have a ring gap of over a cm!!
ive done the same calculations to get:
top ring gap = 10.12mm
second ring gap = 12.88mm
oil ring gap = minimum of 0.38mm
does having a ring gap of over a cm really make sence??
92.0mm = 3.622" x 0.0045" = 0.016" = 0.414mm
92.0mm = 3.622" x 0.0055" = 0.020" = 0.50mm
92.0mm = 3.622" x 0.015" = 0.054" = 1.372mm
Please check those figures as it's early.
Handle every stressful situation like a dog. If you can't eat it or hump it, piss on it and walk away!
cheers for that gerry 
ive just rung up Scholar Engineering, im dropping off the block, pistons and rings to them tomorrow afternoon (after my speed awareness course :oops: 37 in a 30 :oops: ) they should be able to gap the rings for me, im thinking about just asking them to install them aswell, save me some time
once thats done, i can crack on with the rest of the build, run it in, then ship it of to cyprus
ive just rung up Scholar Engineering, im dropping off the block, pistons and rings to them tomorrow afternoon (after my speed awareness course :oops: 37 in a 30 :oops: ) they should be able to gap the rings for me, im thinking about just asking them to install them aswell, save me some time
once thats done, i can crack on with the rest of the build, run it in, then ship it of to cyprus
JDM Blobeye STi