Cylinder head O ring conversion
-
I'm doing an O ring conversion on a 3MB 'p' cylinder head. I have the YZ o ring which is 1.7 mm thick. A general engineering shop is cutting the grove but is asking how deep the grove needs to be. Any advice appreciated
-
@moggy74 I can't comment on YZ or DT conversions I've not done it myself.
The Aprilia RS 125 uses O-Rings and I had a cylinder lying around. 1.50mm
-
@Calum what thickness oring
-
Could try this calculator, do some more research and go for most logical one worst comes to the worst could use a thicker of thinner oring
-
@moggy74 said in Cylinder head O ring conversion:
I'm doing an O ring conversion on a 3MB 'p' cylinder head. I have the YZ o ring which is 1.7 mm thick. A general engineering shop is cutting the grove but is asking how deep the grove needs to be. Any advice appreciated
I think PJME other this service for DT heads as quite a lot of people struggle with head gasket problems + they can be expensive in comparison to an O ring.
The reason I mention is PJME also provide the o-rings.
Either get into touch with them or find a suitable O-ring for the application / size and measure it as you’ll only ever replace one o ring for another, not like you’ll need different sizes
-
@Stevie-Wonder That's interesting, in the 12 years I've had my DT I've never had head gasket issues. The only person I know to have problems is @SpookDog
I assumed it was so they can run higher compression and therefore more power.
Always Originate, Never Pirate!
-
@Calum Me either bud, so I can’t personally attest. Over the years though I have seemed this be a frequent issue although I’m pretty certain most of the time that’s caused by cheap gaskets or uneven mating surfaces
Poor @SpookDog too
Regardless £50 for a gasket Vs £5 for some O-rings + the added benefits that come with it isn’t bad shout
-
@Stevie-Wonder Yeah, especially as OEM gaskets rise in price and get harder to obtain, it's certainly worth considering. And again, if it does raise compression for more power
-
@moggy74 said in Cylinder head O ring conversion:
I'm doing an O ring conversion on a 3MB 'p' cylinder head. I have the YZ o ring which is 1.7 mm thick. A general engineering shop is cutting the grove but is asking how deep the grove needs to be. Any advice appreciated
Did you try a custom copper headgasket,less hassle,reusable and is used in high compression/performance. In a DT does perfect the job.
-
@Calum said in Cylinder head O ring conversion:
@Stevie-Wonder That's interesting, in the 12 years I've had my DT I've never had head gasket issues. The only person I know to have problems is @SpookDog
I assumed it was so they can run higher compression and therefore more power.
I never had a DTR headgasket leak when I was younger but I've had two fail this year; one on my 12,000 mile '93 which I'm fairly certain had never been stripped (I bought it completely original at 6k and the bore is standard) and a '98 French import with 60,000 km, the highest mileage DTR ever sold by Unit 5. And when I stripped it it was still on the standard bore as well!
I guess the previous owner must have had so many rebuilds they ended up having to buy a new cylinder, I know they used it to commute in and out of Paris every day for over 10 years so maybe it's just age/wear on both counts if they racked up some of those miles on the new cylinder. Certainly seemed OK after I replaced it and lapped in the cyl head.
I didn't know PJME offered the O-ring prep service, might be interested in that.
-
@HOTSHOT-III They certainly don't last forever, can't recall the service intervals but it should be rings at 7k miles which means new gaskets etc.
But I've heard stories of people running 30k km on original everything lol.
