boomerang
Member
- Messages
- 412
Years ago i mounted an oil prelube system, as some of you may remember.
My Gransport only runs very occasionally, so it is nice to see oil pressure being built even befor the engine is running.
Meanwhile, some of you (and me) where investigating the occasional rattle at start up, even with these dry sump engines.
Then the function of the accumulator in the variotor circuit came up.
I am convinced now, this part is the big culprit.
Especially when cars are standing for months or even years without running.
After serious discussions with guys that do a lot in hydraulics, it became clear that this piston design accumulator, mounted in the wrong way (horizontal) wil wear very fast and will loose its nitrogen filling soon.
Its internal piston is pushed back to the end of the housing, when its nitrogen filling is lost, as soon the engine starts running.
What happens after that, at its next cold start: you start the engine, oil pressure is built, but the oil has to fill the accumulator first, before pressure is provided to the variators.
So they will rattle for seconds.
After a long search, i found a provider who could deliver a bladder type of accumulator built to spec.
I fitted the unit now, on the original bracket, all seems fine.
The occasional two second rattle is gone now. (prelube system NOT used of course)
Lets see how this behaves in the coming weeks, will keep you posted.
My Gransport only runs very occasionally, so it is nice to see oil pressure being built even befor the engine is running.
Meanwhile, some of you (and me) where investigating the occasional rattle at start up, even with these dry sump engines.
Then the function of the accumulator in the variotor circuit came up.
I am convinced now, this part is the big culprit.
Especially when cars are standing for months or even years without running.
After serious discussions with guys that do a lot in hydraulics, it became clear that this piston design accumulator, mounted in the wrong way (horizontal) wil wear very fast and will loose its nitrogen filling soon.
Its internal piston is pushed back to the end of the housing, when its nitrogen filling is lost, as soon the engine starts running.
What happens after that, at its next cold start: you start the engine, oil pressure is built, but the oil has to fill the accumulator first, before pressure is provided to the variators.
So they will rattle for seconds.
After a long search, i found a provider who could deliver a bladder type of accumulator built to spec.
I fitted the unit now, on the original bracket, all seems fine.
The occasional two second rattle is gone now. (prelube system NOT used of course)
Lets see how this behaves in the coming weeks, will keep you posted.
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