Custom turbo
Custom turbo
08-31-2020, 10:55 AM
#7
(08-27-2020, 05:54 PM)Austincarnut(08-11-2020, 09:27 AM)OM616I was running no more than 1100*F going up hill with ac on at full boost on a hot day(08-10-2020, 09:30 PM)Austincarnut I over rev'd it and dropped a valve. Well more like stretched the shit out of it then it hung open and kissed the piston. All 5 cyl have valve guide material imbedded in them. I was a blast till the end. If only the valve train was more resilient...
What was your average sustained and highest EGT while you were thrashing on it?
Valve seat spring pressure has a lot to do with valve cooling. As boost (for intakes) EMP (for exhaust) pressure increases effective seat pressure decreases.
Additionally, if the spring pressure is not enough, the valve will bounce on the seat which significantly reduces the cooling of the valve which can result in the valve sinking or dishing. As far as I know, the OM61X engines redline is around 4500 ish at only 10/12 PSI of boost which on a stock T3 would generate around 15lbs of EMP. And that is will very little fueling. It sounds like you have increased fueling, boost, EMP, and RPM enough to push the valvetraine beyond its working range.
Valve cooling is all about seat pressure, and in really extreme set ups, seat material. Springs need to matched to suit the cam profile, boost, EMP, and RPM range.
Another thing I have seen is the valve nuts coming loose.
(08-27-2020, 05:54 PM)Austincarnut(08-11-2020, 09:27 AM)OM616I was running no more than 1100*F going up hill with ac on at full boost on a hot day(08-10-2020, 09:30 PM)Austincarnut I over rev'd it and dropped a valve. Well more like stretched the shit out of it then it hung open and kissed the piston. All 5 cyl have valve guide material imbedded in them. I was a blast till the end. If only the valve train was more resilient...
What was your average sustained and highest EGT while you were thrashing on it?
Valve seat spring pressure has a lot to do with valve cooling. As boost (for intakes) EMP (for exhaust) pressure increases effective seat pressure decreases.
Additionally, if the spring pressure is not enough, the valve will bounce on the seat which significantly reduces the cooling of the valve which can result in the valve sinking or dishing. As far as I know, the OM61X engines redline is around 4500 ish at only 10/12 PSI of boost which on a stock T3 would generate around 15lbs of EMP. And that is will very little fueling. It sounds like you have increased fueling, boost, EMP, and RPM enough to push the valvetraine beyond its working range.
Valve cooling is all about seat pressure, and in really extreme set ups, seat material. Springs need to matched to suit the cam profile, boost, EMP, and RPM range.
Another thing I have seen is the valve nuts coming loose.
Messages In This Thread
Custom turbo - by OM616 - 07-29-2020, 01:46 PM
RE: Custom turbo - by Austincarnut - 07-29-2020, 10:07 PM
RE: Custom turbo - by OM616 - 07-30-2020, 01:27 PM
RE: Custom turbo - by Austincarnut - 08-10-2020, 09:30 PM
RE: Custom turbo - by OM616 - 08-11-2020, 09:27 AM
RE: Custom turbo - by Austincarnut - 08-27-2020, 05:54 PM
RE: Custom turbo - by OM616 - 08-31-2020, 10:55 AM
RE: Custom turbo - by Austincarnut - 09-02-2020, 09:45 PM
RE: Custom turbo - by OM616 - 09-09-2020, 04:27 PM
RE: Custom turbo - by vica153 - 09-30-2020, 11:09 PM
RE: Custom turbo - by OM616 - 10-02-2020, 05:21 PM
RE: Custom turbo - by vica153 - 10-02-2020, 08:29 PM
RE: Custom turbo - by OM616 - 10-03-2020, 04:08 PM
RE: Custom turbo - by vica153 - 10-04-2020, 12:25 AM
RE: Custom turbo - by OM616 - 10-04-2020, 12:08 PM
RE: Custom turbo - by vica153 - 10-04-2020, 02:01 PM
RE: Custom turbo - by OM616 - 10-04-2020, 06:28 PM
RE: Custom turbo - by vica153 - 10-04-2020, 08:40 PM
RE: Custom turbo - by vica153 - 10-04-2020, 08:52 PM
RE: Custom turbo - by 50harleyrider - 10-11-2020, 09:11 PM
RE: Custom turbo - by vica153 - 10-11-2020, 11:39 PM
RE: Custom turbo - by OM616 - 12-06-2020, 02:11 PM
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