Discussion
My valley gasket is leaking oil at the front and rear but only when the engine is really worked hard. Is it possible to replace the end seals without removing the entire manifold ? There appears to be a hook at each end of the seal which presumably hooks onto the main gasket. Do these hooks stop me from changing just the end pieces ?
To get them in properly the inlet has to come off. There maybe worse to come? If the engine is forcing oil out of the end seals the crankcase is possibly overpressurising, if you're lucky the breather pipe has a partial blockage, if not the engine is producing so much by-pass gas the pipe cannot cope. If you suspect the latter get a leak-down check done before you you do anything more.
GreenV8S said:
If I were you I'd sort out the underlying problem with the breathers, I suspect the valley gasket leak will then magically disappear.
That would be nice.I have had a problem all year with them leaking front and rear but only when the engine is really loaded, or so I thought. They never seemed to leak on the road but the engine always needed a wipe off after a hill climb run. So could be it was not actually engine load but engine load combined with a bit of oil surge getting oil up round the crank. Have suspected that the oil level has been too high so took the sump off last week to see where the fill mark is compared to the crank. Full is slightly (about 5cm) below the lowest moving part. However I have a baffled sump and would think ideally the oil should be under the windage tray rather than above it. If that is the case I have had too much oil.
Initially the engine was breathing to the inlet via the normal system and I formed the opinion the crank was pressurising when closing the throttle at high rpm. To fix that possibility I replaced the oil filler with another flame trap and have two 15mm id pipes to a catch tank so don’t think the breathing is compromised.
Quinny said:
chris52 said:
Quinny is that a specific gasket for the ported heads? or did you have to to agjust/cut it to match the wider ports on the 5.0ltr engine? if it is a direct fit I would be very interested to find out where you got it from.
Chris
Hi ChrisChris
It came from V8D, it was a close fit, but I opened it out with a dremel to match the ports
steve-V8s said:
Initially the engine was breathing to the inlet via the normal system and I formed the opinion the crank was pressurising when closing the throttle at high rpm. To fix that possibility I replaced the oil filler with another flame trap and have two 15mm id pipes to a catch tank so don’t think the breathing is compromised.
Perhaps not, but it still seems to me that the engine needs better breathing than it has. If the breather is already better than standard, perhaps the real problem is that you have far too much blow-by and it's overwhelming the breather. If you can arrange it, it'd be interesting to see what crankcase pressures you actually get on the road. I've never tried measuring it, but I'd try the same technique I've used on the exhaust: Find a threaded hole (lambda sensor boss works great on the exhaust - on the rocker cover I'd try the vent inlet, or the lead clip mounting holes), screw in a threaded adapter, connect to a metal pipe to act as a heat sink, connect to a silicon vac hose to get away from the heat, connect to ordinary plastic hose to a vac/boost gauge inside the car.GreenV8S said:
It would be interesting to see what crankcase pressures you actually get on the road.
Now there is a good idea. Somewhere I have a hand held pressure differential meter with a nice long sampling tube. It is intended for measuring the pressure differential between controlled environment rooms. I wonder if I could measure the pressure at the dipstick tube, that may reveal what is going on in the crank area. If so it would be a nice easy way to make a comparison with another engine.Thanks Peter, a sensible suggestions as always.
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