Step change in oil consumption
Discussion
Through last year my Griff 500 was using around 1600 miles/litre oil.
I'm now seeing around 500 miles/litre. It's not the consumption that concerns me it's the change.
Subjectively I'm seeing more oil underneath, with droplets reaching the rear ARB after only a 100 mile run. It's definitely engine oil so pinning my hopes on oil loss though she's always been a little moist underneath.
There is fresh oil down either side of the back cylinders of the block, around the rear bolt line of the sump and all around the inside the bell housing.
I've run the engine on idle for half an our inspecting inderneath and nothing appearing.
The rocker gaskets are new and dry below at rear.
Had plenum off recently and feels dry below rear valley, top of bell housing is dry as best as can tell.
Oil breather system cleaned & clear.
Removed the bellhousing plate front cover so can see rest of flywheel. No fresh oil on rear of flywheel or drips evident from rear seal though difficult to see clearly.
I'm just opening this up for ideas now before I dig deeper.
I'm now seeing around 500 miles/litre. It's not the consumption that concerns me it's the change.
Subjectively I'm seeing more oil underneath, with droplets reaching the rear ARB after only a 100 mile run. It's definitely engine oil so pinning my hopes on oil loss though she's always been a little moist underneath.
There is fresh oil down either side of the back cylinders of the block, around the rear bolt line of the sump and all around the inside the bell housing.
I've run the engine on idle for half an our inspecting inderneath and nothing appearing.
The rocker gaskets are new and dry below at rear.
Had plenum off recently and feels dry below rear valley, top of bell housing is dry as best as can tell.
Oil breather system cleaned & clear.
Removed the bellhousing plate front cover so can see rest of flywheel. No fresh oil on rear of flywheel or drips evident from rear seal though difficult to see clearly.
I'm just opening this up for ideas now before I dig deeper.
First thing would be to renew the sump gasket or at least replace it with a good quality silicon type gasket seal and apply in the correct manner.
I checked mine yet today and after about 1000 miles there isn’t a drop around the sump. Rare for a RV8!
Another source of the problem could well be the rear crankshaft oil seal especially as you have oil in the Bell housing.
Those above and the rocker box gaskets are the usual suspects.
I checked mine yet today and after about 1000 miles there isn’t a drop around the sump. Rare for a RV8!
Another source of the problem could well be the rear crankshaft oil seal especially as you have oil in the Bell housing.
Those above and the rocker box gaskets are the usual suspects.
phazed said:
First thing would be to renew the sump gasket or at least replace it with a good quality silicon type gasket seal and apply in the correct manner.
I checked mine yet today and after about 1000 miles there isn’t a drop around the sump. Rare for a RV8!
Another source of the problem could well be the rear crankshaft oil seal especially as you have oil in the Bell housing.
Those above and the rocker box gaskets are the usual suspects.
Thanks phazed, nothing like a reply to give confidence to crack on.I checked mine yet today and after about 1000 miles there isn’t a drop around the sump. Rare for a RV8!
Another source of the problem could well be the rear crankshaft oil seal especially as you have oil in the Bell housing.
Those above and the rocker box gaskets are the usual suspects.
Nothing untoward inside the sump but cruciform ends are at least a mm short of the face. That's not going to help.
That brings me back to a couple of years ago when there was plenty of poor copy cruciform seals around.
Even the professionals like Turner Engineering were caught out by their supplier and they had to accept engine rebuild returns to renew these.
The problem was that the pattern parts were of a poor rubber construction and shrink after a short time leaving you with gaps top and bottom and consequently not sealing properly.
If I was you and there isn't any obvious leakage from the crank oil seal area, I would fill those little holes up with a good quality sump gasket maker type silicon. I usually use Whynns gasket maker and then create the sump seal in the same product and check it out from there.
If you decide to go down this route, clean the sump and the underside of the block with brake cleaner, apply a silicon bead on the sump lip all the way around and around every hole being careful not to use too much of the product. To make life easy, obtain two longer bolts, same thread as the sump bolts, cut off the head and screw and Loctite them in place mid row on each side of the engine. That way you can raise the sump and position it accurately without it sliding around .
Fit the rest of the bolts and the two nuts on the two studs and tighten barely more than finger tight so you leave a good band of gasket sealant nicely stuck to the sump and the block. Return some hours later and tighten up. This leaves you a nice set bead of a few millimetres thick and you shouldn't have any trouble from the sump in future.
Even the professionals like Turner Engineering were caught out by their supplier and they had to accept engine rebuild returns to renew these.
The problem was that the pattern parts were of a poor rubber construction and shrink after a short time leaving you with gaps top and bottom and consequently not sealing properly.
If I was you and there isn't any obvious leakage from the crank oil seal area, I would fill those little holes up with a good quality sump gasket maker type silicon. I usually use Whynns gasket maker and then create the sump seal in the same product and check it out from there.
If you decide to go down this route, clean the sump and the underside of the block with brake cleaner, apply a silicon bead on the sump lip all the way around and around every hole being careful not to use too much of the product. To make life easy, obtain two longer bolts, same thread as the sump bolts, cut off the head and screw and Loctite them in place mid row on each side of the engine. That way you can raise the sump and position it accurately without it sliding around .
Fit the rest of the bolts and the two nuts on the two studs and tighten barely more than finger tight so you leave a good band of gasket sealant nicely stuck to the sump and the block. Return some hours later and tighten up. This leaves you a nice set bead of a few millimetres thick and you shouldn't have any trouble from the sump in future.
Hedgehopper said:
I would definetly include the cruciform seals in your rebuild. It took my TVR Indie 'expert! three attempts to discover this. Now totally leak free at last.
The engine/box is in the car, only the sump is off. I was just confirming that he cruciforms can't be changed without box or engine out.Yes, when I do the crank seal, will defo also do the cruciform.
Hi, I know it's probably not anything to do with your situation, but my oil consumption went from minimal to loosing over a litre every 100 miles, and the cause has turned out to be oil being blown out of a head gasket. My leak though, also seemed to be coming from the rear of the engine/gearbox, but that wasn't the source, it was only ending up there after it was blown onto a chassis rail and trickled down to that point, very misleading. Also wouldn't leak out at normal tick-over, only under load.
griff59 said:
Hi, I know it's probably not anything to do with your situation, but my oil consumption went from minimal to loosing over a litre every 100 miles, and the cause has turned out to be oil being blown out of a head gasket. My leak though, also seemed to be coming from the rear of the engine/gearbox, but that wasn't the source, it was only ending up there after it was blown onto a chassis rail and trickled down to that point, very misleading. Also wouldn't leak out at normal tick-over, only under load.
I was following your post with interest. Like yours, I can see nothing coming out when on the ramps but oil is reaching the rear ARB after a short drive, so yes, only coming out under engine load. It's still up in the air, sump off, so will have a more thorough look by the heads just in case.I do strongly suspect the cruciform or rear seal, but as Sherlock Holmes once said, "Eliminate all other factors, and the one which remains must be the truth"
KevtheRev said:
To close this thread, my leaks & losses were down to the sump, bone dry after resealing and putting 100 miles on it. Previously she would have been moist after a run, so cruciform & rear crank seal would appear okay.
Thanks to all.
Thats "good" news, glad it wasn't anything more serious.Thanks to all.
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