where is my oil going?

[Major Stare]

Opened this topic expecting it to be a X-Flow topic.... loosing oil.

But it isnt yipeeeeeee

VX, the new X-Flow  

Sorry, hope you solve the oil problem  

[Stevo]

I had a similar problem on old smokey. Basically the dipstick was hitting the edge of the baffle and bending before it touched the oil. It was only when the crank chewed the end off the dip stick that I realised what had happened.

[smithydar]

this wont solve your oil problem but if its any help,i have a spare head. i had it on my car for about 100 miles with no probs.untill i had oil pressure probs.i then had a rebuild and used a coscast head from a spare motor.

all valves have been reseated and its in perfect order.

it may be of some help to you.

darren

[cozzy]

oooohh oooh i'll pm you regarding the head smithydar, as i also have a burnt or slightly bent valve (it gets worse doesn't it   ) and a replacement head i can drop on will be a big help.

[Man On The Clapham Omnibus]

That level of oil consumption rivals my 1980 2200HLS Princess (Co. car) which would use a gallon of oil in a return trip between London and Rochdale.

Is the newly arrived "popping and banging" significant?

[Martin Keene]

500 or 600

I could understand if it drips out the bottom or burns out the exhaust, but it doesn't.

Can we just confirm that. Your using about a gallon, i.e. about 4.5 (four and a half) litres of oil in ~500 miles?

If so I would avoid driving the car until the solution is found, because for it to be using that much something is *very* seriously wrong.

[cozzy]

yes that is correct, 1 gallon in 500 miles or therabouts. The car was run recently on the rollers at redline, makes good power(155 at the wheels) and drives extremely well. Exhaust valve on number 3 at tickover rpm is not sealing properly and is pushing the mixture straight out into the exhaust, but once the revs are up then it seems to seal ok.

I'm going to ptfe tape up the sump plug at the weekend as this is the only visible source of a small leak, unless its absolutely squirting out here when driving then stops instantly and doesn't drip when i park up. Also going to check out the dipstick & the tube. I expect when I drain it to do the sump plug then I will get about 2.5 gallons out  

[Paul S]

I also have the same sort of oil consumption problems with my XE, although it's getting better. It's averaged about 4 litres on the trip to Le Mans for the last few years.

At first I thought it was the rings on the high compression pistons that had not bedded in - even though there was no evidence of oil burning. So I got the bores re-honed, fitted new rings and ran them in pretty agressively using Millers running in oil. This had no effect on the consumption at all.

Then, I thought it might be caused by the oil being flung around in the sump, getting whipped up by the crank, and overcoming the oil control rings - despite no evidence of oil burning and despite having a windage tray.    So I increased the windage tray's crank scraping ability, and fitted extra baffles, to keep the oil in its place. Result: no change

The next theory was that my Q450 cams were pushing the spring caps down far enough to distort the valve guide oil seals. This theory coincided with a slightly catastrophic meeting between valves and pistons which necessitated a rebuild. With the head off, I took some measurements, and this latest theory had some merit. There was evidence that the spring caps might just be touching the seals, which could be flexing and letting too much oil down the guides - despite no evidence of oil burning. So I had the new guides fitted a few thou lower in the head. This coupled with the recut seats and thinner shims meant the spring caps were clear of the seals. Result: no change. and double

So, it has to be an oil leak, something I've discounted all along due to lack of evidence; lack of oil burning evidence obviously doesn't have the same importance     My thinking has always been that  that quantity of oil leak would mean the garage floor and car undersides would look like Prince William Sound, post Exxon Valdez    

The bottom of the car does get a bit oily, and there is a bit of a damp patch on the garage floor, but nothing to explain the amount of oil used!

The oil usage seems highest when the oil gets hot, ie track days and very hot blasts to/from Le Mans. It seems to be less on local running. So, my next theory is that there's a tiny crack/leak somewhere on the high pressure side of the oil system, which only leaks when the oil is hot/thin and under lots of pressure (high revs)  and points a fine spray of oil at the ground. This would explain the slightly oily film under the car, the odd drip on the garage floor and the monumental thirst!!

I'm not sure how to track this down though. I'm in a thinking phase at the moment.

I said above that it's getting better. Le Mans 2001 used 6 litres of oil; this year it was down to 3 or 4 litres. I think this improvement is caused by the switch from Comma Eurolite 10W40 Semi Synth to Millers Semi Synth 20W50, rather than any (admittedly partial) cure.

ETA, The SBD cam cover mod mad no difference either!

[Martin Keene]

I think for the cost of a gallon of oil I'd be tempted to drain it when it is off the bottom of the stick and see how much comes out.

Some questions...

1. How long have you had the car?

2. When was the enigne re-built?

3. Why was the engine re-built?

4. Did youre-build it yourself?

[S8ight]

thats a lot of oil in a short mileage.

if it was all coming out through the sump plug the whole underside of the car would be covered in oil.

get a cylinder leakdown test done, you will have fun though if you have a valvet that doesnt close, try to seal the exhaust post.

it is possible to use quite a bit of oil through glazed bores without the engine being smokey though.

[Man On The Clapham Omnibus]

thats a lot of oil in a short mileage.

if it was all coming out through the sump plug the whole underside of the car would be covered in oil.

get a cylinder leakdown test done, you will have fun though if you have a valvet that doesnt close, try to seal the exhaust post.

it is possible to use quite a bit of oil through glazed bores without the engine being smokey though.

I tend to agree. An engine that's using oil via the bores doesn't have to appear to smoke, unlike one that is sucking it down the valve guides. In the latter case it all happens when you are on a trailing throttle and then a huge cloud of smoke emerges when you accelerate again. When it's blowing by the pistons the smoke is thin and constant - or only when you're on power, most of the time - you might not notice the smoke at all. A leak-down test, or even a compression test, should give you a clue.