normal or acceptable oil consumption?

[patrickt]

Originally Posted by mreid

Really depends on how bearing clearances are set...

That makes sense for oil pressure, but not oil consumption. Was that just a temporary mind-fart or am I missing something?

[Grubby]

In the mid 90s I was a product engineer with GMC Truck. Anything up to 1 quart per 1000 miles was considered acceptable. Policy was not to replace engines unless they used more than that.

As noted earlier, all engines burn some oil.

With the above said. I would not be happy with the amount of oil consumption you have. I would expect no more than 1/2 quart per 3000 miles of normal street use. Hard use should burn more oil.

John

[FWB]

Originally Posted by Grubby

In the mid 90s I was a product engineer with GMC Truck. Anything up to 1 quart per 1000 miles was considered acceptable. Policy was not to replace engines unless they used more than that.
John

or if they bi***ed alot .....


worked for just about every manufacturer at the dealer level and most brands share that same policy.....however try telling the customer that just dropped 45k on a new ride that 1 quart in 1000 miles is acceptable and you will be amazed on the soreness of your sphincter after.....i lost count of the factory rep mediations i have been to from the 1980's....and most times the motor gets ripped down right at the dealership.

[mreid]

Originally Posted by patrickt

That makes sense for oil pressure, but not oil consumption. Was that just a temporary mind-fart or am I missing something?

Patrick, that was a mind fart! I was doing three things at once and repeated what the Mercedes dealer had just told me about my 6.2 litre AMG engine. It uses Mobile 1 and goes through a quart every 1000 miles or so (has since new). I told him that made no sense and I couldn't understand a new car using that much oil. Anyway, what I meant to say was depends how ring gaps are set.

[Mike Huddart]

Originally Posted by patrickt

That makes sense for oil pressure, but not oil consumption. Was that just a temporary mind-fart or am I missing something?

Actually, bearing clearance, rod side clearance and such have quite an influence on oil consumption particularly if too much clearance is compensated for with a big oil pump. Excessive oil throw off from the bearings can swamp the oil rings.
If you are running something like an Eagle bottom end you might be seeing something like .028" rod side clearance and unless your bore job is on the money then you will see heavy oil consumption. Why do they build so much clearance into those things, I reckon something like 99 % of Eagle assemblies sold will only ever be used for street use so why give you side clearance that is excessive even for race motors.
Have you mentioned what SB you have, why I ask, is a long stroke short piston stroker motor will give you problems unless your bore clearances are at a minimum. Some machinists we have come accross seem to like to give the pistons "an extra couple of thou just to be safe " and just you wait for the smoke !
Mike

[patrickt]

Originally Posted by Mike Huddart

Excessive oil throw off from the bearings can swamp the oil rings.

That makes sense.

Originally Posted by Mike Huddart

Have you mentioned what SB you have, why I ask, is a long stroke short piston stroker motor will give you problems unless your bore clearances are at a minimum.

I'm not the OP -- I have an old fashioned FE, that drinks about a quart every 1500 miles or so.

[Mike Huddart]

Sorry, should have asked if anyone has mentioned what sort of SB we are discussing here.
Mike

[patrickt]

Originally Posted by Mike Huddart

Sorry, should have asked if anyone has mentioned what sort of SB we are discussing here.
Mike

I just assumed it was a POS SB, like they all are....