normal or acceptable oil consumption?

[D111]

what might be the normal or acceptable oil consumption for these type of motors ? small block 400 to 500 hp 10 to 1 compression.

[mreid]

Really depends on how bearing clearances are set and how it is driven. Oil loss can be higher initially, reducing as the engine breaks in.

[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

[Rick Parker]

1000 per QT

[redmt]

0. Oil consumption is not acceptable. Change oil brands or find the source of the usage.

[PatBuckley]

Some things that may affect oil consumption include viscosity and type of oil used, cylinder wall finish, ring type, valve guide clearance, how the car is driven, external oil leakage.......

All engines use oil, the age old standard is about a thousand miles per quart.

[redmt]

Originally Posted by PatBuckley

Some things that may affect oil consumption include viscosity and type of oil used, cylinder wall finish, ring type, valve guide clearance, how the car is driven, external oil leakage.......

All engines use oil, the age old standard is about a thousand miles per quart.

Key word here is old age. New condition, street motors shouldn't use oil. The only way for oil to "go away" is to bypass the rings, sucked down the intake one way or another or to leak out. In my book, none are acceptable.

[PatBuckley]

We are talking about a 500 horsepower Cobra motor - pay attention.

[redmt]

Originally Posted by PatBuckley

We are talking about a 500 horsepower Cobra motor - pay attention.

"what might be the normal or acceptable oil consumption for these type of motors ? small block 400 to 500 hp 10 to 1 compression."


Some how you equate horsepower to oil consumption? I equate oil consumption to engine condition. If you don't like my opinion, delete it. Don't get your panties in a knot just because you don't like what you read.

[Gaz64]

ALL four strokes will use all, period.

Oil control rings "control" or limit the amount of oil that gets to the compression rings.

Any engine that uses no oil is wearing the top of the bore with a taper and it will be an oil burner eventually.

The larger the engine is, or more horsepower it produces; the more the consumption.

Generally, the dipstick could show no usage, but only because the oil is being topped up with hydrocarbons and acids from combustion.

Some people only complain about consumption after a good highway run, they've simply burnt off the "topup" from the raised oil temperature.

Oil analysis would reveal the levels of byproducts added to the oil.

[redmt]

I guess I could have qualified my answer a little. If your burning a qt. per thousand after break in, I'd be looking for where it went. If you change your oil at 3500, then your doing about a 50% replacement per change. My 428 never used a bit of oil at over 100k. My 7.3 PS uses about a qt between 3500 mi changes Both are in the 450hp range.

[redmt]

You don't like what my reply was so you resort to name calling and an attempt at insults?

[PatBuckley]

Name calling? Nope. Calling you ignorant was a statement of fact based on your answer - and I see that you completely changed your answer in a later post.

I don't get it when someone asks a question and it is answered by someone who doesn't have a clue yet insists on posting a reply - any reply.

Are you going for post count or something?

[Dually]

you guys are pretty passionate about oil consumption......

To get back to D111 question, I think it is dependant on too many variables to suggest a one size fits all answer. Driving conditions, engines parts and assembly, type and weight of oil, etc. As long as there are no puddles of oil under the car and no plugs show visible signs of oil consumption in any cylinder, I would go with it. If I was burning 1qt, 1/2 qt or some other amount in any given mile range and I had a spark plug suggesting I had an oil conrol problem in that cylinder, the consumption would be abnormal and I would fix.

I have built and run huge strokers and high winding small blocks and every engine has been different.

If I have a great running engine that shows the same oil usage over a number of miles, it is what it is. If all of a sudden an engine starts using oil that historically did not, gonna find the problem.