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.

[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.

[PatBuckley]

Originally Posted by 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.

Absolutely - thanks.

[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.

[PatBuckley]

Originally Posted by redmt

"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.

Perhaps you do, but I don't wear panties.

My objection to your "opinion" is that it is wrong and you are giving an opinion on something your are apparently ignorant about.

This issue is not a matter of opinion - it is a matter of fact. As I said, all internal combustion engines use oil....I was trying to be nice and let you slide on the street motor thing but you insisted on pushing your erroneous opinion and saying that no engines should use oil.

Do some reading.

[PatBuckley]

I hate it when posts cross.

[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?

[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.

[Dingocooke]

Originally Posted by 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.

Many years ago, and lets remember, we are talking about old tech iron V8 engines here; Ford in the UK where a 3 litre V6 was a 'big' engine at the time; would not entertain a warranty claim on oil consumption unless it was more that 1 pint per 400 miles; so your quart could easily go in 800 miles and still no warranty claim allowed (oh and UK 'imperial' volumes are bigger than US ones too, so even worse!); and remember all this on very 'cooking' low state of tune fairly low revving standard 'new' engines; not reconditioned and tuned30 year old ones!
To see 400 or 500 hp from a small block, you usually need big valves, more rpm's, more compression, and probably a bore and stroke job too; so you have a lot more crank case pressure variation (increasing blow by) and more opportunities for valve guide and bore wear. I would say two pints in a thousand miles is bearable; my aussie headed 351 cleveland used around a pint in a 1000 miles, and was better on Valvolene than other more 'modern' oils. So that is what is probably normal ? As for acceptable; how much does a quart of oil cost compared to the cost of a rebuild; my guess you can buy a lot of oil for what you would spend in gaskets valve guides pistions etc!!!
I find if you drive faster you don't notice the smoke ;-)
Just my opinon, and have big fun with you Cobra whatever you decide!!