Rebuilt 454 in motorhome, oil weight

Status
Not open for further replies.
Joined
Jan 21, 2014
Messages
606
Location
AZ
I think i know the answer to this. But I'm curios what you all think.

If you had a 454 with 40k on the engine, would you stay with 15w40?


The guage shows 30 psi oil pressure @ idle hot and 45/50 down the road
 
Maybe, maybe not. Yes, there is some liquid friction in the bearings. But if the sump is hot enough, the 40 has thinned down pretty well anyway ...

The answer to this question lies in what the bearing clearances were set at when the rebuild was done? If the rods and mains are at 0.002" I'd run Chevron Delo 15W-30 SD (severe duty) with annual changes. If the rods and mains are 0.0025 to 0.003 or 4, then 15W-40 is your friend and it will not be happy on 30 ...
 
In Arizona, you aren't hurting a thing. Many BB Chevys seem to do better in terms of consumption on thicker oil. A motor home, class A by chance? It would be working hard if it was. If you would care to, run a synthetic to handle the heat better. I have hauled with many BB Chevy 496 and
454s. They ran hot, some super hot. 235* or less is normal for a working BBC used in hot weather.
What's the builder say?
 
I'd run a syn blend or better - I use Schaeffer's 7000 10w30 in my 454. It's not in a motorhome, but based on how much more limber mine was when I switched from 15w40 to 10w30 (same brand and type) I'd use a stout 10w30 if possible. 15w40 won't hurt it, especially in your climate, but I think there are 10w30's that will protect plenty well and save some power and fuel.
 
So a full synthetic 10w30 would run cooler then a 15w40?

I have no idea how many miles are on this cycle. An oil change is in the near future.

The rv is in great condition motor wise. I mean, the guy was driving it 4 hours away to go camping....
 
Last edited:
If he does not know the main and rod clearances, could he use the oil pressure gauge as a guide? Try some 10w 30 and watch the pressure as it warms up, stopping to check pressure idle pressure at various stages of heating up. If the pressure drops too low at idle dump and go with the 40wt.
 
Originally Posted By: spasm3
If he does not know the main and rod clearances, could he use the oil pressure gauge as a guide? Try some 10w 30 and watch the pressure as it warms up, stopping to check pressure idle pressure at various stages of heating up. If the pressure drops too low at idle dump and go with the 40wt.
.

That's how I would go about gauging what weight oil an engine likes/will tolerate. If idle pressure is at least 25 at a good hot idle, with a high quality 10w30, and the engine isn't making a racket, no reason to think it needs a thicker oil.
 
I'm going to check the oil level next time i make it to the house. Ill add 1 quart of marvel mystery oil to it ( if it's low ) and I'll see how it does.
 
Originally Posted By: leroyd92
I'm going to check the oil level next time i make it to the house. Ill add 1 quart of marvel mystery oil to it ( if it's low ) and I'll see how it does.


Yes, why? Adding that much MMO seems more dangerous to me than stepping down to 10w30 and running it without keeping an eye on it.
 
Originally Posted By: skyactiv
10W30. Your engine oil temp will run cooler than a 15W40 would on a hot Arizona day.


I could see this being the case with an air cooled engine, but liquid cooled not so much.

Look at the wide spectrum of approved oil weights for vehicles in Australia. Zero catastrophic oil related failures with 20w50 or thicker.
 
I like M1 15W-50 in that high heat, heavy load situation. I used it many times in my Suburban when I was towing heavy loads in very hot weather down South. Save the MMO for door locks and rusted bolts.
 
Originally Posted By: Alex_V
Originally Posted By: leroyd92
I'm going to check the oil level next time i make it to the house. Ill add 1 quart of marvel mystery oil to it ( if it's low ) and I'll see how it does.


Yes, why? Adding that much MMO seems more dangerous to me than stepping down to 10w30 and running it without keeping an eye on it.


I figured it would thin the oil out to 10w30ish range.

No other reason.

I did that to a batch of 20w50 one year in my bike. Burnt 2x times the oil.... Oil was a lot more thin in the jug. Bike did have more pep and ran a little cooler. I only saw 5psi oil pressure change
 
Status
Not open for further replies.
Back
Top