Oil for Motorhome

[dnewton3]

One or two UOA(s) could let us know if insolubles would spike to "non-normal" levels contrasted to the universal averages. Also, the vis would let us know if it were significantly thinning or thickening from the heat.

He's planning on year-round use, so perhaps a plan of 10w-30 for winter and 15w-40 summer would suffice? Again, his annual mileage and OCI plan can either be complimentary, or contradictory ...

I don't have any expierience with the 454 BBC, but I've read good things about it. The lube system is fairly robust, is it not?

He indicates that his engine temps are 200F on flats, and 212 climbing hills. That's not very hot, and quite reasonable. Dino oils are certainly safe FOR SHORT BURSTS up to 250 deg F, although I would not want to sustain that temp long. Still, pulling an occasional hill isn't going to kill the sump in one season.

If his annual milegae is less than 5k miles, I suspect his UOA would confirm that either 10w-30 or 15w-40 would both work equally well. The issue really becomes that of cold starts for winter.

I suspect that the winter time advantage of 10w-30 HDEO would outweigh the summer time advantage of 15w-40. He could use a 5w-40, but for short OCIs, that's just overkill. In fact, as you know, the T5 in 10w-30 pumps just about as well as the T6, for much less cost. The engine would not know the difference, but his wallet would.

 

[440Magnum]

Given how long big-blocks have been around and the fact that there's such a large knowledge base of how they generally behave in this application, I think good advice can be found even without the UOA.

But the UOA would certainly spot something unique to this application that the knowledge base couldn't, so I won't argue that a UOA is the best way to go.

Its a bit of a toss-up... do you "overkill" with a synthetic 5w40, or do you spend more than you'd save on dino 10w30 on a UOA?

 

[dnewton3]

That's often a good point.

The cost of a UOA can easily be negated by simple, inexpensive OCIs. But the knowledge of individual performance is never attained with the short OCI plan in lieu of the UOA. If one is confident that the engine is in good operational shape, it does make more sense to simply OCI on a reasonable term.

But once people visit this site, they often seek advice that can really only be fairly answered with UOA data, for an unique individual application.

Again, I see his temp issue in winter outweighing his temp issue in summer.

But the reality is that 10w-30 or 5w-40 would both work equally well; T5 it just cheaper and more easily attainted. I suspect he could get T5 for the same (or less) cost as the Delo LE 10w-30 he's currently using. I know the LE exists, but I've never seen it on the shelf anywhere. T5 is EVERYWHERE, costs less than T6, and behaves the same at cold temps.

I'm not a big fan of semi-syns, as they often are a "negative compromise"; they don't fulfill the whole promise of synthetic, and cost more than dino. But in this one case, given the cold temps, the T5 might be the "best" all-around compromise. And at W/M prices, T5 certainly won't cost more than the LE Delo.

 

[bullwinkle]

I would think the T5, especially at WM/$11.50/gallon prices, would be a good way to go-as long as his bearings are still in good enough shape to sustain good hot oil pressure. The UOAs would need to be taken with a grain of salt-a carburated, old BB w/flat tappets would be high on the iron side, and probably show fuel dilution as well. Still think it's going to give that 10W30 a workout in summer, though!

 

[440Magnum]

Originally Posted By: bullwinkle
I would think the T5, especially at WM/$11.50/gallon prices, would be a good way to go-as long as his bearings are still in good enough shape to sustain good hot oil pressure. The UOAs would need to be taken with a grain of salt-a carburated, old BB w/flat tappets would be high on the iron side, and probably show fuel dilution as well. Still think it's going to give that 10W30 a workout in summer, though!


I agree big-blocks are prone to throwing iron, and old air cleaners leak more dust and silicon than modern plastic air-boxes. This one of mine always seems to have high iron numbers... still running fine though. But fuel dilution and carbs need not go hand in hand....

 

[ftv37]

Just took a 1000 mile trip in our 28ft Chevy p30 chassis motorhome, it has a 454.Current fill is Rotella T6 and it seem
to sound clacky like more valvetrain noise than on the previous
fill of delo 400le 10w30.Stop at O'reilly's on our way back and
picked up some Delo 400le 5w40 synthetic. My question is should I change the current fill to the delo or wait

 

[Cause4Alarm]

personally i would change it, i hate things making noise when they shouldn't and the big motor likes thicker oil due to thermal expansion being more due to the increased size of things and the looser clearances of the design....what year is it?

 

[SuperDave456]

You have only been a 1000 miles on a very robust Synthetic oil.
I would wait at least another 4000 or 5000 before an Oil Change Interval.

What oil filter are you using?
I found that changes in filters have more to do with engine sounds than the viscosity of the oil I am using.

Also, do you have any known issues with your engine?

 

[Bambam]

What was in it prior to the T6?

 

[ftv37]

It's an 1986 Winnebago 28ft class A 12,000gvw
Had Delo 400le 10w30
Filter is a Napa Gold 1060
When I first got it last year I put a new timing gearset in,water pump,ect every thing was precautionary so no known
issues with the engine.It took 7% grades just fine

 

[Gokhan]

It has probably nothing to do with oil. I would suspect fuel, ignition, or emission problems. You are probably hearing some knocking due to a fault in one or more of these systems.

Switching to a thicker grade usually decreases the metallic valve noise although might increase the low-frequency (RPM) vibrations as the engine must do more work.

Check your ignition timing, carburetor, and choke first. It might also have compromised a seal and started consuming some oil from switching to PAO-based oil, which could also cause knocking. You are considering another synthetic oil; so, I don't know whether it could cause seal problems.

 

[vinu_neuro]

Sorry to be blunt, but it's been a while since I've read this much nonsense in one post.

Originally Posted By: Gokhan
It has probably nothing to do with oil. I would suspect fuel, ignition, or emission problems. You are probably hearing some knocking due to a fault in one or more of these systems.

Switching to a thicker grade usually decreases the metallic valve noise although might increase the low-frequency (RPM) vibrations as the engine must do more work.

Check your ignition timing, carburetor, and choke first. It might also have compromised a seal and started consuming some oil from switching to PAO-based oil, which could also cause knocking. You are considering another synthetic oil; so, I don't know whether it could cause seal problems.

 

[Gokhan]

Originally Posted By: vinu_neuro
Sorry to be blunt, but it's been a while since I've read this much nonsense in one post.

What's nonsense about it?

 

[bullwinkle]

If it's pinging when going uphill you may have gotten some weak/low octane gas that would make it noisy-but "clacky" might be a sign of poor hot oil pressure or worn lifters. How many miles has that beast got on it?

 

[Gokhan]

Originally Posted By: bullwinkle
If it's pinging when going uphill you may have gotten some weak/low octane gas that would make it noisy-but "clacky" might be a sign of poor hot oil pressure or worn lifters. How many miles has that beast got on it?

Remember that these are old cars with mechanical distributors and a mechanical fuel system -- a carburetor and a choke. On top of that, you add the complicated emission systems of mid 80s with a maze of vacuum lines and diaphragms.

Therefore, the main reason these cars usually break down is a fault in one of these systems. Fewer and fewer mechanics these days know how to fix them as most cars on the road today have electronic fuel injection.

Sure, it could be an oil-related problem as well, but it would be far less likely, especially if it started happening suddenly.

You can listen to the nature of the noise and how it varies with coolant temperature and engine load. This might give you a better clue on what the problem is.

The main point is that, with these old cars, you need to keep your fuel, ignition, and emission systems in top shape, as they are not autotuning as in new cars, before you can even think about problems in the valvetrain, cylinder head, or cylinder block.

 

[ftv37]

No it's not pinging it's more like noisy rocker arms, not bad
just more noticeable with the synthetic T6 than with the delo 400le 10w30 dino.

 

[Gokhan]

Originally Posted By: ftv37
No it's not pinging it's more like noisy rocker arms, not bad
just more noticeable with the synthetic T6 than with the delo 400le 10w30 dino.

You might want to try a valve-clearance adjustment then. It's a somewhat difficult adjustment as it requires a lot of precision and some experience; so, find a good mechanic. I've become an expert on doing it on my car. I had screwed it up the first time I did it a decade ago. Now, I do it every other year, even though it's not really necessary.

If the valve clearances are not the problem, it would be interesting that you see less noise with thinner oil. The dino Delo has a lot of friction modifiers (moly and boron) and probably also more ZDDP than Rotella T6. Synthetics tend to have less ZDDP and little or no friction modifiers. Perhaps that's what you need -- a dino such as Delo with generous amounts of ZDDP, moly, and boron.

 

[Cause4Alarm]

Originally Posted By: Gokhan
Originally Posted By: ftv37
No it's not pinging it's more like noisy rocker arms, not bad
just more noticeable with the synthetic T6 than with the delo 400le 10w30 dino.

You might want to try a valve-clearance adjustment then. It's a somewhat difficult adjustment as it requires a lot of precision and some experience; so, find a good mechanic. I've become an expert on doing it on my car. I had screwed it up the first time I did it a decade ago. Now, I do it every other year, even though it's not really necessary.

If the valve clearances are not the problem, it would be interesting that you see less noise with thinner oil. The dino Delo has a lot of friction modifiers (moly and boron) and probably also more ZDDP than Rotella T6. Synthetics tend to have less ZDDP and little or no friction modifiers. Perhaps that's what you need -- a dino such as Delo with generous amounts of ZDDP, moly, and boron.


If it's in a motor home it has a hyd cam......DO NOT try to adjust the valves

 

[Bambam]

Originally Posted By: Gokhan
It has probably nothing to do with oil. I would suspect fuel, ignition, or emission problems. You are probably hearing some knocking due to a fault in one or more of these systems.

Switching to a thicker grade usually decreases the metallic valve noise although might increase the low-frequency (RPM) vibrations as the engine must do more work.

Check your ignition timing, carburetor, and choke first. It might also have compromised a seal and started consuming some oil from switching to PAO-based oil, which could also cause knocking. You are considering another synthetic oil; so, I don't know whether it could cause seal problems.



I am a fool for asking again but, proof?

 

[Gokhan]

Originally Posted By: Bambam
I am a fool for asking again but, proof?

Regarding level of valve noise vs. viscosity, it's only a conjecture from personal experience, not an absolute statement that can be proved. In his case he was actually seeing opposite of what I typically see; so, this point is probably not even relevant to his problem. I am only trying to help him determine what the problem is, not advocating thinner or thicker viscosities. Thinner and thicker viscosities have both their advantages and disadvantages; otherwise, they would be selling only one viscosity grade, say 0W-10, for all cars. There is nothing to prove or disprove.