Synthetic oil in the engine and burning fuel

[JamesSummerville]

One of the bad things about the multi fuels is the dry start where 12 seconds metal to metal rub. Synthetic oils change that with out the need for a Pyro (not sure what that is) I understand what it does. Here is my two questions would not a synthetic oil stick to the bearings? 2nd part does synthetic oil burn in the fuel system?

 

[JamesSummerville]

Here is my thoughts, pure oil lacks o2 when used it gains o2 that allows it to combust under pressure, synthetic oils have smaller molecules and don't allow enough o2 saturation to combust. But for in engine use would solve the dry bearings problem with out a upgrade. What do you think.?

 

[welldigger]

Wrong on all accounts. Synthetic oils have smaller molecules and tend to be "runnier" or "slicker". Which sounds nice, but in reality with these old engines and the looser tolerances in them your better off with conventional oil. Conventional actually clings better than synthetics do. As far as burning it for fuel, I don't know which is better but synthetics will combust just fine.

If your are worried about dry starts get Jatonka's spin on oil filter kit. It has anti-drain back filters so you get full oil pressure in 2-3 seconds.

Also, a pyro or pyrometer, has absolutely nothing to do with oil, start up, bearings, or anything like that. A pyro is used to measure EGT's. EGT stands for exhaust gas temperature. When turning up the fuel or burning alternative fuels it helps to know your EGT's. I'll let you research why.

 

[JamesSummerville]

Wrong on all accounts. Synthetic oils have smaller molecules and tend to be "runnier" or "slicker". Which sounds nice, but in reality with these old engines and the looser tolerances in them your better off with conventional oil. Conventional actually clings better than synthetics do. As far as burning it for fuel, I don't know which is better but synthetics will combust just fine.

If your are worried about dry starts get Jatonka's spin on oil filter kit. It has anti-drain back filters so you get full oil pressure in 2-3 seconds.

Do you have a link to buy a jatonka spin? I can Google it but you never know.

 

[welldigger]

http://lmgtfy.com/?q=jatonka+spin+on+oil+filter+conversion

Here ya go.

 

[JamesSummerville]

Lol that was sick, you are talented buddy. That is on the list now. Thanks man appreciate it.

 

[hunderliggur]

http://lmgtfy.com/?q=jatonka+spin+on+oil+filter+conversion

Here ya go.

Love that website, tempted to use it for some people at work but that would probably not go over that well!

 

[Ford Mechanic]

Synth. oil burns fine in my tank.

 

[Flyingvan911]

I highly recommend the spin-on oil filter conversion.

 

[two.fiveM35]

The spin on filters cut the pressure up time dramatically. When you install then, let the engine sit for a few days so all the oil can drain out of the filters and there will be no mess when you remove the old ones.

 

[brianp454]

I have all of jatonka's spin on filters and really like them. The filters are not terribly common, but NAPA can get them in a few days. I carry a spare set in my tool box just in case anything bad happens. The filters I use are Primary Fuel NAPA 3405 (10 micron), Secondary Fuel 3336 (6 micron), and Oil 1458 (16 micron).

I'm also looking into using my used filters to filter WMO. Unfortuanately, the threads to not allow the oil and secondary fuel to fit NAPA's readily available 1"-14TPI thread pattern NAPA 4770 filter bases. I've been meaning to look into this with jatonka and haven't gotten around to it. If any of you know of a spin-on base to fit the 1"-12TPI and 7/8"-16TPI threads please let me know.

 

[Ford Mechanic]

Here you go for bases for filters! Page 5 for spin on stuff! http://www.steelsoldiers.com/showthread.php?79728-NAPA-part-numbers-for-WMO-filter-set-up/page5

This thread helped alot during the building of my filter station.

 

[JasonS]

Wrong on all accounts. Synthetic oils have smaller molecules and tend to be "runnier" or "slicker". Which sounds nice, but in reality with these old engines and the looser tolerances in them your better off with conventional oil.

Are you trying to say that a 15W40 synthetic has a lower viscosity than a 15W40 conventional? http://www.valvoline.com/car-care/motor-oil-myths/

 

[welldigger]

Are you trying to say that a 15W40 synthetic has a lower viscosity than a 15W40 conventional? http://www.valvoline.com/car-care/motor-oil-myths/

The initial viscosity may be the same. However when the oil is at operating temperature they seem to behave differently. I won't proclaim to be an expert in engine oils. My personal experience with using both types of oils in everything from cars, boats, atv's, motorcycles, large trucks, and heavy equipment tells me the 2 different oils have their places but synthetics aren't always the best choice. Both in performance and cost vs. benefit. I have also discovered that if there is potential for an oil leak to happen, synthetic oil will find that weakness and begin to leak.

The biggest issue (for me at least) is I don't want to buy 23 quarts of synthetic Rotella at double or triple the cost of regular Rotella for no foreseeable benefit. I have gas and diesel engines will well over 300,000 miles still running strong on conventional oil. My deuce hardly gets driven that much. I see no need for spending that much on oil. If anyone else feels that synthetic is a must for them to run in their deuce I would love to know if there is a difference in performance one way or another. I'm just not going to spend the money.

 

[welldigger]

In my boredom of this evening and the issue of synthetics vs. conventional on my mind I did a little research. Mobile1 has a very informative FAQ section on their website. After reading there and several other places they all claim that it is perfectly acceptable to put synthetic oil in an older, higher mileage engine. But, of course they then recommend you use their even more expensive "high mileage" synthetic oil. If an engine is experiencing noticeable blow-by they suggest synthetic is still acceptable. To help with blow by they suggest moving to a higher viscosity grade...well Duh.

But, when you get to reading between the lines, or rather, through the sales pitch b.s. they kind of explain why synthetics may cause a formerly not leaking engine to leak. Synthetic oils have more detergents in them and have a higher cleaning ability. The theory is synthetics clean very well, so crud that was blocking a potential leak path in a gasket gets cleaned away, allowing oil to pass through. Also, the high mileage synthetics have "seal conditioners" in them to help prevent seals from leaking. It seems that synthetics, in some cases, can cause a seal to expand or contract depending on the material it is made of. I don't know how definitive that is, but, it was hinted at more than once.

All of the sources I found did suggest that if you switch from a conventional oil to a synthetic you should do a sooner than normal oil change for a change or 2. This is due to the higher cleaning ability of the synthetic oils. They admitted this can cause sludge to break loose and to prevent oil filter clogs you should change at least the filter after 2000 miles instead of 3-5000 miles.

Again, there can be definite advantages to synthetics. The issue becomes what value do you place on these benefits. At 2-3 times the cost of conventional oil is better lubricity and a little cleaner internal parts worth the cost? That is up to you, the condition of your truck, and how much/often you drive it. For me, the extra cost isn't justifiable since, outside of a severe mechanical failure, I will never drive this truck enough to actually wear it out.

 

[steelypip]

You've got a few different things going on here that keep there from being one correct answer to this question:

1. Yes, deuce engines are an old design, most are well-used, and tolerances aren't as tight as they would be on a newer engine design
2. Yes, old elastomer seals get stiff/dry out. This is a function of age, operating temperature, exposure to chemicals, and probably other things.
3. Yes, synthetic oil removes crud from oil systems very well. This doesn't have the 'crisis' effect that changing from non-detergent to detergent oil can have, but it does mean that an old engine changed to synthetic oil can weep more, and if ring grooves get cleaned out, etc, might burn more oil too.

but also,

4. Most deuces don't really get worked all that hard. If you consider that the standard diesel White engine that was modified into the multifuel was used by LTL heavy truck operators and probably racked up 100s of thousands of miles/year pulling heavy loads in all weathers, the average deuce tooling around unloaded isn't working very hard. They also don't usually hit usage-based limits for oil changes, but time out (a year or whatever) instead.

With that in mind, there's probably not much of a benefit for synthetic oil in a deuce. It will still need changing on about the same time interval because it isn't any more resistant to crankcase moisture than petroleum oil is. OTOH, if you are regularly hauling heavy loads with your deuce for hundreds of miles/day and you're changing oil based on used oil analysis (like a commercial truck operator) then maybe you should consider synthetic - it is a better oil for a hard-working engine and it does allow longer change intervals.

 

[brianp454]

Nice conversation guys! It’s nice to see some thoughtful, researched postings.

When I pulled my valve covers I found that my engine is ultra-clean inside. So, I’m not worried about any crud breaking loose inside there. That being said, I’m happy running Delo 15W-40 in my engine and will stick with it.

I think if there’s a potential benefit to synthetics or blends in a deuce it is the differentials. In my experience the fluids are not changed at proper intervals, crud gets in but not out, and sludge builds up inside the housing, especially in the tubes going out to the hubs. As I get other maintenance and other things tidied up on my truck, I will investigate the options with conventional and likely synthetic blends for the differential gear oil. I would hope it can help a tad with parasitic losses on the road and prevent crud buildup. I have no intention of ever submerging my truck in water or mud unless it’s truly necessary!

I haven’t decided about the transmission though. Mine doesn’t shift very nice and wonder if the lube can help or if the synchronizers are not up to snuff. Time will tell.

 

[steelypip]

I think if there’s a potential benefit to synthetics or blends in a deuce it is the differentials. In my experience the fluids are not changed at proper intervals, crud gets in but not out, and sludge builds up inside the housing, especially in the tubes going out to the hubs. As I get other maintenance and other things tidied up on my truck, I will investigate the options with conventional and likely synthetic blends for the differential gear oil. I would hope it can help a tad with parasitic losses on the road and prevent crud buildup. I have no intention of ever submerging my truck in water or mud unless it’s truly necessary!

I haven’t decided about the transmission though. Mine doesn’t shift very nice and wonder if the lube can help or if the synchronizers are not up to snuff. Time will tell.

An excellent point! I have, among other things, an assortment of old Chevies. They have the same sort of metal compositions in the transmission that the deuce transmission has. As gear oil formulations have changed, there have been periodic 'panic attacks' among old car people until somebody actually bothers to either read the tech info put out by the oil manufacturers or talk to a qualified tribologist or lubrication engineer about these things. Then we just have to deal with old wives' tales cropping up periodically from those who didn't get the memo x number of years ago.

The good news: every transmission I've ever put synthetic gear lube in has rewarded me with better synchro performance (particularly when cold), better fuel economy (particularly when cold), and no more shavings of either color in the fluid at change time than I had with dinosaur juice. I also have some anecdotal evidence that the resistance to low temperature thickening of synthetic gear lubes causes better splash lubrication at low speeds and temperatures.

If there are no friction clutches in the component in question, any lube that meets the gear lubrication requirements (generally Hypoid/EP) will probably work very well. This would generally cover differentials, transfer cases, and reduction boxes (if any).

The bad news: Newer gear lubes have to be certified for yellow metal compatibility by the manufacturer or they might eat your brass synchro clutches. There are quite a few newer transmission designs that use composition or white metal synchro clutch material, and these need a different lube chemistry.

Viscosity range choice stays the same as with petroleum gear lubes - you want the top number to be equivalent to the specified value for the temperature range of interest - generally 90 for light vehicles and 140 for medium/heavy vehicles, but check manuals - including civilian manuals if you can't cross the mil spec # to a commercial lube grade. The good news here is that there's (almost) no magic in non-automatic trans driveline lubricants - they have a pretty standard set of expectations and defined variables - Military truck driveline components are generally similar/identical to their civilian brothers in lubrication requirements.

And for the record: synthetic gear oil weeps out of shaft seals better than petroleum gear oil does, just like engine oil. Consider changing seals if you have more than light weepage before changing to synthetic in that component.