Effect of diesel-rated oil on cam lobes and valve lifters in gas engines

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In a gas engine, will a diesel-rated oil lead to an increase or a decrease in cam lobe and valve lifter wear compared to a friction-modified synthetic that was desigend for gas engines? What about the reduced amount, or lack of, friction modifiers in diesel-rated oil?
 
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Hi, Moribundman - The valve gear on the modern OHC heavy diesel engine is quite complex with 4 valve heads and injector actuators requiring very high cam wiping pressures. API rated oils from CG-4 onwards on do an excellent job in minimising wear in that area, and CI-4 oils do it better As well these oils must handle soot well enough to minimise valve train wear When using an HDEO oil in a petrol engine it MUST be dual rated ....as an example say - CH-4/SL....and should have ...mixed fleet... on the label as well HDEO oils that are NOT mixed fleet may have an ash level that may cause problems if used in a petrol engine application. There are a number of these but they are usually formulated especially for individual applications such as Marine, some Japanese and some Euro engines. They will usually say for; ...diesel engines only... or ...not for use in petrol engines...on the lable So, if anything a high quality conforming HDEO oil will be better than a high quality petrol engine oil in minimising valve train wear. Bear in mind of course that a number of petrol oils are rated as SL/CI-4 in any event Regards [ February 20, 2004, 07:32 PM: Message edited by: Doug Hillary ]
 

moribundman

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Thanks Doug, I just wanted to make sure that using the M1 5W-40 won't have some detrimental effect on my Audi gas engine. Of course, that oil is rated for use in diesel and gas engines anyway. I guess it will be doing fine in my motor. Still, what's with the lower amount,or lack of, friction modfiers in oils for diesel engines? What's the reason behind that?
 
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Hi, Moribundman - You are doing the right thing. The M1 SS 0w-40 (in Oz ) is what I would use in these vehicles if Delvac 1 was not readily available to me I use Delvac in my BMW Z3 2.8, Porsche V8 and Subaru Outback 2.5 AWD I have used HDEO's in most of my cars since about 1960 Regards
 
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quote:
Originally posted by moribundman: Still, what's with the lower amount,or lack of, friction modfiers in oils for diesel engines? What's the reason behind that?
I'm curious too. I will assume for now that friction modifiers are for CAFE and reduce the film strength of the oil and thus reduce the oil's ability to protect bearings.
 
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Hi, I believe that metallurgy, engine design and chemistry also play a role in the engine manufacturers specifically excluding FM's from approval in some diesel engines I will revisit that issue again and see if I can get a more specific response for you but I think TallPaul you are correct in part I remember having a discussion with two Company's Chemists ( Oil Company and Additive package supplier ) and Engineers on this issue but it was along time ago. Anyway it made a lot of sense at the time! Regards
 
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quote:
Originally posted by moribundman: In a gas engine, will a diesel-rated oil lead to an increase or a decrease in cam lobe and valve lifter wear compared to a friction-modified synthetic that was desigend for gas engines? What about the reduced amount, or lack of, friction modifiers in diesel-rated oil?
Like Doug touched on, cam lobes in a diesel engine are placed under extreme pressures during operation, and having a lubricant that can protect properly is absolutely vital to long life and proper operation. For instance, just the other day, I witnessed with my own two eyes a late model Volvo day cab with a ISM Cummins come in to the shop...upon teardown, the cams, for lack of a better word, were "flaking" apart..lobes were literally falling to pieces. Exact cause is unknown, but I can easily tell you the owner or maintenace dep. was not taking very good care of the lubrication needs of this engine...entire top end of engine was coated in a black varnish and coated with a high level of soot. Older engines could get away with lower quality oils and less than ideal mainteance practices, but like I mentioned, modern engines exert such high pressures on cam lobes that a high quality oil with a great barrier/extreme pressure additive package is gonna be required. With that said, I firmly believe, that based upon intended usage, an HDEO synthetic can protect cam lobes better than a PCEO synthetic oil. I don't care much for friction-modified oils unless I'm trying to acheive maximum fuel efficiency levels, but I'd much rather have MAXIMUM WEAR PROTECTION than maximum fuel economy...but that's a whole other discussion. Like I've said, HDEO's are meant to put up with exteme camshaft lobe pressures, and thus the additive package is designed to tackle this challenge, so I'd easily say that an HDEO will offer lower lobe wear levels, but because they aren't heavily GF-3 friction modified like modern passenger car oils of lighter viscosities, you'll be exchanging higher levels of protection for a small, and most likely unnoticable drop in fuel economy. Sorry if I repeated myself too much... BTW, I don't know if I can make this more clear: Only reason for friction modifiers = fuel economy That's the only reason (IMHO)... [ February 21, 2004, 01:49 AM: Message edited by: Jelly ]
 

moribundman

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Thanks guys! The friction modifier issue has so far been pretty much ignored, and what you guys know regarding this issue is very interesting and puts my mind at ease. I think I've now figured out why VW/Audi have in the past (maybe they still do) required any oil that did not meet VW 500/502 to meet at least VW 501.01, which is an oil spec for diesel engines. And hasn't Porsche always required the diesel rating? [Cool]
 
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As Doug mentioned in his post, modern HD diesel motors have VERY high cam loads. As an example, the Cummins ISX in my fleet have DOHC gear driven. One of the cams is just for actuating the individual unit injector, much like the new VW "Pumpe Duse" design, the other cam is for actuating the valves (Two intake and two exhaust per cylinder). You MUST use an oil certified to Cummins CES 20078 or the cam lobes will fail. Cummins has a short-list of oils that prevent this, and Delvac 1 is the top of the list. CG-4/SG are very good at preventing cam lobe wear, and the CI-4/SL are much better. As most HD diesel motors have had OHC designs for a LONG time, the oil had to take this into account. The primary reason most HDEO's don't have the "energy conserving" additives is that they contribute to "Top Grove Fill" in modern HD diesel motors. So the slight 1-3% fuel economy "improvement" is MORE than offset by engine damage! Top Grove Fill is the result of EPA-mandated emissions reduction that moved the Ring Land much closer to the Crown Land. Since the Ring Land now sees much higher temps, a poor oil and/or additive package will break down and leave deposits in the ring groves. This causes stuck/broken rings. Some HDEO's, like Mobil Delvac 1 5W-40, are able to include "energy conserving" additives that do NOT cause or contribute to Top Grove Fill. This also dramatically increases the price of the oil, so Delvac 1's claimed 3% economy improvement goes unnoticed. So if an an oil like Mobil Delvac 1 5W-40 can withstand a Cummins ISX with DOHC, it can easily handle other valvetrain wear, including gasoline motors. It's dual-certified to SL for gasoline motors. I'm not sure if it has specific Porsche-Audi-VW approvals though. As far as the Volvo tractor with Cummins ISM motor and "flaking" cams, it sounds like the owner/operator did NOT use the proper CES 20078 certified oil. Also, extended OCI without proper bypass filters will place HEAVY soot in the oil, which will cause those symptoms too. I'm truly amazed that for what the Cummins ISM and especially the ISX motor costs, some fleets and owner/operators STILL insist on using a "Brand X" oil to "save money." Hope this helps. Jerry
 
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Don't most gas engines have roller lifters? I don't think the friction modifiers would cause any noticeable decrease in engine life. However, I also like HDEOs and would have no problem using in a gas any engine, as long as the temp isn't extremely cold. Here in Central VA, fleets can use HDEOs in gas engines year round
 
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Jerry, I just want to say thank you for sharing your knowledge regarding HDEO's with us and taking the time to type out these fact-filled, well-written, detailed replies! [Cheers!]
 
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quote:
Originally posted by cousincletus: Don't most gas engines have roller lifters? I don't think the friction modifiers would cause any noticeable decrease in engine life. However, I also like HDEOs and would have no problem using in a gas any engine, as long as the temp isn't extremely cold. Here in Central VA, fleets can use HDEOs in gas engines year round
Depends. The LS1 and the new truck Vortec motors use roller lifters. That doesn't seem to prevent the CLACK CLACK CLACK noise though. The CI-4 reformulation appears to have thickened HDEO's quite a bit, so their cold temp use is now suspect in senstive motors. Some HDEO's, like Esso XD-3 0W-40, are still quite good in temps colder than -30 F. In a moderate climate, HDEO year-round are fine. Jerry
 
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quote:
Originally posted by Jelly: Jerry, I just want to say thank you for sharing your knowledge regarding HDEO's with us and taking the time to type out these fact-filled, well-written, detailed replies! [Cheers!]
Thanks! BITOG is a great place to pick up tips on oil-related issues. The best thing for us as a group to do is share our own misadventures, caveats, and tips. For example, in an older Cat 3406B motor, the oil pump is gear driven off the front. If you attempt to use a regular 15W-40 in temps colder than -25 F, you WILL shear the oil pump drive. This will result in no oil pressure and you'll go boo-hoo-HOO when the motor blows up. Of course, it "cost too much" to run a good synthetic in that extreme cold temp. Jerry
 
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Just to add a small twist to this subject...would it be safe to conclude that a HDMO or fleet type oil would likely give more protection to an older flat tappet type engine...say my 1969 Big Block Chevy or the millions of other older flat lifter engines still in service vs the newer FM oils ?
 
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Hi, Calvin - yes, your assumptions are correct although most SH and above PEOs control valve train wear very well indeed. HDEO's just do it better. For this reason the Japansese have a special valve train wear test protocol for the oils they recommend Of course most diesel engines do not have automatic valve clearnce adjustment Jerry - Cummin's seem to always get the cam area wrong first time around in their engines. Going way back to the 14ltr engines - Big Cam 1,2,3. The L10, M11 and Signature ranges they all had such problems. Yes the ISX as you points out has the same issues. Flaking sounds like the lack of hardening problem is alive and well again in NA Sometimes to be fair it can be a cam production - quality control issue The roller cam components are "cam followers" - the roller follows the cam lobe. Because they are rolling their wear ( if any ) over their whole contact surface area - not localised as in a normal cam lobe/valve rocker contact surface The valve's auto adjust actuator clearance at the valve stem is "cushioned" by oil pressure. A measured dump occurs here and various oils seem prone to hang up in the pressure valve/dump area causing the clack clack clack. If it only lasts for about 20 seconds it is of no consequence Some engines/designs are more prone to noise than others and seem to trap air in this area exacerbating the problem. Oil foaming may also be a problem here as it is a pump up/let down situation occuring at half engine speed HDEO oils keep this area cleaner than others assisting flow back and etc. In using Delvac 1 we have really eliminated programmed valve actuator adjustments every 200kkms due to the very low wear rates We simply no longer need to do them at all once the engine is out of warranty Regards [ February 21, 2004, 04:07 PM: Message edited by: Doug Hillary ]
 

moribundman

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Jelly wrote:
quote:
Jerry, I just want to say thank you for sharing your knowledge regarding HDEO's with us and taking the time to type out these fact-filled, well-written, detailed replies!
It totally second that! Doug, there are no VW oil specs on the approved list for the M1 5W-40, but after all I've read, I'm confident this oil meets and probably surpasses VW requirements. [Cheers!] [ February 21, 2004, 04:29 PM: Message edited by: moribundman ]
 
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Hi Doug: Although I've never had a bit of trouble with my fleet Cummins ISX motors, I do know that Cummins is NOT a "first run" motor of any choice. I've heard the camshaft horror stories. I'm actually a Cat Man and have always liked the 3406B motors. There are some 20 year old 06B's in stationary use (Portable sawmill, jury-rigged generator, large water pump for irrigation and fire control, etc ) that are still slugging away. I went with the ISX as I'm a real sucker for "gee whiz" science-fictiony gadgets. The ISX motor has plenty of electronics, and the Cummins PowerSpec program allows you to really customise the motor performance. I can set long-term idle speed, idle shutdown temp, engine shutdown parameters (Coolant temp, oil pressure, etc), can monitor total idle hours, can graph RPM-vs-gear, can set variable and total governor RPM's, etc etc etc. Cummins did offer their generous "no questions asked" engine warranty, so I took the bait and ordered them. I must admit I'm quite pleased with the ISX motors. I know that using Delvac 1, once you get the initial follower adjustment out of the way, they seem to keep adjustment forever. I think Delvac 1 also protects the Cummins camshafts better. I'm still not sure why the GM LS1 and LS1-derived truck Vortec motors have roller lifter clack-clack and other valvetrain noise. A lot of comment has been made on the rear sump pan, the very long oil pickup tube, and the gerotor oil pump at the very front of the crank. I did try Mobil 1 15W-50 a couple of summers ago, and the 5 months I left the oil in, my Vortec truck motor was SILENT on start and in operation. Seemed smoother too. So I'll be going back to Mobil 1 15W-50 this summer. So it does appear the LS1 (5.7 litre V8) and the Vortec truck motors (4.8 litre, 5.3 litre, 6.0 litre, and 8.1 litre V8's) all seem to "like" a thicker oil. All other things equal, a HDEO will protect the valvetrain of a flat-tappet engine better, especially in regards to scuffing. Of course, if you have radical valvespring tensions, no oil will protect a flat tappet camshaft lobe. It is MUCH prefered to use a roller-lifter arrangement. Doug, you'll be pleased to know that my nighttime temps are "only" down to -15 C, and the high today was -3 C. Spring must have Sprung! Jerry
 

moribundman

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Augh, I'd like to make a correction to something I claimed earlier in this thread: VW 501.01 is not an oil spec for diesel engines, but an older spec for gas engines. [Eek!]
 
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Jerry, one fleet I work with - a long term Cummins purchaser - had a very bad run with the Signature 500/600hp engines. He sold the lot after about 18 months use. He has had a good run with about 50 ISX motors but has just commenced a purchase programme based on Detroits. He has also tried the Cursor/Cummins range ( made by IVECO ) and has had an excellent run so far Indirectly, independent tests here on the troublesome GM V8 have shown that M1 5w-50 is a great brew that they tolerate very well. Oil use has been reduced dramatically with no adverse effects. M1 R appears to do the trick too! I am in Townsville, Far North Queensland today - 400kms north of where I live at Airlie Beach. The temperatures here were 27C overnight and at 2pm today it was 41C! The Z3 had a good work out for an hour or two above 100mph at the same time I'm pleased to hear spring is springing for you!!! Moribundman - your oil choice is an excellent one Regards [ February 22, 2004, 01:10 AM: Message edited by: Doug Hillary ]
 
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Quote: I don't care much for friction-modified oils unless I'm trying to acheive maximum fuel efficiency levels, but I'd much rather have MAXIMUM WEAR PROTECTION than maximum fuel economy...but that's a whole other discussion. Friction modified oils are nothing new . The only thing that's changed in the last 10 years or so is the type used . API SL ISLAC GF-3 placed a premium on oxidative thickening . The traditional oxidation inhibitors were ineffective so three way combos of Moly , Nitrogen containing complexes " Borated Dispersents " and Sulfurized Ester Olefin " controls oxidative thickening " were developed and used in the low cost oils and now expands to include use in better oils. " witness Mobil SS and other formulas ". ISLAC GF-4 will also place a premium on piston ring belt cleanliness using sequence III-G in purpose , demands and requirements . All I'm saying is these oils friction modified or not does not depict how long a cam/lifters will last in modern gas motors "modern is a keyword here" . A combo of quick flow to them in these modern OHC engines along with ample amounts of anti-wear such as zinc would be better in reasonable drains than an Army [Smile] of zinc that took forever to get to the battlefield " flow/pumping ". I'm not talking 20wts either though just so to be clear . None of the current gasoline motors needs huge amounts of Zinc these days due to ever decreasing open and closed valve spring pressures and ability to use less of due to lighter valve train components and the newer variable valve timing to aid in reduced valve overlap w/o cost of top-end power . Long drain intervals and increased ZDDP...different deal . Zinc is also a good anti-oxident [Smile]
 
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