Diesel oil in a old Musclecar

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I have used diesel oil in my muscle cars for years. Last night, I pulled the valve covers off my 70 442. The insides were 100% spotless. As clean as a new rebuild. I use DELO 400 15w-40, with 6 oz. of LC20 at every oil change. With Baldwin oil filters.
 
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I'm using Delo 400 in a '71 Mopar 340 and it seems to love the stuff. It is in an ARX rinse phase right now, but I think I will continue to use it as long as I'm going to be driving it regularly and get a UOA after about 6k to see how it holds up. Probably do 10k easy w/LC. I believe the Delo 400 is a top contender for best dino to use in older V8s. I was considering going syn after the ARX treatment, but worried about leaks developing in this old mill.
 
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I'll third this practice. I've been using Castrol RX Super (now called Castrol Diesel) 15W-40 in a bunch of older cars that I've owned over the past 10 years or so. Some of the cars were foreign, some domestic models, some 4 cyls, some V-8's. Something about the additive package in these oils works amazingly well in older motors that are in reasonably good working order. The cars I used (and continue to use) it in are mostly 1960's and 1970's vintage, and don't see lots of miles...more sitting. I've recently tried some DELO 400 15W-40 in (ironically) a 73 Mopar 340, and it seems to be working excellent so far. Once the steady diet of these oil was begun on a particular car, I noticed significantly cleaner running and cleaner exhaust (no visable smoke), less (or none) external oil leaking, and markedly less oil consumption. Acewiza....I'd stay away from syn in an older motor. When I tried AGIP SINT (synthetic) in a '76 Ferrari 308 it was not good. Lots of consumption, lots of exhaust smoke under hard acceleration. My mechanic suggested that the synthetic oil was probably causing issues with seals, specifically the valve seals and lots of oil was breaching them and being burned. I agree with that. I then went to the Castrol RX Super because it had worked so well in other older motors in the past and the results were much better. I continued using it for years in that car.
 
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To get better pumpability with the same add pack and benefits of an HDEO, you all might want to check out some of the 10W-30 HDEO's I have linked in my thread below. Usually you can never find them in stores, so, you'd have to get them through a local retailer or the internet, but, I'd think they might be even better as their not as thick as a 15W-40. I left a jug of Delo 400 15W-40 (the CI-4+ stuff too) outside one night in my truck (Chicago winter). I turned it upside down and looked at it and the oil literally was just sitting there in the jug...like thick molasses barely moving. If you drive your rides in the colder climates during the cold season, might seriously want to think about getting either an oil with a better pumpability, a heater, or using a 5W like Shell Rotella T "Synthetic" ("" since it's Group III) 5W-40. Just a thought... Are there any xxW-30 CI-4+ diesel oils? Chuck
 
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Good info chucky2....I was not aware of the lighter vis HDEO's. Also, in the November 1999 issue of "Car and Driver", Patrick Bedard's monthly editorial column was titled "Searching For The Right Oil for Keeper Cars", and featured a discussion with a former Exxon Labs engineer named Ed Kollin. It's a great article and Kollin specifically says that the add pack in the HDEO's are more beneficial to older cars than the modern PCMO's. He cites that in older cars that do a lot of sitting, internal engine corrosion is more of an issue than regular wear, and HDEO's deal with corrosion better. If you have access to back issues of Car and Driver, I highly recommend digging this one out. I tried the C&D website, but their editorial online archives look like they start at year 2000.
 
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Another recommendation that was proposed to me in that thread was to add some of MolaKule s SX-UP or whatever it is to a PCMO 5W or 10W-30 and bring the add levels in it up to the older levels. That might actually be the best of both worlds, as you've have much better cold pumpability, and high add levels. Just throwing out some thoughts... Chuck
 
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I had considered the Rotella 5w-40, but not sure about the GrpIII vs. "any other syn" aspect, in terms of the old seals and potential leakage issues. I don't normally drive the old cars in the bad or very cold weather. But the weather is very changeable here. I work 12-hr shifts and it is not ususual to see 50-60 degree or more temp swings in a day's time in the spring and fall. So every once in awhile we get caught by an unexpectd snow or hard freeze.
 
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quote:
Originally posted by BrianWC: Or you could just add something lke LC20 to your Delo to thin it a bit. [Wink]
Per Terry, and my own experience with it, LC20 won't thin oil unless it's used in massive amounts. In the GC fill I just dumped (after over 7000 miles use), I had added a total of 26 oz to LC (12 at initial fill, 2oz every 1k thereafter). The system is 5 quarts, and the oil was still in the upper half of the 30wt range. You'd have to add a lotta LC to cut down the host oil's vis significantly. [Cheers!]
 
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In my old 68 Mopar...I have been mixing 3qts of Chevron 10-40 with 3 qts of Amsoil 10-30. I have a bypass oil filter on it for a total oil capacity of 6 qts. Next Spring I am going to the full 10-30 Amsoil. I have not experenced any leaks at all. I think a full or partial synthetic oil has enough shear oil strength to protect the flat tappet cam. On a side note, I drive both my Mopars year round, but I know why the front wheel drive was invented...the rear wheel only drive is very unstable on slippery surfaces. If the roads are really bad I fire up the old 4X4 to get to work.
 
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Hi. I have always wondered whether the excessive zinc in diesel oil would shorten the life of the catalytic convertor. Any idea? btw, what's LC20?
 
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SteveS, The shear strength of synthetic oil does protect the cam and valvetrain. In different types of tests...synthetic oils shear film strength was superior to dino's...thus anti wear for your cams etc... Tourist, they say that the additives in diesel oil that cause cat clogging are going away and this is why flat tappet folks and diesel folks will be getting less of these cat clogging additives...yes, new diesel engines have cats...yuk So a full synthetic or a SL formulation with an additive like SX-Up and others will be needed for old flat tappet engines.
 
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