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MG TD TF 1500 - Engine oil change

I searched through the archives and there is so much stuff on engine oil that I thought I'd just post the question AGAIN - forgive the newbie!

I'm in Tucson so we're talking about a very hot climate most of the year.

I've just installed Bob Grunau's aftermarket spin on oil filter system (thanks to all and esp to Bruce C on this forum, who kindly supplied me with correct TD oil lines, and Bob Grunau who supplied the filter and helped with identifying correct filter, bracket and parts etc). This 51 MG TD hasn't had any oil filter system at all, for about fifteen years!

So I'm looking to drain the existing oil and replace and start fresh.

With a non-hardened engine, what would be the best oil choice for this hot dry climate? Any additives? Tips on changing the oil? Should I fill the filter with oil before installing? Haven't done this in twenty years...

Thanks in advance.
Geoff Baker

I use always Castrol Classic 15w 50 it is specially made for old cars

Read the archives- volumes about oil and zinc needed to protect the camshaft in there. Generally 20W-50 weight best due to relatively large clearances in these motors. Zinc (and phosphorus?) removed from most modern oils due to catalytic converters, led to major and many camshaft and lifter failures. Local store told me now Kendall GT-1 has zinc, I think Castrol has a special oil for classic cars? Moss sells the additive.
George Butz

I soak the filter and fill what I can, however, mine is a horizontal filter....
There is lots in the archives about getting your oil pressure up before starting, but if it has been running that shouldn't be too much of a problem....

Geoff, regarding the archives and beyond. there has been laboratory testing done on the new oils and they are guaranteed to meet or exceed all current application needs (read flat tappet). i have never seen independent lab test results for any ZDDP additives for modern oils.
one of the events that pushed the ZDDP issue was a letter from a crane cam (who since filed for bankruptcy) employee. this letter comes from a company that was in financial difficulty when the letter was written. doesn't it seem a little too coincidental that a company facing bankruptcy puts out a letter blaming its failing cams on something other than ..oh, say, cheap steel bought by a failing company , or..oh, i don't know..short cuts taken in their machining/hardening processes.
zddp wasn't put into consumer oils until '46. funny, i don't remember seeing any archived articles about premature cam failure from 1903 to 1946 cars.
i am obviously of the opinion that modern oils don't need any more ZDDP than they currently contain. i have not found a single independent lab report showing a problem with modern oils in flat tappet engines. there are a lot of anecdotal stories but i have not found a supporting article in a reputable publication. i have not been able to determine if the oil refiner just dumps a ZDDP additve in at the end of the refining process. if not, why should the consumer believe that dumping the additive in their crankcase would have the same effect as refiner added ZDDP?
if, after you do your research, you come to the conclusion that you want to use an additive, keep in mind there is a maximum concentration level, if exceeded, lab tests show will accelerate internal engine wear. regards, tom
tom peterson

I would advise against prefilling oil filter. Learned that lesson nearly half century ago. Changed oil and filled filter, and zero oil pressure afterwards for long minutes of waiting. Had to empty filter. An air bound oil pump can not hardly push the oil downstream of it to get primed. Granted, not all pumps drain back during oil change but an empty filter makes a big difference.

Another case in point. I was recently checking new oil circuit to Marshall supercharger on an engine that hadn't run in about 6 years. With plugs out and oil shot into cylinders, I cranked the engine for about a minute and no oil. Had to remove a plug at the pump to bleed the air.
jrn Northrup

Tom, I think there have been accross the board failures of lifters with flat tappet cams. The problem with the XPAG engines was not failure of the cams but of the lifters. At less than 3K miles 3 or 4 of my lifters were badly pitted with a new cam, proper assembly lube and break-in. Pretty sure my lifters cam from ASL and were made in England, so they weren't overseas junk or anything. That is partly why Moss did the special lifter hardening, increased the lower oil supply hole size, etc. My recollection is that the problem was more with new cams/lifters than seasoned ones. George PS- just googled "flat tappet cam failures" - lots of articles, especially the one in "Hot Rod" intersting. Seems it is a multi- cause problem. Too bad Len F.'s roller kits weren't out when I did my motor!
George Butz

Gents, please remember that we are talking about engines that were designed and (many) built 60-70 years ago when all that we know today was unknown. We can easily be guided into "over protecting" our cars for zero gain. These cars were used daily without any fuss, especially during WW2 and are the cars that we now drive and are still going strong. We now use them infrequently and use lubricates that have new and better protection, so my suggestion is don't go overboard, just be sensible and enjoy the car for what it really is, a lovely vintage vehicle and fun to keep going. 15-50w is fine and mine loves to burn a bit!!!!

Regards Ian
I Denton

i agree with the tappet problem. when i did my motor two years ago ALL of the lifters were pitted. the only oil they ran on were the old, high ZDDP oils. per the advice of my 30 plus year overhaul shop after overhaul i broke in with standard reduced ZDDP motor oils through break in and beyond. i pulled that same motor after 2300 miles for another issue. the tappet faces are perfect. my one engine experience only helps me, but for me it proved up everything i have read in any reputable automotive maintenance/ restoration journal. i also agree there are a lot of anecdotal stories that come up on a google search. i still have not found any independent lab test results on a google search. i still have not been able to determine if the refinery dumps in ZDDP at the end of the refining process as the owners who choose to use ZDDP additives effectively do when they pour in the substance an additive producer tells you is good for your motor. as always, the owner should do what his/her research proves to be the best choice. regards, tom
tom peterson

I did 'burp' my filter after a few cranks and heard a little 'puff' of air.... I also used a gravy baster and shot oil into the head at the oil fitting....pumped for a few minutes.... The oil pressure popped up after about normal cranking...3 seconds or so.

I never install a dry filter - either horizontal or vertical. I presoak the filter with oil before installing. If horizontal or angled, I empty out the excess to avoid spilling. In my years of vehicle servicing, the only time I have had an issue of air in the lines was with newly assembled engines. A routine oil change has never had a problem with oil pressure coming up as it is virtually impossible to drain all the oil from the pump and lines.

If possible, I change oil with the engine warmed up. After my recent trip to acquire my MG-TA, I pulled my truck in the driveway after the 600+ mile trip and grabbed the drain pan and pulled the plug while it was still hot. I wanted to get as much of the old oil out while it still held the contaminants in suspension. After refilling with fresh oil and a new pre-soaked oil filter, the pressure came up immediately. With nearly 150,000 miles, the truck still runs like new. Last time I had a valve cover off, it was clean inside. No trace of sludge buildup.

Any run time with zero pressure can be damaging. So, by prefilling, I reduce this time to almost nothing. If in doubt, pull the spark plugs and crank it over with no load until pressure is indicated. Then reinstall the plugs and fire it up. Our old engines are too expensive to risk internal damage from lack of lubrication.
John Masters

One thing that I don't think was mentioned,,,, Change the oil envery 3,000 miles or once a year HOT. If you are going to put the car away for the winter, change the oil before the car is put away,,, don't let the old stuff sit in there while it is in storage.

Steve Wincze


Glad the lines worked for you. If your engine is brand new, go to GM dealer and get their engine start up lube. Very high ZDDP content. Someone said that GM may have taken this off the market. Hopefully not. STTP Red container also had a high zddp level, but again, not sure it still is.

For oil, I use Valvoline VR1 20 50 racing oil. It has a high zddp levels. Pretty much all I use now in both my MG's.
BEC Cunha

geoff, after an oil change you can spin the motor over with the ignition off until you get oil pressure. then you don't have to prefill the oil filter. if you want it to spin over faster you can pull the plugs before spinning, but not necessary to get oil pressure. regards, tom
tom peterson

Tom Peterson -
Well, I have a bunch of original research papers c1955-57 documenting the saga of figuring out why some cam/lifter systems failed, why it was increasing in incidence, and how ZDDP came to be used to correct it, along with a lot of metallurgy and design work.

Yes, the additive package is added at the end of the refining/compounding process. And some of the reasons modern engines get away without it are new additives which may or may not suffice in old engines, lower spring pressures due to multivalve configurations, roller tappets, much more sophisticated metallurgy, better filtration, and much less oil contamination as a result of improved combustion and temperature control.

And, I fill all filters as full as I can get them, and have never had trouble getting oil pressure, on old or newly rebuilt engines.

FR Millmore

This thread was discussed between 05/12/2009 and 08/12/2009

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