TR6 Tech Forum

Engine Oil

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foofnik Avatar
foofnik Lew M
I am about to change the oil in my 74 TR.
Anybody have any reasons to suggest that I NOT use Mobil 1 15w50 Synthetic?
I believe the engine had an overhaul about 15000 miles ago. I just got the car. The oil is fresh, as is the filter, but I need to change it so I know for sure what is in it.
Pressure is running around 100 cold, 80 hot running, and around 30 hot idle (850) so I would think the bottom end is solid.

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80Racer Jim Spillane
Charleston, USA   USA
My 02Cents. I wouldn't switch to a full synthetic. Either keep to 20w/50 GTX or go w/a high milage oil blend of dyno & synthetic. I beleive older cars run better and need the heaver dyno oil. Now on my newer cars I run nothing but a full synthetic, 5w/20 and 5w/30. Again my 02cents.

poolboy Avatar
poolboy Ken D
Sandy Hook, MS, USA   USA
Food for thought:
Search online "ZDDP + flat tappet engines"

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wah864 Bill Humphrey
Greer, USA   USA
My thoughts, I used Mobil 1 for two or three oil changes at 5,000 miles each, and my consumption was about 1 qt between changes. Switched back to Castrol and 10w30 and no loss of oil between changes. I do add zdpp from the roadster factory.

foofnik Avatar
foofnik Lew M
Isn't 10w-30 a little light for the TR? I'm using the 15w-50. Usually you see owners using Castrol 20w-50.

britsnspits Avatar
britsnspits Michael Stoliker
Bethlehem, PA, USA   USA
1976 Triumph Spitfire 1500 "The Phoenix"
1978 Triumph Spitfire 1500 "Lucky"
And there you've answered your own question! I'd go with the Castrol GTX or Brad Penn oil.

wah864 Bill Humphrey
Greer, USA   USA
Brain fade! Castrol GTX 20W50 I just went to the garage to read the label.

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okanagan tr8 Avatar
okanagan tr8 Gary Stoutenburg
Kelowna, Canada   CAN
Don't forget there are some brands, Edelbrock comes to mind, that now make synthetic with the ZDP already added for our flat tappet cars. I use this in my TR8 and haven't noticed any consumption issues at all. I know there is at least one other brand as well but I can't remember the manufacturer...... might have been Royal Purple.

cbuhls Chuck Buehler
Cedarburg, WI, USA   USA
I use Valoline Racing Oil 20w50. So far, so good

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maddmapper Avatar
maddmapper Ken Prentice
Victoria, BC, Canada   CAN
Was using Penzoil 25W50 racing oil but can't seem to find it local anymore. Back to Penzoil 20W50 with ZDDP

tomshobby Avatar
tomshobby Tom Smith
Windsor, WI, USA   USA
I really like Brad Penn. Valvoline Racing oil is also good as well as Castrol GTX.

Several years ago there was a rash of cam failures and other problems seemingly due to zddp levels in modern oils. I had it happen and at least one other person in this thread also had trouble. That person purchased his car from a person that had made a serious engine rebuild and was proud to use Mobil 1. Whether or not it was due to the oil while is possible is not certain, but, it did happen.

There was a lot of discussion and research into zddp levels in oil and how it related to our engines. I learned that too little is bad and too much is also bad. Everything I found at the time indicated that 120 to 160 ppm is the best range. Over 220 ppm is not good and can cause problems.

That told me that it would be best to use oil that had the correct amount to begin with. Also that adding zddp to be in that range would be difficult. One would need to know how much is in the oil purchased and how much is in the zddp additive. Then calculate how much zddp to add to be in the correct range.

When I had my engine built several years ago many brands of oil were changing the amount of zddp to comply with newer engine requirements partly due to to the use of catalytic converters. The problem was that nothing was said to inform the public.

At that time I actually called engineers at different oil companies to find oil with the zddp level that I wanted.

What ever happened since seems to have helped because I have not noticed the numbers of engine failures these days as seemed common years ago.

I have used Brad Penn in my TR6 since my engine was built. Now with nearly 60,000 miles, some of them aggressive driving, my engine does not use oil and runs great.

Tom Smith
1976 TR6
1974 Midget

Edited 1 time(s). Last edit at 2015-12-08 11:05 AM by tomshobby.

SteveKJR Steve KJR
Stockbridge, GA, USA   USA
I use Rotilla 15w 40. Never had a problem and it wears well.

hogan1945 Avatar
hogan1945 Silver Member Douglas F
Woodbury, MN, USA   USA
1968 Pontiac GTO "Tempest"
1976 Triumph TR6
1976 Triumph TR6
1976 Triumph TR6    & more
second Brad Penn

cdozois Avatar
cdozois Gold Member Craig Dozois
Englewood, FL, USA   USA
I use vr 50 racing oil

shelovesouzo Michael P
Slc, UT, USA   USA
Tom, are you using Brad Penn 20/50 W semi synthetic blend?

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