Lucas Engine Break-In Oil

J

jdp530

Joined
Dec 14, 2014
Messages
5
Location
Texas
Hello, I am now running Mobil 1 15w-50 in an early 1990s engine with overhead cam, hydraulic lifters, and rocker arms. I live in S. Texas and it's pretty darn warm several months out of the year. I changed valve stem seals last month because of smoke at start-up or if I was revving engine lightly while sitting. I had been running 5w-40 so the heavier oil definitely helped reduce or even eliminate the smoking.

Capacity of engine is almost 9 qts with oil cooler I installed recently. I did a Liqui Moly flush after changing stem seals. Then I added the thin oil and engine continued smoking. So I changed to heavier oil a week or so ago but I also added a bottle of Lucas Engine Break-in Oil with the ZDDP. I dont have cats on the car so I thought the ZDDP would be beneficial. But, a friend of mine said to get rid of the Lucas because it can turn gummy and stick the oil pressure relief valve. Does anyone have any experience with this issue? I hate to waste a $60 oil change just to dump the Lucas. I can't imagine that it would cause a problem before the next 3000 mile oil change.

I never did figure out the the M1 15w-50 had the phosphate and zinc additives so I dont know if the Lucas additive puts the amount way over the recommended levels.

Thanks,
 
Last edited:
The are only a few times when break-in oil is a good idea:
- when you have a freshly rebuilt engine
- high-lift cams and flat-tappet lifters with a very high spring force
- brand new cams to break-in.

New valve stem seals do NOT require "break in" oil.
Get rid of that Lucas stuff and use a decent 10w-30 or 10w-40; those would be a good year-round vis for south TX.


BTW ... first post in 10 years????
Talk about restraint!
 
Last edited:
Thanks, dnewton3!

I dont usually run additives in the oil but i thought the ZDDP would be beneficial for an old motor.

smleng.webp
 
Last edited:
ARCOgraphite said:
I run Lucas in my E38. Just Because!

A candidate for R&P? or do these wear guide inserts like my old Audi LS.
Click to expand...
Car has 160k miles on it and valve stem seals have never been replaced. Valve guides probably need to be replaced eventually. I am tempted to look for an M73 block to rebuild and use my heads on it, but I have too many other projects to look after.

PXL_20240719_211059517.webp
 
OVERKILL said:
That looks like a perfect candidate for an @High Performance Lubricants Euro 5W-40 oil. No additives needed.
Click to expand...
I put M1 5w-40 in it a couple of weeks ago because that was all i had on hand but engine was smoking some at start-up or under light revving while sitting. I changed to 15w-50 and smoking seems to have stopped. Engine probably has some worn guides with 160K miles on it. I changed to stem seals but that didn't help when running with the 5w-40.
 
jdp530 said:
I put M1 5w-40 in it a couple of weeks ago because that was all i had on hand but engine was smoking some at start-up or under light revving while sitting. I changed to 15w-50 and smoking seems to have stopped. Engine probably has some worn guides with 160K miles on it. I changed to stem seals but that didn't help when running with the 5w-40.
Click to expand...
Yeah, sounds like the guides may be shot then, so the 15W-50 is basically just a band-aide, though I appreciate you probably not looking forward to diving into that, lol.

I guess another option is the BMW/Castrol TWS 10W-60?
 
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