rebuilt engine, what oil to use

OLD AS I

OLD AS I

Senior Member
I know this has been brought up many times but doing a search doesn't bring up much, never have much success with search on here. Did a Google search and links to Barn, V8 club and HAMP provided results. Shell Rotella T15W40 with STP added had 7 users, Castrol 20W50 5, 10W30 4, lot of comments to get highest ZDDP/Zinc content, anyone have any comment to add
 
Haven't changed the oil yet on my Merc, but on my '63 MG, I use Valvoline VR1 20W50. It has a high ZDDP content and is pretty readily available.

The only reason I use 20W50 in that is because it is an MG, which means it leaks oil. The 20W50 slightly slows down the leaks.
 
oldasi said:
I know this has been brought up many times but doing a search doesn't bring up much, never have much success with search on here. Did a Google search and links to Barn, V8 club and HAMP provided results. Shell Rotella T15W40 with STP added had 7 users, Castrol 20W50 5, 10W30 4, lot of comments to get highest ZDDP/Zinc content, anyone have any comment to add
Click to expand...

I used Castrol 20/50 in a NOS WW 2 engine from start up. It has
over 130,000 miles on it don't burn any oil and runs quiet. I
recently changed to Valvoline Cummins blue due to the additives
in it. I have several small diesels and based upon the attached
oil test comparisons switched to the Cummins oil. G.M.
 

Attachments

Well you still didn't get much of an answer. Seems like, if the engine is properly built and broke in, it doesn't matter. I personaly believe the brake in prosses is more important. Just install the engine in your car or truck and drivre like you stole it. I use 10-30 oil.
 
My engine re builder said to use 20-50. He is a major re builder and would certainly not recommend anything that would cause him warranty problems IMO.
 
The old flatheads have pretty tight clearances if set up to factory specs. SAE 20W20 was what we used when I was a kid. In the summer we used SAE 30. After those went away we started using SAE 10W40 for everything but all the old engines were fairly loose by then. That was in the late 60s or early 70s and we used the old cars & trucks a lot back then. My first car was a hand me down 51 Merc and I was glad it survived long enough for me to inherit it but it was well worn. I was the last of 4 kids to use it and I wore the old motor out the rest of the way before I finally overhauled it.

Warranty problems due to motor oil would most likely be to forget to put some in. I think you can run just about any kind of motor oil in them within good reason. Any oil is better than none at all.
 
I think I have mentioned before that I have been buying my oil at Dollar General for the last few years. They usually have a known brand (the last I bought was "Peak") in 10w-30 and 10w-40. On sale it's usually $2.49 a quart. On the label it says "Not to be used on vehicles manufactured after 1985". That says there is to much zinc for current emission standards. Now, if they would just start selling filters..:).
 
With the number of hard miles I drive my car, 1,000 per month, I use the best there is - Mobil 1 total synthetic 10W-30 since last rebuild. My main bearings only lasted 55,000 miles with conventional oil prior to last rebuild.
 
Professor, I think your engine will last forever, be nice if it had a full flow filter. I don't think the synthetic oils ever ware out. I believe that cooling the bearings is very important for longevity, and a heaver oil only makes the gauge happy. However, the flathead, with approximately 80 HP, Has the same amount of bearing surface as a 350 chevy. So the loads are very small.
 
The synthetic lube part could be cleaned of combustion by product & reused but the polymers get beat up too. If you could remove the old & add new polymers, the lubricant would last forever.
 
DEUCE_ROADSTER, you sure got that right, am more confused than ever, was set on either Shell Rotella T15W40 with STP or Castrol Syntec 20W50W. Think I'll go with one or the other, flip a coin
 
oldasi said:
DEUCE_ROADSTER, you sure got that right, am more confused than ever, was set on either Shell Rotella T15W40 with STP or Castrol Syntec 20W50W. Think I'll go with one or the other, flip a coin
Click to expand...
There is really nothing to be confused about! Just because different people like different products does not make one better than another. If I like red and someone else loves blue that is not a reason to get confused, LOL :)
 
Brad Penn break in oil I believe its 30 wt. I used it on my last rebuilt engine and no problems just like we want. There oil has great reviews. I`ve heard excessive ZDDP is not a good thing. Let the guys at the oil companies add it so its the right amount.
 
If you smell gasoline in the oil I say change it (not just a faint hint). Other than that common sense on color and texture, time and mileage . I always felt the oil companies want us to change our oil more frequently than necessary! As for as oil I like Royal Purple its pricey but the research I've done its worth the investment, especially with the older Early V-8 Fords without oil filters.
 
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