The Stovebolt Site Forums The Shop Area Engine Shop 10w-30 oil

should I be OK using 10w-30 valvoline and ZDDP in a fresh rebuilt 235? Plastigage specs were right on during assembly

You'll probably be OK. Personal preference is that 10 weight oil is too thin. I run 15-40.

Since you are in Florida you could probably run a heavier grade like straight 30 too. And change oil after the first break in of the rebuild.

Wether you use 10w30 or straight 30 oil you are doing the right thing by adding zddp. Otherwise the results could be total cam and lifter failure.

I prefer something a little heavier than 10 weight, which is the physical thickness of 10-30 all the time. It just lubricates like 30 when it's hot. I've been using 15W-40 in all my vehicles for several years, including a couple that needed 5W-30 when new. After 100,000+ miles, I think the clearances are probably wide enough to need a thicker base oil. Since I use 15-40 in the farm tractor, it makes sense to me to buy it in bulk and use it in everything.
Jerry

the weird thing is I had straight 30 in it for break in. The pressure guage was around 50lbs and never varied. I bought another guage to check against it and it seems to hold steady at about 40. no fluctuations with RPM. I'm beginning to wonder if my pressure relief valve isn't working. New Melling pump.

I found Pennzoil 30W SL oil at a local farm supply store and I'm using that in all my older vehicles. SL still has zinc, SM has the zinc removed.

Joe D.

Farm stores are an excellent source for SL oils. I buy the oil for my 38 at the local farm store. You need to read the label because they also carry SM oils.

If you've ever torn a penzoil engine apart, you would run from that stuff afterward.

Or better yet, Quaker

A friend once told me the same about Quaker State.

Joe D.

I have been into engines that have used penzoil all thier life and they were clean. Not sludged up. The custmers changed oil regularly and drove the vehicle around 50 miles each way to work and back. The reason I had to open one up was someone was kind enough to drop a piece of metal down his carb and ruined a piston. The othere had too many miles to count and had flat worn out.

I opened up a Chev 305 that had Mobil 1030 from new, changed every 3,000 miles and you had to scrape the sludge out. At 65,000 miles the engine had to be replaced. But it was started, driven 1 1/2 miles and shut off for the day, then 1 1/2 miles home. Never warmed up. Say what you want about Penz. but I have had very good luck using it. But I change oil when needed, and my vehicles get driven rather than just short trips.

Heard all sorts of things about every brand of oil out there. Heard Quaker State and Penzoil both foam at high temps.
I own an 81 Malibu with over 500,000 miles on it, an 81 Buick regal with about 250,000 miles and a 49 Chevy half ton with 111,000 miles on it.
I have never touched or rebuilt any of the engines except valve stem seals on the Malibu. I use Quaker state 10W30 exclusively and change the truck every 1000 miles and the cars at every 3000 miles.

For the fact it is a flat lifter and not a roller then I would use any diesel grade oil in it. Thats what I run in my dad's 29 GMC truck. It has the extreme pressure treatment in it and it helps to prevent cam wear from the oil being pressed out from between the cam and the tappets for those who choose to be correct on parts names. so I run 10w30 diesel in all my vintage cars and yes even in my 9N Ford Tractor.

you have to love manufacturing tolerances. unless your gauge is calibrated to NIST standards, then the best you can get is an approximation of pressure. if one gauge measures 40 and one measures 50, then you have about 40ish to 50ish psi

As far as oil goes, only oil rated for diesel still has zinc in it. Its what I have to run in everything I own.

A fellow dirt track racer called me to help troubleshoot his new race engine that would start, and stall immediately. After several attempts to keep it running, he fired it up and kicked the throttle wide open. It shuddered and shook for a couple of seconds, and then split the oil filter can wide open from top to bottom. Since I was standing right beside the left front wheel (open-wheel car), it soaked me in warm oil. He had shimmed the relief valve down for lots of oil pressure, and the pump was getting into a hydraulic lock and stalling the engine. If your relief valve was stuck, the oil pressure would increase without limit as you rev the engine up. it sounds like the pump is delivering enough oil to keep the relief valve open at its preset pressure all the time, and recycle some oil back to the pan. As the engine warms up to full operating temperature, the pressure will probably drop a little, especially at hot idle. Be happy you've got a good pump, and drive on!
Jerry

Scott, didn't some of the diesel oils cut back on the zinc back about a year ago? I remember reading something about it.

Yes, they are cutting back on the ZDDP in Deisel grade oils, same reason that they did it in passenger oil, mucks up the emissions system.
Personal opinion, too much is being made over the whole deal. From what I've seen, most of the cam failures point back to improper break in and/or incorrectly matched parts/faulty assembly. If you hav correctly matched parts (I'm talking stock to mild hop up, not full race parts) and follow the specs and assemble/break in procedure correctly, there shouldn't be any problem running SM grade oil. I can't speak for other brands, but I do know that Valvoline does their cam wear test using a flat tappet engine. Also, we put SM grade oil in flat tappet engines every day at the shop I work for, have yet to see an engine fail due to the oil. Maybe from lack of oil, but never from having current spec put in.

I still run Rotella for that reason.

I'm not sure if this thread is an oil quality debate or what is best for the engine. Any oil sold or produced by a well known manufacturer, selected for the proper loading and temperature will give good results when changed regularly. My operators manual recomends SAE20 for daily temperatures of 32'F to 110'F. SAE30 for Heavy duty operation and High temp of 90'F-120'F. I had SAE30 oil in an antique tractor that on a 32'F day starved the engine of oil because the pump could not suck it thru the pump screen fast enough because of the straight grade, Yet I had started it with a hand crank! without difficulty. States also in the book that: "The use of lighter oils will not only lessen the cold weather starting difficulties, but will result in better fuel economy and longer engine life". If you realy want less wear a little powered lead in the oil is wonderfull and let the environmentalist ponder that one.

.... I agree with Bill. A lot has been said about the zddp/zinc in oil. If my memory serves me correctly this all started over some cam failures.
The MAIN concern here is on startup/break-in of an engine. The break-in or the first 20-30 minutes of engine run time will decide if the cam fails due to lack of zddp or not. I always put a quart of EOS (Engine Oil Supplement) from the Chevy dealer in my engines. They stopped carrying it for a while but I hear they have it again? After that I never use it anymore and just make sure I change my oil on a timely basic.
The "action/marriage/hardening" or what ever the proper name is, for the cam/lifter metal conditioning happens in the first few minutes and then its over!
About 2 or 3 years ago, while delivering parts to garage "David" told me about engine failure on a Chevy engine he built and that it was the oil...he never added any supplement, that caused the cam/lifter failure. I looked at the actual lifters and they were eat out on the bottom pretty bad in what amounted to maybe 100 miles. David then showed me letters he received from cam companies who responded to his concerns. The articles spoke of many failed cam/lifter sets due to the lack of ZDDP. Well, David used the same stuff again, put in a quart of EOS,ran the engine in and never had any problem. Lesson learned.
It was also a lesson for me. Even though I always used the EOS I had not heard at the time about the elimination of ZDDP. It does pay to stay abreast of what is going on.... .which the Stovebolt does a good job of at least getting it on the front page!!

This is first hand info.... what the other details involved I don't know but its all in the break in that we should "mainly" be concerned. Thats when the damage is done. In my opinion it really don't matter on existing running engines except for maybe on the really old stuff and I can't properly addrsss them.