The Stovebolt Site Forums The Shop Area Engine Shop Best Oil for a 1955 Chevy 235ci

???

The best oil kind of depends on the condition of your engine, the amount of miles on it and the climate (how cold. ) where it is driven. It is not that cold here in southern California so I would use a non-detergent 10/30 or 30 weight oil in a good engine and a 10/40 or 40 weight in a worn, smokey engine.

It runs pretty good...but have no idea how many miles....and it was supposedly rebuilt within last 2 years...again this one does not run a oil filter either....5 quarts right about amount of oil?

Mine came from the factory with 20 weight break-in oil when new in May of '55. I switched to 30 wieght Havoline 5,000 miles later and still use that oil. It has over 138,000. miles on the odometer and no significant problems yet. BUT... mine still has a factory Canister filter on it. The later filter types showed up in '56.
Normbc9

What later filter types showed up in 1956 on 235 engines?

I agree with truckcamper53, "The best oil kind of depends on the condition of your engine, the amount of miles on it and the climate (how cold. ) where it is driven". Regarding engine oil, multi-grade oils are OK - GM listed them for later 235 engines. I use multi-grade diesel oil and have used 20W-50 oil in an old engine (and even 50W oil in an old engine in the summer).

Use a multigrade detergent oil. The best you can buy. I agree with Tim about using a diesel oil, as they are usually the best. I have been running 10W-30 in mine since 1973. I rebuilt the engine (1953 235 powerglide) around 1984 and have been running Lubrication Engineers 10W-30 since then. No problems at all. Engine still runs like new.

Kurt

Thanks guys...I looked for 15 minutes trying to find the Oil Filter...Blew my mind that it did not have one...i am 32 and have never heard of a engine without one.

A canister by-pass oil filter was either optional equipment (from the factory) or accessory equipment (after-market from GM or from others) equipment (not standard equipment) on 216 and 235 engines.

For flat tappet engines, I like using Valvoline Racing oil because it has a zinc additive. The zinc cushions the high load metal to metal contact between the cam and lifters. Hard to find oil with zinc in it anymore and thus a big cause of cam failure on newly rebuilt flat tappet engines.

What about using synthetic oil? Any better or worse?

DavidF - Look into Hicks Collector's Choice (or Muscle Car) Oil. I believe they are also re-branded for the stuff Hemmings now sells. The Hicks brand is cheaper than the Valvoline Race Oil and I believe it contains a tad more ZDDP.

...I'll see if I can find the spec sheet from Hicks

Anything you buy now is better than the best oil you could buy when the truck was new.

Unless your motor is a fresh overhaul with a new camshaft and lifters the ZDDP is not really an issue. As mentioned the oil today is far superior to oil that was available back when these engine were new.

Even then, unless you're running a high lift performace cam with stiff racing vavlesprings, the extra zddp is really only neccessary on break in.

Many older types of rubber & rubber / cork gaskets (and many RTV sealants)don't hold up well to synthetic oils.

Hi. I don't use my stovebolt in a truck. Someday I'd like to have one, but in use my 1950 flint built 235 in a 1950 chevy deluxe. The motor was rebuilt buy the owner before the guy I bought it from in 1991. I don't know to what extent. It's had straight 30 weight non-detergent in it, but many have told me to use 10-30 detergent. What do you all think? I bought the car and have only owned it in below freezing temps, so there is some smoking. She purs like a kitten once she warms up, and relatively clear exhaust. I have an oil filter btw. Fram c4p.

Modern oils have the same level of ZDDP as oil did in the 50-60s.

ZDDP is being replaced because there are other additives that do the same/better job...high ZDDP levels prevent oil oxidization.... not wear. High ZDDP levels actually destroy metals.

API has a specific test for flat tappet wear... the API spec for tappet wear started in 1959:

This test technique was accepted by Section G-IV of Technical Committee B of ASTM Committee D-2 in October, 1959 as Test Sequence IV. This test was one of a series of test sequences to be used for evaluating oils for API Service MS.

You can read about it HERE even has pictures!!!!

So any API current spec motor oil will be fine for flat tappet motors (which are still made by the millions.. called inverted bucket lifters).

If you have a HIGHLY modified race engine (double springs, aggressive cam etc) then you might have a need for high zddp levels.... but at that point you should be using roller followers and rockers.... which need little to no ZDDP.

So yeah... any API oil is fine. Specialty/Race/custom blends do little for a stock/warmed over motor. Pouring ZDDP into your oil is completely useless... unless its part of the additives package it will not emulsify nor 'stick' to the wear surfaces.