VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 Piston Ring Types for the 216

I am rebuilding a 1938 Chevy 216 and my cylinders are in good shape (about .005 oversize) I would like to hone and put in ductile iron rings with either a chrome or moly coating. Another possibility is to go with the original grey cast iron rings. Anyone have any experience using or getting either of these types of rings? Most people do not know what the rings are made of, but I am a metallurgist and am very particular. Usually grey cast iron is weaker and not desireable on high compression engines that use thin rings (like modern engines, < 1/8 thickness), but may not break so easily in 1/8 inch thickness of lower compression engines such as the 1938 Chevy. i would not use a steel ring for it will not wear well. I want to put the best I can into this part of my restoration. Getting what I want is the hard part. Thanks for any comments.
Mike
Ingition on, push real hard, jump in, grab second, pop clutch, and ...away

I rebuilt my 47 216 with .030 Aluminum pistons, and a set of NOS chevy rings. Runs like a top.

The original equipment rings that Chevrolet used were cast alloy iron with no expanders behind the oil ring.These were very gental on the cylinder walls and gave satisfactory performance for the standards of the time.They were designed to be used on new straight , round cylinder walls.The greatest problem was with the oil return holes in the oil ring and piston cloging with carbon and causing oil consumption.This was more of a problem with the old oils.Also in the "olden days" adding a Qt. of oil every 500 miles was common and 1000 was excellant.
In the 1940's Chevrolet offered a replacement ring thru parts that was better for an engine overhaul job.The oil ring was the steel rail type with spacer in between and expander behind.We had excellant results in the dealership using these rings.The part number for a standard size set was 608201 and I bet I handed out hundreds of sets of these over the years.They were pre chrome.
The next ring came along in about the mid '50's.It was called the Chrome-flex ring.The oil ring was chrome plated,there was a secondary thin rail type center ring that was chrome and used expanders behind the oil and center comp. ring.The part # for a 216 was 3704008 in Std. size.They were available for all 6 and 8 Cyl engines for replacement.They were made by Muskegon Pistion Ring in Mi.....and were also an excellant ring.I have a set of them in my '39 and along with improved valve seals the engine will consume only about 1 Qt. of oil in 2000 miles of high speed driving. If I remember correctly fleet47 put these rings in his engine.The still come up on Ebay etc.
There were also some other good replacement rings available such as Perfect Circle.
The replacement rings went from Std. bore to about .009" over but if the walls were greatly out of round the engine should be rebored.

My ring story for the day :)

As long as I am on the roll lets get back to the crankshaft.
There was only one crankshaft used from 1937-39.The main braings are the same from 1937-47 except for the 1937-39 rear main.It was different due to the fact that those years had no rear main seal.
The connecting rods were the same from 1937-47 although different forging numbers were used thru the years.

The 1939 manual list the main bearing journal sizes as
#1-2.6835-45
#2-2.7145-55
#3-2.7455-65
#4-2.7765 -75

The 1941 Motors manual shows-
#1-2.683
#2-2.714
#3-2.745
#4-2.776

Rods-2.311

The beauty part of it is the engine had 2 .001" and 2 .002" shims between the cap and block (on each side) so there was some room to play with for adjustment.

The 1937-47 rods were babbited with a medium thickness babbit.If lubricated properly and kept adjusted so they made no noise (adjustment usually every 40,000 miles depending on how maintained and driven) they lasted 100,000 miles or more (few cars went that far in 1938).The 1948-53 rods had still thinner babbit and would go twice the distance between adjustments....can not be used in previous years as they were not as wide.
I have no experiance with inserts but they do have an advantage.The thinner babbit.This is important if undersized bearings are required because on the babbited rods they just made the babbit thicker to make them undersized.This caused the soft babbit to pound out.
Teh insert would need the same center oil grove and pocket on the bottom around the dipper oil opening.Also the inserts are best for a new or reground journal.The babbited bearings can be fitted better to a slightly worn journal.
At 90,000 miles the crankshaft is the only major part left in the engine of my '39.The head cracked, the block cracked, but the crankshaft keeps going around.Maybe its because I have a new crank on hand should I ever need it.

Chev Nut are you sure on the 35,36 crankshaft being the same as 37up; last time I looked there was a difference. 37 to 39 I believe are the same. I'm sure it was just a typo error.

Thank You -that was a typo error that has been corrected and the secretary has been "released'

I have a lot of different makes of rings, when you deside what you want I might be able to help.