Hot Rod Forum banner

sbc 350 piston rings?

21K views 19 replies 13 participants last post by  cobalt327 
#1 ·
my engines over bored 0.60" with standard stroke and I bought pistons for it but now I'm having problems finding pistons rings for it.
Ive been told that if your not buying total seal rings your wasting your money so Ive been looking and Ive noticed that they only have overbore size 0.45" or 0.65" not 0.60" now is this a problem? I thought it is because I didn't think it would fit since the obvious size difference?
the stroke is 4 inches

see these:http://www.jegs.com/p/Total-Seal/Total-Seal-Gapless-TSS-Street-Piston-Rings/750291/10002/-1
(# Gapless TSS Street Piston Ring SetOversize: .060"
# Top Ring: 5/64"
# Second Ring: 5/64"
# Oil Ring: 3/16" ) would work except that the pistons I got are meant for 11:1 c/r and the rings are meant for 10.5 to 1 c/r

will the small size diff matter? is there a different brand I should look into?
 
#2 · (Edited)
Somebody is pulling your chain, to start with the standard stroke on a 350 chevy is 3.48" not 4.00" ..... the stock bore is 4.00, now it's 4.060. The .045-.065 rings are the gapless type which you really don't need if it's for a street car .....unless you just have to have them and don't mind spending the extra money. What is the engine going to be used for and whats the rest of your parts combo? You really have to think this thing out completely before you start buying parts, they all have to work together.

You can get standard ring sets in .030, .040, and .060 just about anywhere. BIG difference in price, look at www.Summitracing.com or in their catalog on page 140. Sealed Power / Speed Pro, Hastings, Elgin or Summits etc. I would get the moly faced rings (not plasma moly) and your piston ring lands will dictate whether you get 1/16 or 5/64 size.
 
#7 ·
Is it unrealistic to think that the gap can be checked and hand filed as needed ? Anyone know if the filing machine is available as a loaner tool at any of the auto parts stores? Thanks.
I got all my parts back from machine shop, ready to build......trying to stay calm but all the fresh new parts have got me wound up pretty good.
EEEEHHAAAWWWW
 

Attachments

#12 ·
Welcome to Hotrodders.

Rings can be measured/hand fit to the cylinders of an engine if you're willing to do the work w/a hand file. But you have to be careful to keep the ends square. Only file one end, leave the other alone. When the gap's right, any sharp edges need to be removed from the end you filed.

You measure the gap by placing a ring into the cylinder its to be fit to, then the ring is squared in the bore. You can use a ring-less piston upside down to press the ring in the cylinder with to square it. Then carefully use feelers to gauge the gap.



If you're using moly rings, you need to be careful to not chip the moly. My recommendation is to use a ring filer machine for this (I know of no 'loaners'), but it can be done by hand w/care.

All that said, there's little advantage in jumping through all the hoops. Just by a normal-fit ring set in the correct size. Check the end gaps as described above. A short page w/ring info is here.

Good luck.
 
#8 ·
PISTONS: Speed Pro L2256F forged + O.S. , .0025" - .0035" cyl. wall clearance

RINGS: 5/64", 5./64", 3/16", plasma moly (60% porosity) ductile iron top, ductile iron second, SS oil.

CYLINDER WALLS: hone 625 grit, finish hone with 3 strokes 820 grit, season with ATF

SEATING: instantly, rings will seat before you can adjust time timing advance.

BREAK IN: Make a full pass or go get some beer.
 
#11 ·
Yes, rings are EVERYWHERE for the 4" bore. Whoever told you Total Seal was the "only" one, well, NEVER ASK HIM AGAIN! Gapless rings were a good idea, they just didn't "work". That is, while they DO seal the cylinder and generate better "numbers" in a leakage test, they don't make any more power or use less oil (often, more) than "conventional" rings. Gapless rings also tend to taper the cylinder quite rapidly. The Sealed Power E-251K mentioned is a very good ring. If the bores aren't "fresh", though, I'd opt for the E-251X instead (ductile iron). The "K" series are "moly" rings and may have trouble seating in a "used" bore. I haven't seen Perfect Circle available in a LONG time. We use SP as said, Speed Pro (EXCELLENT race ring) and Hastings. We've used Grant in the past with success, as well.

"File fit" rings are among the more used and abused products among DIY engine builders. When building a RACE engine ("custom" specs), one must "fit" everything. Generally, standard clearance (piston-to-wall) is inadequate for racing. As a result, the bore size may increase as much as .005-.006". The "file fit" ring allows you to do this without ending up with too much ring gap. Aside from that, there is no "advantage" to a file-fit ring. We use "drop-in" rings in the majority of our builds.

Jim
 
#15 ·
my engines over bored 0.60"... ...overbore size 0.45" or 0.65" not 0.60"...
Not to nit pick- and I know what you are saying- but for your own benefit, get the decimal places correct. You mean to type 0.060", 0.045", etc.

...would work except that the pistons I got are meant for 11:1 c/r and the rings are meant for 10.5 to 1 c/r...
There is- generally speaking- no difference in the rings used between these different those two compression ratios.

Now, there may be a different ring called for if the engine will be run at an exceptionally high rpm (generally thinner), and sometimes they'll be made from a different material (if nitrous or super-/turbocharging is to be used), and there are different ring tensions used for different applications, but generally rings will be the same regardless of the CR, all else being equal.
 
#16 · (Edited)
.. KB hypereutectic pistons use top rings gaps up to double what used to be recommended, depending on your overall setup/power adders/usage...

.. Pre-sized "drop in" rings can have the gaps filed bigger, if needed... usually, the gap needed is never smaller than what the drop in rings will already have...
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top