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Reusing Old Rings?

9K views 27 replies 9 participants last post by  powerstrokeace 
#1 ·
Is there any disadvantage of using old rings? Last summer I had a lifter failure that was pretty bad and I tore the engine down to clean everything up and put it back together. The short block got new cam (roller) bearing as well as rod,mains. At the same time the heads received a fresh valve job and all the springs where check and given a clean bill of health. Now the replacement cam from comp was not something I wanted. I was wanting the same grind but was told that it was 10 years old and that this new grind is better. So atfer having my arm twisted in to this newer grind it was installed just as the cam card recommends. now after running the car its a DOG. It struggles to build rpm. It use to go through the finish line @ 7400 and 157 mph and some change. Now 6800 and 154 and some change. I have tried timing adjustments @ 2˚ at a time from 32˚ to 40˚. 36˚-38˚ having the same results as best et and MPH. next we tried carb jetting and pretty much slowed the car jetting up or down. Now over the winter I sent the converter out to be freshened and only found one of the bearing cages cracked, but didn't come apart. Last we had an oil pan crack when this build toke place last summer and replaced it with the same(UPDATED) pan. the old pan had a crank scraper and windage tray (solid aluminum) built in the pan. The newer pan has the windage tray ( screen) on the crank mains. I first ran the motor with out the windage tray ( last summer) and this year with it and have the same results. So with that being said I called Tim Cole back at comp cams and tried to discuss the matter and and after what started out as a normal conversation turned out vert HEATED. He said I should have put rings in the motor even though my compression tests are the same and the leak down was still 3-5% and he HUNG up on me. So what do you think.

FYI. I run a super comp class and even though the car slowed down .3 tenths and 2-3 mph. it dose seem it is more consistence for throttle stop racing. but I hate losing the ET

Ace
 
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#3 ·
The camshaft may be installed into the engine the very way the card says but, it probably isn't the right way for what the engine wants.
Without a belt drive it's awfull tough to change it a few degrees, one way or the other, at the track in order to find out.

Geez ... dyno tuning would have been nice.

The oil rings won't make any difference in horsepower; just maybe oil in the chambers.
 
#7 ·
Ok here we go
Dove A block 4.440
Roller cam bearing (spun cam bearing and this saved the block)
4.140 offset ground crank
Eagle 6.800 H beams rods
Venolia dome pistons Size unknown (10 cc’s ?)
A460 motorsports heads 2.300-1.88 vavles. Very minor clean up work flows 383 @ .700 intake and 247 @ .800 Exhaust. Also milled .060 so the chambers are around 75-80 cc’s
Old style intake
Holley box stock 8896 jetted 91 square and no power valves and 35 squirters

Old cam was installed with no advance ( straight up on timing ) and we have 108˚ Intake center with the Intake opening @ 31˚ BTDC and Close’s @ 68˚ ATDC. This cam was to be installed at 106˚ per comps spec’s. for some reason we installed it straight up.

New cam is installed at 4˚ advanced to get 109.75 Intake centerline with the intake opning28˚ BTDC and closing @ 67.5 ATDC


this is backed by a powerglide trans 5600 stall 1:80 first gear. 4.10 rear gear and a 33.5x15x15 tire in a 1850lb dragster

Ace
 
#9 ·
Is there any disadvantage of using old rings?

Ace
In reply to the general question and without getting between you and CC: Yes, it is absolutely possible and can be perfectly acceptable to re-install and run used rings....just as it is possible to re-use a block, rods, bearings, etc. What's important in the case of the pistons rings is knowing how to evaluate their current condition and take other considerations such as engine applciaton and what the condition of the mating parts (to the rings) also are. Things such as inspecting the wear at the ring's taper, or barrel, etc.

I don't know what you inspected prior to re-installation but your 3-5% leak rate sounds good.

Paul
 
#10 ·
I installed used rings before without any problems,it sounds like Tim cant believe there just might be a problem with the cam or the spec card is off a little maybe i mean jeeze like there's never been a flaw in mass produced parts before.
 
#11 ·
If they ain't hurt a set of used rings should be fine. You can usually see the contact area pretty clearly. New rings will show line contact at the lower edge of the seconds, and in the just below center of the tops. As the rings wear the contact area widens out.

Tops work OK until they're pretty well worn out since they seal with combustion pressure. Seconds get worse with wear since they are squeegees and count on wall tension and point loading to function.

Unless you do something stupid to them oil rings last an awfully long time. I have seen Top Fuel and high boost Pro Mod/Pro Street rings that looked like waffles - the top & 2nd had failed and the cylinder pressure formed the upper oil rail into the expander. The Speed-Pro fuel expanders were designed differently for that reason - no big "windows" in them.
 
#12 ·
Well after having a conversation with Scooter Brothers @ Comp Cams he very well feels that the current cam They speced out is very wrong and suggested that I install the reground damage cam. If the performance comes back they will take the bad cam( design) back and get me something else. So as of right now I'm looking to put it back in the motor after the Mile High race do to limited funds and testing this year.

Ace
 
#13 ·
Greg,
I was digging in my cam info folder this afternoon and found a copy of the cards for the two cams that you posted.
The 'old' cam has 60* of overlap...the 'new' cam has but 53* of overlap . From what I've seen the 53* aint gonna get it done. I'm sure by now you have installed the old unit and if you have you are going in the right direction.
 
#18 · (Edited)
Lem

When I damaged the cam from the roller lifter I ordered a duplicate new cam. NOT WHAT I GOT its the cam in the motor now. I took the old damaged cam and sent it back and asked for it to be duplicated and instead they regound it. this is what is on my shelf now. I'm really not to fond of Comp right now because in my eyes the messed up twice.

Ace
 
#22 · (Edited)
Well ..huh...seems Scooter don't know about your engine comb.
Seems 60* ran the best and you have been sent everthing but that . Comp has very good stuff...just a matter of getting the correct lobes.
Here is THE DEAL......and the context. Back here [425 above sea level]...good heads manifold 14/1 or more...big engine.......65*ish works for overlap. So....you are on a mountian so maybe 60*ish maybe more like it.
 
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