Thread: quick re-ring

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Ok, now before anyone slams me for what I am about to ask, I am a mechanic and I know what I am planning on doing is not optimal. I race a 4wd 3/4 ton is a super stock mud bog class and am very limited to mods I am allowed to make. we have a 3 bolt-on rule (carb intake and headers) and the engine must pull 15" of vac. I noticed last season that my 454 was getting tired, so yesterday I pulled the heads off for quick look. While I did not find any obvious damage you could measure my ring gap with a tape measure. I'm assuming this is where my power loss is coming from ( 5 seasons without a rebuild). I have a rebuild kit on order and I have a couple of quick questions for people with experience.
1. I realize standard rings probably are not going to fix my gap ( worn cylinders) so could I use .010 over rings for a little less gap.
2. Would I be better off going to a file fit and if so what is the best gap for a naturally aspirated 454.
3 Does anyone have any other hints for cheap power ( this is a claimer class so I don't want to spend a lot of cash.)
If It helps the 454 is stock with an rv cam and small chamber med truck heads for a little compression boost, also I have a 3 keyway timing set that is currently 4 degrees advanced. any help would be appreciated.

Originally Posted by clinto

Ok, now before anyone slams me for what I am about to ask, I am a mechanic and I know what I am planning on doing is not optimal. I race a 4wd 3/4 ton is a super stock mud bog class and am very limited to mods I am allowed to make. we have a 3 bolt-on rule (carb intake and headers) and the engine must pull 15" of vac. I noticed last season that my 454 was getting tired, so yesterday I pulled the heads off for quick look. While I did not find any obvious damage you could measure my ring gap with a tape measure. I'm assuming this is where my power loss is coming from ( 5 seasons without a rebuild). I have a rebuild kit on order and I have a couple of quick questions for people with experience.
1. I realize standard rings probably are not going to fix my gap ( worn cylinders) so could I use .010 over rings for a little less gap.
2. Would I be better off going to a file fit and if so what is the best gap for a naturally aspirated 454.
3 Does anyone have any other hints for cheap power ( this is a claimer class so I don't want to spend a lot of cash.)
If It helps the 454 is stock with an rv cam and small chamber med truck heads for a little compression boost, also I have a 3 keyway timing set that is currently 4 degrees advanced. any help would be appreciated.

Pat hasn't weighed in on this BBC question yet, so I'll take a whack at it. If pistons are cast or forged, ring end gap for your application should probably be in the area of 0.006" per inch of bore (0.0255" on a std bore, naturally-aspirated BBC). Hypereutectics would need in the area of 0.008" per inch of bore (0.034" on a std bore, naturally-aspirated BBC).

With a short cam advanced that much, you are probably making some tremendous cylinder pressure from idle to about 4000 (heat), so you may even need more end gap than what I posted above. Inspect the rings upon removal for shiny spots on the very ends of the rings, an indication of butting.

I know I really didn't answer your question, but just wanted to make a couple of points before Pat shows up.

Actually you made me think of something else, this this mill does run hot. by the time I have made 4 passes (in the heat of july and august) my rad is usually boiling. the only reason I ran the cam 4 degrees advanced is to make some more vacuum. I think I will put it back to 0 and see where my vac is at after the re-ring. I plan on adding a larger electric fan also to help my cooling issue. this sport is hard on engines and overheated trucks are normal. up untill last season this truck always placed, but last year I just seemed to run out of rpm in top gear. my engine used to pull to 5700 rpm right now. when I ran it on the week end before I tore it down all it could pull under load was 4200. that extra 1500 rpm is what is keeping me out of the winners circle. all I know is it is really embarassing getting beat by small block trucks. back to the topic of heat though, this engine seemed to run best when it was right on the verge of boiling. I guess that was do to better ring sealing at high temps. food for thought.

i would be checking your valves /seat valve job guids valve springs and timing chain for slop a re ring may not help if your bores are tappered or out of round .i do not think your going to see much on just end gap .as for heat bbc run abit hot there many thing that can be done that may or may not help

the valves only have a 50 or 60 runs since the last valve job and the timing chain is only one season old. when i last freshened this motor the rings were not changed only valves and bearings. I had pretty good luck with this motor, all I really need from it is a few more passes this season then it will get a new set of .030 pistons with .100 domes ( this is a claimer class after all). so if the bores don't have a stupid amount of taper what would you recommend for my new ring gap. thanks in advance.

you first need to know the bore size if you make the wall s strait your going bigger so end gaps are going up if cast pistons they will not take the bigger bore .not all hypers pistons need adde end gap sorry i not going to tell you were i put my end gaps but i will tell you check your ring lands that the rings fit good and not all worn out for a carb engine and no Nos you should not need any more then 004.5 pre bore if your more then 0025 then you may what to go file fit but your piston to wall could be way to loose then there is some things i do to get that back were i can live with it by krunling the pistons some look down on this but they do not know one damn thing i done this many times on a $1000 set of pistons were haveing nice round bores this what we wanted

Wow, I would have never thought of knurling pistons. how much of the piston and what part did you knurl. did you just chuck them in the lathe and use a knurling tool. I am just using cast pistons right now so I wouldn't cry if I wrecked them in the process. I guess this week I will take some mikes and bore guages home from work and measure my bores.

Originally Posted by pat mccarthy

not all hypers pistons need added end gap

Thanks Pat, you're correct. I was on Keith Black's site when I answered this. Their hyper pistons take more gap. Other manufacturers do not.

Originally Posted by clinto

but last year I just seemed to run out of rpm in top gear.

I'd be thinkin' valve springs.

I have seen a ton of rotating assemblies for sale with kb's but I think I will save my pennies and go for something forged when I build my 489. I have known a few guys who bought kb's and they seem to have about a 50% failure rate in this sport.

ya tech inspector I probably should put some new valve springs on. any recomendations on what to go with. my heads are basically stock with a valve job.

Originally Posted by clinto

Wow, I would have never thought of knurling pistons. how much of the piston and what part did you knurl. did you just chuck them in the lathe and use a knurling tool. I am just using cast pistons right now so I wouldn't cry if I wrecked them in the process. I guess this week I will take some mikes and bore guages home from work and measure my bores.

no you do not just throw them in a lathe its a machine that only knurls pistons

yep valve spring sound good to me as well 8 posts ago better look at that valve job make sure the seat s are not beat in from weak springs

Originally Posted by clinto

I have seen a ton of rotating assemblies for sale with kb's but I think I will save my pennies and go for something forged when I build my 489. I have known a few guys who bought kb's and they seem to have about a 50% failure rate in this sport.

Yeah, hypers are great for a street ride with an occasional blast down the quarter mile, but in the end, they are still cast pistons and unsuitable for competition.

What springs would I use? With a short cam like you're using, probably these....
http://www.summitracing.com/parts/CCA-911-16/

are you running ex rotators ?? if so you need to get them off as some springs will not work so hot with them on the head.that spring may not work very good as your heads will set up at only 1.850 and them are 1.900@ 122 lbs that s not going to work less you have hi set up retainers or longer then stock valves or hi set up locks .better off with a spring that sets in with no work theres many out there get your setup and go from there