ring gaps for 20psi +

[josh1095]

doing some research on ring gapping. never rebuilt an engine and am gonna start in a month or so. Just wondering: if i plan on running high boost wont the gaps have to be a little larger to accommodate the heat/expansion under boost?
and would this not cause a small amount of slap while cold?
will piston slap "oval" out the bore or is it ok?
wanna do this myself and not pay a shop to do it. i will have the shop do the boring and crank shaving and balancing tho, dont have the skill for that

 

[mitsu-luver]

it doesn't matter what psi your running, but you are right on the heat. say for instance that your going to be doing road racing or any type of racing where keeping the car cool is a challenge. you are going to want a bigger ring gap. but if your going to be drag racing where your car is only on the track for seconds then you want to keep the gap as small as possible. it all depends on what the manufacturer recommends and what you plan on using your car for, that information is usually included.

 

[josh1095]

thank you. i plan on a daily driver that is very reliable(for a mitsu haha) so i wont be running high boost very often at all. as long as my gap seals at normal operating temp then i shouldnt have a prob with burning too much oil right? i have a 96 that i boosted for about 5 miles til a bolt came off the flywheel and shit exploded. im doing it right this time and taking in as much advice as i can. long post but one other question: if i run a msns and all the goodies to make 25psi can i still get 30mpg on the highway? without boost it should retain its NA characteristics correct?

 

[Diamondrev]

if i plan on running high boost wont the gaps have to be a little larger to accommodate the heat/expansion under boost?
and would this not cause a small amount of slap while cold?
will piston slap "oval" out the bore or is it ok?

I would slightly gap the rings...

I dont think you will get anymore piston slap then you already have...

heres how it was explained to me...

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Factory Specs are...

Top ring .009-.020 in. Clearance (.031 in. wear limit)
2nd ring .019-.031 in. Clearance (.031 in. wear limit)
oil ring .009-.026 in. Clearance (.039 in. wear limit)

hope this helps alittle. good luck. if you need more help pm me. I have a step by step on how to disasemble this engine, what and how to measure and how to reassemble. I got it from my school when I built this motor, its for a neon 420a but basically the same block.

 

[bullettdsm]

Yup, the old man is correct^^^ BUT, more importantly on a ring with too small a gap, would be the ring seizing in the bore and scraping up the sides of the bore (what's with the kid in the background? No Wheaties that day, ).

OP, do make sure that you get the MANUFACTURERS numbers for the pistons/rings you are putting in. The numbers Dave posted are for stock set-up.

MB

 

[Diamondrev]

(what's with the kid in the background? No Wheaties that day, )

He didnt do very well in this class. He was lost during the build.