i cant get the pistons back in the bores

[Fireman431]

Re: i cant get the pistons back in the bores

Don't use a broken piece of ring to clean the ring grooves. Get a ring groove cleaner. They're not that expensive and they get all of that hidden residue out of the groove. If all of the parts are correct, that's the main thing that will keep them from going back together.

 

[Apollo75]

Re: i cant get the pistons back in the bores

Hello;

I was a mechanic for many years. I usually buy oversized rings and set my own gaps so they are usually a tight fit in the bores.

Just look at the ring compressor around the piston and it should be tight up against the piston at the smaller tapered end and that end should be just lower than the oil rings so they will be fully compressed. If the ring compressor is not tight against the piston or you can see any part of the ring under it, you are not compressing the rings enough. If this is the case -- and you cannot get the ring compressor any tighter then there may be an issue with the ring end gaps, stubborn oil control rings, or some left over crud in the ring groves. Wrong rings not tapered may be an issue with some piston as some piston ring groves are tapered --- some ring manufacturers use tapered rings or barrel shaped rings.

"Ductile iron top ring is barrel shaped for improved sealing while the iron second ring is tapered to deliver increased oil control."

From "Sealed Power Cast Piston Rings"

When using the wooden part of the handle the piston should slide in snug with every tap --- on used pistons and new rings you should be able to just use the handle to slide them in without tapping on the piston tops.

1. Oil everything with engine oil --- inside of bore, piston and rings, inside of ring compressor.

2. They should just slide in with a hard push.

3. Cast iron rings will wear fast and seat with or without a good hone on the cylinders. I always use chrome moly rings with a 400-grit stone on my hone and a nice cross hatch pattern with just a drill motor on very low speed.

4. Drive as usual --- I would think in a boat with open throttle while planing and backing off to cruise the rings will get enough wash with fuel to seat.

5. Use regular oil not synthetic initially -- change the oil after 20 hours of operation then use the manufacturer's recommended intervals.

OFM

 

[KRH1326]

Re: i cant get the pistons back in the bores

I would check and double check your ring set.

Also, I do not know if the chevy oil rings are the same or similar to Ford oil rings. The ford ones are a royal PITA. My eyesight is not what it once was, and I get real frusterated with those oilers. If the two thin rings are not seated perfectly around the serrated band, it will not compress and enter cylinder. Also, if the serrated band managed to overlap itself where the ends meet, it will not compress either.

The coffe can and oil post by fishermark is a must. There is alot of high quality answers to your post. The only thing I would add is to use a couple of pieces of cut hose to slide on your rod bolts, to protect your walls and crank.

Good Luck

 

[fishingman220]

Re: i cant get the pistons back in the bores

the oil ring is my problem, i cant get it to compress to the size of the piston, i double check the parts number and it is right, i just dont see another way of puting them on that would change

 

[fishingman220]

Re: i cant get the pistons back in the bores

and by the way thanks for all the great imput

 

[dr_bowtie]

Re: i cant get the pistons back in the bores

the oil ring is my problem, i cant get it to compress to the size of the piston, i double check the parts number and it is right, i just dont see another way of puting them on that would change

make sure you have put it on right...

I put the serrated band on 1st and then the bottom ring and then the top ring...

When I put the serrated ring on I hold the tabs at the joing ends with my thumb as to not let them over lap while installing the top and bottom rings...

I will say this I never dip the piston in oil nor do I oil the rings or dip the whole thing in oil...this can cause the rings not to fully seat beings there is too much oil in between the rings and lands...there should never be any oil there other than the micro-scopic particles left from the top edge of the oil ring...

you can have oil control issues with too much oil between teh rings...IE: carbon build-up behind the rings...with excess oil in the rings/lands there can be too much oil between the ring and the cylinder wall and that can cause the ring not to seat properly...you gotta be careful here...

I wipe the cylinder bores down with Lacquer Thinner to make sure all teh grit is gone and the bore is perfectly clean then I take regular motor oil and with my fingers I coat the bore lightly...once I set the rings on the piston and set teh ring arrangement I give a quick squirt of Rislone and stuff it in the hole..done deal...

 

[Polar_Bus]

Re: i cant get the pistons back in the bores

Are you having issues with all the pistons not fitting or just an isolated piston(s) ?

 

[fishingman220]

Re: i cant get the pistons back in the bores

all of them

 

[Howard Sterndrive]

Re: i cant get the pistons back in the bores

the oil ring is my problem

make sure the "chain" part of the ring is not interlocked.

The two ends must butt up against each other
they must not overlap

there will be two paint colors on there - you must be able to see both colors before piston is installed

 

[fishingman220]

Re: i cant get the pistons back in the bores

yeah i got that part, it is a yellow and pink end and they hit each other and then top and bottom ring, but i just cant get then to compress all the way down

 

[dr_bowtie]

Re: i cant get the pistons back in the bores

if they arent compressing down then they are either the wrong size or the wrong type...IE: Ford rings or something...

make sure that if you have the bore size at .030 or whatever that you have .030 rings...

if you just did a little cleaning hone you MUST use the same size rings and not go oversized...

rings come in packages from .010, .020, .030, .040, .060 and others....

edit...the ring thickness plays a role as well as for having the right size rings...when the ring is started it should be less thick than the ring land itself...

meaning that the thinckness of the ring should be smaller than the ring land...

I am talking the thickness of the ring laying flat....not the small edge of the ring...the 1/8in part is normal standard....

 

[fishingman220]

Re: i cant get the pistons back in the bores

the bore is standard bore 4.000 the rings are standard bore, here is the part number from sealed power, e-251x

 

[fishingman220]

Re: i cant get the pistons back in the bores

i used a set of calipers to measure the old rings and he new rings, there is about .005 differences, but i figured that was just wear. it seems like it shouldnt be sitting on the little edges of the expander ring but if you put them in without the expander, they over lap each other

 

[dr_bowtie]

Re: i cant get the pistons back in the bores

i got the same thing too....

http://www.jegs.com/i/Sealed-Power/844/E251X/10002/-1

I was going to say match them with the old or go down to the auto parts store and match them up to a new set..might have gotten the wrong ones in the box...

and yes the oil top and bottom rings are suposed to sit on the little lip of the expander ring...

once the assembly is togetther is should spin on the pistong freely and the top and bottom scraper rings should slide freely around the expander ring...

when i put them together like I said i hold the expander mating ends with my Left thumb...I hold them so they stay mated and not over lap...

those would put them at the 9o'clock position then I start with the bottom scraper ring..I start that onceat the 6o'clock position and wind it around the expander...once done it should slide easily anywhere...

but I leave them in that position....then I start the top scraper ring and I start that at 12o'clock...and wind that on....

after that they should be free and the installer tool should compress the rings easily...

I would try it with just the oil ring installed...once you get it in the bore to make sure it fits then add the other rings and seat them too....

here is a little something that may help....

http://books.google.com/books?id=p1...e&q=how to install oil expander rings&f=false

 

[Fishermark]

Re: i cant get the pistons back in the bores

The two thin rings hold the expander ring together. If you look at the instruction sheet that came with the rings, it will explain how to put the lower ring on to the right of the butt joint, then push the ring down and around - it will snap in place. The top thin ring will go on in the opposite direction - starting to the left of the butt ring and going to the right and pushing down and around. When both thin rings are in place, the whole oil ring assembly will be together as a whole. It is easy to do once you get the hang of it, but difficult to explain in print. Perhaps you could do a youtube search for a visual demonstration.

When you checked the end gaps - did you use a piston to push the rings down in the bore an inch or so to get them level - and then check the gap?

 

[fishingman220]

Re: i cant get the pistons back in the bores

i put a ring in the bore and check the gap, without pistons. that was with the top ring, i havent checked the bottom

 

[dr_bowtie]

Re: i cant get the pistons back in the bores

they should be the same but it never hurts to check...

did you compare the new oil rings to the old ones too?

 

[Fishermark]

Re: i cant get the pistons back in the bores

I did a quick search and found these videos. The first shows a typical piston installation, while the second deals with the rings. Nevermind what they are building in the video - you are simply looking for an idea of how to do it. At the very end of the second video he shows (briefly) how to install an oil control ring:

Video one

video 2

 

[jtybt]

Re: i cant get the pistons back in the bores

I tried this type ring compressor last time. It helped by keeping the band square to the block and not letting the band get between the piston and bore.

http://www.amazon.com/gp/product/B0009OR93I

 

[fishingman220]

Re: i cant get the pistons back in the bores

the compressor in the first video is the exact same one i got. yeah that is a whole lot easier than mine there is def something wrong, i am guessing i will just wait untill my head guy comes by on tuesday and let him look at it. thanks for all the great answers and advice. if anyone else has had this problem, feel free to give some imput.