intalling pistons in rebuild

[tyhoppy]

rebuilding 7 bolt motor. When attempting to insert pistons in block the bottom oil ring spacer pops out and keeps the piston from going in.. after a few HOURS i got one in and it is really really tight, i can't move it by hand inside the block. How can i check to see if I got the wrong rings? are there certain spots for the ring gaps to be at? please help. thanks... any other suggestions will be helpful as well.

 

[VelocitàPaola]

rebuilding 7 bolt motor. When attempting to insert pistons in block the bottom oil ring spacer pops out and keeps the piston from going in.. after a few HOURS i got one in and it is really really tight, i can't move it by hand inside the block. How can i check to see if I got the wrong rings? are there certain spots for the ring gaps to be at? please help. thanks... any other suggestions will be helpful as well.

What rings are you using? The manufacturer usually suggests the proper ring gap, which needs to be measured with a feeler gauge and adjusted with ring files or a Dremel with a fine flat stone.

To actually install the pistons, you'll need a ring compressor so the rings clear the cylinder wall. The pistons should move with a little resistance once inside the cylinder, but don't go forcing anything if they won't move - one of the rings might not be seated right and you could damage something.

 

[TwoLiterLaser]

With a ring compressor it should be no problem to get them in.

 

[tyhoppy]

i am using a ring compresser, I acutally cut myself on the compressor today and had to get 3 stitches, the edge of that thing is sharp, and when pushing down on it and hitting my finger with the handle of a hammer, OUCH. anyway. I didn't check the ring gap before putting all the rings on the pistons. If i take all the rings off of one of the piston and they are ok then do i have to check all of them, and the one I got in i have to tap with the hammer to get it to move, I have never had a piston that tight before. I only got one in, so hopefully all will be well once i see waht is the matter, what is the ring gap suposed to be?

 

[VelocitàPaola]

The ring gap depends on who makes the rings. Like I asked before, what kind of rings do you have?

Also, the gap isn't something that merely needs to be checked. In almost all cases, it needs to be adjusted.

 

[tyhoppy]

they are hastings chrome.

 

[TwoLiterLaser]

How many engines have you built? Ring gap is very important!

 

[tyhoppy]

I have never replaced rings in an engine like this. I have rebuilt dirtbike and fourwheeler motors, and have done a little bit of work to top and bottom end of cars, but not replaced rings.

 

[VelocitàPaola]

http://www.hastingsmfg.com/Service Tips/ring_gaps.htm

Don't mess around with ring gaps. Do it right or be prepared for the consequences.

 

[TwoLiterLaser]

Oh I see. In any case, check the gap on them bad dogs!

 

[tyhoppy]

thanks alot.

 

[tyhoppy]

I checked the ring. compression ring and second ring are not the problem, it is the oil ring spacers the top and bottom won't push in far enough. the wavy oil ring, not sure technical term has things that keep the spacers from goin in all the way, the old ones had it, but the spacers on the old ones went in all the way... HELP!

 

[groundPork]

Ok... this is the kind of help I love to give! I used to put hondas and toyotas togather, and now i just sell parts. so follow the check up steps first, then proceed with assembly. Keep in mind you are using aftermarket rings, and from hastings no less. you could have anything from a 2.8mm oil ring with 8 lbs. of radial tension that could feel like no ring at all to a 20 lb 4mm oil like the ones used in a lot of older american and euro vehicles (crap by the way). you'll have to do this anyway... so pull the piston out, and make sure you didn't bend the oi RAIL SCAPERS (technical term). If not good, measure the end gaps while they are square in the bore (no less than .013"... if less call whom ever you bought them from and ask why... and no more than .0040" only cause it may mean the wrong sized oil RAIL... again call the dealer you bought from).

Now... here's what I know you are probably going through. You are likely using a band type ring compressor either a BLUE POINT type with bands and plyers, or the ratchet type (less prone to popping out metric oil rails). if using the plyer/band type GET YOUR BUDDY to HOLD DOwn the BAND AS YOU TAP ON THE PISTON. what you're likely seeing is the very tiny oil rail popping out as it meats the edge of the compressor band and the deck of the block because there is little difference in the two diameters.

Now I forgot to address the oil ring not going into the groove all the way... if it is an after amrket piston pre assemlbe the oil ring, adn slide it into the groove... it should not pass the edge of the second ring land (just above the oil ring groove). if it does, you may not have enough back clearance (also call the dealer they may have mispackaged or HAStings may have... hastings unlikely).

Now if none of that sounds like you do as I said for the assembly keep in mind, your buddy will have to press pretty hard to get thte rail to not skip out of the gap when you're tapping down the pistons. also if you see any deep grooves from the ends of teh rings going down the bores you're screwed (this only happens when you keep hitting the piston down after the oil rail pooped out, and it is dragging down the bore). shinney streakes usually ok as long as you don't see a groove (like from a pin or nail). Hoeps this helps you my friend, wish someone could have told me the first time I ruined a bore! Oh well!

PS as any good engine builder'll tell you, when it gets frustrating... step back, breathe deep, maybe even sleep on it... finishing at two in the A.M. is not worth the possible mess ups.

 

[luvmygst]

I had the same problem when doing my motor. First pull the first piston out you may have messed up an oil ring(I did). The motor has a slight taper at the top of the bore. Put the ring compressor on up side down on the piston tighten it up., make sure to use some oil and they should go right in. THis may not work for all compressors but it worked perfect for me, I would give it a shot and see of it helps. Good luck.

 

[tyhoppy]

I know that the one that I do have in the oil rail did not pop out, but it is really really really hard to move in the cylinder, like hitting it with the handle of a 3lb hammer hardly moves it at all. if I put the rails in the cylinders without pistons they fit fine, and without the oil ring they fit in the pistons, but the oil ring has thigns on it to keep the spacers from going in all the way. how hard should the piston be to move in the cylinder? ANY SUGGESTIONS> I need some help ASAP>

 

[96dsmftw]

Sorry to bring up an old thread but I am having the same problem. I just reringed my pistons and gapped them correctly but am having this same problem as the guy above. The 2 oil rail scrapers seemed like they would never compress close to the piston. All of the bags that had the ring sets in them say 3.346 so I know they are right. I put the first one and it went in tight and it is really hard to move up and down. I can get it to move but only with the end of a mallet and a good hit. I made sure the ring compressor was on the block while I was tapping them in as well. I feel like it shouldnt have been as hard as it was. There are no scoring marks from a ring scraping the block either. Help please and thanks.

 

[jery1234]

I would pull it out and inspect it again .

 

[96dsmftw]

I just did that and I had to force it out. The rings look fine they were not bent or messed up. No scoring on the walls from the ends of the rings or anything. I am confused now because if all 4 go in like that I don't think the starter could move it when I do get it back together. It has taken off some of the hone job where it was so tight. Everything I have seen in videos they like plop in and just a light tap can move them down.

 

[96dsmftw]

I was looking at the oil ring again this is what I saw. The oil rail scrapers are pushing in on the wavy ring so hard it left impressions on the piston. I rotated a bit so you can see the indentations on the piston. Anyone have an idea what is going on???