boostedlt1

iTrader: (2)

hey guys, trying to get my motor together.

got all my rings filed last night, tried to get my pistons installed tonight but no luck.

got cylinder number one in after countless tries. moved to cylinder number two, countless tries again, me and my brother switch spots, i was watching the rod as my brother was tapping the piston. it stopped moving, he hit it again.. broke the 2nd piston ring.

the compressor tool didn't seem to be circular at all with it as tight as i could possibly get it, thought maybe the compressor was bad. went and bought a new one, tried for another 20 minutes or so... no luck.

we just assembled a 383 for my brother's 260z projects a couple weeks ago, every single one of his pistons just slid right in.

using the same tool, same method.


i'm using JE forged -24cc dished pistons part# 279581 and matching rings.

i gapped the top rings at .020" and the 2nds at .022" as recommended by JE

anyone have any ideas why they refuse to go in? it's almost like the compressor wont compress the rings all the way, it gets stuck on the oil or 2nd ring every single time >


thanks for any help you guys can give me

FormulaJoe

iTrader: (5)

I'm thinking that if it's that much trouble to put it in, something must be out of line or something... Right? Then you shouldn't even bother with trying to install until you figure it out, as you might be setting up a disaster. I have only simple knowledge on the bottom end, so correct me if I'm wrong and why, but it just seems like simple logic right there?

TAEnvy

iTrader: (2)

I dont know whats going on with your pistons, but Im curious if the stock bottom end let go?

gregrob

iTrader: (8)

Sounds like you have a cheap ring compressor and the piston isn't sitting square in it. Mic the cyls and pistons ....

LilJayV10

iTrader: (39)

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Added! Does the piston go into the cylinder OK without the rings installed? I just wanted to add that in case of a machine shop error which do happen.

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Depending on what style of ring compressor you have can be kinda tricky to use if you are not use to it.

If you get it to tight it can cause problems too.

The way I do it is this, not saying it's the right way or the only way, just the way that has worked for me.

Put the crankshaft whatever cylinder you are working at the bottom. Have the deck facing up so its level. When you put the ring compressor on as I mentioned you don't want to get it super tight. You just want to compress the rings down to the same diameter of the piston(obviously). Make sure you lube the cylinder walls and the piston. I normally take a clean container of some sort. Put the piston in the container and put oil in it till if covers the rings and will get into the wrist pin. It's important the wrist pin gets lubed or it can seize up.

Take the piston out of the oil, let the excess run off. Put the ring compressor on and sit the piston in to the cylinder. Use rubber rose or something similar on the rod bolts. It's not a bad idea to have someone hold it either.

With a rubber/plastic mallet tap around the perimeter of the ring compressor on the top. This squares the ring compressor up with the block. If it's cocked some the oil control ring will jump out of the side. Go around it several times making sure its flush against the block.

Start to tap the top of the piston until the oil control rings are just above the deck surface. I normally tap the ring compressor after this to make sure its still flush.

After everything is flush/square and the oil control ring is above the deck give the piston a good smack. Don't try to knock it out of the park but don't act like you are driving in a finishing nail either. After you get the piston in the block make sure it doesn't twist and the bottom of the rod or rod bolt hits the crankshaft.

I use a snap on hammer that has sand in the head of it. It delivers a firm "thud" and transfers the energy into whatever you are hitting.

After a few you will get the hang of how much force you need to use. Three or four good smacks should get it in there. You don't want to hit too hard in case a ring pops out the side and could damage it. You do want to hit it hard enough so when the ring makes the transition from the compressor to the cylinder wall it doesn't have time to fly out.

The most important things are to keep the ring compressor square and to get the rings right above the deck and then smack it.

Sorry this was long winded. Hope it helps you out some.

gregrob

iTrader: (8)

and BTW thats a TIGHT ring gap for a power adder app

boostedlt1

iTrader: (2)

yeah, i measured it really quick and it seemed like all the cylinder's weren't bored to .030 over? idk.. it was late, i was tired. i'll check again in the morning and see what i come up with. :/


turbo took a ****, took out all the bearings, building a new motor meant for boost. other than that motor was perfectly fine after two years of me beating the **** out of it on boost

i just went off the specs that came with the rings. what kind of gap would you suggest?


LilJayV10 - i'll check the pistons tomorrow to see if they go in okay alone. and that's pretty much exactly what i did when i was trying to install them


thanks for the input everyone. i'll let you know what happens tomorrow

gregrob

iTrader: (8)

How much boost?

97Z28SS

iTrader: (5)

Sounds to me like the machineshop didn't measure the pistons or bore and hone the block correctly. Also 2618 material forged pistons require more piston to wall clearance that 4032 forged pistons do, I'd take the block and pistons back to the machineshop and have them measure the piston to wall clearance again. If you're breaking rings on install then somethings to tight.

Blackbirdws6

iTrader: (7)

I had a similar issue when installing pistons in my engine. I used a tool I borrowed from my buddy and it just wasn't doing the job. I used my cheapo tool from summit that I already bought and it was able to get enough squeeze to get them in there with no issues. I think I just wasn't getting enough squeeze from the borrowed tool.

Make sure you have the compression tool perfectly flat against the block and the piston is square in the tool.

boostedlt1

iTrader: (2)

right now however much will max my 42lb injectors out. in the future once i upgrade the fuel system shooting to run 12-14psi





well... went back out this morning.. and got them all in...

now i feel stupid.. lol


now i just gotta get a new piston ring ordered and figure out push rod length

LSWHO

iTrader: (1)

I've got a PR length checking tool, but I assume you already have one.

boostedlt1

iTrader: (2)

yup, borrowed sean's. thanks tho!

nitrous2fast

iTrader: (2)

Humm... i was thinking the same thing!

also to add to gregrobs Q.. what is the cylinder to wall clearance? that changes it also.

95 TA - The Beast

iTrader: (2)

Actually, those gaps are inline with a mild turbo setup (and <15lbs of boost is considered mild)...

To be safe I am running .022" top and .023" second gaps in my setup (around 12-14lbs of boost, supercharged myself, but with a 10.5:1cr on a forged 5.85" rod 383 LT1), but with the higher compression, my combustion temps will be quite a bit higher...

Actually, JE recommends a .024"/.024" set of gaps for race-only blown apps...

With the pistons this guy is running, and thus the lowered CR, 12-14psi is considered mild...

I did look into recommended gaps with other vendors rings and yes, some of those vendors specify a bit wider gap on the rings.

Oh, and for reference the pistons he is running are 4032 material, just like the JE 146997 pistons I am running on my setup... I prefer the pistons I have because of the thicker deck (comes at the expense of a +.010" installed height)...

ZGOBYBY

iTrader: (14)

Interesting thread here, very useful information for my upcoming completion to my turbo build. Although I will run 18-20 lbs.

boostedlt1

iTrader: (2)

got push rods today, just waiting on my arp rocker studs and this baby will be together!

here's some pics for you guys (everyone loves pics!) i'll probably start a build thread soon with better and more pics. and specs



stock push rod length turned out to be pretty much perfect!

LSWHO

iTrader: (1)

Slow. You need Colorado nitrous in order to compete.