sh!tsWEAK!

iTrader: (1)

I hate to have to make a thread on this because I'm sure the topic has been beat to death. I have searched the threads and tried my best to do my homework, however I would like some verification and/or advice before I go ahead with assembly of my block. This is the first bottom end that I am assembling on my own, so I hope you can understand my need for some piece of mind.

The rundown:

- GSR block: bored, decked, honed by RLZ Engineering
- 81.5 mm bore
- Piston-to-wall clearance: .001
- RS Machines 81.5 mm PR3 (B16) pistons
- Oversized Hastings rings (came with the pistons)


I have checked the gaps on the compression rings as-is, meaning straight out of the box without filing them. The results are as follows:

Piston #1
Top Compression Ring: 0.018
Second Compression Ring: 0.021

Piston #2
Top Compression Ring: 0.019
Second Compression Ring: 0.018

Piston #3
Top Compression Ring: 0.017
Second Compression Ring: 0.019

Piston #4
Top Compression Ring: 0.018
Second Compression Ring: 0.022

Questions:

1) The standard OEM specs for top compression ring gap are 0.008-0.014, with the service limit being 0.024. Although my gaps are larger than the standard specs given, they are well within the "service limit". So are my top compression ring gaps OK?

2) The standard specs for the second compression ring gap are 0.016 to 0.022, with the service limit being 0.028. My second compression ring gaps all fall within the recommended range, however the numbers fluctuate from 0.018 to 0.022. Is this OK?

3) Final question: As long as each of my ring gaps is within spec, does it matter if the gaps for each individual ring vary between cylinders? ie: Can I have 0.018, 0.019, 0.017, 0.018 as my top compression ring gaps, or do I need to file them so each cylinder has the SAME top piston ring gap? ...ie: 0.019 across the board?


I'm not building this motor to set any hp records. The goal is simply to have a mild, reliable build utilizing mostly OEM parts. The compression will be around 11.4:1 and I will more than likely be utilizing an ITR valvetrain and cams. So again, nothing crazy, but I'd like this motor to LAST.

Thanks in advance for any input!

-Tony

DonF

Your rings are a bit on the wide side, so do not file any of them. On the good side, you actually checked, most do not.

sh!tsWEAK!

iTrader: (1)

Thanks Don. I'm trying to my best to double-check everything before I put it together - the last thing I need is to have to tear it apart again. Do you foresee me having any oil consumption problems or loss of compression due to the wide clearances? I would order a set of rings from Honda, however they only offer an oversized set for 81.25 mm pistons..

DonF

"Honda" rings would not help you at all. Wiseco USED to make a good file-to-fit ring, but seem to have stopped doing that along with the low tennsion oil ring.

lude98SH

Are they good to go though ? I'm interested in this also.

sh!tsWEAK!

iTrader: (1)

Oh.. I was under the impression that Honda rings come pre-gapped? I feel like I read that somewhere, but I could be mistaken.

Do you have any suggestions on what I should do? Do you think I'll be ok if I use this set of rings?

mar778c

iTrader: (1)

In the handful of RS machine piston builds I've done, those are within the range of numbers I've seen.

Also, I spoken with one of the machinist at RS for one the 1st motors I had ever assembled and he thought numbers like that were good.

4g hatch

you may get a set of 82mm and file them to where you want. i would maybe get a actual ring filer to take off that much material though

mar778c

iTrader: (1)

The rings for RS machine pistons come in one size for there pistons. They are hastings rings.

sh!tsWEAK!

iTrader: (1)

I might try giving Laskey Racing a call tomorrow to see what they think. My biggest concern is having oil consumption problems or loss of compression in the near future. I want this motor to be healthy and last for a while. Would gaps like this cause me to start seeing puffs of smoke after, say, 20k miles?

sh!tsWEAK!

iTrader: (1)

I called RS today to verify that these were in fact oversized rings to complement the oversized pistons. According to the rep I talked to, there's a stamp that reads "020" near the barcode which indicates that they are oversized rings, which mine are.

mar778c

iTrader: (1)

Ok, I've got the box that my last set of rings came with for 81.5 mm pistons and on the the bar code it says 81.00 1.0 2.0 2.8

Call hastings and they can confirm the ring size.

mar778c

iTrader: (1)

My motor was rebuilt more than 1.5 yrs ago. I had slightly larger gaps and I don't have a issue with oil consumption.

The last leak down was less than 2% on all cylinders.


This motors has seen 5 dyno sessions and about 40 pulls and it used to be a DD about 120 miles/day.

sh!tsWEAK!

iTrader: (1)

Do you mean you had slightly larger gaps than mine? Or slightly larger gaps than the standard specs? Did your gaps vary from cylinder to cylinder like mine do, or were they all uniform? Thanks, and sorry for all the questions!

mar778c

iTrader: (1)

Slightly larger than yours, about 0.018 to 0.020 for the top ring and 0.021 to 0.023 for the second ring.

They varied pretty much like yours.

Chris Tune

should be more then ok...

sh!tsWEAK!

iTrader: (1)

Awesome, thank you very much for your input!


Can anyone offer opinions or real life experience concerning this?

Chris Tune

omg...

sh!tsWEAK!

iTrader: (1)

Omg what? I'm simply asking for the advice from people who have actual experience building motors or who have dealt with these products themselves. There's so much "hearsay" on H-T and misinformation from people who try to give advice based on things they've "heard". Frankly, I don't care for that. I'm interested in the opinions of those who have REAL EXPERIENCE and know what they're talking about.

Anyways, back on topic...

Chris Tune

why not pm the ones u want to hear from that its ok then?

and its true bout the hearsay...

btw they are more than fine... a little wide but ok. it will not burn oil nor have comp issues

ruffrhyder

iTrader: (1)

Just from personal experience, I built 2 motors in the last month with RS machine pistons, 81.5 and 82mm. Both motor's ring gaps varied from .012-.020" Both motors are running fine, no smoke, compression and leak down test are perfect.
A few motors I've built in the last couple years with the same pistons/rings and ring gaps are daily driven and still pass strict cali smog test, with perfect compression and leak down test results. I think the quality of your machine work, assembly and break in are just as important as the ring gap clearances.

Garcia-Racing

0.001" piston to wall? Isn't that tight?

Combustion Contraption

Not on a cast piston. Some OE stuff is more like, .0008"

sh!tsWEAK!

iTrader: (1)

Hahha.. thanks man. I appreciate the input. I'm not sure who is experienced on here or who specifically to pm, so I'm hoping they will chime into this thread. Also, if the responses are documented here in the thread then it might help someone in the future who is searching for answers to the same problem.

Thanks, I really appreciate the response. Puts me a little more at ease.

Like Combustion Contraption said, that clearance is perfectly fine for an oem cast piston, and it's well within the Honda specs.


So I think it's safe to conclude that my clearances are not too big and that I will be ok. Now can anyone confirm that it's ok for the clearances to vary between cylinders, or do I have to have the SAME clearance for each ring across all cylinders? ie: 0.019 top compression ring clearance across the board.

Thanks again!

Furyof4

^Don just told you. He's a good one to listen to.