So this is the first B-series build I've done alone.
GSR block and head
RS machine 81.5mm ITR pistons NPR rings
ACL Race HX undersized bearings

So here are the clearances in inches. The bearing clearances were first estimated using precision measuring tools, then verified with plastigage.
Mains
1 = .020
2 = .020
3 = .023
4 = .020
5 = .019
Rods
1 = .018
2 = .019
3 = .018
4 = .018
Piston to wall
1 = .0007
2 = .0007
3 = .0008
4 =.0010
Piston Ring End Gaps
1st Ring (Top Compression)
1 = .0011
2 = .0012
3 = .0012
4 = .0013
2nd Ring (Second Compression)
1 = .0016
2 = .0016
3 = .0016
4 = .0018
Oil Ring
1 = .0010
2 =.0011
3 = .0012
4 = .0012

What I'm worried about are the 2nd compression ring clearances since they are on the very minimum of the OEM specs. I was thinking, since the build is a bit overbore and will see some ocassional abuse, should I file them to get more clearance. If so, how much do you guys recommend as a minimum? Also, how do the other clearance look? Thanks


Modified by ruffrhyder at 6:23 PM 9/18/2008

 

Any thoughts on the ring clearances?

 

I wish someone had answered you lol.

I just got some 81.5mm NPR rings in, and the 2nd ring is measuring .035"+ gap.

The NPR rep is trying to tell me .030" - .039" is correct for 2nd ring gap on an NA gsr motor...

I think they put standard 2nd rings in an 81.5mm box.

 

 

I think your piston rings are too tight, unless you missed a zero and still I think they are too tight. You want a little looser to handle more abuse/heat

I will tell you my experience with my rebuild with NPR p30 pistons/eagle rods/npr rings. 81mm standard bore b16.

I did the rebuild in car on a stock b16, it was burning oil but compression was even across the board ~220, 250 wet. I used a 240 grit 83mm flex hone to do a deglazing hone, I got about 20-25 up and downs on each cylinder before I got the desired cross hatching that I wanted, At first the hatch marks I did were too shallow (first time here for me).

I then paid the 'extra' money and got the hastings rings. I put them in the cylinder and the top compression ring was coming out to .025" ish on each cylinder. I was freaking out. I thought I overbored my cylinder some how with the flexhone. I then put the oem ring back into the block and it came out to around .016-.017. I then put the hastings ring in a stock short block I had lying around (lol), it still came out big but not as big as the one I bored, maybe around .023". Turbo guys run looser ring gap, around .020" inch top and .023" or so second, I didn't want to run too lose and burn oil again and also my turbo build is a small time one.

Long story short I was going to buy oem rings and put them in or run the risk and purchase a set of npr rings. I went ahead and got npr rings off ebay, met the guy (he was local) and tried them out. They fit perfect (for what I wanted) .016-.017 top ring around .019-.020 2nd ring and for oil rings I don't gap them.
I installed these rings and the engine has 400 miles on it so far and is not burning or nor has it blown up.

I do plan on putting a light duty turbo kit on this car ~270-300whp.

I did replace the crank bearings as engine was in the car, but I did replace the rod bearings as I was going eagle rods. I put in standard acl rod bearings and they plasti-gauged out to around .020" which some say is loose but turbo guys say is good, I am also running 40 weight oil.

As for the head gasket, put copper spray on both sides, get the head at least resurfaced/pressure checked, also put hondabond around the oil rings in the head on top and bottom (block and head side) I didn't do this and got a very small leak near where head meets block near vtec solenoid (not vtec solenoid so don't say it is). I put some toyota gasket maker on that part and it seems to be holding fine, next time I'll do what this engine builder does (attached image) in addition to the permatex copper spray. Make sure you install head gasket with the 'up' part facing you guessed it up.


I contacted the NPR retailer on ebay to say the hastings rings fit loose, he/she said they fit loose because they are made of a different material and seal up differently. I read a lot online after this of folks complaining how they fit loose. anyway I didn't want to risk it and put in the npr and so far I am happy.


I hope this helps. I followed these guys on youtube to learn more:

This guy also has a good informative channel:

Do not forget to replace vtec o ring on cam cap three and be sure to run the dowel in there and the 2 dowels intake side of block to help align head. If you shaved your head down a lot, shave these dowels down as well to help prevent them from preventing the head from seating.

 

An addition to go with the post above me....

Copper Spray is only meant if your head gasket is clear of any coatings (bare metal). Many head gaskets come with a thin Viton rubber coating of which copper spray is not recommended.

 

I am in the same boat. GSR block, NPR P30 pistons, Hastings rings (probably from the same retailer as you). The top compression rings are all 0.024-0.025ish. Contacted Hastings after the retailer, was told by them that "it won't cause any issues" haha. Sitting right now trying to figure out what to do, between exchanging them for 81.75 or 82mm rings, or going with a different brand. Engine is going to spend most of its life above 4000RPM so I want everything to be perfect the first time. I would go for OEM rings as I work at a dealer but they only make them up to 81.25mm bore.

 

Not recommended, or not necessary? I've seen it said that, although the likelihood of it helping is slim to none, it doesn't hurt anything to have it on a 'coated' headgasket.

 

The head gasket manufacturers state it can interfere with the coating. So that would imply it can "hurt" the situation.

In my research, some other experts had a different spray for the viton coated gaskets, I'm guessing it was a chemical that aided the coating on the molecular level.

It's my understanding the copper spray is to fill micro fissures in the head and block surface. The viton coating is also to fill micro fissures in the head and block. I don't see the benefit of doubling up, especially when the manufacturers who do all the serious testing say it can impede their specially designed coating.

 

I ordered a 2nd set of NPR rings just to see what the difference would be, still got .038" 2nd ring, .016" 1st.

They say that's within spec due to their material.

Guess we'll see.

 

Am I the only one looking at the bearing clearances and thinking that a decimal place is off?

 

The mains and rod specs listed seem like it. .02 is a hell of a lot of oil clearance.

 

How do you solve the ring gap problem finally?
I am facing with problem too, 0.024 for the top ring with hasting. they also tell me "it won't cause any issues" and they says the second ring gap small than top ring is fine. I am confusing about this

 

Never found a proper solution, engine is still sitting there. I made a combination of 3 different brands of rings work for the compression rings only to find out all of the oil control spacer rings are waaaaay too long and won't even fit in the cylinders.

 

yes, hasting oil spacer is provided tension, it will compressed by the oil ring.
are you success with combination of 3 different brands? which brand are you use for?

For my measurement of hasting:
top : 0.024
second: 0.018

Hsating told me i can run with these gap , I am still confusing do i go ahead with this.

 

I'm in the same boat. Just got a b18 block bored to 82mm and purchased YCP pistons with Hastings rings. These are the gaps I recorded below.
#1 cylinder .020"
#2 cylinder .022"
#3 cylinder .022
#4 cylinder .024
These are just for the top ring. I stopped proceeding with the other rings when I saw the number. I contacted Hastings and they first sent me numbers of the ring gaps and I told them that the gaps are too big.

I wonder if you can just buy other rings to go along with the YCP pistons. I wouldn't mind buying new ones. I surely think that these gaps are too big. I'm pretty sure theres more Hastings rings usee out there than can chime in.

 

same as me with hasting get these gaps. Top:0.024'
I buy a new set with JE proseal, they are all in spec

 

Which set did you get? I guess I'll buy another set of piston rings.

 

Finally I use the JE ring set, they are much better in my case.
Top :0.015
Second: 0.02

Hope can help for you

 

ill be building a gsr this week with cp pistons and rings that were supplied with pistons. ill post what measurements i get...im sure ill have some questions also

 

ok so i put the rings in and getting a second ring measurement of .025....talked to cp and according to them for my build they recommend. 016 for the top .019 for second. .025 is pretty far off from their .019 recommendation. im a lil nervous. anybody have any opinions on this? would i be fine running .025 on my second ring?(stock bore, turbo, around 350 whp range)

 

try to measure the bore diameter and piston to wall clearance.
How about top ring measured?

 

top ring measured .015/.016.....i dont have any micrometers available at the moment so not sure on ptw clearance. will find out though because it's somethin i need to know. talked to cp pistons today and they said .025 on the second ring would be fine so that was a little reassuring. thanks for replying