Hastings Ring Gap

I am installing +0.040 JCC pistons and Hastings rings. When I fit a compression ring in the cylinder bore it has a gap of 0.003 in., and the oil ring rail (3 piece) has a gap of 0.030 in. The oil spacer has an overlap of 0.065 in. The cylinder bores measure 2.930.

What should the gaps be? I was under the impression that Hastings rings did not require "file to fit".

Slick

texasSlick said:

The cylinder bores measure 2.930.
Slick

Click to expand...

assuming 750 norton 2.875"+.040" = 2.915"
I would never have gotten as far as rings? :roll:

It's easy to get bore measurement wrong.

You can't run with 0.003" gaps on compression rings, if they're "normal" rings. That's too tight.

texasSlick said:

. The oil spacer has an overlap of 0.065 in.


"file to fit".

Slick

Click to expand...

The spacer should butt its' ends in the piston. It should never be overlapped or cut because it seems to be too big. Careful assembly of the three piece oil ring will see the rails located on the tiny little flanges on top and bottom of the spacer effectively locking the whole assembly together. Fear not, it WILL compress into the piston groove when introduced into the bore.

I have the instructions that came with the last set of Hastings rings I installed
Both compression rings should have a gap of .004 times bore diameter with the ring in the bore and pushed down to mid cylinder with a piston. If your bore is 2.930 the gap would need to be .0117 Your bore measurement doesn't have to be super accurate because of the size of the numbers, 2.875 times .004 is .0115.
On the oil control ring there should be a slight gap between the ends and the ends should point up towards the top of the piston.
Do you have the instruction sheet there is also info on how to tell which way is up on the compression rings. I could scan them for you.

Thanks guys:

The instructions that came with say nothing about filing or proper ring gap. Neither do instructions on Hastings website.

Biscuit wrote: "The spacer should butt its' ends in the piston. It should never be overlapped or cut because it seems to be too big. Careful assembly of the three piece oil ring will see the rails located on the tiny little flanges on top and bottom of the spacer effectively locking the whole assembly together. Fear not, it WILL compress into the piston groove when introduced into the bore."

My ring compressor seems to be having difficulty compressing the spacer. I cannot get the assembly into the bore past the oil ring. But knowing compression is required, I will give it another try.

@htown16: I would appreciate the instructions you have. Please PM me.

@DynoDave: FWIW, I am not doing a rebuild. Only want to shuck the 10.5 CR pistons that I put in 45 - 50 K miles ago when fuel was 103 Octane at any pump, and replace with 9.0 CR to use with 93 non ethanol. I do not want to take the bores to the max. The engine does not smoke or burn excessive oil. I figure with new rings, I can get another 50K miles out of the barrels.

Thanks again, all. I welcome any more input.

Slick

What I'm thinking...
Who ordered them?
What was bought? ...2.915 or 2.930 15 thou slop WOW and you expect 50,000 more miles :roll:
Did you buy a packaged "set" or individual rings by part #
Do you have deep or shallow ring groove pistons? ....been there done that...

I have no cure cause I can't define the problem. :?:
Not enough data :roll:

dynodave said:

What I'm thinking...
Who ordered them?
What was bought? ...2.915 or 2.930 15 thou slop WOW and you expect 50,000 more miles :roll:
Did you buy a packaged "set" or individual rings by part #
Do you have deep or shallow ring groove pistons? ....been there done that...

I have no cure cause I can't define the problem. :?:
Not enough data :roll:

Click to expand...

I bought a package from British Only. JCC pistons .... I was not aware I had to be concerned about groove depth. I supposed it was a plug and play package.

Pistons measure 2.915. With 5 - 6 mil mandatory clearance, that leaves me with 9 - 10 mil wear slop. I would think any engine with cast iron cylinders and with 50K miles is running down the road with that much wear. My only option is to Nicasil the bores and bring them back to 40 over plus clearance, or bin the 40 over pistons and bring the bores back to 20 over. Recommendations?

Slick

texasSlick said:

Thanks guys:



My ring compressor seems to be having difficulty compressing the spacer. I cannot get the assembly into the bore past the oil ring. But knowing compression is required, I will give it another try.



Slick

Click to expand...

I don't know what sort of ring compressors you have, and yes it takes quite a bit of compression to get the oil control ring assembly suitably compressed so the piston will enter the bore, but don't be tempted to do any trimming of the spacer. You mentioned the pistons and rings came packaged as a set so I'd assume the ring depth and piston groove are correct for each other but do check. Just make sure the assembled and installed three piece oil control rings will float fairly easily in the piston groove and pushing it inward anywhere on it's circumference will bottom it in the groove without its' being proud of the piston at this point.
I'm aware that the subject of trimming the spacer being sometimes necessary for fitment. I would not be tempted to do this. It needs it's full length for correct expansion pressure applied to the scrapers.

texasSlick said:

dynodave said:

What I'm thinking...
Who ordered them?
What was bought? ...2.915 or 2.930 15 thou slop WOW and you expect 50,000 more miles :roll:
Did you buy a packaged "set" or individual rings by part #
Do you have deep or shallow ring groove pistons? ....been there done that...

I have no cure cause I can't define the problem. :?:
Not enough data :roll:

Click to expand...

I bought a package from British Only. JCC pistons .... I was not aware I had to be concerned about groove depth. I supposed it was a plug and play package.

Pistons measure 2.915. With 5 - 6 mil mandatory clearance, that leaves me with 9 - 10 mil wear slop. I would think any engine with cast iron cylinders and with 50K miles is running down the road with that much wear. My only option is to Nicasil the bores and bring them back to 40 over plus clearance, or bin the 40 over pistons and bring the bores back to 20 over. Recommendations?

Slick

Click to expand...

I think you are set-up just about perfect to have Nikasil applied to the bore and restored to the proper clearance. I believe in a typical application Millenium suggests providing the cylinder at ~ 0.008" over the size of the desired finished bore, they add ~ 0.004" thick plating (reduces cylinder dia 0.008") and hone to desired size. So if you've got 0.015" clearance now, say they add 0.009" Nikasil and you're left with a perfect piston fit of 0.006" with the existing pistons.

Don't waste your time putting it together with 0.015" clearance as it would already be worn out before you start. Pistons would be noisy/rattle and ring life would be extraordinarily short. A real waste of valuable time.

Nothing you are relaying really adds up
1/tight ring gap, either wrong rings , wrong size bore or the bores are still good and a little fitting needed
2/Oil ring gap sounds about right, doesn't fit, check when assembled up off the piston that the assembly doesn't stick out above the skirt, oil ring assembly doesn't touch the bottom of the groove in operation
3/0.010'' slop, whats slop, pistons rattling in bores ?

I had exactly the same problem with the Hastings oil ring expanders.
Apart from asking for a replacement set (which are likely to be the same) the only way forward is to take off sufficient metal to allow the oil scrapers to enter the bore without the expander forcing them outward.
It worked fine for me, but I got called a wanker for doing it!

The expander is there to keep the scrapers apart, the rings alone should provide the pressure against the bore.

I really don't think forcing them into the bores in their current state is going to end well!

dynodave said:

What I'm thinking...

Do you have deep or shallow ring groove pistons? ....been there done that...

I have no cure cause I can't define the problem. :?:
Not enough data :roll:

Click to expand...

I just came down from measuring the ring groove depth on a std atlas. then tokeiku, then "MC",then GPM, then early commando, then late 750 commando.
.100" to .165"
Do you think late 750 rings will fit just any atlas piston? think again....no..... measure...verify!!!
If I measured correctly you need the oversize added to nominal groove depth.

I went through this exercise to get my friends late rings to fit NOS 650 pistons. Chuck them up in a lathe and bore the bottoms or the rings were NOT going to go...

What pistons are your ring pack made for?

B+Bogus said:

, but I got called a wanker for doing it!

Probably rightly so
Then followed up with this misinformation

The expander is there to keep the scrapers apart, the rings alone should provide the pressure against the bore.

Probably the only piece of correct information

I really don't think forcing them into the bores in their current state is going to end well!

Click to expand...

dynodave said:

[
I just came down from measuring the ring groove depth on a std atlas. then tokeiku, then "MC",then GPM, then early commando, then late 750 commando.
.100" to .165"
If I measured correctly you need the oversize added to nominal groove depth.

What????, place the rails either side of the expander,place upside down in oil groove, ring assembly should sit below skirt , run a small ruler along to cofirm

What pistons are your ring pack made for?

Click to expand...

Shouldn't be the issue because slick purchased new pistons and rings as a package and they ''SHOULD'' match, his ring gaps would indicate his bores are still good or the rings are wrong
his description on sizing and clearances is all up the shit
As for his original question, 0.012'' ring gap would be ok and the oil ring sounds about correct, it should be able to move about in the groove
Slick all rings should always be checked for gap before assembly

we have been there before on this and you are totally wrong. jim comnoz even did a video on this to prove another member how wrong this is. if as you say you trimmed your EXPANDER and are not using oil than you got very lucky.

B+Bogus said:

The expander is there to keep the scrapers apart, the rings alone should provide the pressure against the bore.

Click to expand...

bill said:

we have been there before on this and you are totally wrong. jim comnoz even did a video on this to prove another member how wrong this is. if as you say you trimmed your EXPANDER and are not using oil than you got very lucky.

B+Bogus said:

The expander is there to keep the scrapers apart, the rings alone should provide the pressure against the bore.

Click to expand...

Click to expand...

For sure! Bill.

I can live with being wrong, or just being in a very small minority, but the fact is these expanders aren't right as delivered, and other folks have previously confirmed the same issue with Hastings rings.

I took the view that if it didn't work I'm no worse off (they were cheap enough) and would use the GPM rings I also had on the shelf.

As it was they worked fine. How can this be?

I've always regarded this forum as a friendly and respectful meeting place, and hope it stays that way

I am wrong too then, 20 odd years ago 850 hepolite rings for a re-ring, only way to get pistons back in was to trim expander rings. Oil burning was cured as thats why they went in, and the rings are still in now and no oil burning.

To all:

I have sorted everything out. All is well! Let me discuss the issues one by one.

Compression ring gap: htown16 kindly FAXed me a Hastings instruction sheet which states for the compression rings "MINIMUM GAP - 0.004 PER INCH OF CYLINDER DIAMETER". This note was omitted on my instruction sheets and led me to falsely conclude the ring pack was 'plug and play'. This answers my original question; I will file the gaps to 0.012 after placing the rings in the cylinder to get the fit. FWIW, my ring pack is date stamped 1-28-2011.

Oil rails: The 0.030 gap I measured seems to be OK. Hastings instructions makes no mention of proper end gap. I would say that as long as this gap exceeds that of the compression rings, all should be well.

Oil Spacer. Following Biscuit's advice, I placed the spacer in the bore, butted the ends, and compressed the spacer into the bore. So fitted, the spacer's little folds must compress like the coils of a spring, and the spacer wants to "recoil" and apply pressure against the cylinder walls.

Hastings calls their oil control rings "flex vent", and touts this system to be superior to the old system of scraper rails and plain spacer or spreader. I bought into their hype, which is why I have the Hastings ring pack.

Now allow me to apply my engineering background to the Hastings flex vent system, and the older type (which B+Bogus refers to).

In the older system, which in my "old school" education, we called scrapers and spreaders, the scrapers gathered the oil, and the spreader kept the scrapers apart and provided a channel for the oil to reach the drain holes. The spreader was not intended to touch the cylinder walls ... there was no reason for it to. The flex vent system, with the spacer recoiling against the cylinder walls, makes the spacer function as more scraper surface, as well as spreading the rails and channeling the oil. I suppose this is why Hastings touts their flex vent superior. When B+Bogus snipped off a piece of the Hastings spacer, he negated the extra function of the flex vent system and reverted the Hastings spacer to the older type system. @B+Bogus .... I would not lose any sleep over it, the older system worked fine for many decades.

Ring compressor difficulty: I think, due to happenstance, my ring compressor simply closes between clicks on the ratchet ... I just cannot get the last click to cinch it up. The tool is a good one. It belonged to my Dad who was a professional auto mechanic when mechanics did full rebuilds back in the 1930's and 40's. Dad always said "never buy cheap tools!" @DynoDave ... the ring grooves are plenty deep. A friend will load me another compressor, and I am sure I will get over this bump.

Bore and piston clearances: I have NO problem with my bores ... I have a CALIBRATION problem with my Mitutoyo calipers!!!

Splatt and DynoDave rightly figured something smelled fishy with my measurements (Splatt alluded to something other than fish :mrgreen: )

I stumbled onto my calipers being off when I measured some drill rod which I expected to be 0.312 and got some crazy number like 0.335! So I got out my old Vernier calipers ... you remember those things .. they have the little scale that must be read with a 5X magnifier Loupe.

I do not have Jo blocks, but I checked the Vernier against thickness gauges and precision reamers and am confident it is spot on.

With the Vernier I have 8 mil total piston clearance, and this checks with an 8 mil thickness gauge wedged between the piston and bore. Considering this vary minimal wear for 50K miles, I intend to go with the bores as is.

IN CONCLUSION: Fitting pistons is not rocket science, but be wary when a rocket scientist fits pistons

Thanks to everyone. I believe we can put this to rest. I now have to go to another thread, and report my calibration error over there where I posted a measurement.

B+Bogus .... don't worry over it.

Slick

texasSlick said:

To all:
In the older system, which in my "old school" education, we called scrapers and spreaders, the scrapers gathered the oil, and the spreader kept the scrapers apart and provided a channel for the oil to reach the drain holes. The spreader was not intended to touch the cylinder walls ... there was no reason for it to. The flex vent system, with the spacer recoiling against the cylinder walls, makes the spacer function as more scraper surface, as well as spreading the rails and channeling the oil. I suppose this is why Hastings touts their flex vent superior. When B+Bogus snipped off a piece of the Hastings spacer, he negated the extra function of the flex vent system and reverted the Hastings spacer to the older type system.
@B+Bogus .... I would not lose any sleep over it, the older system worked fine for many decades.

Click to expand...

Regarding this 3-piece oil control ring, when the expander was snipped off it resulted in a significant reduction in the force the rails exert on the bore, which in turn reduces the ability of the rail to effectively scrape the bore and maintain oil control. I mention the foregoing solely for the purpose of informing others that snipping off a segment of rail is not without consequence. If you have any doubts about consequences of snipping expanders, see the video posted by Comnoz on page 4 of the following thread to see quantitative data regarding expander length and how it affects proper rail tension against the bore.

http://www.accessnorton.com/850-cylinder-wear-t25151-45.html