5/64 & 1/16th ring and max bore size

[AJ71DUSTER]

this is a two part question the first one is about the piston ring Gap being 5/64 wide and the ring size being 1/16 of an inch thick, what are the pros and cons for this and what has to be done to make this combo work?

Second question is how big can you bore a 360 small block?I was always told that on any small block the max you could go would be .040 anything big would cause over heating.

I have a 360 in the shop now and he's telling me that it can be bore to .060.


THANKS

 

[moper]

There is no real con to the 1/16 ring stack. It's lighter, less friction, and lasts plenty long. The stock size is 5/64 so most older designs, or stock replacement pistosn still use it. Most everything else uses the thinner rings. End gap is a function of piston and ring manufacturers and use. When in doubt, use the larger recommendation.

On boring any engine... there is no factory max beyond I think .040 depending on year. If this is a race or stroker build, have it sonic tested and see what it can take.

 

[Guitar Jones]

I'm not sure I understand the first part of your question. You can't use a 1/16 ring in a piston designed for a 5/64 ring, you have to use the ring the piston was designed for. Other than that moper said it all.

 

[ramcharger]

I'm not sure I understand the first part of your question. You can't use a 1/16 ring in a piston designed for a 5/64 ring, you have to use the ring the piston was designed for. Other than that moper said it all.

X2! Don't use a 1/16 ring on a piston designed for a 5/64 ring.

 

[perfacar]

hi, total seal rings, use to have spacers for using a 1/16 ring in a 5/64 groove.
they do have spacers for, 1.2 mm and 1.5 mm for use in a 5/64 groove. many stock elim motors use spacers , because the 5/64 groove has to be maintained, rings can be any thickness. just food for thought.

 

[AJ71DUSTER]

the engine that I have is at the machine shop.I bought the engine from Blue print engine, and they put 1/16th rings in a 5/64th groove KB pistions with no spacers.I've had the engine for almost a year and I have more drive time on my lawn mower than this engine,right now I have a ASE certified master Machinist looking at it and each day the price to repair is going up & up.
He tells me that the block can be bored 60th's over but I always believed that on small blocks that most it could be bore was 40th's

I'm gun shy on what to do because of all the issues that I have WITH THIS ENGINE.if anybody has had good or bad issue with blue print let me know please

Thanks for all of your input I really does me under stand better.
Alan

 

[fishy68]

Some machinists will tell you anything to get your work. Not saying that's the case with yours but don't let him bore it .060 over unless he sonic tests it like Moper suggested. A few engines will allow a .060 over bore but you definitely have to sonic test it to make sure the walls are thick enough.

 

[fishy68]

Oh and your the 3rd guy I've read about that got a junk Blueprint engine. Sorry to hear that.

 

[moper]

There are a few guys on both sides of the Blue Print reputation. I still maintain that if you are shopping by cost first, you are riolling the dice. I'm not saying that was your particular reason for buying one. But the end is always justified by the means providing all the participants have the abilities they profess to.

 

[AJ71DUSTER]

thanks for the the info on boring the block, I will make sure that he sonic test it first. if i get it bored,on the purchase of the short block your are some what correct as to the reason for buy the Blue print, the price was a factor but they also talk a very good game before I bought it.at this point I know that I have been screw and tattoo BLUE. I would like to discuss more about the the reboring of the enigne, the enigne has only 1000 miles on. I went to the shop on monday to see the block and reviewand he has the cylinders already honed and they look pretty good so i,m starting to question what he wants to do, is there any honest people out there anymore???? would you have it bored????

thanks
Alan

 

[Petzschler]

did your "machinest" just look, or did he actually measured the bores? shouldn't need a redo after only 1000k. unless the pistons clearances were way too tight. but that would be obvious. regardless sonic testing is the only way to know for sure how far the bores can be taken out. 1/16 rings with spacers are fine.

 

[AJ71DUSTER]

he has messured the clearance between the piston and the cylinder wall and it,s .003ths.I will find out what the size of the cylinders are, that is why I'm starting to question The direction he whats to go after a 1000K I find it hard to take that it would require a rebore which adds another 600$ to the bill.

Alan

 

[perfacar]

hi, after 1000 miles , should be no wear period. unless a pin rubbed on bore.
wall clearance is determined by piston skirt dia. I measure bore, then piston dia to determine clearance. .003 is not excessive. what kind and brand is the pistons? just food forthought.

 

[Petzschler]

he has messured the clearance between the piston and the cylinder wall and it,s .003ths.I will find out what the size of the cylinders are, that is why I'm starting to question The direction he whats to go after a 1000K I find it hard to take that it would require a rebore which adds another 600$ to the bill.

Alan

.003 is fine (but as stated, what pistons?). by measure i mean he should have mic'd the bores, and measure the taper in them (widths at the top,middle,and bottom of the cylinder bore). can't just measure the piston/wall clearance. a good hone job would fix that. he has no way of knowing wether a .060" overbore is OK without sonic testing. IMO he's just running through the motions and giving you the bill.

 

[fishy68]

hi, after 1000 miles , should be no wear period. unless a pin rubbed on bore.
wall clearance is determined by piston skirt dia. I measure bore, then piston dia to determine clearance. .003 is not excessive. what kind and brand is the pistons? just food forthought.

.003 is fine (but as stated, what pistons?). by measure i mean he should have mic'd the bores, and measure the taper in them (widths at the top,middle,and bottom of the cylinder bore). can't just measure the piston/wall clearance. a good hone job would fix that. he has no way of knowing wether a .060" overbore is OK without sonic testing. IMO he's just running through the motions and giving you the bill.

I totally agree. Very few pistons run less clearance than .003" so why does it need bored out if there is no damage in the cylinder? I think it's your wallet he's trying to bore out. JMHO

 

[Guitar Jones]

Well was boring and honing with a torque plate being discussed? If the block was previously bored and honed without the plate then it may need to be bored again. Just honing it may not get it round. I've seen this before and believe that using a torque plate is going to make for a better ring seal and thus more power.

 

[Cudafever]

Sonic check is the answer, as many have said. But if it is a early 360 it had the 340 bore core.

In other words, it a 340 with the 360 mains........the later 360 don't have as thick of a bore and would be a crap shoot to bore it to .060" with out a sonic test.

having it bored with only 1000 miles on it is suspect................why did you pull the motor out after only 1000 miles any ways?

 

[AJ71DUSTER]

thanks for the clearing up clearance for the piston to cylinder issue.The pistons are Keith black hypers.he has already honed the block and there is no damage to the cylinder walls, the reason that the engine is out is because it developed a knock at 631 miles, i do believe that the block is 1983 casting. He told me that the knock is from a bad rod when he was checking one of the rods he found a shadow at the point where the cap and rod meet, ever heard of that before? also is it possible to replace just two pistons using the same bore 40ths over?I have two plstons will very little scoring on the skirt.and thats maybe why he's tell me that i should bore it.I really do value all of the input that you guy have given me it will help make a decision on what to do. I'am starting to think he's trying to empty my wallet.

 

[Petzschler]

thanks for the clearing up clearance for the piston to cylinder issue.The pistons are Keith black hypers.he has already honed the block and there is no damage to the cylinder walls, the reason that the engine is out is because it developed a knock at 631 miles, i do believe that the block is 1983 casting. He told me that the knock is from a bad rod when he was checking one of the rods he found a shadow at the point where the cap and rod meet, ever heard of that before? also is it possible to replace just two pistons using the same bore 40ths over?I have two plstons will very little scoring on the skirt.and thats maybe why he's tell me that i should bore it.I really do value all of the input that you guy have given me it will help make a decision on what to do. I'am starting to think he's trying to empty my wallet.

the shadow that he is refering to is most likely the rod cap moving around making the bearing fail. yup, you can replace to pistons as long as they are IDENTICAL to the rest. I wouldn't worry about a little scoring on the skirt. as long as its smooth. if a hone cleaned up the bores then np.
now,
my question is this. why would he HONE the bores FIRST, then tell you it NEEDS a overbore? if thats the case. FIRE him. becouse he obviously never measured/inspected anything to BEGIN with. JMO.

 

[AJ71DUSTER]

Thanks A-Bomb for the reply, it make perfect sense about what you say in your post. I will call my so called ASE machinist or should I money grabber and get this straighten out.hope to reply with good news next time.

Thanks

 

[moper]

Take it easy on him. If you didnt know what he was talking about, it's possible you still dont understand his opinion. I know plenty of engines I'd bore and re-hone simply because of the bore finish. .003 is a little big for hypereutectic piston to wall. That might have something to do with it too. It's not always just the cash. I'd talk to him about why he wants to do what he says.

 

[Guitar Jones]

Maybe he honed it first to see if it would clean up. I wouldn't be to quick to judge.

 

[Petzschler]

again. if he measured the BORES first. he would have got his answer right away. .003" clearance is ok with those pistons. why would anybody hone then measure the bore then hone. measure->bore (if needed)->hone. done. its HIS cash. and IMO he has a right to question his methods. you guys must have $$$ to burn.

 

[moper]

Not muney to burn. But if a customer walked in after buying a lower dollar crate that had a fatal issue, I would plan on a clean slate first, then work back from there is things end up better. Again, I dont know what was asked for.. "I want a 500hp small block" and "It knocks and I need to keep it cheap" are not the same. I would not consider the bores good enough if I measured zero taper but .003 clearance, and the hone pattern was rough. Because after the right bore finish is applied, the piston to wall is too large. Almost double what is recommended. It's simply a case of two different results and two different approaches. I had a perfectly straight set of bores but they had a shadow and visible marks down at the skirt on my present customer's project. The engine got bored another .010" to get the clearance and finish I require for the result he expects and is paying for. So I guess I've totally wasted that money there too by your definition.

 

[Petzschler]

ok one more time here. and i should make myself more clear. IF he measured the bores in the first place and compared to the oversize piston diameter, subrtacted the difference and it came out to .003" and according to you that isn't acceptable, then why would he REMOVE more material buy honing it out further? thats makes ZERO sence. sorry if i seem harsh.