392 ring gap question

F

Fife

New member
Hey all , im building a 392 its 40 over on the bore . Checking the ring gap on the first and second rings and im seeing a gap of .027" books saying .012 to .023 . Cylinder shows 4.165 rings are hastings 6095 - 040. What am I doing wrong ? Second set of rings same brand .
 
Is this a new bore? Have you personally verified the diameter with a bore gauge? Each .001 in bore diameter will change the ring end gap .00315"

if the bore not new and has any wear in it, that too will increase the gap.

Also make sure the ring is placed into the bore perfectly perpendicular to the wall. Us a piston on top of the ring sliding it down to place it more accurately in the bore.
Min end gap by the book is the bore x .0035. I would use bore x .004 on a high load engine like these. That puts you at .017 top ring and the second a bit larger to prevent inter ring pressure build up.

If you still come out at .027 call hastings and explain your issue to them.
 
The engine is a fresh bore and hone , pistons were at the machine shop for final fit . New pistons .040 over . I did use a piston to square up the rings and measured a first and second ring , same measurment . All parts were ordered thru IHPA , I have 2 sets of hasting rings . First set was vintige old (1988 stamp on box ) second set looks current . Just going nuts and wanting to get it together .
 
fife said:
the engine is a fresh bore and hone , pistons were at the machine shop for final fit . New pistons .040 over . I did use a piston to square up the rings and measured a first and second ring , same measurment . All parts were ordered thru IHPA , I have 2 sets of hasting rings . First set was vintige old (1988 stamp on box ) second set looks current . Just going nuts and wanting to get it together .
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All parts of the engine need to set up at nominal including bearings to crank and, piston to bore. You can't believe how many times I have had to fix problems that ended up to be simple tolerance issues. Or rooky mistakes that a machine shop made or an extra/ missing machining step that was or was not necessary with unintended consequences.

Your numbers are all well and good on paper but what does the bore really measure. I know you said 4.165. While that is the designed bore, most shops measure and bore the block to yield a given/desired piston to cylinder clearance did the guy bore the thing and set you up loose like .005+ clearance?
You need to know exactly what the bore is. Do you have a 4-5" micrometer or a minimum of an accurate caliper? Do you have a proper bore gauge (in the large black box, or telescoping hole (snap) gauges in the red organizer.
If you don't call the machine shop and ask exactly what he set the piston to cylinder clearance to and what toe bore ended up being at that.

I know this is a rpita but other wise it's all a risky guess at best.

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Monday morin I'm taking a trip to the machine shop so they and I can get it figured out . :thumbsup:
 
Fifi, you're making the right move. Wait until you know what is wrong for sure then you can have a plan of action that will yield known good results.

I know you said that you have 2 sets of rings and, at least one set is from IHPA. If you have any issues with hastings, Jeff can help you. I used to be able to get file fit rings that were tight by design so you could get what you want.

I hope you can post your findings. Please post any dimensions you get from the machine shop.
 
So, a trip down to the machine shop today was fun ! The block is like a 60/40 , one bank 40 over and one bank 60 over ......sweet :incazzato: now I get to dig out another 392 block and have them start over ! They said they will make it right with me and that is good .... Still sucks at all the frusteration and time .
 
fife said:
so, a trip down to the machine shop today was fun ! The block is like a 60/40 , one bank 40 over and one bank 60 over ......sweet :incazzato: now I get to dig out another 392 block and have them start over ! They said they will make it right with me and that is good .... Still sucks at all the frusteration and time .
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Here's my suggestion. This lands square on the shop. They need to buy you pistons and and rings, bore the other bank .060 over. There is no way you should have to find a block and pay for it.
I am glad you found the problem but sorry you have to deal with it.
 
I have another block that I am taking tommorow and we will go from there . If the first one is messed up beyond the .060 spec its easily time to build the other . Or if its still in the .060 bore specs maybe maybe ??? But would like to keep the .040 over build theme . If the first block is beyond .060 range save for another build with different pistons .
Yes it really sucks big time , lots of banging my head and a few new words created . But will keep chugging and make sure the machine shop takes care of me and zero out of pocket on my end if possible .
 
What were they thinking anyway's ? Damn....parts manual show's .040 piston's were available....060 will have o be special made...big $$ unless the mopar 1's are close ? Maybe it took that much to clean up that side ? Or the guy just liked cutting out them hole's ? Lol. Sry for your dilema, but damn why ? Jeff:shocked:
 
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