TBucket Engine Project (Dart SHP)

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theres absolutely nothing wrong with perforated sheet as a shrapnel screen, but obviously theres a wide variation in the types available
aluminum perforated sheet used for ceiling air return ducts is once source, stainless perforated sheet and mesh are both available in several places
 
I'm ready to set the RING END GAP. Mahle documentation that came with my file-to-fit rings says for "Street, Strip, Circle Track:

Top Ring: Bore x .0045"
Second Ring: Bore x .0035"
Oil Ring: Minimum .015"

With my 4.125" bore that would give me

Top: .0186
Sec: .0144
Oil: .015

Mahle is not recommending a larger gap on the second ring. Also I'm not wanting to push any limits, with a street engine that may in it's lifetime over heat to some degree. So I'm thinking about using these numbers keeping it simple for the top and second ring being the same. Less chance of a mistake and a compromise between two different theories for the second ring end gap.

Top: 4.125 x .005 = .0206 or .021"
Sec: 4.125 x .005 = .0206 or .021"
Oil: .018

The ring set is a 1.5mm, 1.5mm, 3.0mm thick.

RingDimensions-Top.jpg


Anything wrong with my thinking?
 
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sounds like a well thought thru and workable plan to me, I would be using similar ring gap specs if it was my engines
theres no reason not to use those, measurements as they fit the application very well, now personally I'm always a bit conservative and rather have a bit more wiggle room on preventing rings butting under high temps but in the real world I doubt it will make ANY DIFFERENCE AT ALL, your right in the ball park, with a well thought thru combo, using the slightly tighter ring gaps will probable make the engine run with a bit less oil burn that a slightly wider ring end gap. probably just as important as the gap, is getting the ends of the rings stoned smooth so the rings don,t scratch the bore surface, and I know your not going to screw up but you might be amazed at the number of times I see engines with rings installed with the wrong side facing upward so verify before installing them, don,t get in a hurry most rings have a DOT indicating the UP SIDE,most rings have the inner edge beveled.
,Id use .022 top
.024 second.
.018 oil ring scraper

(years ago the thinking was that because the second rings did not endure the same high temperatures as the top ring the second lower ring could have less gap as it would expand less from heat, modern thinking resulting from testing shows the second ring should have a slightly wider end gap to prevent the top ring from loosing its seal pressure and developing RING FLUTTER at higher rpms, the problem is that "higher rpms" differ with every combo built)

this thread great


viewtopic.php?f=53&t=3897

ringup.jpg

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filerings.jpg

oilgap.jpg

RingEndGapNotParalla01.jpg



file.php
 
grumpyvette said:
sounds like a well thought thru and workable plan to me, I would be using similar ring gap specs if it was my engines
theres no reason not to use those, measurements as they fit the application very well, now personally I'm always a bit conservative and rather have a bit more wiggle room on preventing rings butting under high temps but in the real world I doubt it will make ANY DIFFERENCE AT ALL, your right in the ball park, with a well thought thru combo, using the slightly tighter ring gaps will probable make the engine run with a bit less oil burn that a slightly wider ring end gap.
,Id use .022 top
.024 second.
.018 oil ring scraper

Concerning the second ring and the bigger end gap, does this mainly come in to play at the higher RPMs. Is this when the pressure can build between the 1st & 2nd ring, lifting the 1st ring in the ring land and breaking the seal between the ring land and ring side ???
 
Indycars said:
grumpyvette said:
sounds like a well thought thru and workable plan to me, I would be using similar ring gap specs if it was my engines
theres no reason not to use those, measurements as they fit the application very well, now personally I'm always a bit conservative and rather have a bit more wiggle room on preventing rings butting under high temps but in the real world I doubt it will make ANY DIFFERENCE AT ALL, your right in the ball park, with a well thought thru combo, using the slightly tighter ring gaps will probable make the engine run with a bit less oil burn that a slightly wider ring end gap.
,Id use .022 top
.024 second.
.018 oil ring scraper

Concerning the second ring and the bigger end gap, does this mainly come in to play at the higher RPMs. Is this when the pressure can build between the 1st & 2nd ring, lifting the 1st ring in the ring land and breaking the seal between the ring land and ring side ???

in theory a slightly larger second ring gap allows pressure between the two compression rings to never get very high, in practice the top ring does about 90%-95% of the combustion chamber pressure sealing so its not critical, having a slightly larger second ring clearance is supposed to be benificial, and ive yet to see it hurt a darn thing
 
While filing the top ring I noticed that it's chipping the Moly. The pictures are taken using an Eye Loupe with 8x magnification, so it looks pretty bad. Not sure what I can do about it, except HOPE that it doesn't happen on every top ring.


The second picture is the actual ring filer I'm using after being modified.

ChippedMoly02.jpg
FinishedRingFiler0565.jpg


Since the end gap was zero when the pictures above were taken, I decided to see what it looked like as I got closer and closer to the final gap. The moly chipping seem to be sensitive to how aggressive I pushed the ring into the grinding wheel. As you can see it look nice now. The edges have been deburred after grinding.


ChippedMoly03.jpg

 
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WOW, I'M always AMAZED at your photographic skills but that magnified ring photo works simply astounding
yes thats a VERY commonly over looked factor, the chipping seeming to be sensitive to how aggressive I pushed the ring into the grinding wheel, and how agreasive the grit used is, the slightly higher cost diamond grit wheel IS worth the cost difference and how fast its spinning all effect results, even the direction the grinding disc spins effects the cut, it generally works best is the wheel , on the ring filer disc is rather smooth and the rings barely moved into the cutting disk with minimal resistance

yes as always theres cheap,functional, and theres expensive precision ring filers

http://www.abs-products.com/specialty-t ... nder.shtml
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INDYCARS, WATCH THIS VIDEO, ITS GOT A GREAT DEAL OF USEFUL INFO, I CAN EASILY SEE FABRICATING A ONE OF A KIND RING FILER FOR SHOP USE
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http://www.sjdiscounttools.com/lis24000.html


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measure carefully as the piston groove depth and back clearance must match the rings you use or youll have major problems
http://www.speedwaymotors.com/Precision ... ,2915.html
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http://www.summitracing.com/parts/SUM-906795/
prf3.jpg

http://www.muller.net/sonny/crx/rings/index.html

http://www.teglerizer.com/triumphstuff/75w_newrings.htm
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http://www.summitracing.com/parts/PRO-66785/

IVE USED ONE LIKE THIS FOR SEVERAL YEARS, with practice it does a nice job
 
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I find very little info about how the expander should be measured. When I put mine in the bore and square it up, it's big enough that it cannot be completely square in the bore. The expander should never touch the bore, so it has to be smaller than the bore.

As you can see in these two photos, the expander has to buckle if the ends are butted against each other.

DSC01347_Expander.jpg
DSC01351_Expander.jpg


So do I just bend the ends until it fits and then how do you measure, it's not like the other two rings that expand out to touch the bore.

DSC01355_Expander.jpg
 
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Good question there.
I dont know the answer, but i would not bend the ring end so they fit. Maby one end need to be over the other?
 
mathd said:
Good question there.
I dont know the answer, but i would not bend the ring end so they fit. Maybe one end need to be over the other?
I'm pretty sure they should never overlap and if you were to file the ends they would be less likely to butt up against each other securely.

I think the big question is how do you know when the expander is the right size.

I appreciate your comments !!!
 
you generally only need to grind the tips of the expander ring (RARELY NEEDED OR DONE) or bend them only a tiny bit (PREFERRED METHOD)
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NOTICE the two totally different OIL ring scraper ring widths in this picture above,OIL RINGS come in dozens of designs so, you can not use all oil rings on all pistons and you can,t swap expanders and wipe rings thru different designs, and you must verify piston groove measurements , measure carefully as the piston groove depth and back clearance must match the rings you use or youll have major problems
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if at all, in most cases they come out of the packager ready to install (THERE ARE EXCEPTIONS) the expander ring should sit level in the bore , and sitting parallel with the deck with minimal tension, their job is mostly maintaining consistent space between the wiper rings, which generally use a .018 gap and allowing oil to drain back thru the groove drain slots in the piston, its the oil scraper rings not the expander that provide much of the MINIMAL tension required to keep the oil ring in contact with the bore surface
as always a call to the manufacturer is a good idea, if you have questions because different ring designs require different clearances

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http://www.hastingsmfg.com/ContentData. ... ntentid=65

http://www.hastingsmfg.com/ServiceTips/ ... depths.htm

http://www.youtube.com/watch?v=slS8CUHRNkc

http://www.chevyhiperformance.com/tech/ ... index.html

http://www.enginebuildermag.com/Article ... rings.aspx

http://www.enginebuildermag.com/Article ... mance.aspx

http://www.hotrod.com/techarticles/engi ... ewall.html

http://www.kb-silvolite.com/assets/auto ... ctions.pdf

http://www.superchevy.com/technical/eng ... ewall.html



file.php


oilgap.jpg
 
grumpyvette said:
if at all, in most cases they come out of the packager ready to install (THERE ARE EXCEPTIONS) the expander ring should sit level in the bore , and sitting parallel with the deck with minimal tension
That make sense.
I never seen an expander ring getting gapped/filed or overlap lol.
 
reading thru this thread, and its sub linked info is a great start for anyone wanting to learn engine building
INDYCARS has done an amazing job with , pointing out what needs to be done, where to look, and what needs to be looked at with both the photography and questions
 
It's obvious that I could not have done the quality job I have done without your guidance. Your responses have also greatly motivated me to do better than I would have of my own accord and I have exceeded my own expectations with your help.

Many, many thanks Grumpy!!!
 
reading thru this thread, brings back 40 plus years of memories on many dozens of individually build engines ,on the more memorable engines and reminds me of how I've succeeded and on occasion screwed up, on those occasion,s when I failed to do the research on how things were to be done correctly, or how they could be improved.
we all learn from our screw ups, and the smarter guys also learn from their buddies mistakes, and its surprising what you can do to improve durability by learning how to verify clearances and never assuming the machine shop actually did the work correctly, without checking and verifying every last clearance, or how a bit of time polishing or grinding or measuring makes, what most people assume is a minimal difference, while in reality those minimal differences combined add up to make a noticeable improvement in the finished results, and in both cases where any mistakes are made, if your smart you step back, and ask why did that happen, what can be done to prevent that, or how can that be done better, looking over the process, and whats been learned over time, makes it rather obvious WHY I never made any really money building engines and WHY I have a waiting list, of customers willing to wait to get an engine built....you just can,t build a quality engine taking all the detailed, and time intensive steps required , and charge even any where near a decent PER HOUR RATE, and be even vaguely competitively priced to factory crate engines, that come with a guarantee, now theres also no comparison the the quality of the finished product or horse power or durability but 99% of the customers are only looking at the price, horsepower and expected delivery time and never see whats involved in producing a quality product thats carefully assembled, you get a sense of pride when you hear an engine you built ran a bit better than the other guys, or when you see the engine you built for a friend is still running strong after 40K-50K miles , when you know their buddies running very similar cars and engines are on their 3rd or fourth rebuild
its also nice to know that your passing on the skills and knowledge to the few guys that will appreciate what it takes to build a really durable engine, so that in a sense all that experience is not limited or wasted on a single person or lost if something were to happen to that person , theres not much sense in more than one person making all the mistakes and doing all the research required to get things done if its easily available and documented for the few people that care, to do it correctly vs the vast majority who will continue to slap parts together , never measure a darn part or verify anything, assume the machine shop did everything correctly,and wonder why they have problems
 

I talked with Eric at Mahle Motorsports yesterday to find out how the expander ring is suppose to work and how can I tell if the dimensions are correct.

According to Eric, there is no good way to measure this, but it should overlap about a 1/2 link when placed inside the cylinder. It's suppose to be bigger than the cylinder bore in it's free state. When you put the 2 oil rails plus the expander in the piston groove and then compress the oil rails it will compress the expander, making it's diameter smaller such that it does NOT contact the bore.

This is where very careful observation of these components is critical. The two oil rails MUST contact the shoulder on the expander. The expander ENDS must NOT overlap, rather the two ends must butt-up against each other or the oil rails will NOT do their job because they will lack the force needed against the cylinder wall to seal properly and control the oil. Don't get this right and your motor is going to smoke badly.

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I found this hard to put into words, so if there are any questions.....fire away and I will take another shot at it !



 
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You found the good word, i understand what you said very well :)
Picture are worth thousands words..
 
With taking Friday off, I fully expected to have all my rings end gap set. But replacing rear axles seals on my 93 Suburban got in the way big time. So now it's Sunday afternoon about 1:30 pm and I'm just now getting started on the rings again. I have 3 more cylinders left before I'm done.

Amazing pictures.......well I think this one is kinda neat looking. You are looking from the bottom end up thru the shrapnel screens in the valley.

DSC01207.jpg
 
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