Harley evolution piston rings - Page 2

Jeff Higgins · 04-11-2014, 07:38 PM

Hey, afterburn, the XXX Root Beer drive-in is still going strong out in Issaquah. We don't meet for breakfast there anymore, but we still have a car show once a year. Breakfast has moved accross town.

I would have to agree with asphalt gambler regarding pistons for hi-po HD applications - replace the stock ones if that is your goal. The KB "eutectic" pistons, however, have a horrible reputation for failure - like the entire top half seperating from the wrist pin bosses. I would go Wiseco or JE, with a normal forged piston.

As far as ring position on pistons, every motor I have ever built and subsequently rebuilt has had the ring gaps in different positions than when I built it. I religiosly space them 120 degrees apart, with no gap on the wrist pin axis or 90 degrees to it. I have yet to tear down a motor and find them still in that orientation. It's my understanding that all rings walk around the pistons, regardless of engine type, ring type, piston type, etc. So, to think you cannot re-use prefectly good pistons, cylinders, and rings because the clocking of the rings has been disturbed is simply incorrect. It gets disturbed by running the motor.

Granted, my engine building experience is probably no match for some others on this forum, but I have built my fair share. Big block MOPAR drag motors, Bug motors, Harley motors (Shovels and Ironheads), 911 motors, and now one Ducati motor. What I state above is based on my personal experiences. YMMV...

afterburn 549 · 04-11-2014, 07:44 PM

asphaltgambler,-Would you go out on a limb please and recomend a piston of close to stock C/R ?
Keep in mind .050 is now off the heads. No going back now....
Yes i know there are different size head gaskts.
My pistons in current form were 2 thou below cyl at TDC.
I am shooting for a very tight squesh !

afterburn 549 · 04-11-2014, 07:48 PM

Ok........new pistons......you guys win LOL
just need to chooose.....................
I would like to go HYP type.......but if they are going to fall apart......(ahem) skip that idea !
Forged require lots of room....
So many choices..

Jeff Higgins · 04-11-2014, 11:52 PM

Adjust squish with base gaskets, not head gaskets. The piston manufacturer should be able to give you the proper range of dimensions for their pistons. Lots of factors come into play in determining proper squish, so they would be your best resource to ensure you get a valid number.

VINMAN · 04-12-2014, 04:06 AM

I went with Wisecos in my 1200.

afterburn 549 · 04-12-2014, 04:27 AM

Jeff , I am Hoping Dave Mackie knows what he is doing......he said just rip .050 off the heads...
So there is a confluence in thought there....

asphaltgambler · 04-12-2014, 07:17 AM

So a few answers based on my experience. I would recommend the KB Hyper "U's" for performance street use as they offer very good fit (tight) and low drag and are available in many different comp ratios. I have personally never seen a KB piston failure in a HD motor unless something else was introduced that was not in the proper 'mix'. IE: poor assembly, poor machining and or not closely checking clearances, detonation, nitrous and or over RPM-ing the motor.

Forged pistons are for all-out street and racing engines where extreme combustion temps, pressures and rpm's are encountered. The downside of running them in an mild street motor is noise, poor ring seal and increased oil consumption over lot's of miles.

As far as base gaskets ........................please run one but with light coat of Hylomar on each side. Those cylinders 'walk' around a lot on the case spigot. Cometic makes several good metal cylinder base gaskets. Hylomar applied very thinly on each side will maintain seal and never hardens but is almost impervious to gas and oil. It's the hot ticket.

You won't know what deck height you have until you have the new pistons installed.

afterburn 549 · 04-12-2014, 05:42 PM

Next questions.
Ok i am going to re piston this thing....I found something i do not like in the bore..
Can these evo jugs be bored with out a re chrome?
Who can do it with confidence ( not NAPA dwn the road LOL)
Now that i am dual plugging it I might as well go bigger in the C.R dept anyway
Next.if Hyp. pistons will not fall apart, i would like to gamble a set...
Where do i get a them.....? molly coated might be nice too!
thanx!

Arizona_928 · 04-12-2014, 09:18 PM

Hammer!

afterburn 549 · 04-13-2014, 03:35 AM

Quote:

Originally Posted by AZ_porschekid

Hammer!

If you have nothing to do go do nothing SOMEWHERE else. Your childish answers impress NO one.

asphaltgambler · 04-13-2014, 09:22 AM

I would first have the bores checked by a good machine shop to establish where that measurement is. You will have to hone to break the glaze so that adds (very slightly) to the existing diameter. I have found that most late model EVO cylinders wear very little under normal conditions so you may be in luck. If the bores are true (round) and in spec then you would source the new pistons and do trial fitment and measuring. Unless you have all the specialty micrometers you may want to leave this to a good machine shop.

If you have to bore the cylinders, they need to done by someone who has a torque plate and experienced with air-cooled cylinder boring. Next there is no factory plating or coating on the cylinder walls like Porsche or BMW. They use a high ductile steel liners.

I'm not sure where you're located but there is shop in Elkridge Maryland called "Zippers Performance" I have personally dealt with them over the last 20 years and they are one of the best HD performance shops out there. Downside to them is they are doing less machine shop services these days and concentrating more on fuel injection development. Check their interweb-site out for parts, services and contact them directly for any further questions. Hope this helps you.

afterburn 549 · 04-13-2014, 10:23 AM

Ok thanx ! This is all very informative. (as always here)
One cylinder has swallowed some FOD..I might get away with a hone...but its in my lap...and I have dual plug heads in the mail.....
So I am really considering a couple jumps in C.R. Clean bore and fresh piston rings. Just need to locate pistons. ( Hyper type)
Maybe Mon will clear the air.
However, if any of you have a lead on them - let me know.

Jeff, we have met there at the XXX. I think you had a green P. car that time....I now live on the "right Coast" LOL

Arizona_928 · 11:31 AM

Quote:

Originally Posted by afterburn 549

If you have nothing to do go do nothing SOMEWHERE else. Your childish answers impress NO one.

http://http://www.hammerperf.com/

If you actually knew something about simple mechanics then you wouldn't be asking questions.
If you knew something about Harley's you would have understood my response.

FYI you're going to want to go to the buell section because they used the same top end on both evo, and XB. Hell if you have money mind as well upgrade to XB heads...
P.s No one wants to walk you through (ie Hold your hand) on how to put together an engine, or how you ****ed up. Most of your questions; a simple Google search would produce answers for. "oh, no my rings moved".

Arschloch

afterburn 549 · 12:12 PM

Yea..well a womans hint was/ is never very helpful. ".Get a hammer"...? really?
Yea i know nothing..and you know everything.....good for you.
Next time word it in a format THAT HAS some sobriety to it.
Because I have never herd of you .......means i do not know nothing?
Again childish.
I ask questions so i am supposed to be ashamed?
WOW really ??
LOL
No one is making you answer anything here so why are you complaining?...
You are very immature for this place.
For your information I do not live, eat, breath Harley. Information today is wrong for tomorrow.
Everything changes .
Its like a Porsche oil restriction question .There is two sides to most opinions.
I value the brain trust here. Is very helpful as per usual, (except yours).
I would appreciate if you did not litter my questions with anymore of your worthless word drool.
PS you can bet i will never ever buy ANYTHING from you .
PSS i am betting you do not know as much as you think you know..........and, you certainly know nothing of me.
When you get beyond a simple Harley let me know...

Arizona_928 · 04-13-2014, 12:20 PM

Quote:

Originally Posted by afterburn 549

".Get a hammer"...? really?

I suggest you re-read my comment.

And I ain't selling anything... ?

Arizona_928 · 12:30 PM

I think you confused my comment on the buell xb piston sets as; I was offering them to you for sale. I'm actually using them on my own 1203 build... I was giving a suggestion on if you were going to go that route, where to buy them from. With that said, If you can give a personal attack, you should learn how to take one.

afterburn 549 · 02:44 PM

Quote:

Originally Posted by asphaltgambler

I would first have the bores checked by a good machine shop to establish where that measurement is. You will have to hone to break the glaze so that adds (very slightly) to the existing diameter. I have found that most late model EVO cylinders wear very little under normal conditions so you may be in luck. If the bores are true (round) and in spec then you would source the new pistons and do trial fitment and measuring. Unless you have all the specialty micrometers you may want to leave this to a good machine shop.

If you have to bore the cylinders, they need to done by someone who has a torque plate and experienced with air-cooled cylinder boring. Next there is no factory plating or coating on the cylinder walls like Porsche or BMW. They use a high ductile steel liners.

I'm not sure where you're located but there is shop in Elkridge Maryland called "Zippers Performance" I have personally dealt with them over the last 20 years and they are one of the best HD performance shops out there. Downside to them is they are doing less machine shop services these days and concentrating more on fuel injection development. Check their interweb-site out for parts, services and contact them directly for any further questions. Hope this helps you.

Next question for the brain trust-
On a evo with their combustion design (stock) sense I am going twin plug...what is the best guess the highest C.R. I could get away with for the street with higher lift more over lap cam ?
Looks like 10.5 to 1 is pretty common...........

asphaltgambler · 03:48 PM

I don't know your cams exact specs but 10:5 - 1 is pretty standard with any high performance street cam as the increased duration and overlap will bleed some of that added cylinder pressure away. Additionally the cylinders and heads are (obviously) made from aluminum so there is added heat loss which results in lower combustion chamber temperatures.

Also if you have not replaced your ignition module with an aftermarket adjustable timing unit, you will need to at this stage. By twin plugging you should be able to pull back total ignition timing by @2 degrees which does not sound like much but it will make more power on the top end with less timing using two flame fronts.

Your stock carb will work but will need re-jetted. With that said you should also consider adding a Thunder-jet to your carb for the added rpm's and increased air flow. It is add on 3rd; high speed fuel circuit for your carb. Zippers developed this and hold several patents. I can have installed many and I consider a must do item on any performance HD. The 411 on the Thunderjets are on Zippers webpage.

LakeCleElum · 05:11 PM

Quote:

Originally Posted by Jeff Higgins

As far as ring position on pistons, every motor I have ever built and subsequently rebuilt has had the ring gaps in different positions than when I built it. I religiosly space them 120 degrees apart, with no gap on the wrist pin axis or 90 degrees to it. I have yet to tear down a motor and find them still in that orientation. It's my understanding that all rings walk around the pistons, regardless of engine type, ring type, piston type, etc. So, to think you cannot re-use prefectly good pistons, cylinders, and rings because the clocking of the rings has been disturbed is simply incorrect. It gets disturbed by running the motor.
.

Jeff is correct.....Space your gaps at 120 degrees and find later the rings have rotated. They do in all 4-stroke engines.....2 strokes have a "pin" to prevent this. That is so the end of the ring does pop out into the exhaust port and get broken off.

As far as CR on any large air cooled 4 stroke; be careful. Twin plug will help, but you have to really watch your timing and octane rating to aviod a problem where it will pre-ignite into self destruction......

I still have those seats I bought off you when you were in Bellingham.....Hope you found the cash I left in the hiding place on your porch........

afterburn 549 · 04-13-2014, 04:13 PM

Quote:

Originally Posted by LakeCleElum

Jeff is correct.....Space your gaps at 120 degrees and find later the rings have rotated. They do in all 4-stroke engines.....2 strokes have a "pin" to prevent this. That is so the end of the ring does pop out into the exhaust port and get broken off.

As far as CR on any large air cooled 4 stroke; be careful. Twin plug will help, but you have to really watch your timing and ocatane rating to a problem where it will pre-ignite into self destruction......

I still have those seats I bought off you when you were in Bellingham.....Hope you found the cash I left in the hiding place on your porch........

Hi ! Nice to hear from ya!
Cash on Porch .I think so,no bad memories, so must all be OK! LOL
Hope the seats will do someone some where good....some time.
I have a fancy Tech 3 modual for dual spark and advance retard...Heads are being double plugged .
If i go to 10.5 to 1 have I gone too far?
I see lots of end users put them in even Screaming eagle kits do it.
I know its on the living edge.....