pistons

[restless]

Well I took the cylinders in to Machinist they need to be bored 60 over to clean them up Can some one please tell me what the best piston I can get for this over size .
Thanks Bill

[1950Panhead]

I have used the vtwin and keith black pistons, they are both good, jp sells them.
Jerry

[caschnd1]

I'm odd man out. I like the forged Pistons. I use Wiseco brand. I put over 100K miles on a set of Wiseco pistons that were 0.060" over.

-Craig

[Panacea]

Craig, how much clearance did you use with the Wisecos? I scored my first set with too tight tolerance, set up the next set loose with better results...Mike

[restless]

Hi after doing some research I would like to go with cast 7.5.
Thanks Bill

[58flh]

With Weisco pistons You have to let the motor get to op-temp. before hammering the wick!--I used cast pistons on bigger bores & Coupled with Hastings Iron rings!-(the black ones!)-This has Always made a Hi-milage low maintenence motor!/& I have GREAT success on NUMEROUS genny bikes from Flaties to shovels!.-They come in any comp. you want!--If you are looking to beat the clock with your pan,,,That is if you have STD heads shovel intake,Nice 4-1/2-inch T-monter stroker wheels,Or junky S&S wheels then Wiesco will no doubt take 8K going threw the lights!.Kbs are of great quality also!-TRW is another goodie forged piston!--But if your looking for daily reliable performance -(you cant go wrong with cast-pistons!)-I have already put over 200K on cast pistons!--Not the same wheels obviously -as I used OEM lower 74-inchers.Usually when you get around 100K-plus theres a distinct vibe-(like nothing you ever exp. unless you have worn out your wheels to where they BULGE at the crankpin!)-It depends how well & OFTEN you change oil,& how much you hammer the wick on!.Craig has put over 100K on Weisco-pistons!-(But he knows how to run them in!)-You just cannot get on & hammer her with a 100 miles on a fresh motor -WITH FORGED PISTONS!-CAST have already found a home in this time & you can Hammer it on if you want!-But I suggest 5-6 oil-changes in 1000-miles!.Whatever your choice & use of this bike DO not use CHROME-MOLY RINGS!-better yet chrome-Moly anything!.This is my exp. from a young age in doing this stuff!--Cast-Pistons & Hastings Iron-Rings!= alot of fun & mileage before it starts cropdusting!/& thats cause the wheels usually need ing new ones-& Guides!.For example--(I still am running the original rods!-There stretched & shotpeened long ago after the first bottom-end!,Yes Grudgions have been replaced & Always you check for straightness!-Simple enuff just like our motors!.I have .040-overbore on OEM/original barrels!/I suspect another bore in like 20-months when I turn the OD to it will be 300K!THIS IS what PREVENTIVE MAINTENENCE will get you if you stick to a steady schedule!.I have replaced lifters 3X & the rollers even more!-(every 18-20 or I do it every 2years!/NEEDED OR NOT!/I run Solid-tappets & steel P-rods!/on a FLH cam ITS a VERY GOOD SET-UP!-I set them at the start of season & I dont have to touch them until next season-thats 10K in a year!.-UNLESS I hear a Roller start making noise!-(usually the front EX.-ALWAYS!)-Then you do all 4.Sorry for the long post -I hope my expierences help somebody -(Factory Heads Factory formula/& you cant go wrong)-If you have STD with shovel intakes-BY ALL MEANS take advantage of the FLOW!-I always stuck with stock comp.-ratio of 8.5-to 1.---All DUE RESPECT----RICHIE

[Panhead Ed]

Craig, how much clearance did you use with the Wisecos? I scored my first set with too tight tolerance, set up the next set loose with better results...Mike

Not to hi-jack this thread but this is an important point....

When you first fire up a fresh engine its best to bring it up to temp and then let it cool down naturally . Do this 7 to 10 times BEFORE you ride it , these heat cycles will prevent scoring and allow things to seat . The tighter the clearance to more cycles you do the better your results . Jumping on for a quick ride on a fresh build will burn her up !

[Panacea]

I carefully broke it in with 500 miles of nice warm-ups and easy acceleration, i was also breaking in a new tranny re-build. I think the problem came from riding with modern bikes, they didn't take the time to warm up their motor, so I wound up thrashing to keep up. With a cold motor, the pistons grew faster than the bore and with .0015-.002 they scored.

[caschnd1]

Craig, how much clearance did you use with the Wisecos? I scored my first set with too tight tolerance, set up the next set loose with better results...Mike

I'd have to go dig out my notes to be sure, but I believe I went with the Wiseco recommended 0.0035" piston to wall clearance.

-Craig

CORRECTION: I dug out my notes and I set my clearance at 0.0030".

[58flh]

PANHEAD ED--Strikes a good point!--Allow heat & cooling cycles!!!!--After this DO a Bubbletest!--& you will see how much MOVEMENT there really is!--After a TOP-END -I do this & Always find a leak!--No matter how small or big-A vacuum leak is NEGATIVE & you cant DIAL in a MOTOR WITH ONE!--I know you guys running everyday Bubbletest every 6-weeks or 8 or as soon as somthing changes!-(your plugs tell the story if you know how to read them!-I call it bubbletesting now ever since I read Cottons post on EML!.I just use to use starting fluid or Wd-40!-Now Wd dont burn -Hell plain water sprayed while a motor is idling will tell you of a VAC-LEAK.If water they lower in RPM/-If Starting-fluid -RPM rises.--Dont use Starting-fluid!-(not safe)-Water costs nothing! & it was simple!--(Now I do it the correct way!-& I found it to be MORE ACCURATE).20-min. more work ,but who cares--& BUBBLES are ACCURATE).A quick way to tell while running-Just rub your finger under the clamps--If wet with fuel & dirt from motor -FIX-IT!---Respectfully---RICHIE

[old.wrench]

Hi after doing some research I would like to go with cast 7.5.
Thanks Bill

Those should do the trick Bill.
The generic cast pistons I've used have been pretty decent quality. Personally, I like the 8.5 to 1's in the older motors; makes for a pretty perky motor without getting into pinging problems even with regular gas, at least that's been my experience.
I have good results with .0015" piston to wall clearance and .015 ring end gap with Hastings rings, but for a while now I've noticed that some of the Hastings rings are coming right out of the package with a larger gap than that.
Lot's of different opinions about using heat cycles as a first step in the break-in procedure, but I've been using that method on rebuilds for about 12 years now and I'll keep on doing it.
I've used forged pistons on a few motors and they work all right too, but it's been quite a few years since I've used them. In fact, it used to be they were the only pistons I'd use, but since then I've changed my opinion. Cast are good too .

Geo.