This site uses cookies to maintain login information on FarmallCub.Com. Click the X in the banner upper right corner to close this notice. For more information on our privacy policy, visit this link:
Privacy Policy

NEW REGISTERED MEMBERS: Be sure to check your SPAM/JUNK folders for the activation email.

Pistons

The Cub Club -- Questions and answers to all of your Cub related issues.
Forum rules
Notice: For sale and wanted posts are not allowed in this forum. Please use our free classifieds or one of our site sponsors for your tractor and parts needs.
User avatar
George Willer
Cub Pro
Cub Pro
Posts: 7013
Joined: Sun Feb 02, 2003 9:36 pm
Zip Code: 43420
Circle of Safety: Y
Location: OHIO, Fremont
Contact:

Postby George Willer » Thu Dec 14, 2006 10:33 pm

David Bennett wrote:
john2189 wrote:If you can get more power with the dometop pistons, why would anyone not use them when rebuilding and engine, even if you had to buy the head to match the pistons ?

how much of a differance is there between the domed and flat pistons ?

The 154 s had 15 Hp The older cubs had 10
It would cost a great deal to by all of the parts needed to make the change Carburator, manifold, cam, pistons, governor etc Then you would
be using a 50 + year old crank that wasnt designed to be turning the extra rpms
I put the doomed pistons in one of my cubs I did not have to change the head, has a little mower power in tall grass.
David


There were many factors involved in the increased power. Probably the least important was the pistons. They were mostly important because of their lighter weight, allowing higher RPM. The higher RPM was made possible by changes to the carburetor, manifold, and governor working in concert.
George Willer
http://gwill.net

The most affectionate creature in the world is a wet dog. Ambrose Bierce

SPONSOR AD

Sponsor



Sponsor
 

Bill E Bob
10+ Years
10+ Years
Posts: 3034
Joined: Wed May 31, 2006 12:09 pm
Zip Code: 74070
Circle of Safety: Y
Location: OK, Skiatook

Pistons

Postby Bill E Bob » Fri Dec 15, 2006 12:29 am

I know this isn't really relevant to this thread, but was wondering if the
cast iron pistons wouldn't up the torque with their add'l weight over the
aluminum?

Bill

User avatar
Larry Barb Dotson
10+ Years
10+ Years
Posts: 216
Joined: Thu Dec 25, 2003 7:03 pm
Location: Oh. Bellefontaine

Pistons

Postby Larry Barb Dotson » Fri Dec 15, 2006 1:41 am

This is getting out of context a little bit, but compression does make a difference in horse power(a big difference). But the main driving force
for our tractors is torque which is the real driving force. The light weight pistons may not increase torque, but do allow the RPM to increase which is a mulitiplication of torque to RPM. I would never consider reducing the compression if my tractor already had the domed high compression pistons, unless you insist on exact duplication of the original pieces (who is going to look inside of your engine?). As our gasoline became better over the years, almost all engines were upped in compression to take advantage of the better gas available, netting in more power.

Larry Dotson
Did I waste my money putting 14 to 1 pistons in my 460 Cu inch Cavalier

Gary Dotson
Team Cub Mentor
Team Cub Mentor
Posts: 5618
Joined: Thu Aug 03, 2006 6:20 am
Zip Code: 43358
Tractors Owned: 48 Cub Diesel (Cubota)
53 Cockshutt 20 restored (Shooter)
52 Cockshutt 20 unrestored
47 Leader "B" (Herckie)
49 Leader "D" (Princess)
49 Leader "D" very rough
48 Leader "D" unrestored
Kubota B6200E
Kubota B6200HST
Kubota B8200HST-D
Circle of Safety: Y
Location: OH West Mansfield

Postby Gary Dotson » Fri Dec 15, 2006 8:15 am

Replacing or modifying the head to accomodate the high comp. pistons only seems to be a maybe. I put them in my 48 years ago with good results. I'd send the iron slugs back & get the good stuff in a New York minute.
While heavier rotating parts will increase torque, heavier pistons will not. They have to start & stop twice on each revolution.
Yes, you can hone .020 with a sunnen hone. Be very careful to avoid taper, it will want to remove more material at the top of the bore.
There is no difference in the con. rods & pins between cast iron & aluminum.
The piston weight will effect balance, but you'll never know it on a cub.

User avatar
Rick Prentice
Team Cub Guide
Team Cub Guide
Posts: 5636
Joined: Mon Nov 01, 2004 7:24 am
Zip Code: 43528
Tractors Owned: 47(circle cub),48(Floyd backhoe),49,,51,54 and another 55
Circle of Safety: Y
Location: OH, Holland
Contact:

Postby Rick Prentice » Fri Dec 15, 2006 8:40 am

I agree with some of the others about the stock head. The '55 I have tore apart right now has those dome pistons in the '55 block with the stock '55 head. They are .020 over and have the number 405008-R1 molded into the tops.

Rick
Image
When I told my dad I've been misplacing things and doing stupid stuff----His reply---"It only gets better"

User avatar
cowboy
10+ Years
10+ Years
Posts: 3414
Joined: Sat May 15, 2004 11:10 am
Zip Code: 49229
Location: MI, Britton

Postby cowboy » Fri Dec 15, 2006 10:12 am

I have to agree with Gary. I would go with the aluminum pistons. It is less stress on the engine. Since it is a older style engine I would put the head on without the gasket and spin the crankshaft over to check for interference with the pistons and head incase the PO clearenced the piston rather than the head when he assembled it.

Changing the piston weight on a inline engine like a cub should have no real effect on ballence. On a V-8 or V-6 that is a different story becuse of the different angles involved coming together at the crankshaft.

Billy
Take care of your equipment and it will take care of you. 1964 cub. Farmall 100 and 130.

"Those that say it can’t be done should not interrupt the ones who are doing it.”

BigBill
10+ Years
10+ Years
Posts: 7388
Joined: Sat Jul 22, 2006 5:02 pm
Zip Code: 00000
Location: in northern usa

Postby BigBill » Fri Dec 15, 2006 10:29 am

You can hone the cylinders oversize if you have the proper Sunnen gear driven adjustable hone. They have coarse and fine stones available for them too. You can find it at goodson on the net. I got into this because of restoring gravely tractors and my sons dirtbikes had to be bored oversize and the local machine shop won't touch them. This hone is so good the cylinder is held within 2 tenths error max if any of being exactly round. I should of never closed up my monster garage when i became disabled i never knew there was life after motorcycles. I have had my share of quads and motorcycles and tractors are even more fun!!!!!

Rather than use a spring type hone for just honing to take off the glaze. I would get a ball hone from snapon tools thats the correct size for the bore your working on if your not borning it. Snapon also has a smaller adjustable hone too for boring 125cc dirtbikes if it has a castiron sleeve.(older bikes)

You can also get alumimum stones for the hones too. I took the goodson hone with an extention and cleaned up hydraulic cylinders too.
I'm technically misunderstood at times i guess its been this way my whole life so why should it change now.

Eugene
Team Cub Mentor
Team Cub Mentor
Posts: 20344
Joined: Fri Jul 02, 2004 9:52 pm
Zip Code: 65051
Circle of Safety: Y
Location: Mo. Linn

Postby Eugene » Fri Dec 15, 2006 10:46 am

Guess it's about time to put a Cub engine on the stand and do a volummetric combustion chamber measurement of a stock block and head with flat topped pistons and again with domed pistons. Without changing the head to accomodate the domed pistons. I can't envision a significant change in the engines compression ratio.

There was a change in connecting rods in the Cubs engine. Was the change associated with the lighter pistons?

A while back we had a discussion on the horsepower to torque curve. In the chart provided the horsepower and torque increased up to 1600 RPM. After 1600 RPMs the horsepower increased with the RPM but the torque dropped off.

Changing pistons without increasing the engines ability breath (intake and expell air) will provide very little effect on horsepower and/or torque. The IH engineers did not change the cubic inch displacement with the piston change. Cubic inch displacement is a much more reliable figure for indicating potential power output from the engine than indicated or advertised horsepower.

Just my opinion.

Eugene

User avatar
Boss Hog
Cub Pro
Cub Pro
Posts: 10290
Joined: Mon Oct 24, 2005 8:35 pm
Zip Code: 23962
eBay ID: dmb2613
Circle of Safety: Y
Location: VA. Randolph

Postby Boss Hog » Fri Dec 15, 2006 12:05 pm

All of the engines i have pulled down with the al pistons had the new rod
David
IN GOD WE TRUST
All others pay cash
Boss Hog
Power corrupts; absolute power corrupts absolutely byJohn Emerich Edward Dalberg

Eugene
Team Cub Mentor
Team Cub Mentor
Posts: 20344
Joined: Fri Jul 02, 2004 9:52 pm
Zip Code: 65051
Circle of Safety: Y
Location: Mo. Linn

Re: Pistons

Postby Eugene » Fri Dec 15, 2006 12:40 pm

g19605 wrote:The replacements are cast iron and are flat topped. Will these be OK? My concerns are two: 1. the cast iron ones are much heavier. George


Back to George's questions. Without knowing which connecting rod is currently in the engine and if there were any other engine modifications, I would try to get new aluminum pistons - replace what's currently in the engine.

Eugene

g19605
10+ Years
10+ Years
Posts: 59
Joined: Tue Nov 28, 2006 7:12 pm
Zip Code: 19605
Location: PA, Reading

Postby g19605 » Sun Dec 17, 2006 11:47 am

Hi Guys,
I got a bunch of numbers from the Cub engine:

ALUMINUM PLATE: F143243, Max Idle RPM 1800 11 - 15 - W
BLOCK: (11 - 16 - W, 2 251341R L), (FCUBM 145805)
HEAD: 11 - 23 - W 251228R1
PISTONS: 405007R1
RODS: 251246R1

I don't have the books and manuals that you suggested (yet), so I don't know whether the aluminum domed pistons and the head are original. The head doesn't seem to be modified to accommodate the domed pistons and I believe that the "W" does mean year 1951. What do you think? I know that Eugene, Cowboy and Gary like the aluminum pistons and the somewhat higher HP, but I kinda' like the idea of keeping it original. Our Association will be using it mainly for pulling "people wagons" during our several Festivals each year and probably some mowing so we aren't going for any pulling records and may not need the extra HP. However, I imagine that Jeff at Yesterdays Tractors would let me exchange the cast iron pistons for aluminum if necessary.

Big Bill, yes I do have the good type hone as you suggest and I have had good success with size and am careful about the taper situation.

George

Jim Becker
Team Cub
Team Cub
Posts: 17242
Joined: Sun Feb 02, 2003 2:59 pm
Zip Code: 55319
Circle of Safety: Y
Location: MN

Postby Jim Becker » Sun Dec 17, 2006 12:10 pm

g19605 wrote:Our Association will be using it mainly for pulling "people wagons" during our several Festivals each year and probably some mowing so we aren't going for any pulling records and may not need the extra HP.

If your people wagon holds more than about 4 or 5 people, I would reconsider this idea.

User avatar
beaconlight
10+ Years
10+ Years
Posts: 7703
Joined: Thu Aug 19, 2004 2:31 pm
Zip Code: 10314
Location: NY Staten Island & Franklin

Postby beaconlight » Sun Dec 17, 2006 12:47 pm

I zagree with Jim. The pulling power is not the problem. The stopping power is. Especially down hill, or if you stop going up hill, sliding backwards.

Bill
Bill

"Life's tough.It's even tougher if you're stupid."
- John Wayne

" We hang petty thieves and appoint the great ones to public office."
- Aesop

Matt Kirsch
10+ Years
10+ Years
Posts: 4947
Joined: Tue Jun 08, 2004 3:04 pm
Zip Code: 14559
Circle of Safety: Y
Location: Rochester, NY

Postby Matt Kirsch » Sun Dec 17, 2006 2:19 pm

The aluminum pistons are definitely NOT original. There is absolutely, positively, without a doubt NO QUESTION that they are NOT original.

Cast flat top pistons and rods were standard in 1951.

Are we clear on that fact? :D :D :D

User avatar
George Willer
Cub Pro
Cub Pro
Posts: 7013
Joined: Sun Feb 02, 2003 9:36 pm
Zip Code: 43420
Circle of Safety: Y
Location: OHIO, Fremont
Contact:

Postby George Willer » Sun Dec 17, 2006 2:28 pm

Matt Kirsch wrote:The aluminum pistons are definitely NOT original. There is absolutely, positively, without a doubt NO QUESTION that they are NOT original.

Cast flat top pistons and rods were standard in 1951.

Are we clear on that fact? :D :D :D


That's true Matt. Another factor that hasn't been mentioned is the minor decrease in the volume of the combustion chamber from using the aluminum pistons. I'd guess that many of our tractors have enough deposits to raise the compression even more. I'm very sure Squatty's deposits raised the compression a lot, since the clearance was reduced beyond zero! :shock:
George Willer
http://gwill.net

The most affectionate creature in the world is a wet dog. Ambrose Bierce


Return to “Farmall Cub”

Who is online

Users browsing this forum: Scrivet and 25 guests