Yesterday's Tractor Co.
Shop Now View Cart
   Allis Chalmers Case Farmall IH Ford 8N,9N,2N Ford
   Ferguson John Deere Massey Ferguson Minn. Moline Oliver
Classified Ads
Photo Ads
Tractor Parts

Discussion Forums
Project Journals
Tractor Town
Your Stories
Show & Pull Guide
Events Calendar
Hauling Schedule

Tractor Photos
Implement Photos
Vintage Photos
Help Identify
Parts & Pieces
Stuck & Troubled
Vintage Ads
Community Album
Photo Ad Archives

Research & Info
Tractor Registry
Tip of the Day
Safety Cartoons
Tractor Values
Serial Numbers
Tune-Up Guide
Paint Codes
List Prices
Production Nbrs
Tune-Up Specs
Torque Values
3-Point Specs

Tractor Games
Just For Kids
Virtual Show
Museum Guide
Memorial Page
Feedback Form

Yesterday's Tractors Facebook Page

Related Sites
Tractor Shed
Ford 8N/9N Club
Today's Tractors
Garden Tractors
Classic Trucks
Kountry Life
Tractor Pulling Discussion Forum

pto dyno question

Welcome Guest, Log in or Register
Author  [Modern View]

07-19-2013 12:09:11

Report to Moderator

Changing the primary reduction gears on a Deere changes the engine to tranny ratio so I was wondering, will it have an affect on horsepower numbers when its hooked to the dyno?

[Log in to Reply]   [No Email]
north puller

07-20-2013 09:22:15

Report to Moderator
 Re: pto dyno question in reply to clampdaddy, 07-19-2013 12:09:11  
Some people don't get this, so i will try and explain in simple terms.

I will use a farmall example, just because i know them.

With a little bit of work, a farmall m engine could go into a 560 or viva versa.

A super m makes 47 hp at a rated engine speed of 1450 rpm. If you wind it up, it will make 53-55 hp at 1800 engine rpm.

now a 560 tractor is set up so that the engine turns 1800 rpm to get 540 pto. If you put the super m engine into the 560 tractor and put it on the dyno, the engine would turn faster (1800) to get a 540 pto speed, and you would read 53 hp on the dyno.

Put that engine back into the super m tractor and put it on the dyno, and it would turn 1450 to give you 540 pto and read 47 hp on the dyno.

You are basically doing the same thing. You are changing the engine rpm in relation to the pto rpm.since in the tractor world hp is measured based on pto rpm, changing the engine input speed will give you a different hp reading.

If you were to use a pony brake belt pulley dyno, you would see no difference on your John Deere because the pulley speed doesn't change with the gearing change.

[Log in to Reply]  [No Email]

07-19-2013 17:15:13

Report to Moderator
 Re: pto dyno question in reply to clampdaddy, 07-19-2013 12:09:11  
Most dyno's you have to input the rpms so yes the reading would change.

[Log in to Reply]  [No Email]
Roger in Iowa

07-19-2013 13:29:17

Report to Moderator
 Re: pto dyno question in reply to clampdaddy, 07-19-2013 12:09:11  
Engine will still make the same HP, just the dyno reads differently.

What brand of dyno?

[Log in to Reply]  [No Email]

07-19-2013 13:52:51

Report to Moderator
 Re: pto dyno question in reply to Roger in Iowa, 07-19-2013 13:29:17  
Quoting Removed, click Modern View to see

No dyno in particular, just curious if it would show a horsepower change even though the engine is still the same.

[Log in to Reply]  [No Email]

07-19-2013 16:31:50

Report to Moderator
 Re: pto dyno question in reply to clampdaddy, 07-19-2013 13:52:51  
If it did tractors would have a 1HP engine and lots of gears to pull a 40ft chisel plough.

[Log in to Reply]  [No Email]
north puller

07-19-2013 12:59:58

Report to Moderator
 Re: pto dyno question in reply to clampdaddy, 07-19-2013 12:09:11  
If it is a transmission driven pto, then yes. If you slow down the transmission by 10% (and therefore the pto by 10%) for example, then you will have to turn the motor 10% faster to get your "rated" 540 pto speed. You will end up reading whatever horse power the engine makes at this new rpm.

[Log in to Reply]  [No Email]
[Options]  [Printer Friendly]  [Posting Help]  [Return to Forum]   [Log in to Reply]

Hop to:

Fast Shipping!  Most of our stocked parts ship within 24 hours (M-Th). Expedited shipping available, just call! Most prices for parts and manuals are below our competitors. Compare our super low shipping rates! We have the parts you need to repair your tractor. We are a company you can trust and have generous return policies. Shop Online Today or call our friendly sales staff toll free (800) 853-2651. [ About Us ]

Home  |  Forums

Copyright © 1997-2016 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy

TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters