Yesterday's Tractor Co. The Right Parts, Right Away
Click Here or call 800-853-2651 
   Allis Chalmers Case Farmall IH Ford 8N,9N,2N Ford
   Ferguson John Deere Massey Ferguson Minn. Moline Oliver
Tractor Manuals
Tractor Parts
Classified Ads
Photo Ads

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
Enter your email address to receive our newsletter!

Harry Ferguson Tractors Discussion Forum
Show Parts for Model:

Intake manifold differences.

Author  [Modern View]
Jason S.

11-09-2013 17:07:47

Report to Moderator

I"ve got two extra intake manifolds laying around. One original and one aftermarket. I had them laying next to each other and noticed there is quite a bit of difference between the two. The opening where the carb bolts on is quite a bit bigger on the aftermarket manifold than the original one. The ports are also bigger on the aftermarket one than the original. From my observations the aftermarket manifolds will reduce the low end torque on a TO-20. They key to building low end torque is small ports which keeps up velocity in the air/fuel charge. The aftermarket one will hurt the low end performance on the smaller cubic inch Z120 engine. The aftermarket manifold would be ok on a Z129 or Z134 engine because of their increased displacement and better breathing because of their larger intake valve. I am going to measure tomorrow and give you all some numbers. Also by the design the aftermarket manifold will cause the exhaust to be louder than the originals.

[Reply]   [No Email]

11-10-2013 18:43:51

Report to Moderator
 Re: Intake manifold differences. in reply to Jason S., 11-09-2013 17:07:47  
If an intake manifold has larger ports, yet the ports in the head remain the same, I fail to see how the size of the ports on the manifold would have much effect.

[Reply]  [No Email]
Jason S.

11-11-2013 08:54:12

Report to Moderator
 Re: Intake manifold differences. in reply to ShadetreeRet, 11-10-2013 18:43:51  
If the port in the head is smaller than the port in the intake then there will be an overhang all the way around the port and the effect would be like turning a fan against a wall. The air and fuel would hit the overhang in the opening and it would go back into the intake. Part of the air fuel mix would flow through fine but around the edges it would constantly blow back into the intake which is bad. Ideally you want both port sizes to be the same or have the port in the head bigger than the one coming out of the intake so there is no disruption in flow.

[Reply]  [No Email]
Jason S.

11-10-2013 18:17:34

Report to Moderator
 Re: Intake manifold differences. in reply to Charles in Aus., 11-09-2013 17:07:47  
Quoting Removed, click Modern View to see

[Reply]  [No Email]

11-09-2013 22:02:38

Report to Moderator
 Re: Intake manifold differences. in reply to Jason S., 11-09-2013 17:07:47  
Smaller ports mean higher velocities that limit max power and torque. Remember the power curves you see are WOT operation so that"s the max airflow for any given rpm.
The reason the torque curve drops off with increasing rpm (or converely increases with decreasing rpm)is due to increased induction system losses(pressure losses due to both manifold friction and losses across the valves). The peak torque occurs at low rpms because the losses are a function of the dynamic pressure ~V^2 and V increases with increasing airflow which increases with rpm. I believe there is an issue of requiring certain velocity levels to prevent fuel droplets from dropping out of suspension in the air stream and screwing up the mixture distribution so there is likely some lower limit on runner velocity for carburetion effects. These are more likely second order effects.
Runner lengths influence the torque curve also due to wave effects but that"s not germain to tractor applications except possibly for the guys running pullers.

[Reply]  [No Email]
Jason S.

11-10-2013 05:29:36

Report to Moderator
 Re: Intake manifold differences. in reply to Jerry/MT, 11-09-2013 22:02:38  
I can't agree with all of that. Runner lengths are important to any engine regardless of the application. You also have to remember that the Z120 had a longer duration camshaft than the Z129 or Z134 which would make the Z120 even more sensitive to plenum and runner size.

[Reply]  [No Email]

11-10-2013 10:58:42

Report to Moderator
 Re: Intake manifold differences. in reply to Jason S., 11-10-2013 05:29:36  
Runner L/D is important for performance improvements that will occur in a vey narrow range of rpms. These engines are designed for operation over a wide range of rpms.

Further, as I recall, the lower the rpm the greater the required L/D to get an induction improvement. It might be practical for a racing application at 6000+ rpm but for a tractor operating between 1200 and 2200 rpm it would be difficult to fit in the allowable space envelope.

[Reply]  [No Email]
Jason S.

11-10-2013 18:07:41

Report to Moderator
 Re: Intake manifold differences. in reply to Jerry/MT, 11-10-2013 10:58:42  
I copied this out of engine building 101

Intake Port Area
Unlike intake runner length which effects power over a narrow rpm range, the size (area) of the runner will affect power over the entire rpm range. If the port is too small it will restrict top-end flow and flow, and if it's too large velocity will be reduced and it will hurt low-end power. The larger the port is, the less strength the pressure waves will have.

There you go, it is the runner length that effects power over a narrow rpm range but the port area effects power over the entire rpm range which is what I'm saying. It would be like putting a large plenum large runner intake on a dump truck motor. Low end torque would suffer because the engine was not designed to move the amount of air and run the rpms that it takes to keep velocity up in that style of intake. There is an old rule of thumb that you never want to have the port size bigger than the intake valve diameter. The original intakes plenum and runner was 1.00" as I measured today. The aftermarket was 1.25" which is closer in size to the 1.14" intake valve size of the Z129 and Z134 engines. Also adding plenum volume raises the rpm that peak torque would would occur at. Look at the picture not only is the aftermarket a 1/4" bigger in diameter look how much longer it is which is adding plenum volume to the intake that only high rpms or added cubic inches could benefit from.

[Reply]  [No Email]
[Options]  [Printer Friendly]  [Return to Forum]   [Add a Reply]

Hop to:
Same-Day Shipping! Most of our stocked parts ship the same day you order (M-F).  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. [ More Info ]

Home  |  Forums

Copyright © 1997-2014 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