Welcome! Please use the navigational links to explore our website.
PartsASAP LogoCompany Logo (800) 853-2651

Shop Now

   Allis Chalmers Case Farmall IH Ford 8N,9N,2N Ford
   Ferguson John Deere Massey Ferguson Minn. Moline Oliver

Attention Forum Users: On the 28th of December 2023 at 9:00am Central Time, we will be taking the forums down for maintenance while we prepare the new forums for your use. Please click here for more information.

Discussion Forum
:

Model Z

Welcome Guest, Log in or Register
Author 
Confused??

01-27-2002 20:41:50




Report to Moderator

Has anyone heard of a model Z with adjustable compression ratio?
If so, how does it work?

Thanks




[Log in to Reply]   [No Email]
Pat

01-29-2002 17:56:53




Report to Moderator
 Re: Model Z in reply to Confused??, 01-27-2002 20:41:50  
I think the ideal of varible compression came from having to take head off and change thickness of the gasket, I think they may have even made a metal shim like gasket to sandwhich between gaskets. I can say that I have never tore an R or Z engine down with multiple gaskets though.



[Log in to Reply]  [No Email]
Kelvin

01-28-2002 12:34:15




Report to Moderator
 Re: Model Z in reply to Confused??, 01-27-2002 20:41:50  
I saw a picture of a power unit (Z engine on skids) on Jeremy Fiorelli's website. He said that it was supposed to have adjustable compression. I have one that looks just like it, not running, but I heard it run in '97. What I have learned is that mine doesn't have adjustable compression, it has some form of hydraulic valve lifters under the cast-iron valve covers. I haven't taken mine apart yet to see what it indeed looks like inside.

[Log in to Reply]  [No Email]
BMG

01-28-2002 13:59:44




Report to Moderator
 Re: Re: Model Z in reply to Kelvin, 01-28-2002 12:34:15  
Kelvin,
I'm glad to see someone has another one of the 206-4A military powerunits with the hydraulic valves. Mines a 1945 206-4A serial # 210558. I saw the pictures of Jeremy's and I've got mine torn down so if you want to know anymore about them let me know. I can tell you that they are definitely NOT adjustable compression ratio. I've been told they were the same engines used in the military MM Jeeps but can't confirm that. The system is simple. A plunger rides on the camshaft instead of the long rocker arm. This plunger forces engine oil up into the cast rocker covers. This oil in turn pushes on a small plunger that pushes on the tip of the valve. The system takes a linear upward motion from the camshaft and turns it into a horizontal motion at the valve tip. I've heard they are hard to get started after sitting because the oil leaks out of the cast covers and you've got to turn them over a while to pump oil up there then you have to bleed the system of air in order for the plungers to push on the valves. I think the thought of variable compression may come from the large hex plugs on the cast rocker covers. These plugs allow access to the small plungers and the hydraulic oil cavity. I think you loosen these caps to bleed the system but I'm not sure since I still have mine torn apart. Someone told me the insides of these engines were in military dimension (standard military spec bearings) but so far the standard 206 bearings are all I've needed. Let me know if you've got any questions.

Brian

[Log in to Reply]  [No Email]
Jeremy

01-29-2002 19:05:13




Report to Moderator
 Re: Re: Re: Model Z in reply to BMG, 01-28-2002 13:59:44  
Very interesting!!

I guess I need to change that!! I was told it was an adjustable compression engine. I've had a couple people tell me that it may have hydrolic valves but they didn't know for sure. I don't own the engine or I'd know for sure. I have also heard that the Jeeps used this engine but I can't say that I know for sure. If you see anything else that you question on one of my pages please let me know. I wont be affended. Sometimes I don't know any better or have been told wrong and some times I just hit the wrong key.

I'll leave a link to the page with that picture.

Jeremy Fiorelli

[Log in to Reply]  [No Email]
H Legrand Christensen

10-26-2002 11:01:34




Report to Moderator
 Re: Re: Re: Re: Model Z in reply to Jeremy, 01-29-2002 19:05:13  
Many years ago my dad got a military unit it was
used to pull big aircraft around it had the re Engine the engine looked just like what is in a 50 Z we put this engie in a 1946 R MM,It was called a military Peep not Jeep.



[Log in to Reply]  [No Email]
BMG

01-30-2002 14:06:55




Report to Moderator
 Re: Re: Re: Re: Model Z in reply to Jeremy, 01-29-2002 19:05:13  
Jeremy,
I wasn't trying to criticize your webpage. I'm glad you've got it for the rest of us to enjoy. I particularly like the pulling forum. Keep it up!

Brian



[Log in to Reply]  [No Email]
Jeremy

01-30-2002 19:20:08




Report to Moderator
 Re: Re: Re: Re: Re: Model Z in reply to BMG, 01-30-2002 14:06:55  
I didn't think you were. Just want to let you people know that I do make mistakes and I don't know everything so if you see anything that is wrong I'd sure appricate knowing. If I wouldn't have seen this I wouldn't have know for sure that it wasn't an adjustable compression engine. I'm glad to here you like my site there is a lot of work that goes into it and it is nice to hear good things.


Thanks
Jeremy

[Log in to Reply]  [No Email]
Confused?

01-28-2002 17:09:43




Report to Moderator
 Re: Re: Re: Model Z in reply to BMG, 01-28-2002 13:59:44  
Correct me if I am wrong, but there wasn't anything that could affect the size of the combustion chamber.



[Log in to Reply]  [No Email]
Kelvin

01-29-2002 15:55:02




Report to Moderator
 Re: Re: Re: Re: Model Z in reply to Confused?, 01-28-2002 17:09:43  
On all Z's that I know of, the only way to change the combustion chamber size is to change the cylinder head-the cast iron piece on the side with the spark plugs in it. I'm thinking, counting Lp, gas, kerosene and tractor fuel, there were four different heads used during production run of the Z engine.



[Log in to Reply]  [No Email]
JK

01-29-2002 19:00:31




Report to Moderator
 Re: Re: Re: Re: Re: Model Z in reply to Kelvin, 01-29-2002 15:55:02  
I understand that M-M made inserts of different shape and thickness that could be bolted to inside of the flat heads (ones with no hump at all) for the R & Z and thus allow you to vary the compression ratio for burning different fuels. I've never seen a setup like this but heard about it from a couple different sources. I assume it was on very early models.
John



[Log in to Reply]  [No Email]
BMG

01-29-2002 15:03:25




Report to Moderator
 Re: Re: Re: Re: Model Z in reply to Confused?, 01-28-2002 17:09:43  
No. The engine I described above is just like any other 206 engine in the combustion chamber area - fixed combustion chamber volume. I've never heard of or seen a MM engine with adjustable combustion chamber volume. The only type of engine I know of like that would be a Farmall M Diesel. It had a third valve in each combustion chamber that when open allowed the tractor to start on gasoline and warm up. A lever was then thrown by the operator and the valve closed at the same time as the diesel pump was engaged. This in effect created a smaller combustion chamber for running on diesel.

Brian

[Log in to Reply]  [No Email]
Enlightened

01-29-2002 18:00:26




Report to Moderator
 Re: Re: Re: Re: Re: Model Z in reply to BMG, 01-29-2002 15:03:25  
Thanks for the clarification.



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

Hop to:


TRACTOR PARTS TRACTOR MANUALS
We sell tractor parts!  We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]

Home  |  Forums


Copyright © 1997-2023 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

Website Accessibility Policy