Dennis Z Type

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135 Z1
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Dennis Z Type

Hello Everyone,

I am new here and have just acquired this...

Dennis Z Type

Dennis Z TypeDennis Z Type Plate

As you can see from the state of the grass I have had it running it cuts (sort of). I think it is great and am looking forward to getting it performing more like it would have done when newer. There are a number of things I will need help with to make it better and these questions I will post in the technical bit of the forum. My first question to you all is. When was it made? As the plate says Z1 so I am guessing it is quite early in the production.

Thank you in advance

Daniel

Will
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I can't help you sorry but

I can't help you sorry but that's a fab mower :) Enjoy...

hdtrust
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Hi your machine does fall at

Hi your machine does fall at the start of the Z series.

Looking at Dennis's dating data (part of The Hall & Duck Trust)

Your machine No 133 Z1 size 24 inch was made in the first year of production 1946.The engine a Dennis E78 was only used in that year there after being up rated to the Dennis E 140

Kind regards

Andrew

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DJD
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Lovely old machine, I like it

Lovely old machine, I like it!

135 Z1
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Thank you.

Thank you.

I certainly will enjoy. I just wish my grass would grow quicker so I can have another go at cutting it.

135 Z1
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Andrew

Andrew

Thank you for taking the trouble to reply.

As the Z type was in production 1946-1960?, so about 15 years, and I have seen a Z53 designation which is basically the same but obviously different to my Z1. I would presume that as they were produced and the design evolved each revision would be given a new Z number sometimes more than once a year. 

On the subject of the engine. Do you (or does anyone else) know how to differentiate between the E78 and later versions?

Thank you again

Daniel

 

 

wristpin
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Your machine No 133 Z1 size

Your machine No 133 Z1 size 24 inch was made in the first year of production 1946.The engine a Dennis E78 was only used in that year there after being up rated to the Dennis E 140

Would the "uprate" refer to the fact that the early engines only had one built in cranking position, the hot start position being provided by an exposed shaft running through a hole in the oil tank and connecting to the reduction gear/clutch assembly.

The later machines incorporated it in the timing gear case as per the OP's images. 

135 Z1
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Last seen: 2 months 1 week ago
Joined: 03/04/2021 - 16:23
Hello Everyone,

Hello Everyone,

Further researching early Dennis Machines I found this post on the OLC Site and although not relevant to the Z type it does provide some dating clues for those who have Dennis Machines from just before WWII

https://www.oldlawnmowerclub.co.uk/forum/general-topics/general-discussi...

It is a parts list Dated September 1938 and covers Machines numbered From 10758 (to whatever was current at date of publication) on searching through this list I found on Page 6 under Crankcase and Oil Box, The part code 20853 which is described as "Cover for Timing Gear (For Twin Starting Shaft)"  Applies to mower No. after 12853.

Further on Page 12 under Frame and Handles with Control Levers I found part code 25441 "Handle Bar" Applies to mower No. after 11287 and part code 25455 "Halves for Handle Grips (Wood)" Applies to mower No. up to 11286

As extra machine identification there is also the flywheel on Page 8 which is described as having an inner and outer half from Mower No. 12090.

So if a Dennis mower has 2 separate wooden handles it has a number < =11286

If it has a pram type handle bar and a single flywheel it has number > 11286 but < 12090

if it has a double flywheel and 1 starting hole in the crank case cover then it is number > 12090 but <= 12853

if it has 2 starting holes in the crank case it is number > 12853

All this, of course, assumes that the machine has not been updated or had parts changed over the last 80 years or so.

I have a lead on a parts book covering the early Z types (Z1-Z9) and hopefully this will yield further clues to identify mystery Denniss and maybe answer wristpin's question that seems to have been floating around for a while. "When was the oil bath rear roller introduced?" At the moment all I can say is that it is after 1946 as my Z1 has a non oil bath rear roller.

Daniel