Dennis premier mk1
Dear colleagues,
I have a Dennis Premier MK1 that I am trying to get back into useful service. It is a 36” but I don’t know how old. Looking at some of the entries on this forum, I think it might have one of Dennis’s own build engines, has “Dennis” in the output casting.
The issue I am hoping you can help with is this: the cylinder head is held on by 6 studs, three have short and three would have deep nuts on them. Unfortunately the deep nut and stud that the Petrol tank mounts on has been sheared off just below the cylinder head. A “bodge” bracket to mount the tank to has been made to fit on the other two deep nuts that hold the cowl in place. It works just looks nasty.
If I can drill out or otherwise extract the remains of the stud, can I get a replacement? Anyone know the thread size of these studs and the stud length?
Can I safely run the mower without that part of the cylinder head being bolted down ?
Thanks in anticipation
Martin
Forums
Many thanks for the replies…
Many thanks for the replies and guidance.
I cannot get the stud out so it will have to stay as is for the time being. It looks like it has been sheared for quite a time, visible stud is rusty. I have revised the tank bracket to fit under the cowl, looks much better.
Having given the carb a good fettle and changed the oils and fuel, she is breathing once again and sounds fantastic, even though there is a little rattling from the prop shaft and various drive chains. The sheared stud does not seem to be a problem.
As for the grass box, i have had to reinforce the split and missing parts of the lip, re painted it looks great and is very sturdy.
She is ready for her first proper run, which she will get in a few days.
Will put some more
pictures up soon.
Thanks for your support
Martin
Guys, Many thanks for the…
Guys,
Many thanks for the replies and guidance.
I cannot get the stud out so it will have to stay as is for now. It looks as if it has been broken for some time as the visible part was rusty prior to my drilling it.
I have revised the tank bracket to fit under the cowl, it looks so much better.
I have reinforced and rebuilt the lip to the grass box that was badly damaged and that is serviceable again.
I have cleaned and given the carb a good fettle, changed the oils and given her some fresh fuel, and after some tweaking she runs again and sounds fantastic. There are some rattles from the prop shaft and various drive chains, but otherwise all seems good. The lack of the sixth cylinder head bolt doesn’t seem to be a problem.
So just needs a test run now, which I will do in a day or so
Here is the only pic I have at present. Will take some more and post soon
Thanks again for your support
sorry about that the duplication, didn’t think the first version uploaded and I can’t see a way to delete an entry 😂
Martin
Thanks for the help so far…
Thanks for the help so far.
Beginning to think I should try harder to get my broken stud replaced, but fear that to do so I may need to strip down the engine, which would likely involve a head off and perhaps more sheared studs.
Before I contemplate that I would appreciate your help on identifying what engine it is I have so I can be looking for replacement studs and head gasket etc. it looks like the parts image as supplied by Shed 14.
I attach an image of the mower plate and a couple of general ones.
Can I also ask about the magneto? Does this look as if it is on the correct flange to you? The lugs on the impulse starter are only partially engaged on the drive and there is a lot of play and a gap behind that drive allowing that cupped washer to float leaving the bearing exposed, just doesn’t seem right.
Any thoughts would be appreciated, thanks again for your support
Martin
The Magneto drive is correct…
The Magneto drive is correct, if you note the diagram sent from my father's forum account, No's 26 & 37 show the magneto drive assembly components.
You would think the drive pins would locate in further, but they are built as is that.
The magneto adaptor base plate looks right.
Only think that could cause slight lack of engagement If the face of the "top hat" bronze bush the drive runs in has wear on its face. You would feel longitudinal movement if you removed the magneto, Plus I recall the hole in the centre of the drive engaging pieces is offset, but would not fit on the wrong way unless the afore mentioned drive gear bush was worn.
The Lucas SR1 along with the Wico A are usual magneto fitments for the Dennis Premier MK1
I note a date of January 1966 for the Magneto, and a serial of the mower of P for Premier and C for 36" cut No. 1029 of the size made.
I am not sure on year, but the machine assembled and sold c.1970.
Dennis kept putting "made in Guildford " / or rather using old stock VIN plates for many years after assembly moved to Stanhay in Ashford.
Looking again at the photo…
Looking again at the photo close up of the drive engagement dog, it looks like bush and gear end worn and somebodies put a washer in, I just attached the parts diagram.
I cannot recall a washer, only the gear, then a felt washer oil seal.
As I say if lots of longitudinal play, removing the timing cover would be recommended.
indeed our policy is to completely dismantle any unknown engine prior to starting.
Mowing Wurzel, Thank you…
Mowing Wurzel,
Thank you very much for your detailed reply. Thanks for the diagram and confirmation that magneto flange is correct. I will investigate the bronze bush situation as there is quite a bit of play in the shaft of those drive dogs. The pictures show the extent of that play in the two different distances the pins locate. If that washer is not meant to be there I will see about removing it, but to do so I guess I am likely to need a new bronze bush and felt washer. Do you know if those are available anywhere?
Thanks again
Martin
Mowing Wurzel, Sorry, I…
Mowing Wurzel,
Sorry, I meant to ask, can you tell me where that magneto diagram is from, I’ve not seen that before. Do you have a version with the part numbers/descriptions on please
Thanks would be very helpful
Thanks again
I thought I had attached…
I thought I had attached extracts from the Premier MK1 Manual, but didn't, so here it is.........
The book is a bit vague, I'm sure there is lots of info. online on the Lucas SR1 magneto, as they were fitted to many British and colonial Engines.
Having said about looking online for information, on this and any other subject; there is an awful lot of falsehoods and misinformation peddled by bodgers and blagers!
Once I get time I will photocopy the whole book for the clubs database.
Regarding the worn out…
Regarding the worn out magneto drive assembly;
I would buy an Oilite Sintered Bronze flanged bush near enough the size off an engineering supplier or popular online site (as I do)
Check the drive shaft with gear on isn't worn, it is likely to be worn, so it would need light skimming.
Naturally if you haven't a lathe you need a good ( and fair payment ) local machinist to do the work.
If no flanged bush close size wise, often its the route of buying a sintered bronze or SAE 660 grade Bronze bar and get machined down.
Mowing Wurzel, Thanks again…
Mowing Wurzel,
Thanks again for all your help.
I have now obtained a PDF of the manual and parts lists. Would you like them sent to you rather than having to scan them.
cheers
Thank you, Send it the…
Thank you,
Send it the manual to The Club / Forum moderator, then it can be put on the database for all to use.
Good Day Martin, Most of the…
Good Day Martin,
Most of the threads on the Premier MK1 are either UNF or UNC.
UNF being a finer thread
with higher TPI than the UNC
I would have thought there would be a classic automotive make, like BMC where studs were the same thread's. Anyway, I attach an extract from the Premier Mk1 Parts Book.
Please send a photo of the Silver VIN plate on the frame side.
The first DENNIS Premier MK1's were Sold in August 1961, after several years of testing and improvements, with an old Z series serial sequence.
Dennis in around August 1963 moved the production from Guildford to Stanhay of Ashford in Kent, (a company still going) With PA,PB or PC prefix serial numbering
Then by in the early 1970's the Hestair Group, who bought Dennis Bros. out, sold off the Mower concern to a separate business' called GODSTONE HOLDINGS, this was managed by John Dennis, so still a true Dennis Mower Company, and still maintaining quality machines, based again in Surrey.
A lot of completely untrue stuff has been unfairly written on this chapter in Dennis's story. Dennis "GODSTONE" being the last to use the "E" type 597cc engine, which they were still using in 1975.......... a few years later, overseas built engines, cheaper in price and quality being offered, (n my opinion.)
So on the cylinder head; these engines are low compression, and the cylinder head is of cast iron and weights more than you think when going to pick it up........ but please ensure all studs are tightened up before running.
We look forward to seeing some photos......