Hi Grumpy, you are correct, I do have a lathe, milling and welding equipment as I have a small 'sideline' business making and selling parts for lawnmower racing which is how I came across the HD8. I originally bought it with the intention of stripping it for racing but when I got it I saw that it was in such good condition I just couldn't treat it that way! Regarding getting parts to me, I fairly regularly import alloy wheels from Australia, Ross Edwards, so I guess that if I found the parts that I needed in Aus I could get them sent to Ross and he would included them in my next import batch.
It sounds as if you are in exceptionally good shape to get HD8 parts then. If you can find them and negotiate successfully, the whole shipping nightmare will not exist.
Good decision when you decided not to rape and ruin that HD8. It's better to have history remember you as a collector rather than as Atilla the Hun.
I've just received some documents from Greenfield that indicate that my HD8 is post 1973, so narrowing down the date of manufacture. Excellent help from Greenfield. Tomorrow I will be putting the clutch and rear axle back together with new bearings and with new belts in place I will be trying it out on my lawn!
Well I put it back together and tried it out on my lawn. It worked really well although it's speed was a little on the high side for a ride on mower so maybe I'd better get a better throttle control fitted as there is no way to change the gearing to slow it down.
The mowing was cut short as I needed to work on the cutter clutch; I had found some cracks in the cast iron I guess as a result of the welding that had been carried out on it (welding cast iron can be tricky due to the carbon content and the need to keep it cool to prevent cracking) so I didn't want to risk it. Just as well really as when I stripped it down again a big piece of the clutch was about to give way! I've made a replacement drive plate to fit to the pulley so will be fitting that together during the week.
I'll post some more photos of the revised clutch and mounting it to the engine.
I've also had permission from Greenfield to upload the documents they sent me so that other may benefit from them.
Rong, as I understand it the speed of Greenfield mowers is set by a combination of the engine speed and the degree of clutch slip. Engine speed is adjusted by the "speed control", which controls the set point of the governor: there is no user-accessible throttle on Briggs engines, just a speed control. The engine speed should be set as low as possible without risk of the engine bogging down under the load applied, so you would need to adjust it when you change slope, length of grass, etc. The other ground speed adjustment mechanism is slipping the clutch. Instead of having a multi-speed gearbox, Greenfield uses large clutches, which are slipped most of the time. I think some other mowers use the same approach. The concept of slipping the clutch continuously is an unfamiliar one to those of us who drive cars with manual transmissions, but realistically a Greenfield has a car-size clutch on a low-geared, low-powered, light-weight machine, and they seem to go for a number of years between clutch re-lines, even when used every day by mowing contractors.
I'm very interested in getting Greenfield technical information uploaded to our manuals section. Perhaps you could let me know what you have (that Greenfield has authorised you to upload) by Private Message and we can see what process will work best.
Last edited by grumpy; 11/10/1207:57 AM. Reason: Add note on data upload
Grumpy, good advice about the speed control, thanks. As you say, continuously slipping a clutch is a bit alien but a good point you make about the size of clutches and how long they are known to last. I've just got to sort out a proper speed control which. looking at various photos seems to take the form of a small lever similar to old 'bike choke levers.
Rodeobob, you are correct in that you must let the cast cool down very slowly. Careful welding in short runs helps keep the temperature of the surrounding cast down therefore helping teh cooling process. The other problem is the weld material and the fact that 'normal' weld material will be very brittle after welding so will always be a weak point. Using stainless as the filler material helps as does brazing. In my case iot was clear that the previous welding had not allowed a slow cooling process so cracks were evident around the weld and I was not happy about running it like that so I opted for making a new piece and bolted that to the cast iron pulley. I have to say that it works very well and unless you look very closely you wouldn't know that I had made it!
I'm going to scan the documents of the HD8 and will let you know when I've done that. They will be ideal for you as they match your model HD8 and do help me with mine even though they are not for my model!
I'm still trying to find out what engine I should have on mine, narrowed it down to a Fuji (Robin) but what model number. I was thinking EY18 but that has a 3/4" output shaft so maybe it was an EY20 as I think that had a 1" one.
I hear you one the pulley. Not much you can do if it was ruined before you got it. I would not like to be anywhere near something cast irong that explodes while spinning at 3000+ rpm.
Oh I thought greenfield had sent you something in PDF. Im wondering if what you got sent is any clearer than what I have.
I would have scanned mine but I do not have a scanner.
Hey guys, Great read, I will try to resurrect this thread and add my bits, I have just acquired a Model 1 greenfield with also a Briggs Engine i it, I have been able to date my Engine to 1970 but i have been informed that it should have a honda engine. heres a few pics
I've Also put up a post in the greenfield section Maybe someone can tell me where to look for the frame serial number? Cheers
