Anatomy of a Puller

So how do you build a Puller?

Epic Fail!

This is the reason you now need to build or fit a sub-chassis! In case you're interested, here are a few more reasons why safety has to come first! Look at the first video. This is what happens when the flywheel fails... This video is a lot closer to home, being Graeme Simpson's 'Big Smoke' at Knockhill before being fitted with Tie Bars...

These two images show Stuart Mack's Puller clearly showing how the entire tractor sits on a sub-frame or sub chassis so in the event of a catastrophic component or casting failure the whole thing stays in one piece...

Giles Moston's 'G-Force' showing a alternative design for the sub-chassis. Note the big steel plate over the clutch/flywheel assembly to protect spectators and track staff if something happens to let go in a big way.

Well, if you are looking to build an 'Independent' Puller i.e. not running under BTPA or PPA rules, based on a 'traditional' agricultural tractor, you have a number of options. The most common version we call Type A.

Type A Puller

Fordson Diesel Major You start with a Fordson Major from any source you can think of (tucked away in the corner of a farm yard, rusting in a hedge or bramble-patch, from a agricultural machinery dealer, etc.).

You get the tractor home and start doing some major (sorry no pun intended) stripping down of the gearbox and back axle. Fortunately the Fordson Major and it's offspring the Super Major and Power Major have incredibly 'over engineered' gearboxes and back axles i.e. they can take far more power input than they were ever intended to take! When you've got the 'back-end' suitably renovated, the next step is to find a new engine.

Major Disaster Your next port of call is a commercial vehicle scrap yard or reclaimers to find yourself a Ford 'D' series or Ford Cargo truck engine. Thanks to Ford's desire to standardize, all the 'D' and 'Cargo' engines share the same bell-housing and spline-shaft as the Fordson Major family of tractors. Your best bet (if you can find one) is a Ford 360T Cargo engine (6.2-litre straight-6 turbo charged unit). The Chassis side-rails will need to be extended to accommodate the longer engine and provide support for the entire engine and back-end (you do know someone who is good with a welding torch don't you?).

The original Sims injector pump should be replaced with a Bosch unit (if you can find one that fits and you can afford it). You then need to find someone who knows all about injection systems and can (fully) open up the injector pump. If you can find a nice big Garrett or Holset turbocharger, so much the better. Replace the original exhaust with a nice chromed straight pipe, fixed to the manifold with two long bolts set at 90-degrees to each other (to stop the turbo impeller from shooting out of the pipe when the turbo blows, because I can assure you, it will!).

Water injection helps increase air density and prevent the pistons from melting but this is a rather specialized field. You need someone who really knows what they are doing! The guys at Aquamist seem to know what they're doing so if you're thinking of going down this route, have a look at their web site.

Apart from a coat of paint, a roll-cage or roll-bar are essential, as is a pair of wheelie bars (or 'chicken-bars') to stop the Puller from trying to flip on it's back if the torquing gets to much (the nasty habit Pullers have or rearing up the front wheels into the air if they can't move forward but the rear wheels are still gripping). Assuming the Puller is a diesel you will need to fit a kill-flap fitted with a cable that terminates at the back of the tractor. This allows the Sledge Operator to stop you engine if something goes wrong on the track. Last but by no means least is at least a quarter of a tonne of ballast weight in front of the rear wheels and right at the front of the Puller. This helps keep the front wheels on the ground, after all you do want to be able to steer, don't you (unless your name is Martin Eady of course).

♣ Note: Probably the most useful source of advice and information I can suggest is the UKTP Board, particularly the 'Workshop' and 'Ask the Experts' forums. These Pullers are the people who know and are only too happy to pass on their advice an knowledge. You have to register (using your real Christian and Surname) before you can post a question...

The Type B Puller will be documented when someone can let me have some pictures of a build, anyone? I live in hope that Steve Knight will let me have some pictures and info on the 'Old Holland'...