Ford GP (series 1) slow build

[Mike K]

Are you sourcing engine parts from Ford 9N ? tractor people. Is the engine much different to the tractor engine ? I guess you are a regular watcher of the G503 GP club .

[Mike Cecil]

Thanks Lionel .... it has been a long time since I first got the vehicle, hasn't it? Still, making progress at a pace I enjoy, so no problem.

Mike, yes, the GP has what is in effect a 9N tractor engine but with some important differences. The 9N is a sleeved engine, whereas the GP is not. But the bore is 3-1/16 which you'll remember is the same as the 85bhp V8 sidevalve, so 9T pistons and rings, available up to 60thou o/s, fit nicely. The block is capable of being bored out to 60 thou o/s, and those 4 ring pistons and ring sets are available. When I pulled the engine down, that's what I found: 9T, 4 ring pistons had been fitted (and I have been recently told, were listed as a change to the GP parts list in 1943, via a respondent on the G503 forum). Other than that, main & big ends, cam shaft bearings, valves, gaskets etc are all 9N and readily available. It has those horrible Ford split valve guides and little horse-shoe keepers, and was originally equipped with non-adjustable tappets, but adjustable tappets are available.

The peripherals are also different: the tractor engine has a front mounted distributor/coil combination with no vacuum advance, whereas the GP has a right angle drive and conventional distributor (the coil is mounted on the firewall). The exhaust/inlet manifold is a downdraught, whereas the tractor is updraught, and the carbie is a Holley. So like the GP in general, some parts are easy to get, and some parts are very difficult and others are outrageously expensive: an original Holley carbie has sold for over $8,000 US!!

Mike

[Mike K]

So you will be looking for eight Johnson adjustable valve lifters ?

So a tractor engine block will not change over... annoying for GP restorers !

[Mike Cecil]

I think the block will change over, but it will be sleeved and won't have that magic 'GP' cast into the block.

It's the peripherals that make the difference: you can't just take a 9N from a tractor, you have to transfer all the peripherals to make it into a GP engine.

The valve guides are available as part of an overhaul kit from David Tractor at a pretty reasonable price: http://store.ford8n.net/product.php?xProd=6315

Mike

[Lynn Eades]

Mike, the Ford V8 went over to one piece guides. If you are doing all new valves
(stainless?) then that would be the way to go. Do they have hard seats?(inserts) Then you don't have issues with fuel lacking the lead.
I assume the v8 bits interchange?

[Mike Cecil]

All part of the investigation, Lynn. The post above has a link to Davis Tractor who are just one of many who supply an overhaul kit which includes one-piece guides, but you'll see that certain other parts such as seats are purchased separately.

Started wrestling with those *7%$#@ horse shoe clips yesterday, after the valve spring compressor arrived from Northern Tool.

Mike

[Mike K]

Originally Posted by Mike Cecil

Started wrestling with those *7%$#@ horse shoe clips yesterday, after the valve spring compressor arrived from Northern Tool.

Mike

There was also a special too available , this was for loosening really stuck valve guides . Ryans in Melbourne used to sell the tool. It was a length of 5/16" rod bored out one end, the bored end had a slot machined into it , the rod was bent into a odd shape, you slid the tool around the valve head , the bored end would fit around the valve stem, and a hammer blow on the tool would force the guide loose . I did have one, I loaned it to A. Browne .