Thank you for the further responses. Dad has started work, and we will let you all know when it's together what we've done and what the results are like.

Location: New Forest

Timothy,

Ian's and R's advice is sound. I would suggest you consult the oracle on this subject - Jack French's 'In sheeps clothing'. This is in the green book, the Companion, and was originally published in a A7CA magazine (I think, or was it 750MC Bulletin?). It expands more on this topic and includes R's sound advice about gearing.

I suspect every one of us has a slightly different view on what works and what's worth the effort in doing, so you'll get a compendium from the Forum! My latest fad on this is getting the cam timing right, those gears and keyways aren't as consistant as I'd assumed! (Assume = make an ASS of U and ME).

It's fun trying to get the best out of your A7; as our American cousins (irritatingly) say - enjoy!

Dave

I have a 1929 fabric saloon in more or less standard trim.
It performs very well and has only minor modifications.
They are as follows:
1) Vertical section of the inlet manifold reamed to the same diameter as the 22FZ carburetor. Important not to go bigger than that.
2) The carb butterfly and spindle have been thinned down as much as I could manage - not a lot!
3) The inlet to exhaust manifold joint is well aligned. Hven't done manifold to block yet.
4) The cylinder head is 1933 and I believe it has been skimmed about 0.050" but not by me.
5) The clutch pressure plate had three new holes bored to make the withdrawal pillars a good fit and give some hope of it being balanced. Still not great but a big improvement. It's worth looking at these plates as they seem to come in a variety of diameters and balance is better if it's a good fit. Some have a very large clearance.
6) The flywheel has been lightened and engine balanced.
7) When I rebuilt the gearbox I fitted an 'Andes' high second gear. This means I can reach 40mph in 2nd. The dog for top is chamfered on these gears making top selection much easier and quicker. This does leave a gap between 1st & 2nd gears but for me is only a small disadvantage.
8) It has a 1-1/8" Phoenix crank.

Visually the engine appears almost standard. Close inspection shows the later head and bronze instead of Mazak carb.

It covers the ground very well. I have just returned from The Scottish Austin Seven Club's AGM in Blair Atholl. I came down the A68 from Edinburgh to Melrose easily able to maintain 50mph on the level. 40 up most hills and 30 in 2nd up the steeper hills. I can on occasions reach 60mph downhill.

Thank you Jim, sounds like we should be able to get some good performance gains with simple work. I had read some thing you had written previously about the andes ratio second, but can't recall seeing whether you still have a 4.9 back axle. Sounds like a great option for the future.

Location: New Forest

Still 4.9 axle. Fitting a lower ratio is possible but not that easy.
I think a lower axle ratio and a close ratio gearbox would work well. By raising both 1st & 2nd gears the gap between them that the Andes gear has would go. However without the lower axle 1st would probably be too high for steep hills/hill starts.
The lower axle ratio would probably give a higher top speed.
The Andes suits me here because there aren't many hills steep enough to need 1st gear.
When on runs with other cars I find I am slower on steep hills where I can't use 2nd gear, but faster on less steep hills where I can climb at 30 mph in 2nd easily but a standard geared car can't.

I had the Andes ratio 3 speed box on my 1931 RL saloon with standard 4.9 rear axle ratio. I found the gap between 1st and 2nd too great for the power of the engine and the weight of the car, especially two up. The clincher to revert to a standard box was on one of my Pennine Runs when I spent almost a whole day in 1st gear grinding up the steep hills of northern Derbyshire and West Yorkshire. The factory knew what they were doing! Jim's car is lighter than a steel saloon so the Andes box is better suited. If ever I put a 5.25 ratio in the saloon I may well have another go with the Andes box.

Thank you both, definitely food for thought, it sounds like both boxes can work well depending on how steep the hills you regularly climb are, and how heavy the car is. For the moment at least getting the engine back together is priority number one, and I'm sure once it's back together it will be a while before dad wants to have the car off the road again (Though with building the gears into another box a swap could be effected reasonably swiftly).

Location: New Forest

I now have special thinner head gaskets which are the right shape for low compression (and Ricardo) heads, but are the same thickness as the ones for the high compression head. See BC29r here. This should give a slight increase in power (every little helps, as they say).

David

A couple of points - Re Jim's boring the vertical part of the inlet manifold, I thought it was of not much use if the horizontal pipes are still restricted, so more recently I cut away the rear of the top bit and ground out to the same ID as the upright. After doing the same to the cut-away piece, I then welded it all together again - mods unseen. Re Bob's comment in October re the small diameter shaft not standing up to too much compression etc - when I raced an Ulster special for an Adelaide friend, his engine was just that, with an Ulster head. He was a brilliant engineer and I don't know what else he modified, but we never broke the light crank. I think I've boasted here before that in one race I beat all the blown Sevens, so please don't think it was slow. I think it silly to make such comments as Bob's, when they don't have the experience. The factory mods done when still using light shafts are legion. UK people would have seen this car first hand when in the hands of Bob Duguid it won a race at Castle Combe during the famous Aussie Raid and I doubt it was altered after I drove it. Cheers, Bill

Location: Euroa, Australia

Location: Teignmouth

The blown cars Bill mentioned were at Castle Coombe Stuart, also remember that with more open regulations the Aussies were well ahead of the Brits when extracting that last bit of speed during the 80's and early 90's.

Location: NZ

Just one point Ian, although I may be corrected. From memory, Max Foster in a blown Oz Seven and Bob D in the unblown car were the only two Raid cars to compete at Castle Combe and I know Max had trouble all day with his. Maybe Tony Johns (s/c) was also there and likewise had trouble. (Haven't had time to check, not at home). Cheers, Bill

Location: Euroa, Australia