Trying Out The New Engine

August 17th 2013

Now that we have a bigger engine in the car, and prior to the first event after the summer break we needed to give it a run to see if all the work has had the desired effect. Ie: more torque and the ability to climb hills at very low revs.

We went to my friend's fell-side farm at the South end of Windermere again for a shakedown run to see what broke or fell off.
The answer was ..... nothing.

A small water leak from a hose. Tightening the clip sorted that.
A bit of fiddling with the mixture.
Slight overheating (up to 95°C) but seemed to solve itself (Purging air?).
Re-connected the vacuum advance which had been giving trouble when trying to set the basic timing.

There was enormous torque from the Suzuki 1600cc engine after being used to the 1040cc Imp engine.
It would drag itself up hills in 2nd and 3rd gear instead of just 1st.

Trialling is not about top end power, but the acceleration in (for instance) 2nd gear from just above tickover was brutal.


The farmer's grandson arrived with a friend in a Defender on his way up to the tarn to go fishing. I offered to give him a ride up.
"There's a big rock step you won't get over" he said. (We'd been up and down it several times already.)

I passed that no problem but nearly lost him out the back when I floored the throttle on a flat bit of meadow. It may not be that fast in reality, but in a small open car on bumpy grass with a loud exhaust next to your ear, it feels very fast.

There isn't actually any extra power. The Imp engine produced 80bhp. However that was at about 7000rpm.
The Suzuki has 82 bhp but at a much more useable 5400rpm.
The torque is the big story. The Imp probably had getting on for 55 ft/lbs but at approaching 4000rpm.
The Suzuki has 93 lb/ft at about 3000rpm.
This means that at low rpm there will be a fistful more torque than the Imp engine had.

However the throttle did deem a bit sharp, not very smooth in application.

Practice Day

In August we went for the club Practice Day at Firbank near Sedbergh on the edge of the Yorkshire Dales. It’s only about 20 miles from home so very handy.

It was a bit of a mixed day. Blistering sun and heavy rain, but overall very passable. The normal format was a bit different with us members laying out the hills and Ian and I did the stupid thing of laying out a Hill (test) that we ourselves had trouble getting up. Mind you, so did everyone else as well. In fact as I remember it we set it up going to the left of a tree. We all got stuck going to the right of that tree. Someone moved the poles.

As it's a practice day the older (what, older than me?) and more experienced members took the time to analyse problems.
This worked very much in our favour.
Our major problem has always been tight turns up hill just after the start.
With help from one of the venerable members we identified that it is not pure momentum we need but a steady throttle. With the smaller Imp motor (1040cc) this has never been possible as the extra load of the hill would either stall it or need a bit more power. That squeeze of power breaks traction and you are stuffed.
With the new 1600cc engine we can approach the corner at a steady speed and turn using the fiddle brakes whilst not having to use any throttle to overcome the incline.

Great.

However it has highlighted the new installation's downfall That I’ve already noted in that the throttle response is linear and too sharp at low speed. I need to get a progressive throttle linkage which feeds power in gently at low speeds.

The video show a corner which stopped everyone. Doesn't look hard but it stopped our best men. Brian (who I bought my car from) went straight round again and tried a different approach which just got him past it.

The video shows Ian's growing aptitude for arm-waving. The first car to get stuck is Rob. We get stuck and so did everyone else. Then we have in-car video by Ian, but he claims he nearly fell out of the car (he films the exhaust) which I'm not sure about.
Then we have a successful attempt at the hill that caused us grief.

The big problem in the pics and vid is that it doesn't give a sense of how steep the hills are. You have trouble walking up them. By the end of the day we had cleaned all the hills. So were well pleased. My bulge was much-admired, as was the installation of the new engine.

The major disaster of the day was that I tried to knock down a (big) tree using my new (very) pancake airfilter. Bit of bending back into shape is required there.

The only mechanical malady was a clutch problem which saw the clutch pedal lock up solid. At first I suspected the release lever in the bell-housing, but am now thinking the pushrod from the slave cylinder is not enough in-line with the piston and the piston is jamming. Luckily I left the bracket supporting the slave cylinder bolted in place instead of welded, so I can adjust it (I hope).

After the Practice Day I decided that the throttle response was too sharp and we couldn’t  improve our performance much if I couldn’t modulate the power delivery.

To this end I went crawling around scrapyards in search of a “snail” cam to fit to the throttle spindle on the carb to make the power delivery more progressive.

This is what I found on a Jaguar.

Once fitted, with some more mods to the cable bracket it looked like this

The theory is that it moves less initially and then speeds up the further you push the pedal. However it didn’t seem to make a huge amount of difference when trying it out in the drive. We would only know when we got to the first event.

Of which more later........