Project Project Elva: Good News and Bad News While Visiting Savannah

We decided early on that we were not going to build this engine ourselves. While not wildly complicated, building a Coventry Climax race engine is perhaps a bit trickier than redoing an MGB or TR6 street engine.

We knew right away who should build this engine. We have known and trusted Ted Wenz and his crew at Savannah Race Engineering (**link to their site) for years and we knew they could do this job right. They are also located just three hours from our shop, just up I-95 in Savannah, Georgia, so the logistics of getting back and forth to photograph, take notes and work with them would be pretty painless.

We took our pump engine up to Ted to inspect and tell us what it needed. The good news was that our pump engine was in nearly perfect condition. The bad news is it really didn’t matter because our Coventry FW is not an automotive engine, meaning it’s not suitable for race car use.

The one bit of good news that we got is that the race cam and bearing cradles purchased by a previous owner were correct for the engine that we need to now source and build.

Our Elva MK VI was originally equipped with a Coventry Climax 1100cc FWA engine. This engine family has a very interesting history.

A hundred years ago, the Coventry company (later renamed Coventry-Simplex) made engines for light cars, tractors, fire pumps, generators and the like. After World War II, Harry Mundy (previously of Alvis, ERA, Morris and BRM) and Walter Hassan (previously of Bentley, ERA and Jaguar) were brought in and by 1950 they had designed a lightweight, all-alloy, overhead cam engine designed for portable fire pump use.

This engine, dubbed the FW for feather weight, caught the eye of racers due to its lightweight, overhead cam design, durability and high horsepower–well, for the size of the engine.

Soon after, Coventry modified the now-named Climax engine for automotive use, and the greats like Colin Chapman and Stirling Moss started to put these engines in race cars. The engine designation was tweaked, too: FWA (the A was added to signify that this was the Automotive” version of the FW engine) and FWB (a larger version of the engine used in the Lotus Elite).

There were a lot of differences between the FW pump engines and the FWA and FWB automotive engines. The pump engine had a displacement of 1020cc, a cast crankshaft only good for about 6000 rpm, and very small intake and exhaust ports. The automotive engine was bumped up to 1100cc to be used in small-bore race classes. The pump engine head also had no mounting points for a generator or alternator.

Another difference is the FWA received an automotive-style oil pan. In our case, we needed an oil pan that was canted over so the engine could sit in the rear at an angle.

Also, the FWA used a distributor instead of a magneto, and an oil filter mounting boss was cast into the block, whereas the FW ran without an oil filter.

There are other subtle differences, but this list was enough to convince us that between the price of machine work and engine builder’s time, we needed to start with an FWA and not the pump engine we got with the car. So finding one will be the next step.

Savannah Race Engineering’s Ted Wentz takes a look at our Coventry FW pump engine and gives the good news: It’s in great shape. And there was the bad news: This is a pump engine that has no business being in a race car.

Our pump engine has no flywheel, a magneto and no place to mount a generator. Fail.

The pump engine’s alloy head and valves were in good condition, but the valves are too small for race applications.

The block was in good shape, too, but without an oil filter housing, an automotive oil pan and only 1020cc of displacement, it wouldn’t do us much good.

One good bit of news is that our project came with a brand-new race cam and five bearing cam holder. We can use these parts on our Coventry Climax FWA.

The standard FW or even FWA engine doesn’t get this five-bearing carrier that we found while combing through the boxes that came with our car. 

Here is what we are looking for, as this Joe Bojalad’s Climax engine in his Elva MK VI. His car carries serial #60/13 and is the first one of these cars built. Note the conventional distributor, twin Weber DCOE 40 carbs and the way that the engine is canted over to the left of the chassis.

Comments

RoddyMac17 Reader
12/18/19 2:24 p.m.

Also, the FWA used a distributor instead of a magneto, and an oil filter mounting boss was cast into the block, whereas the FW ran without an oil filter.

The statement about the oil filter boss is incorrect. The FWA blocks never had an oil filter boss, instead the lines from the oil pump go through the block with suitable fittings and used a remote filter (the block is stamped "in" and "out"). The FWB blocks (and FWE) had a filter housing cast into it, and are typically machined to use a filter, though most people end up plumbing in a remote filter. And, as it was local to me for a while, one of the first FWB blocks lacked the oil filter casting, it too had the remote set up (was in the only Lotus 17 that raced with the FWB motor in period, but I don't recall if it was entered in an FIA sanctioned event). I had to make up a set of fittings for the conveted pump in my car:

And in regards to converting the pump motor, it can be done, and has been done, but does require a bunch of money and parts thrown at it.

BBGun New Reader
12/23/19 10:35 a.m.

The pic of that cam carrier on the red shop towels triggered memories of Marilyn Monroe's calendar with her lying on red velvet. I'm concerned sometimes about how my mind works.

wspohn Dork
12/23/19 10:51 a.m.

It must be difficult (and expensive) to source Climax parts these days.

One guy who had a small sports racer used a Rally Imp engine (998 cc) which is also Climax designed and looks right but they are probably pretty scarce now as well. 70 bhp stock but up to 100 or so when race tuned.

Just tell them that your car ran Le Mans for the Index of Performance!