A change of heart
A chance meeting has netted me with a bunch of 36 horse parts. I popped out to buy a number plate bracket for the Type 34 and ended up coming home with a bunch of 36 horse stuff. This has nudged me to change direction with my plans for speed week and look to build a 36hp power plant instead of the planned 50 horse - literally a change in heart. Having been an avid follower and support of the 36 Horsepower Challenge for a number of years its probably fitting that I enter at least once. So with a selection of 36HP parts now at my disposal it has given me a chance to take a look at whats possible with these early engines.
It obviously goes without saying that the engine will be blown and feature one of my kits. Ironically I have yet to put together a kit for a 36 horse and so this will allow me to develop the necessary changes to fit the blower onto the smaller 36 horse engine. Other plans at this stage are very similar to the 1600. I actually want to see if I can match the capacity - 69.5 stroke by 83 bore will give me somewhere approaching 1600cc. Exceeding this capacity requires a expensive 356 72mm crank which I simply don't want to stretch to in this build. I also will continue down the EFI path using the megasquirt and throttle body I bought for the 1600. The general goal will be the same - high boost - so EFI for ignition retard under boost will be a necessity.
My initial thoughts were to use 40 horse P&Cs and even maybe 50 horse heads. Whilst it's possible to use 40 horse P&Cs (necessary to get 83mm) the cylinder spacing on the 1600 heads is simply too far apart to be used. I considered cutting them and making them into split heads but it's probably a little too much work. This leaves me with no other option than to go with Wolfsburg West Okrassa heads (Denzil are simply too rare/expensive). This is the only viable way I can get a twin port head which is an absolute must for EFI.
In the hoard of parts were three cases. One has been machined, full flowed and is ready to assemble, one has been cleaned, checked and is ready to machine and the last one has suffered a bit of corrosion and so is going to be my test case which I will use to experiment on. The machined case even came complete with a high flow oil pump, so there's one less thing I need to worry about.
Taking a look at the 36 horse engine it's quite a bit different from the later 40 and 50 horse units. The push rods are altogether different as they are attached to the lifters which are in turn held in alignment with the case. These can be swapped out for 356 units which are more like the later 40/50 horse parts and use a separate push rod - a necessity really as the all-in-one 36hp style look like they will flex a little given the change in push rod geometry. The crank pulley looks like it will fit but has a different offset from the 36HP version, not a massive problem as I will make these to suit. At this stage I don't have heads but will be looking to use ratio lifters which means either purchasing the speedwell versions or doing some machining work and retrofitting 50 horse versions.
Of course I had to do the obligatory blower test fit to find out how I will fit it. Interestingly, without the distributor to get in the way there is a perfect space to the left side of the generator. Given that I also do not have to worry about carburettor orientation I have opted to fit the blower in a horizontal configuration with the throttle body sitting directly on top. Not exactly very vintage speed looking, but then I'm aiming to make much more power than a Pepco or Judson powered engine
Of course it is still early days for this build, I have a lot of parts to collect and a lot of things to learn about the 36HP engine. I also need to read up on some machining practices for machining the case and heads. Designing and making the mounting hardware for the blower will be a relatively straightforward task, the only issue here is what material to use.