Tim777

My piston pins are 22mm as supplied with pistons and the knuckle pins are 18mm. The main pin was made from H13 – orvar material , you were correct. I have fitted weaker valve springs as the engine is low rpm engine to offload the cam drive train. I have oil tank beneath the crankcase and large oil return holes in the front chamber (cam and tappet area) and one between the 2 lower cylinders. I will use a driven fan on the front of the engine to blow air over the 5 cylinders. I would like to fit the engine to a motorbike if it runs well enough. I have a donor bike with shaft drive , but thats a long way off. I am fitting a window in the front chamber of the crank case for viewing and hope to fit a window in the rear back plate as well.

Engine made with basic machinery like you. I thought the interconnecting rods might be a little weak so made new ones which set me back. Assembled the engine to get the cam timing sorted. Timing is minefield because of the low rpm I will be running. I looked at Harley's which varied massively and also the engine on my PA28 (fly from White Waltham)which has similar rpm. In the end I settled on what I think should be OK. Compression ratio i am aiming for just over 7:1. I changed the design of the master-rod many times and settled for phospher bronze main bearing which will be pressure fed. The interconnecting rods are ally and didn't want to weaken them with the oil hole at the knuckle pin end so drilled in from the inside of the rod lightening groove instead of the outside like the piston pin. It is quite amazing the forces involved when it is turning which is why I think 2000rpm with max 2500rpm will be safe. I am familiar with the Kinner balance formula which I am using. Bob weights are finished now and nearly ready to balance. I am using a slave test pin to hold the 2 crank webs together for balancing then I will press the crank together. The main pin I machined from HE15 and had hardened and tempered. I think I went to just over Rockwell 40 to prevent it being too brittle. The pushrods i used were basic VW rods which are light weight ally but incredibly strong. I cut them to correct length and turned the rods down on one end until the hardened steel insert fell out, then pressed it back in with rod the correct length. The top end is all exposed, no lubrication so I will fill the pushrods which are hollow with grease for lube of the rockers and tappetts cheers Tim

Hi Ptwizz. Awesone post, excellent creativity to circumnavigate engineering problems. I have also been building my own designed radial for past 3 years. Interesting to see how you made the master rod, very clever, I made mine in 2 separate assemblies as well but like a cotton real. I machined crankcase from 11 inch billet and I am using VW bettle heads and barrels. I went for 5 camshafts and 5 carbs. Mine is 5 cylinder , 2200cc , will run at 2000rpm. What stage are you at now, have you got to run yet. I am rushing to get the basic engine running this summer. Would be great to share some info with you, all the best tim