Engine specs

I dont like to be the bearer of bad news but you have fitted the front main bearing in the wrong position.
 
I dont like to be the bearer of bad news but you have fitted the front main bearing in the wrong position.
Hi Richie,you are of course technically absolutely correct:thumb
I've made a mental note to myself that in future I will fit the bearing shell with the join 26 degrees to the left of top centre,,if only to please the purists and those of an OCD nature:D:D
 
Hi Mikey, there is a very good reason why the bearing split is fitted to the correct position, if you look at the way the oil is feeding from the oil filter up into the front main bearing, the slot in the bearing will line up with the feed hole so it gets a direct feed to the crank, as opposed to an indirect feed.
 
Hi Mikey, there is a very good reason why the bearing split is fitted to the correct position, if you look at the way the oil is feeding from the oil filter up into the front main bearing, the slot in the bearing will line up with the feed hole so it gets a direct feed to the crank, as opposed to an indirect feed.
Ah ok,surely the later style bearing with the 6 slots is going to allow more than enough oil to the bearing given that the oil pressure will be equal around the whole bearing.
just because the slots may not align exactly ,the hydralic pressure will be the same as it would be if the slot were aligned,I fully understand the point you are making which was obviously critical with the original style of bearing but I feel with the newer style of shell the position of the join(as long as it is not in the same place as one of the drillings made after installation) is irrelevant..
Mike
 
An interesting exercise would be a side valve turbo with modern production methods to overcome the inherent inefficiency of this engine layout. I wonder if the inadequate combustion chamber could be overcome with turbo charging? It would be a very small and light engine compared to the overgrown beasts we see on bikes and cars. Look at a modern boxer engine. See where the head joins the barrel? It's possible to have a engine about 1 inch bigger than that. Yes you would loose some efficiency but would the lighter weight and size coupled with a turbo compensate? After all when you put a turbo on a engine you would normally lower the compression ratio. JJH
Always looks like a good idea on paper, just like rotary engines, but the reality is not as straightforward.
The low compression ratio provides the ability for massive boost, so ultimate power is not a problem.
The disadvantages are:
Lousy/Rotten/Awful fuel consumption.
Distortion under load.
Once you start to use the power, you will start to use almost as much oil because of bore distortion caused by the side valve layout.
Myke
 
I read somewhere that some of the Harley side valve flat trackers had the piston rings pegged like a two stroke in the hope that they would bed in to the shape of the distorted side valve cylinders - often wondered if anyone had ever tried it on an airhead as some folks recon that airhead cylinders heat up pretty unevenly too.
But I suppose the same could probably be said for most air cooled motors and if it was a problem at the design stage it wouldn't have been that hard to redesign the fining to help alleviate it.
 
New timing chain kit and sprockets,front cover on:D
need to save some pennies up now,as the rest of the parts are:yikes
oh and get my ktm done:blast
 

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Always looks like a good idea on paper, just like rotary engines, but the reality is not as straightforward.
The low compression ratio provides the ability for massive boost, so ultimate power is not a problem.
The disadvantages are:
Lousy/Rotten/Awful fuel consumption.
Distortion under load.
Once you start to use the power, you will start to use almost as much oil because of bore distortion caused by the side valve layout.
Myke
Thanks for noticing my post. In a side valve engine (ones I've seen anyway) the valves are upside down and work in a side pocket to the block. The combustion chamber is over the piston and also to one side. The bores and piston rings wouldn't wear any faster than a ohc or pushrod engine. I'm sure? JJH
 
Thanks for noticing my post. In a side valve engine (ones I've seen anyway) the valves are upside down and work in a side pocket to the block. The combustion chamber is over the piston and also to one side. The bores and piston rings wouldn't wear any faster than a ohc or pushrod engine. I'm sure? JJH
Wear is not the problem. Distortion is.
The problem is that because the exhaust valve is in the block, one side of the block gets extremely hot when the engine is worked hard. As a consequence, the bore is no longer round whilst working hard. Thus, the engine drinks oil.
Myke
 
Wear is not the problem. Distortion is.
The problem is that because the exhaust valve is in the block, one side of the block gets extremely hot when the engine is worked hard. As a consequence, the bore is no longer round whilst working hard. Thus, the engine drinks oil.
Myke

Would more modern materials and production methods not get around that? JJH
 
A Norton rotary developed to give gobs of mid range torque and decent fuel consumption. Yeah, I know ... If we had eggs, we could have bacon and eggs if only we had bacon!

Edit: it would of course have to be an air cooled rotary!
 


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