After buying an aluminium head that was advertised as a 350 cc model 50 head, I've ended up with an ES2 head for my Surrogate Manx budget racer. Right, something went wrong there...
Trying to find an actual Model 50 head has proven fruitless, so to get anywhere with this project and keep an eye on budget, I have to look at different options.
I can choose to demo race in 350 or 500, so both cylinder capacities are still an option.option.made me think: 'Would it be possible to use an ES2 cylinder, without needing to modify the crankshaft or crankcases?'
Maybe the cylinder needs to be shortened, but if that's it, it might be doable and I'd end up with an engine with a shorter stroke and bigger bore ratio. Would that work?
And another thing; I'm not planning on really tuning the engine, but I'm a bit worried about the crankcases. What is it that makes them crack? Is it high rev vibrations or big bangs?
To be clear, I'm not trying to build a high end racer, I'm just trying to prove you can go out there on a budget and enjoy yourself. I have to admit it's tempting to go all the way and make it as fast as possible, but that's not the mission here.
Anyway, I definitely don't really know what I'm doing, but I do thoroughly enjoy the process getting there. That also means asking for advice and learn.
Cheers!
Tim
Cheap tuning.
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You could always speak to…
You could always speak to Mike Pemberton at push rod performance, I'm sure he could build you a crank with upgraded rollers and do any other machining you might need if you cant do it, he also has race cams. He's the club single specialist
Dan
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Cheers both!
Richard, I'm getting really hopeful, reading your tips and information. It does sound interesting and completely in the spirit of the project.
And Dan, your advice is very sound too and I know Mike could be the solution for all my problems. However, I wouldn't learn something then and it would cost me dearly. Please note that I don't use the word expensive, as I think it's great what he's doing and making a living out of it. It's just not the route I'm taking.
My head is an aluminium one with the adjustment cover mounted on the rocker axles, if that makes sense. I've got all the pictures and the goings on on this website. That might clear things up.
Cheers!
Tim
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As I need to source all…
As I need to source all parts anyway, the B50 piston option sounds like the best one. With all options being equally expensive with only the piston varying in value, this would give me most speed.
I do have a small problem, as in not being able to identify the parts needed. Mainly the iron head '48-'54 ES2 barrel.
As much as I don't like it, I have to source most of my parts online as I yet have to build-up a network of like-minded enthusiasts and useful contacts. And a mistake (a wrongly advertised 350 head being a 500 is one of them) is quickly made. So I could use a bit of guidance if I see something for sale. I tried sending a direct message Richard, but I don't think I did a great job. Nor do I see where I can check them if they were sent to me.
Cheers!
Tim
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email address.
Hi Tim,
I did reply to both your messages, so obviously these did not get through to you. If you contact me direct on my personal email address I can resend them to your own email rather than go through this forum.
ricco490@hotmail.co.uk Landline telephone (44)1494 482750
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Written down
Cheers Richard,
I've written it down, so you can remove your details if you'd like. As soon as I have time, I'll be in contact. Thanks for giving me the opportunity. I'm sure your input will help this project to move forward a bit faster (no pun intended).
Tim
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Hi Tim,
You can fit an ES2 top end to your Model 50 with-out too much expense. You need to get an ES2 cylinder barrel from one of the iron head engines used between 1948 and 1954. You also need an ES2 con-rod with 7 Inch centres which will fit your flywheels and a new big-end and main bearings. The cheapest piston will be a W.D. type 16H side valve which will give you 435cc and a compression of around 8 to 1. You can also use a BSA B44 piston which will give you about 9 to 1 compression or a larger B50 84mm piston which will make the capacity 487cc and again about 9 to 1.
The crankcases are fairly strong and usually only break if you use extreme tuning methods. Carefully prepared, these should not be a problem, the weakest part is the low specification big-end bearing, but for short track events you should be O.K.
You don't say which type of aluminium head you have as this may affect the carb you can use, but 1+3/16th could be possible. Used with the above mods, this should give you up to 150 KPH.
Decide how far you want to go with the tuning and I can give you more details of the modifications you need to do on the above parts.