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Stage 2 tune 1293

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4tecdog

4tecdog

Jedi Hopeful
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When I purchased my frogeye two years ago I was told it had a stage 2 tuned 1293 unit I think it was rebuilt about ten years ago but it had very low mileage when I became custodian. Could anyone tell me what a stage 2 should have been in that era and how I can check if it is. Would there be any markings on the cyl head could I tell by compression ratio etc etc. It has a lbc manifold with twin SU’s
I would like to increase the performance but don’t want to duplicate improvements already made.
 
Stage 2 tuning is a very nebulous description. It could mean anything the person making the statement wants it to mean. In theory stage 2 would be somewhat more modified than stage 1 which is equally vague. In my unprofessional opinion it MIGHT include an overbore, mild port & polish, somewhat hotter cam, electronic ignition, headers with a "performance (loud) exhaust" or none of this. Only way to find out is to start measuring and compare the results to a stock example. Sorry to be no help at all. Bob C
 
Bob Claffie said:
Stage 2 tuning is a very nebulous description. It could mean anything the person making the statement wants it to mean. In theory stage 2 would be somewhat more modified than stage 1 which is equally vague. In my unprofessional opinion it MIGHT include an overbore, mild port & polish, somewhat hotter cam, electronic ignition, headers with a "performance (loud) exhaust" or none of this. Only way to find out is to start measuring and compare the results to a stock example. Sorry to be no help at all. Bob C
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Bob is right. The only factory literature I'm aware of that speaks in terms of Stages is the "Special Tuning" Manual for the Mk I Sprite with a 948 and it gives tuning stages 1-5. The 1275 manuals only talk about a Stage 2, cylinder head, but nothing more. Add to it that every individual tuning company would have their own specs for what constituted a Stage 1, Stage 2, etc. which generally meant you could buy a "Stage 2" package for a certain amount of money and a "Stage 3" package for even more money.
 
Thanks for your replies what I expected really, I seem to remember in my youth stage 1 and 2 kits were offered with specific items and mods. I suppose it’s head off cam out and have a look?
 
If youi're thinking of modifying the engine, then I presume that you'd be tearing it down and may want to wait until winter/non-driving season - me, I work so slow that I'd probably lose the bulk of the summer if I was to pull the head now. Do a compression test; have a look at the rocker gear (stock?); maybe measure valve lift to see if the cam is stock. Do a compression test (wet and dry) before you pull the head and maybe a vacuum pull down test to check overall engine condition. Pull the carbs/manifold to see if the ports have been matched or any polishing. Check if the SUs are original stock or a larger size. If you've got the stock exhaust manifold I'd be doubtful if anything much had been done to the engine, but gather information by stages. Doug
 
Thanks Doug that was my thoughts on the subject as well enjoy the summer and look forward to the serious work on those dark nights. I am a little in the dark as to what has been done and your suggestions will certainly help, the engine runs really sweet and I don’t want to upset the balance but I would like to know if the head has hardened valve seats and if it has the original cam, I know it has had some tuning lcb manifold etc. Do you know what the compressions should be in psi? and how much lift a standard cam would give. Thanks again for your help. Rob
 
I believe the standard cam lift for the 1275 motor is .250" at the cam for both intake and exhaust. The valve lift depends on the rockers. If Standard 1.3:1 rockers then 0.318". If 1.5:1 rockers then 0.375" at the valve.
If you have a upgraded cam you should notice a slight lumpiness at idle.
1293 cc should be a 0.020' overbore. Hard to tell the compression without knowing the dish of the piston.
What exhaust manifold? You can easily tell the stock big ugly cast iron manifold. Upgrade of the manifold is an easy first step.
 
Hello Joe the manifold is an aftermarket long centre branch type with a fairly straight throu exhaust. Idle isn't too lumply and plugs are a good colour. Ignition is still on points.
 
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