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MG MGB Technical - performance engine advice

hi guys, ive got a 1968 MGB GT which has been extensively modified. I put the engine together myself, and had it tuned buy a mechanic that uses mobile diagnostics and meters etc (a mobile tuner).
The spec is as follows:
stage 2 ported and polished head
BL 714 camshaft
+.020 overbore
stainless exhaust manifold and system
K&N filters on HS4 carbs with AAA needles
double valve springs
magnetronic distributor

The engine runs great albeit a few teething problems when first built. It goes really well but i cant help but wonder if it would be worth having the car rolling roaded, not to see how much power it has but to see if it can be improved. I have the standard simplex timing gear and also wonder if the vernier type timing gears would be worthwhile.
I would like to take it to Peter Burgess but its a bit too far to travel as im way down south in kent. Any thoughts?
A P New

Hi AP New

Did the camshaft get timed in or fitted on the dots? It is most important to ensure the cam is set correctly.
Head specs vary from person to person so don't tend to mean much as there is no 'standard' of gas flowing. The 714 cam tends to prefer a weber carb. It was designed (I am reliably informed) as a Rally cam for shale use whereby the engine needed to be able to rev to say 6500 and not have a sharp influx of power to keep the wheels from breaking traction on the loose stuff.It tends to rev but show no real bhp increase until above 5000rpm.

Peter
peter burgess

AP-
Vernier timing sprockets are pricey, but allow the camshaft to be dialed in much, much quicker than the technique of changing offset Woodruff keys. This pays off when you go to adjust the timing as the chain wears and stretches. It also saves cost when using a rolling road to fine-tune the engine. Setting the engine up on a rolling road will permit accurate diagnosis and thus enable you to get the best out of the engine, both in terms of power, smoothness, and fuel economy. You're only 3 1/2 to 4 hours away from Peter, so go ahead and invest the time to get it done by someone who knows these engines better than anyone else. You'll smile all the way home.
Stephen Strange

On an engine with easily accessible timing gear, and where you have some reliable way of knowing the position of the crank within a degree without removing the head then vernier gears would be great. But if you are going to do the job only once ie to set the cam timing according to the cam manufacturers specification, which I suspect is more likely in this case, then the offset keys will do the same job, in the same time, for a twentieth of the price. The problem with vernier gears in the 'once'off' situation is that they are behind the timing cover - which needs to be removed each time you want to adjust the timing. For sure, you'll save the time of taking the actual crankshaft gear off, but you still have to do the long, annoying bit ie removing the head so that you can find TDC properly (if you are going to use a stick down a plughole then you'll not be needing the accuracy of a vernier!), undoing the crank nut and removing the timing cover bolts each time. In other words, the vernier gears will save you a bit of time, but not much in the grand scheme of things. You'll save a bit of time next time around I suppose, but if you're going to be adjusting the timing to take account of chain wear then you're going to have to get the head off (etc) again to do it properly - so again the time saved is minutes out of hours?

HTH

Neil
Neil22

AP I would take it to Peter B. If you keep the spec of the tune (timing, mixture etc) you can always know where to set things in the future. Three hours is just around the corner in OZ.
Denis
Denis4

thanks guys, i think ill give peter a ring in the morning and see what we can do. All im after is getting the engine running at its best. I have thought about using a weber but iv'e heard they are hard to set up and of course, there damn expensive. Ill keep you posted
A P New

This thread was discussed between 21/02/2010 and 22/02/2010

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