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MG MGA - Dynamic timing
|what advance setting is considered to achieve optimum performance when dynamic timing an MGA 1500? |
My workshop manual indicates 7 degress BTDC for static timing, however I can't seem to find the setting when using a timing light.
I suggest you have a look at the following page on Barney Gaylord's website:
With changes in modern fuel and engines that might have been modified by a PO, timing is often an experimental process. The setting you set statically or dynamically will generally give you a good start point but the best test is on the road: does the car pull smoothly when accelerating from low revs in high gear or does it ping? If it doesn't, I usually advance the timing by a small amount progressively until a bit of pinging is discernible. Then I back the timing off a bit. The idea is to advance it as far as it will go without pre-ignition under load.
Dynamic timing is also useful in identifying distributor faults that might make good timing difficult. As you open the throttle when using the timing light, does the timing advance smoothly or is it hestitant, jumpy or unsteady? If so that suggests that your distributor needs a bit of TLC.
|sensible advice. However, to put some figures to your question. Assuming its a standard distributer it is about 32 degrees at 3500 rpm with the vacuum disconnected.|
|This is a replacement flame thrower electronic distributor. Barney Gaylord's advice on his website (for a standard dizzy I presume)is to set idle at roughly 800-850 and adjust dynamic timing to 20 degrees. That's where it is currently set. With the car parked and reving and holding at about 2500 rpm, i detect a slight misfire. The car seems to run okay and accelerates smoothly.|
|Fran As Steve said the most critical timing setting on an engine is the total advance. After all thats where you will be doing most of your driving and if its wrong you will be causing unnecessary stress on the engine and higher fuel use. 32* max (no vac) has been shown to be "very close" to the optimum setting on most MGA-B. If your timing is then of at lower speeds the distributor needs work. Denis|
This thread was discussed between 24/12/2009 and 25/12/2009
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