XE V8 BOSCH DIZZY

[CHESTNUTXE 7,334]

Hey how much degrees would the advance have on the factory xd-xe dizzy ? i seem to have to put a fair bit of timing into mine for it to go better,it does have a mild cam but nothing outrages,and what should the total timing be 32 -34-36 ? at 3000rpm

[gerg 10,871]

The answer to that is whatever your engine likes. If it runs ok how it is, keep it there, but if you hear some pinging going on, it needs backing off or re-curving. Mine takes about 45 total but is a stock comp 302 with a mild cam.

 

Depends on what comp you run, open or closed chamber, how hot you run it, what grade of fuel you put in it, vac advance connected at idle or ported, lots of factors.

 

Basically if you've changed the cam or anything else in any way, the factory timing goes out the window.

[CHESTNUTXE 7,334]

ok cause i started at 12 initial ,then over the past week i bought a vaccum guage and timing light and did a tune and set the mixture correctly,it seems to run better with heaps more timing around 20 deg and 35 total ,it doesnt ping ,open chamber heads,9.1.1.comp,98 fuel,most advice i can find say 10-12 degrees for a street engine ,and a total of 34-36 degrees,with 12 degrees set the power hangs on all the way but you can tell it needs a bit more,so over the next week i will do a number of tests,i knocked it back today just a little bit and it seems ok but i will keep playing with it,buying the vaccum guage was cool i have 16 inches of vaccum so the 6,5 powervalve is fine,and it helps setting the mixture.

[gerg 10,871]

Is your dizzy a genuine Bosch or one of those Chinese repros? My engine came with the latter and besides having a dud vac cannister, the advance was way too aggressive. Too.much timing and too early. I'd get it running nice at cruise and light throttle, cranked over fine, but under load above 2500 it would knock its head off. So I'd knock it back to where it was happy under load, and it was too doughy down low.

 

Then Mr MSD 6AL-programmable came along, with an MSD billet dizzy, solved all the dramas. I then proceeded to throw that stupid Bosch copy into next week. What a piece of shit!

[CHESTNUTXE 7,334]

Nah she is a genuine dizzy,i just watched a video on changing the springs in the advance to a bit stiffer than stock to stop it advancing so much,the way its set up would be for a stock low lift 420 cam ,so i mist change the rate of advance,so i can run smaller initial 12-14 and 32 total,at the moment its 20 and 36

[CHESTNUTXE 7,334]

ok i dropped it back to around 12 and 32-33 and the plugs have cleaned up seems the factory dizzy has about 16 degrees of advance in it,probly not worth changing the springs unless it was a more aggressive cam say over .500 lift,down the track i am going to fit a ICE dizzy system on the engine,as there is not much available for the later cleveland blocks with the different size bushing,unless you mill the MSD.

[MNTL.XD 3,831]

I'm running a genuine Bosch too. I sent it in with my cam sheet and had it curved to suit and a new vac unit fitted. $450 or something stupid he charged!!

[CHESTNUTXE 7,334]

wow thats half way to owning a ice dizzy