7a distributor in 3B engine

[GurjinderSembhi]

Hello all,

i've recently had my distributor refurbished and while I finally got the engine running it was clear it was running rough and misfiring. Leads where to blame first which I changed, but misfiring continued to happen. The first rotor arm however that was supplied ended up destroyed inside of the dizzy cap (no driving, just idling) after a few runs which also destroyed the pin inside of the dizzy cap.

I got supplied a new rotor arm (they told me they had supplied me with the wrong one the first time) - got second rotor arm and dizzy cap installed, and the car doesn't start anymore (starter motor has been checked and is working).

Read both on the FB page and on the forum that these cars are very particular about the rotor arms, so i'm wondering which one is the correct arm to use for my setup. I'm assuming I need a 7A rotor arm as its a 7a distributor?

Engine is a 91 3B with what appears to be 7A cams (bought car like this)
Distributor p/n is: 034905205J (7A according to etka)

Would be good if someone could help to confirm....otherwise contemplating just ditching this setup and going for coils instead (but prefer to keep the car oem)

Thanks in advance

[newsh]

Check you distributor static timing
3B is very sensitive to this.

[GurjinderSembhi]

thanks will check again (not the most inspection friendly place!) - however is the rotor choice anything to worry about? I am not confident with the rotor arm supplied so thinking about getting a 3b specific one (not 7a one)

[newsh]

You need the 3B rotor with the narrow tip.
Very important that you don’t use the one with the wide tip.

[GurjinderSembhi]

uhmmm....wrong one for sure then!

Will get the narrow one. How do I know that something bad has not happened?

Thanks

[newsh]

With the wide rotor it’s possible to get spark hop inside the dizzy and bend a rod.
It’s pretty unusual though!

http://www.sjmautotechnik.com/troubl.../20vboost.html


https://www.audiworld.com/forums/aud...en-3b-2198363/

[GurjinderSembhi]

hoping nothing major happened then!

Just cancelled my order from TPS seeing the article from SJM and ordered the correct part from Quattro Corner who was very helpful.

Thank you very much for your help Newsh - with any luck I can get it ready for AITP

[newsh]

No worries
You need to check timing using the window on the bell housing and the marks inside the dizzy, the mark on the front pulley is not accurate.
Put the car in gear and roll forwards to the Zero mark then check the dizzy (spark plugs out makes it easier)

It would be a good idea to check the marks on the cam wheels and cam pulley too, just to be sure the valve timing hasn’t slipped. The keyway sun the cambelt sprivkets are prone to breaking.

[larsaskogstad]

Correct tip should be 11mm

[GurjinderSembhi]

Got the new rotor today finally. A few screenshots for comparison and the right one on the far right including the Bosch box.

waiting for the rain to stop so I can go test it out