I forgot to take photos of this, but I might in a few days. On my rebuilt dizzy, I noticed that the cam lobe for the FI trigger points was at a different location than what my stock dizzy had it at.

Going from memory, on the stock dizzy, the point on the cam lobe was pretty much lined up to at the #1 spark. On the rebuilt, it was like 30-45 degrees off of this point. I can't remember if it was before or after #1.

Anyone ever notice this before?

Would it make a difference for the fuel timing?

Doesn't the fuel charge just sit in the intake anyways waiting for the valve to open.

I'll try to get some photos later on.

DJet fires injectors in pairs, so two cylinders get squirted more-or-less in sequence with the intake valve open, the other two have the charge waiting in the port. i don't recall which two fire in which pairs, but i bet Brad Anders page has the whole deal. (i don't know nothin' 'bout no T-IV's ...)

as for the point lobes lining up with anything in particular - i donno. on most cars you want the rotor pointing pretty much directly at the plugwire tower on the cap when the points open. the T-IV dizzy is keyed to go in only one way (unlike the 911 dizzies, f'rinstance, which have a drive gear...). the T-IV dizzy drive shaft has a gear, but AFAIK they're all the same - so once again - i donno ...

Hmm.. Not a lot of interest in this topic. I guess I should have asked people to post a photo of mommy along with there responses....

(Please, no mother photos....)

2 and 4, and 1 and 3. Trigger points fire the injectors in those pairs.

Im interested in this Topic as I am planning to go this route as soon as I collect a core Dizzy from Geoff.
What FLAPS did you use to aquire that Dizzy?
I recall from another thread that this is the second one and the first was a 411 or 1.7 listed (scribed Part #) dizzy?
Also is it true that it came fully loaded with Trigger Points ?

This is actually my 3rd try at getting a rebuilt dizzy. I purchased them all at Schucks.

The first one had the 'housing' of a type 3. I got nervous with that one and sent it back.

The second one was also from a type 3, it had the same numbers but was a different dizzy. I decided to keep this one and try it out. I figured that when they rebuild these things they more than likely break them down and throw the parts into 'big bins' of individual pieces awaiting refurbishing. Then just grab parts out of the bins and rebuild them, I don't think that housing number on the side even matters.

Well, I got this one home and took it semi apart to check it out. It looked ok. When I was installing it, it turns out that the damn rotor was to big to fit on the shaft!..so this second one went back.

The third one I got actually arrived with an 022 number on it, but I noticed that the lobe inside was in a different location. I installed it and the car seems to run fine with it.

This 3rd one had new points, a new condenser and rebuilt FI trigger points.

The pissy thing about this whole process is that it didn't cure my problem of the car stumbling at 2500 RPMs and up. I think it might have been my FI injection harness because I wiggled a lot of the connections and the problem went away.

Oh one more thing...there was a $1 core charge. I kept my old one for parts.

So where did the third one come from?

Oh just noticed that they all came from Schucks. I think that is the same as Checker Auto out here.

And "Kragen" elseware

hi eric

sorry the dizzy didn't fix it (at least you won't have to mess with that for a while now), but i'm curious if you "permanently" fixed the stumbling problem by messing with the harness? were you able to track down were the problem in the harness was?

i've still got that flatspot at 4600 rpm. not a huge deal because my engine rarely sees more than 4500, but annoying when the occassion comes up

have your tried swapping MPS's yet? recalibrating mine helped; but now i'm wondering if there is a small mechanical failure inside it....

n

Guys, I would not mees around with those Shucks parts, go to Otto's in venice, he has a web site, and sells rebuilt Type 4 FI dizzys on the front page.

he is a real legend and a pro at what he does.

rich

Rich, that is still an option....

I was planning on getting one from Rich over at HPH for $120 if the 3rd one didn't/doesn't work out.

There seems to be a few mass produced rebuilt dizzys out there, so here's some more info for the archives.....

Well, these are not the photos I was originally going to get, but I think they should illustrate a little better of how the two dizzys compare as far as differences of the cam lobes.

My stock dizzy is the two diagrams on top. The two below are the rebuilt dizzy.

The notch in the dizzy for the #1 cyl. is marked at approx. the 4 o'clock position and the notch for the cap is marked at 6 o'clock. Typical.

The dark zone illustrates the continuity area on the FI trigger points as the rotor/shaft is rotated. The left diagrams are for terminal pair 21/12 and the rights are the 12/22 pair. The "continuity zones" didn't seem to be quite 180 degrees....but I was just eyeballing it, so the zones could be off a few degrees.

I'm not sure if this difference even matters because the injector is only going to fire (milliseconds) at one spot within the zone.

Ok, I'm not really following this, here's a question.

If we take the points out and put in Electronic ignition with one of the plastic things that pass thru a electronic Eye. Does the points trigger have to line up with the FI trigger points in some way?

(if you understood that I'll be shocked..)

DanD
Still runing on points...

What the heck is that Eric? Very weird....

The whole point of the rebuilt is to get a dizzy with the shaft rebushed. Its easy to install all the rest of the parts yourself.

Geoff

It was my very good attempt at confusing everyone...but it was a bad attempt to show the position of where the FI trigger points are in the closed position as the dizzy shaft is rotated.

Rusty

My 2 cents

I think I get what you are trying to show. It looks to me like the lobes on the dizzy shaft are 90 degrees off in relationship to the cam and 180 degrees off in relationship to the crankshaft. I suspect that both charges from the injector are sitting in the intake manifold waiting for the intake valve to open. Normally, I believe, one injection pulse would be at the back off an open intake valve. It seems to me that the problem with this would be when the intake is cold and fuel vapor could condense.

I took apart an old dizzy to see if the lobes could be rotated. I don't know how those suckers are put on but I couldn't budge it.

I guess if it was me I take it back.

I feel for ya, I know it gets frustrating

Dave

I got a rebuilt dizzy at Advance Auto Parts. It is the A1 Cardone. It had the correct numbers. I didn't take it apart, but I will be firing it off this weekend. I'll let you know.

BTW, that was on the first try. Yes it came fully loaded with Points and Condensor.

-Matt

I've FINALLY come across some information about the "existence" of different FI injector pulse timings in the 914/4 distributors.

Clymer service manual, 914 1970-1975
page 129, Fuel System

"On 1970-1971 models, injectors 1 and 3 inject when the respective intake valve is open, while injectors 2 and 4 inject when the respective intake valve is closed. On 1972 and 1973 models, all injection takes place behind closed intake valves. Fuel is effectively stored in the intake ports of cylinders until the intake valve opens."

No mention is given to engine sizes. Interesting stuff.

¿And that URL would be...?

There is only one Otto in Venice...do a search, but it is something like www.ottosvenice.com

http://www.ottosvenice.com/
See how easy that was

I dunno...$250 is a bit steep for me.

Thats why I say try to get one from your local Flaps. If you have a 2.0l one just transfer the internals to the new rebuilt one. What you need is the rebushed shaft mainly plus the trigger points.

Geoff

Ok...so what are the tricks to get the internals out without destroying everything?

How do you remove the stuff below the points plate...for instance the FI trigger points cam.

Eric,

I did some checking into this. The lobes for the points and the lobes for the trigger points are on one solid shaft. The reference in the Clymer manual may have been refering to the 1.7s vs. the 1.8, but failed to note that. The D-Jets all fire FI as mentioned for the 70-71 years. The 1.8s I believe fire each cyl independently.

Now its not unreasonable to consider that perhaps someone rebuilt the dizzy with the wrong shaft. Not necessarily the 1.8 shaft, as it would have four lobes for trigger points - right.

Good luck. This is interesting!

IIRC -- AFC injection (L-Jet) uses the tach (spark) impulse for injection timing and does not use trigger points. there might still be trigger point cams in the L-Jet dizzies - i donno - i've never seen one.

i also can't tell you -exactly- how the injectors are pulsed -- singly, in side pairs, fore/aft pairs, or all at once ... somebody must know, but it ain't me ...

you don't remove all the stuff below the points plate! Just switch over the rest of it.

Geoff