Distributor for Fitech TBI

[ray1970 88]

I look at the timing control as an added toy..(That I like)

But it can add more problems for yourself and Fitech if you dont understand it.

[det0326 179]

yes I can find plenty of 351w distributors that have mag pickup and I think the late 70's early 80's with the mag pickup will work also. My problem is the 351w I have was an efi when it was in the 1991 bronco which had the longer shaft below the distributor gear. When I built the engine back I used the old oil pump drive hex shaft and I don't know if the shaft needs to be longer or not for the earlier style distributor that has the shorter shaft. With all that said I can not find a longer shaft for 351w they all seem to say 1969 to 1996 are all the same. It appears  I was not correct the first time I checked to see how much the distributor slipped over the hex shaft the first time I got I think was .265 but actually it will be more like 1/2" and I think that is all there is on any carburetor engine,I;m not 100% sure of that but I think it is correct. I guess I was worrying about nothing. However I wold like a conformation of that before putting an early type dizzy in and calling it a done deal.  

 

Dave

[Rsmach1 71]

Well here's the deal, most of the aftermarket drives do in fact say 69-96. However the FRPP shaft says 69-74, so there must be a difference for a reason. I've seen posts saying the ARP shaft is too long, some too short. Too long and you can bind the oil pump, or cause dist/cam gear issues. Too short and you run the risk of it rounding, especially if you have a HV oil pump (do you?).

 

Also I would NEVER use/reuse an old stock oil pump drive, it's a $25 part that can cause serious grief if it fails. EVERY engine I've done gets a new one. I don't know about the late model shafts, but the early ones are thin, and I've seen them twisted before.

 

I know it will be a royal pain, but I would highly recommend you drop the pan. Once you pick out a dizzy (and a NEW driveshaft) you'll be able to check endplay.

 

PS I've never have any issues with ARP's oil pump drive's, and I always check endplay.

[det0326 179]

Oil pump is stock replacement no HV.   I don't know maybe I am old school but the shaft looked perfect no wear or stress and is OEM.  With manufacture company's of today importing so much stuff and putting there name on it I figured the OEM shaft would be a world ahead that has proving itself verses putting something in I know nothing about. The bottom line is I cannot find one that states it is any longer.  Would you be so kind to post the link where you saw 1969 to 1974. Which that doesn't sound right either because if there was a difference in length it should be from 69 to 86 since they went to efi in 87. Because the difference in the longer and shorter distributor shafts seems to be when they changed from carburetor to efi.  

 

Dave

[Rsmach1 71]

https://m.summitracing.com/parts/fms-m-6605-a341

 

Some catalogs list it as 69-73/74 and others don't specify.

[Rsmach1 71]

OK straight from ford, as I originally thought, the drive shaft itself are the same length for all 351w. The difference comes into play when using any of the performance shafts, as they have more "meat" in the center, and are not typically machine far enough down to accept the EFI equipped dizzys. So if your comfortable with your old shaft, length wise it should be fine with an older dizzy.

[det0326 179]

OK straight from ford, as I originally thought, the drive shaft itself are the same length for all 351w. The difference comes into play when using any of the performance shafts, as they have more "meat" in the center, and are not typically machine far enough down to accept the EFI equipped dizzys. So if your comfortable with your old shaft, length wise it should be fine with an older dizzy.

Thanks  for taking your time to help figure this out that makes perfect sense. I had called my local ford dealer here but they were no help since it's changed owners a few years back there are probably no old timers left around.  Again thank you this pretty much sums it up.

 

Dave

[Rsmach1 71]

You're welcome :)

[Mach1 Driver 560]

So Dave, your motor is a 91 351w which was EFI so you'll need a different dizzy with a magnetic two wire pickup for FiTech. Since I'm not looking at the dizzy's drive end I don't really understand Rsmach1's explanation; what distributor do you think you'll get, an older Ford Duraspark?

[det0326 179]

Yes 1991 351w efi from a bronco.  The dimension (length) from the bottom of thrust surface of gear where it rides on the boss in the block to the very bottom of distributor shaft have 2 difference lengths the efi being 1-1/2" while the carburetor engines being 1".  What RsMach1 was talking about is the OEM hex oil pump drives have the hex machined the whole length of the shaft where as the aftermarket performance shafts  only have the ends  machined  for a certain distance and in between it is a bigger dia to supposedly make it stronger if you try to install a dizzy with the longer shaft it will not seat. I was thinking that the extra length on the efi dist. was for more engagement but I posted this same issue over on VMF and a member named Paul, over there explained it this way which makes sense. 

 

 

 it has nothing to do with oil pump drive shaft engaged length per se. On the old carb type dists when you install the dist the dist and cam gears engage each other before the oil pump drive shaft engages the oil pump drive shaft. Once the gears begin to engage the dist is 'locked' (cannot free rotate) and if the hexes in the dist and drive shaft are not lined up the dist will not install. One has the remove the dist, slightly rotate the oil pump drive shaft with a pre-oiling tool, etc and try again. Now on the later TFI distributors with the extension the dist shaft and oil pump drive shafts engage before the dist/cam gears engage. One simple can turn the dist shaft back/forth from the rotor end to get the hexes lined up. Once the oil pump drive shaft is engaged the dist will drop right in as the gears engage. Ford finally got it right...

 

 

I am looking at the older type dist.  because I am reading that the MDS dist. quality has went down and that some are being made in China don't know that the be true are not. I certainly don't won't to pay MDS prices for a made in China part tho. I called FiTech and they told me that the duraspark dist. would work with there system.

 

Dave

[det0326 179]

Well I may have screwed up, I just pulled the trigger on an MSD 85840 dist.      The listing does say country of manufacture USA so that's a + i guess. I could not find a new one under $312 but I was on line looking for one at advanced auto and happen to see a promotional deal that I could use that was 20% off up to $50 total. So I got $50 off there price making the discounted price $266, couldn't pass that up so it is on the way.

 

Dave

[Rsmach1 71]

Great deal with the coupon.

[Mach1 Driver 560]

Dave, in my discussions with Chris Straub- the custom cam and engine builder, he suggested a Crane distributor because they are the only one left with a descent gear. I didn't mention this because you were intending to use an older Duraspark which would have been OK. Apparently all the other dizzy manufacturers are buying cheap gears from China, and he said they were a pile of excrement. If I wanted to use an MSD he said to get a Crane gear and machine it to fit the MSD dizzy or the MSD gear will chew-up the cam gear. He specifically mentioned MSD.

In a recent post (I believe on this forum) I was reading that the gear should be a press fit to the dizzy and use a roll pin. If just the pin holds the gear, then the pin will eventually snap, as happened to the person posting. Seems like you've got to check everything and things just can't be easy... just because you lay down descent bucks doesn't mean you'll get a reliable part.

Edit, it was on this forum, the post was "Pedal to the metal, now car stumbles and turns off" down around 

#16 is the reference to the press fit. The distributor with the broken pin was a Summit "Ready to Run" but no telling who made it for them.