F8b Dizzy rebuild?

Sat May 05, 2007 9:19 pm

Hey ppl,

I'm having trouble with my F8b atm, it's chewing thru points, and when they get about half worn down, i can't adjust anymore gap in them, so the lobe on the shaft may be too worn out. Set the points in position, and rotate the shaft and you don't get the points opening up. Stick in a brand new set, you get them opening up, as they should.

Has anyone rebuilt their own dizzy and know where to source parts, or if you have had one built for you, what did it cost you?

Cheers

ToranaGuy

Sat May 05, 2007 11:40 pm

Did you replace the condenser? You MUST replace points and condenser together as the one you don't replace will wear out quickly.

Sun May 06, 2007 11:21 pm

What is wearing on the points? The contacts aren't the only point of wear - actually they erode due to the spark - the condensor minimises this wear and gives you a fatter spark. The other point of wear is the follower - some hi-temp grease helps the life of this. The cam part is usually hardened so shouldn't wear appreciably.

Mon May 07, 2007 8:07 pm

Check the top bush for wear - slop in that will make it difficult for the lobe to centre correctly, so your points gap varies significantly, wearing the points out prematurely.

Mon May 07, 2007 10:17 pm

mowog wrote:Did you replace the condenser? You MUST replace points and condenser together as the one you don't replace will wear out quickly.

Last time i did the points, about 3k kms ago, yes i did. This time, i'm rather strapped for cash and can only afford the points. I know that sounds bad, but i've got a crap load of bills & i have to pay my ins excess for my Ford soon, i was rear ended but the ar$ehole wouldn't give me his license details. Got his rego and vehicle description, and description of him, been to cops & reported it( he was driving on canx license!), but it will take ages before i get my excess back.

When i put the new set in i'll put in some hi temp grease, as it may also be wearing the follower too quickly. The shaft in both dizzies i have do have obvious wear marks on them, but without knowing it's original measurement, i couldn't measure how much wear it has or not. As for the top bush, dunno if it's worn, possibly, dizzy is 111k kms old.

Where can the bushes/bearings for the dizzy be bought? CBC? I wouldn't mind doing a full reco on one of my dizzies when i have the $$$.

Cheers

ToranaGuy

Wed May 16, 2007 5:13 pm

Nobody has any info on where to get the bits to rebuild the dizzy?

Oh well. I've been thinking about how to convert it to electronic, and i've got an idea. Just need to find out how much the module will cost me, and if i can afford to do it anytime soon. If i can, i'll let the forum know for sure.

Cheers

ToranaGuy

Wed May 16, 2007 6:44 pm

ToranaGuy wrote:Nobody has any info on where to get the bits to rebuild the dizzy?

Besides the springs on the counterweights and the bearings I can't think of any other serviceable part inside the dizzy.

Thu May 17, 2007 8:53 pm

The only thing I've come across with dizzys is the bush for the shaft. This will wear in time making the shaft sloppy as Brayden mentions. It will also make the timing flaky. As for where you'd go for such a thing, I don't know - ask a auto elec methinks. Pretty easy to check - does the shaft wobble? If the cam is worn - you're bound to see wear marks as the points follower doesn't make contact with the whole of the cam surface.

Tue Jun 19, 2007 8:26 pm

I think i'm in the same spot as ToranaGuy, keep munching points and car running like crap. Any drama with putting a F8B dissy in a F5A? I know they are weighted and sprung differently, but will they still run? Will I have too much advance or not enough, or will it not advance at all.....that sort of thing. It will only be while I am getting the F5A one rebuilt, I cannot get a replacement up here at the wreckers because all they have is hatches with seized up F8B's..which is why I can get one of them!! Willing to buy a reliable F5A dissy if anyone has one for sale.

Whitty

Mon Jun 25, 2007 1:12 pm

For those that care, you can slap any dissy into an F5A. The F8B dissy is working fine in my car - no drama at all.

Whitty

Mon Jun 25, 2007 2:25 pm

Using an F8B dissy in an F5A motor should work, you'll just flatten out ignition curve and drop a bit of power.

Putting an F5A dissy in an F8B will cause it to ping.

Mon Jun 25, 2007 3:44 pm

Drop what power?? Down from where??

It seems as good as before, although I have a new exhaust as well so I can't really compare apples with apples this time. Bit more timing and it will be as good as gold!!

Thu Aug 16, 2007 12:18 am

ROFL @ power drop.

A F8b is a good 50% more powerful then the F5a. Loosing some of that power means your just wasting your CC's that you shoehorned in. Bugger that!

I think i've worked out how i can go to electric dizzy, and it also gives me the option to go to full EFI later on.

A MegaSquirt, running ignition only for a starting point. Modify the guts of my spare F8b dizzy for the electric pickup, run a EA-ED Ford Bosch TFI module, which will give a base 10deg BTDC timing lower than 600rpm for cranking & has 10deg BTDC limp mode, so the engine should crank & idle long enough to work out the ignition maps. Only problem with this solution is the $$$ required, i'm a bit thin on them atm! I'm pretty sure i've got a spare TFI or two lying around. I should probably run a bosch coil for more grunt than original as well. I think i have 2 or 3 of them lying around also . Just gota get the MegaSquirt.

I'm close to having the drawings for the dizzy mods done. Just need to work a couple little things out & how to machine the bits i need to make fit.

Cheers

ToranaGuy

Thu Aug 16, 2007 10:16 am

Its the mechanical assembly that sets the 10 degree BTDC timing,not the module! You can set whatever base timing you want - the general idea is that it is sufficient for the engine to start and run.

Thu Aug 16, 2007 11:48 am

Kartman wrote:Its the mechanical assembly that sets the 10 degree BTDC timing,not the module! You can set whatever base timing you want - the general idea is that it is sufficient for the engine to start and run.

You mean as in where the #1 on the dizzy cap is relative to the crank angle?

The Ford TFI can run the engine even without a computer controlling it, it will just have no adv or retard, atleast that is what a number of documents on the net has to say about it. Has base timing set on the module.

Kartman, was it yourself that was working on a coil setup for a mighty boy, using a V6 commy coilpack? How did that turn out?

Cheers

ToranaGuy