How do You Stop Crossflow's killing Dissy's

[XFGHIA747 76]

As the title says lads what are some of the best ways to fix crossflows killing Dissy's a mate had one completely rebuilt in his drag bus a season ago same deal killed it again, can you buy new dissys for crossflows or just rebuild them and hows the best to prevent them. cheers lads

[Mr Polson 10,214]

Killed it how?

Mine keeps chewing out dizzy gears which is apparently related to either a bad/bent oil pump driveshaft or a misaligned block.

[XFGHIA747 76]

Well he is running a xe dissy, but its a common problem in high reving crossflows to flog out the shaft between the gear and the rotar hub and when they flog out the contacts hit each other in the to of the dissy. When he sent it away last time they built up the shaft with some metal spray or something to make it tighter in the shaft..

[XTREME KARTS XF 1,212]

Polson is in the right track, its was very much Incorrect machining, a hardened distributor gear will solve this problem, Crow Cams make the gear to suit, part no. DG2

 

I bought this gear not long after i rebuilt the engine in my BnS basher back in July 2011, 3 years later and no problems since

 

[slydog 7,873]

Well he is running a xe dissy, but its a common problem in high reving crossflows to flog out the shaft between the gear and the rotar hub

 

No it's not...

[ando76 4,354]

They flog out the bush at the top of the dizzy first - then the stupid chopper wheel comes in contact with the outside and snap. 

 

If it is wearing out the shaft in that position then there is other stuff going on, most probably they have replaced the bush in the top of the dizzy with something that doesn't wear like the proper oil impregnated bush does. 

 

Gave up using those XE dizzy's in speedway motors a long time ago because of this very reason.  Your lucky to get a season of drag racing out of them - we used to have to throw a new bush in after 2 meetings - try for that 3rd meeting a snap!

 

There are only two ways to truly fix the problem;

•  replace the dizzy with an EST or TFI dizzy and go to programmable ignition - or if you want to live in the dark ages - just lock the timing or
• go to crank trigger and just have the distributor being responsible for distributing spark. 

If you try and persist with the XE dizzy in this application you will be on a hiding to nothing and eventually it will lead to engine damage.  You can change to the DG2 gear and check tooth engagement all you like - it won't fix the problem. 

 

We looked at trying to put in a needle roller bearing in place of the factory bush and all those sorts of things and at the end of the day it is just wasn't worth it when there is a far superior and easier solution as close as your nearest wrecker. 

[Clevo120Y 815]

I'm interested in this roller bearing idea Tony, we have to use the XE dizzy in street stock.

[bear351c 10,271]

Speedy sleeve on the shaft, ream out the bush ???

[ando76 4,354]

the idea was to bore out the housing to take a suitable sized needle roller bearing.  This issue is trying to lubricate the fecker - just not sure whether there would be enough going up the shaft to lube it, that is one of the reasons why I ditched the idea.  Use the XE dizzy - just put a crank trigger on the front.  know one said the dizzy had to function did they???

[Xelisty 366]

Polson is in the right track, its was very much Incorrect machining, a hardened distributor gear will solve this problem, Crow Cams make the gear to suit, part no. DG2

 

I bought this gear not long after i rebuilt the engine in my BnS basher back in July 2011, 3 years later and no problems since

 

 

 

I have one of these too. I chewed two dizzied in a month and changed to these and zero issues since. About 3000km and 30 off drag runs

Do the job and timing is spot on

 

 

Sent from my iPhone using Tapatalk

[slydog 7,873]

Yes so I just assumed everyone would be using the much better TFI EST unit but apparently there are rules for speedway and some people don't use em on street engines for some reason ? A simple Street Fire CDI box and TFI dizzy is the best bang for buck ignition mod for a xflow ever.

 

There's a lot of mods needed to make a electronic stable and safe it seems and again if not needed by some sort of rules reg's just convert it to TFI/EST as soon as possible.