Dizzy gear

[Anonymous]

Recently my car chewed the gear off the dizzy, one side of the gear is almost gone and the rest is sharp. I have checked the gear on the cam as best i could with it in the car and it doesnt appear to be damaged. The dizzy in mention is rebuilt and curved to suit my cam etc etc so i would like to use it again. I have a spare gear to put on it but i'm unsure what caused it. I thought maybe the shaft? but i dont know. i dont want to put a new gear on it then have it do it again this time stuffing the cam.

Any thoughts?

Cheers

Simon

 

[Anonymous]

you can get a hardened gear fitted reccomended with new cams i choose to use standard gear and replace it every 6-12 months rather than riush the hardened one eating the cam away

 

[addo]

Is your oil pump dodgy?

 

[Anonymous]

Simon,
If we look at this situation with the distributor gear. The two things come to mind.
First off,
Is the distributor gear the correct one for the camshaft fitted.
The after market cam suppliers usually specify if an alternative distribuor gear needs to be fitted or the original can be used.
Secondly,
The distributor drive gear drives the distributor "obviously" and the oil pump.
Any excessive resistance will cause rapid wear and premature failure of the weakest component. This being in this case the distributor gear.
Does your car have a modified or aftermarket oil pump?
High volume or pressure will increase stresses on the drive system.
if the car has an original oil pump and it is in a serviceable condition.
Contact the camshaft supplier and check that the correct gear has and will be used on this distributor.
Check the distributor itself for excessive wear or end float.
If all these are acceptable, fit the required gear. A new one of course.
Run this for amonth or so and pull the distributor and check for excessive wear on the distributor gear.
If unsatisfactory, i.e. too much wear then the cam will have to come out and be inspected. Probably replaced.
Noel.

 

[80broncoman]

Do you have a high volume oil pump? Have you shimmed up the pressure relief spring in the oil pump? Either of these can cause gear wear.

 

[DYNOED250]

mate, DONT DONT DONT use the standard gear with any after market cam, they can wear out in just a weak of driving, use a crow gear and you wont have any problems at all..

 

[Anonymous]

Thanks guys,

I did have a high pressure oil pump but when i put the cam in i put a standard jp pump in. I have a crow cam in it, so i will get there HD gear sent up. Its funny, i had a standard dizzy in it for the whole time and had no problems. Its only been since i put the rebuilt/curved dizzy in that it lasted about a week. Maybe the standard dizzy had a decent gear on it.

Oil pump and whole motor is only about 800km old so i presume most of the parts should be in good order.

Thanks again for the replies,

I'll let you know how i go.

Cheers

Simon

mate, DONT DONT DONT use the standard gear with any after market cam, they can wear out in just a weak of driving, use a crow gear and you wont have any problems at all..

 

[wagon]

I have just fixed my distributor for the same reason - teeth sharp enough to cut fingers and lots of timing variation! I had some trouble getting a new gear, but ford had one that fits but the holes for the roll pin had to be drilled. I have a newish cam and std oil pump (~~10k old). I paid $50 for the poxy thing - and now I find out there is an aftermarket one! Oh well.

 

[DYNOED250]

The ford gear is no good it will still chew out. The after market gear is hardend better..

 

[alloydave]

I got a ford one that had to be drilled ...........shagged that in about 100k on a brand new engine .There was that much play in the gear that you could not time the engine ,you could move the crank 10deg at the rotor hadnt moved.
Not sure if its the hi vol oil pump that contributed to the problem.The problem with having to drill your own hole could be part of the problem as you would have to be very accurate or you could end up with to much thrust. The crow DG2 is the way to go .My gear problems cost me a cam ,a set of rings ,bearings ,and a set of gaskets .The only bonus was that i know everything is clean and thers no shit floating around in my sump.

 

[Anonymous]

The problems not with the distributor gear. When ford made the crossflow, it let the beancounters into the engine. !@&)##$ accountants!
Problems;
-no front bolt in the harmonic balancer
-thread in crank snout not tapped full length
-fitting a multi link hy-vo style timing chain (good for load, no good for revs; too heavy
-1 woodruff key driving timing gear and balancer
-only tail of woodruff key drives timing gear and when engine is revved hard, tail of key snaps

result
-engine has coarse sound at 2000 revs which is timing gear rattling on crank.This is transferred to the cam and wears the distributor gear.
Mine had 13 thou of wear on the snout with a worn distributor gear as you describe.

Fix;
-fit good roller timing chain
-tap crank snout full length so that threads do not have a side load on them ie bolt length is longer than balancer snout length
-re groove crank snout
-check balancer for cracking up woodruff key slot from being loose.


The other places they didn't let the accountants into work damn fine!

 

[alloydave]

Rnb ,those processes you mentioned may stop some wear in some engines but not all . My engine had a jp double chain timing gear set up ,a re profiled crank snout , a romac street/race damper , a damper bolt and washer and new woodruff key .Here in NZ we still get at least one claim a year on camshafts due to unusual cam and gear wear,most reconditioners seem to want to blame the camshaft but alot of the cam manufactures blame the poor block and dissy alignment.
QUOTE...from supplier...
Distributor and Camshaft gear wear.
It is possible that some blocks may have a misalignment problem with distributor.if in doubt ,confirm camshaft end float is correct,as per workshop manual ,and bearing blue the gears to check tooth contact.If tooth contact proves to be incorrect ,or you are still in doubt ,a replacement gear is available to compensate,under the following part numbers-
DG2 0.490" SHAFT
DG2A 0.530" SHAFT
*The use of a high volume oil pump is not recomended in this application due to the added stress on the distributor drive.

This was included in the cam box from CROW CAMS

Cheers Dave

 

[DYNOED250]

the prob is def in the differnt cams. stockys will last for ages put a different cam in them and instant dissy gear wear...
i doubt the wear is caused by timing chain..

 

[Anonymous]

I haven't heard of the misalignment problem, but that does not mean it doesn't occur under production tolerances!!!!!!!
As for the timing chain, the oscillating load of driving the camshaft and the power pulses from the crankshaft combined with a loose crank gear would cause the wear of the distributor gear ie you are asking the "constant load" oil pump to speed up and slow down very quickly thus causing chatter and wearing the gear. The timing chain will only transmit it. (A chain will transmit less harmonics than a gear drive though.) Also, the huge wiping effect of this style of drive and the fact that the oil pump cannot back drive the cam means the gear is not able to transmit the extra harmonics anywhere, leading to increased wear of the smaller distributor gear.
It is not a lubrication problem because the block has an oiling hole in the block spraying directly on to the drive.
Can anyone shed any more light on the subject?

 

[DYNOED250]

Well you can talk about harmonics and all that for ages... Simple fact is that once u change a cam a 250 will usually always chew the dissy gear out, put a crow gear on and its all fixed. My old man had an xf with a 200 5 speed, it done 280,000 km and never stripped a gear, its cam was never changed... .. I build a new motor with a new cam and the gear strips in a weak, its deff a missalignment issue, crow have researched it and have come up with a fix.. Ive never striped a crow gear simple as that.

 

[Anonymous]

I agree with you there dynoed250. before i rebuilt the motor i never had any problems with the dizzy, i did a 1000 km on a brand new dizzy with a crow cam and it was completely f****. My stock EFI XF that i drive everywhere has just hit 320000 km and i have never replaced the dizzy.

Cheers

Simon

 

[Anonymous]

How does changing a dizzy gear fix a mialignment problem? Sounds like the 2 gears wear to each others profile in service.

 

[DYNOED250]

the prob with after market cams is in the cam... Ive fitted a factory brand new cam in a customers car and it worked fine new chew the gear....
Even if u use a factory brand new gear with a aftermarket cam it WILL 100 PERCENT chew the gear . Im only telling u from my experanices factory cam and gear 200,000 km, remove the dissy and there will be nearly no wear at all, repplace the cam and next week it will chew the gear off. Im not making this up it happens, just use a CROW GEAR and no worries at all problem solved, i havnt cheewed a crow gear out ever and i run 70 psi oil pressure and rev to 7000 rpm.

 

[addo]

So it could be something as simple as a different worm angle/pitch?

 

[Anonymous]

Adam,
You could be on the right track here, as a subtle variation. Would have profound consequences to the life of the gears in contact.
Does that sound smart or what?
Noel.
Could also be related to the case hardening or even the composition of the material used in the gears manufacture.