Unusual problem HELP

[D14 AYS]

Evening gentlemen,

Some advice sort as I have a major problem with my distributor drive, it keeps wearing out. I have had 2 brand new distributor drive coggs fitted in the last 4 weeks and the distributor has eaten them to the point where there are no teeth left on the cogg. The distributor cogg stays fine it is just the one fixed to the cam. I am assuming that there is some horrizontal travel in the cam but we cannot seem to come up with a solution.

Have spoken to all the major engine people with no help, everyone seems to be pretty baffled with this.

I am desperate to get this resolved as the car has been in the garage for the last 6 weeks out of 8.

Any suggestions or advice would be much appreciated.

By the way the problem happened and we thought it had been cured by fitting a new cam and all relevant parts to no avail it reoccoured within 400 miles with all new parts.

Cheers guys
Dean

[350Matt]

Sounds like some misalignment is involved either that or its not getting any oil?

Try checking oil ways by blowing an airline into the oil pressure switch take off also is the front cover straight and not warped in anyway?

Matt

[K4000JB]

just a thought if the oil pressure is to high (above 60psi when warm according to the des hamill v8 book) it can cause this problem dont know how quick it would happen though, sounds more like lack of oil imho
hope you get it sorted in time for summer when it gets here
ant

[D14 AYS]

Quinny said:

Dean have you spoken to Rob at V8D??

When he did my cam he fitted a retaining plate at the front, pretty sure this was to stop cam float. Might be worth a call, he's very helpful

Hi Mate,

Spoken to V8D they were pretty baffled aparently.

[D14 AYS]

Quinny said:

Dean have you spoken to Rob at V8D??

When he did my cam he fitted a retaining plate at the front, pretty sure this was to stop cam float. Might be worth a call, he's very helpful

The guys fitted one of those retaining plates with the new cam

[GreenV8S]

Are you saying that this problem started on an engine that was initially working OK and hadn't been disturbed at all around the time the problem started?

[D14 AYS]

GreenV8S said:

Are you saying that this problem started on an engine that was initially working OK and hadn't been disturbed at all around the time the problem started?

Hi ,

Yes the car was running fine in my ownership (10 months) until this happened the first time,problem occured ,sent to garage had new cam,lifters,both distributoer drive cogs,timing gear and chain set,cam locking plate and all relevent other stuff, car drove for 4oo miles and it happend again, im waiting for the guys at the garage to sort it but it seems that it is something very rare that has happend.

Cheers Dean

[D14 AYS]

Quinny said:

Ok

I'm thinking if the cam ain't moving, it could be worn bushes or bearings in the dizzy itself.

I'm pretty sure that the gear that drives the dizzy (the one on the cam) is made of softer material than the gear on the end of the dizzy, this is so it dosen't damage the cam gear.

Also when you've replace the cam gear did you also replace the dizzy gear,?? as really you shouldn't mix new with old.

The only other thing I can come up with, is, is the cam gear fitted the right way around?? it has an oil groove to help lubricate it.

It should be fitted like this below.



If it were mine I think I'd be inclined to refurb or replace the dizzy bearings etc, fit 2 new gears and give it another go.

Hi,

the distributor seems pretty new and apparently in very good shape.
Thanks for the picture and your suggestions.

[GreenV8S]

I don't know what the problem is and can't offer any practical advice, but at the back of my mind I seem to remember reading about a gotcha which put the dizzy drive gear in the wrong place leading to exactly this sort of problem. It may be a complete red herring, and if there's any substance to it then I'm sure that anyone who works with these engines would know about it. I'll try to remember where I read it, but with a memory like mine I wouldn't hold out much hope ...

[Uncle Fester]

The fault finding you've done sounds expensive.
An alternative would be to fit an aftermarket ECU and do away with the dizzy.
Fester

[spend]

You have no details as to which engine you have. Do you have just the dizzy or the oil pump also driven from the cam?

Dave

[Uncle Fester]

A positive displacement pump, like the oil pump, can't pump if the outlet is blocked. It will hydraulic lock and the force driving it will try to break the drive or stall the motor.
If the outlet is constricted then it will increase the load on the pump and the pressure on gear teeth driving it. This will accelerate wear in the pump and its drive.
The constriction need not be in the pump itself, just down stream of it.
The pump wouldn't show extraordinary resistance on the bench as it is unprimed.
The picture in the OP's profile suggests a pre-serp.
The Hamill comments about high oil pressure may refer to a symptom of this problem. I haven't seen that book, so I can't be sure.
Fester

[D14 AYS]

Uncle Fester said:

The fault finding you've done sounds expensive.
An alternative would be to fit an aftermarket ECU and do away with the dizzy.
Fester

Hi,

Your not Kidding about the expense , That could be the way forward, what sort of cost is there to do away with the dizzy ?

[D14 AYS]

spend said:

You have no details as to which engine you have. Do you have just the dizzy or the oil pump also driven from the cam?

Dave

Hi,

My car is a 92 4.3 precat, not sure where the oil pump is driven from .

[spend]

Don't do away with the dizzy then, you will not get any drive to the oil pump.....

You would have to convert to a later serp front end, which is not exactly straight forward.

Dave

[Uncle Fester]

D14 AYS said:

Uncle Fester said:

The fault finding you've done sounds expensive.
An alternative would be to fit an aftermarket ECU and do away with the dizzy.
Fester

Hi,

Your not Kidding about the expense , That could be the way forward, what sort of cost is there to do away with the dizzy ?

You can have it all done for you at a cost of about £2000 by giving the job to someone like Trackcar to fit an Emerald setup. If you can DIY it can be done for less.

The benefits are not only the getting rid of the distributor, the whole running will be better and it opens up the path to more tuning.

However as you have a pre-serp you still need to drive the oil pump. distributorless route may not solveyour problem as it would in the latter serp engine.

My previous comments that oil flow problems could be causing the gear failure apply to the pre-serp because if the oil pump is trying to hold the distributor still then that force is transmitted via the dizzy drive gear.

If you have an oil flow problem then the expense of not finding it will be nasty.

What is your oil pressure gauge showing recently and how does this compare to well before the problem first appeared?

Fester

[D14 AYS]

Uncle Fester said:

D14 AYS said:

Uncle Fester said:

The fault finding you've done sounds expensive.
An alternative would be to fit an aftermarket ECU and do away with the dizzy.
Fester

Hi,

Your not Kidding about the expense , That could be the way forward, what sort of cost is there to do away with the dizzy ?

You can have it all done for you at a cost of about £2000 by giving the job to someone like Trackcar to fit an Emerald setup. If you can DIY it can be done for less.

The benefits are not only the getting rid of the distributor, the whole running will be better and it opens up the path to more tuning.

However as you have a pre-serp you still need to drive the oil pump. distributorless route may not solveyour problem as it would in the latter serp engine.

My previous comments that oil flow problems could be causing the gear failure apply to the pre-serp because if the oil pump is trying to hold the distributor still then that force is transmitted via the dizzy drive gear.

If you have an oil flow problem then the expense of not finding it will be nasty.

What is your oil pressure gauge showing recently and how does this compare to well before the problem first appeared?

Fester

The oil pressure gauge shows very little oil pressure, i have been told the gauge is faulty.Do you think this is the case ?

[Uncle Fester]

D14 AYS said:

Uncle Fester said:

D14 AYS said:

Uncle Fester said:

The fault finding you've done sounds expensive.
An alternative would be to fit an aftermarket ECU and do away with the dizzy.
Fester

Hi,

Your not Kidding about the expense , That could be the way forward, what sort of cost is there to do away with the dizzy ?

You can have it all done for you at a cost of about £2000 by giving the job to someone like Trackcar to fit an Emerald setup. If you can DIY it can be done for less.

The benefits are not only the getting rid of the distributor, the whole running will be better and it opens up the path to more tuning.

However as you have a pre-serp you still need to drive the oil pump. distributorless route may not solveyour problem as it would in the latter serp engine.

My previous comments that oil flow problems could be causing the gear failure apply to the pre-serp because if the oil pump is trying to hold the distributor still then that force is transmitted via the dizzy drive gear.

If you have an oil flow problem then the expense of not finding it will be nasty.

What is your oil pressure gauge showing recently and how does this compare to well before the problem first appeared?

Fester

The oil pressure gauge shows very little oil pressure, i have been told the gauge is faulty.Do you think this is the case ?

I wouldn't take a chance on it.
If the garage has identified an instrumentation fault then why hasn't it been fixed?
Unless the oil pressure gauge reading has been verified with an independent, accurately calibrated instrument, or a certain instrument component is known to be defective then they're assuming that because they can't account for the reading, the reading must be wrong.
This is risky. Remember what happened when a NASA engineer assumed a gauge that was reading "off the scale, high" was faulty, Just because he couldn't think of an explanation to account for the observed reading?
Err, Houston, this is Apollo 13, we have a problem...Nuf said.

Lets assume the oil pressure gauge is correct, how can we account for the symptoms?
Lack of oil pressure could be causing the worn gear to run without sufficient lubrication, leading to rapid wearing. But why would this affect that gear in particular? As far as I know, low oil pressure doesn't normally kill just that gear, without damaging lots of components.

I have a serp and am unsure of the relationship between the pump and oil pressure sender on the pre-serp. However, if there is an obstruction between the pump outlet and the sender then this would cause a pressure drop, accounting for the gauge reading. The pump would be subject to much higher loading, as explained in my previous posts. A combination of extra load and reduced lubrication would kill the gear.
A blocked pump inlet might also cause it, but less likely.
If the engine has been running without sufficient lubrication for any time then it may need a complete strip down inspection. It is a possibility that the low oil pressure is caused by engine wear.
Unfortunately, just replacing the cam in an engine that's got low oil pressure will probably damage the new cam too.
Who is currently doing the work on your car?
I think you need to get the engine to one of the top engine builders. Get him to verify the oil pressure and if it’s low, sort it. In the course of stripping to do this he will be able to check for oil way obstructions.
Whenever something odd like this is going on then its a false economy to sling bits on without finding the underlying problems.
Fester

[spend]

The engines will normally run happily with low oil pressure... If the oil pressure warning light comes on thats a different matter. 10000's of these engines are run happily with only the warning light, why make such a big issue about a faulty oil pressure gauge reading?

If you weren't getting oil to the top end of the engine you would have noticed it sounding like a bag of spanners I would have thought. You should also be able to see whether there has been oil starvation at the cam/dizzy gears when you strip the front cover. Some tuners drill the block to allow extra draining from the valley to this area, but that is in addition rather than replacing the oil feed, if you are getting oil starvation it may simply be that the cam fitters have managed to block an oilway - cleanliness is essential...

Dave

[350Matt]

Just a thought isn't is possible to block off the oil way into the front cam bearing if the bearing is fitted incorrectly?

Not sure if it is or not?

Matt