Slightly rough running.

[craggle]

HT Leads are Taylor Spiro Pro 8mm all new 652.5 miles ago. spark plugs are Champion RC12YC.

Have removed the distributor cap and surprised at the amount of carbon dust in the centre of the rotor arm and the amount of build up on the 8 contact points inside the distributor. I have cleaned the bits off now and wire brushed the contacts inside the cap with the dremmel. and will stick it back together.

Removed the ignition module and that is nicely seated on white grease.

Mechanical advance weights move freely as does the vacuum advance.

I had a similar problem once with a Rover V8 and cheap rotor arms. When compared with a Lucus one the arm was much thinner material and shorter forcing the spark to jump a bigger gap.
I think I will buy a decent cap and rotor arm and keep the current one as a spare. MSD do replacements with higher powered coils unless I decide to go fuel injected in which case it may all get replaced anyway.

Cheers

Craig.

[craggle]

Me again.

Here's a couple of picture of my rotor arm. Can you see the black lines running out from the centre where the cap contact it made?

Do you reckon the dust may have caused tracking to the two bolts holding the rotor arm in place?

Craig.

[mikey]

Originally Posted by craggle

Me again.

Here's a couple of picture of my rotor arm. Can you see the black lines running out from the centre where the cap contact it made?

Do you reckon the dust may have caused tracking to the two bolts holding the rotor arm in place?

Craig.

If you have not got it sorted and you have a Holley or similar carb I would just check the tightness of the fuel bowl securing bolts. It is very common on carbs up to 3 or 4 years old for the screws to slacken or for the gasket to settle. All you need is a microscopic gap and the fuel bypasses the gasket causing an enrichening effect. Bit like having a choke slightly out on a hot engine (for those that can remember chokes) (or magnetos in Wilfs case).

This particularly happens when the car has been stood for a while (as in months) and then started. Over the length of a run as the carb warms this seems to bring it on. After a few years it seems to stop happening.

For the sake of two minutes it is worth a shot - I remember Stoneleigh about 8 years ago where it sorted out about 4 cobras that were running horrible on tickover - it had been put down to electrics or cam.

Mike

[craggle]

Hi Mike

Carb is an Edelbrock 750cfm.

I will check all the screws I can see for tightness.

Cheers

Craig.

[mikey]

Originally Posted by craggle

Hi Mike

Carb is an Edelbrock 750cfm.

I will check all the screws I can see for tightness.

Cheers

Craig.

That screws that theory then. I dont think the carter design suffers with this problem like the Holley.

Did you check the timing to see if it slipped.

miek

[craggle]

No, Haven't checked the timing yet but will give it a go at the weekend.

I am thinking of changing my spark plugs as I have had previous problems with Champion spark plugs in my Range Rover.
I found the NGK equivalent to the ones I have fitted but I have read about different temperature plugs?

Any good recommendations for a 350 running 10:1 CR and Edelbrock aluminium heads?

Craig.

[mikey]

Originally Posted by craggle

No, Haven't checked the timing yet but will give it a go at the weekend.

I am thinking of changing my spark plugs as I have had previous problems with Champion spark plugs in my Range Rover.
I found the NGK equivalent to the ones I have fitted but I have read about different temperature plugs?

Any good recommendations for a 350 running 10:1 CR and Edelbrock aluminium heads?

Craig.

Heat range 5 or 6 no more unless you are on the circuit. I would actually opt for 5 for road use as 6 can foul with intermittent use although it is classed as Ok

I have attached the table for NGK choice which makes it simple

NGK spark plugs symbol code

eg if you were to choose iridium then it would be a BPR-5EIX depending on if you are using a capacitive discharge or other you may want a plug with a larger gap so that the electrode and groung remain as near parallel as possible. In that case you would use a BPR-5EIX-11.

Just choose the type of nose you require depending on what you want to spend and use the relevent symbols in the latter part of the plug type. If you want to check if you have got it right just post.

Just a last comment - a common thing is for owners to look at tables that give compression, head type, compression ratio etc. This can lead you to a heat range around 7 quite easily. The reality is that if the car is not being driven hard all the time, this can lead to fouling on a cold plug. Better to get the 5 or 6. If I were a betting man the 5 would be the one for road use.

Hope this helps

Mike

[craggle]

Many thanks Mike.

That helps a lot. I did a comparison search for the Champions I have at the moment and the NGK equivalent is the BKR5E.
I will take a look for some Iridium ones though And get the BPR-5EIX-11

Wonder if Halfords sell them?

Thanks again.

Craig.

[mikey]

Originally Posted by craggle

Many thanks Mike.

That helps a lot. I did a comparison search for the Champions I have at the moment and the NGK equivalent is the BKR5E.
I will take a look for some Iridium ones though And get the BPR-5EIX-11

Wonder if Halfords sell them?

Thanks again.

Craig.

If you are using the 16mm hex there is no reason to change if it gives you more space. The equivalent would be BKR-5EIX-11

These guys are pretty competitive:

NGK Iridium Sparkplugs List

All the best
Mike

[craggle]

16mm Hex is useful to give a bit more clearance around the cylinder head.

BKR-5EIX-11 It is then

Many thanks

Craig.