Diagnosis help required please!

[_DeeJay_]

I've just got the Chimaera back into regular use and noticed that it sounded a little bit tappy on tickover.

I assumed this was probably the manifold gaskets, so raised the bonnet to have a look to find the lead to the coil shorting every so often with the terminal on the front of the coil.

I rearranged the lead (after electricuting myself - doh!) and it seemed better.
So, when I got to my destination I lifted the bonnet again to check it was behaving itself to find the thick section of exhaust, below the y piece glowing red hot.

Could anyone guess at what the problem is (and whether the glowing exhaust relates to the ignition problem)?

The only symptom when driving is that the car runs out of legs at about 5000 revs (maybe a tad below), accelerating far less briskly.

This was usual on my Griff 500, but I presume the 400 is supposed to rev more?

Could the cat or precats be on their way out and be blocking the exhaust?

Thanks all,
D

[chassis 33]

Sounds like you've assumed correctly, I'd put my money on a blockage at the top of the main cat, caused by one or both of the pre-cats collapsing and blowing themselves out.

Regards
Iain

[_DeeJay_]

chassis 33 said:

Sounds like you've assumed correctly, I'd put my money on a blockage at the top of the main cat, caused by one or both of the pre-cats collapsing and blowing themselves out.

Regards
Iain

Hmmm, could be worse - I've just been reading threads about leaky valves and more woe/£
If it's just the pre-cats, and I've not managed to damage anything else then it'll be a good excuse to rip them out entirely.

My only concern is noise - will it add much? I'd rather keep it as quiet as possible for trackdays.

cheers,
D

[chassis 33]

Removing the pre-cats will only have a marginal effect on noise levels. Even with a full decat (and standard silencer box) the racer has only managed 103db this year, or 92db once (I shift at 5k guv' )

Regards
Iain

[_DeeJay_]

chassis 33 said:

Removing the pre-cats will only have a marginal effect on noise levels. Even with a full decat (and standard silencer box) the racer has only managed 103db this year, or 92db once (I shift at 5k guv' )

Regards
Iain

Great, thanks Iain. I'll get it down to Offords and see what they can do with those precats (if they're still in situ!)

Darren

[Cider Andy]

Was the king lead shorting through its insulation? This kind of ignition fault can certainly cause the exhaust to glow, although it's normally just one or other of the manifolds. It's certainly worth checking and/or replacing the plug leads and shrouds. Also check the condition of the rotor arm and distributor cap. If it still has Lucas items fitted and they're serviceable, keep them! Some of the aftermarket rotor arms don't seem to work very well.

[_Deejay_]

Cider Andy said:

Was the king lead shorting through its insulation? This kind of ignition fault can certainly cause the exhaust to glow, although it's normally just one or other of the manifolds. It's certainly worth checking and/or replacing the plug leads and shrouds. Also check the condition of the rotor arm and distributor cap. If it still has Lucas items fitted and they're serviceable, keep them! Some of the aftermarket rotor arms don't seem to work very well.

Yes, it was shorting through the insulation. The odd thing is that the manifolds aren't glowing, it's further down (just below where the two join into the thich section by the main cat).

I've got some plug extenders in the garage, so I'll order some magnicore leads and see if that helps.

thanks,
Darren.