This Does Not Sound Good ....

[V8burble]

Has the vacuum advance on the distributor been ruled out as a cause (split diaphragm) BTW?

[conrod]

A quick update! I woke up this morning feeling lousy - I had a headache yesterday which I put down to the noise () and to quite a high dose of petrol and exhaust fumes!

I had other things to do today anyway - that I should have been doing instead of working on the Cob, as 'er indoors reminded me

So I've put it all on hold today. I'll start again tomorrow, and I'm going to go right back to the beginning with the leak location and repeat all the tests. I must have missed something - hopefully returning to this after a break and with a clear head will yield a positive result ......

Thanks for all your input and moral support!

[Wilburn]

Hi Alan,

Just listened to your video and it does sound just like my carb when it was sucking air through the spindle on the secondaries!

Paul

[conrod]

Originally Posted by Wilburn

Hi Alan,

Just listened to your video and it does sound just like my carb when it was sucking air through the spindle on the secondaries!

Paul

Yes - the secondary spindle is ridiculously loose on my 4150 - been like that since I fitted it, mind. But if it is the cause, or a contributor, then the package you've sent will solve it. Thanks again Paul - you're a star!

But for now it's time to light the barbie and pull a cold lager from the fridge!

Cheers.

[Wilburn]

Good idea, think I'll do the same

Let me know tomorrow how you get on ............


Cheers

Paul

[conrod]

What a difference a good night's sleep and a refreshed, logical mind makes!

I found the leak at last - in the inlet manifold between 6 & 8. And I was really lucky with the manifold removal. I used a modelling knife with a 1" long blade (1/4" going down to a point at the end) and cut through the RTV front and rear. Then I inserted an old blunt 1" chisel at the site of the leak and it just popped up - happy days!!!

So now for the clean-up and the reassembly. And now I have the coolant drained I can replace the leaking core plug - every cloud has a silver lining ......

[Vidge]

Well done Use No Nails to refit it, that'll learn it to leak on you. /Joke

[wilf]

Hurrah!

Better put a good straight edge on the inlet manifold to see if it has warped to cause your gasket breakage.

[conrod]

Originally Posted by wilf

Hurrah!

Better put a good straight edge on the inlet manifold to see if it has warped to cause your gasket breakage.

Wilf,

Have checked. Totally flat on the LH side, and also flat on the RH side except for the last 3" (across the rear water port) where I can squeeze a 3 thou gauge at the end. That's the side that was leaking, but as the warp is beyond nos 6&8 inlets (where teh leak was), I'd say it's probably OK. What say you?

[conrod]

Next question! I blocked the ports in the head, and laid clean cloths in the valley before I started removing the old silicone sealant and gaskets. I'm pretty sure nothing has dropped into the valley. It's the silicone I'm concerned about - stray pieces are very good at blocking oilways, and I've seen the damage that can cause!

I'm therefore going to change the oil and filter - it was due for a change anyway. The question is, should I drain it cold (before I fire up the engine), or should I let the engine warm up then drain the oil. I'm thinking of the latter at present.