Outer Limits 4x4 Board

Hi

My '86 rangie has developed a continual ticking noise and a choofing noise when the engine is worked hard.

The tick and the choof are reletive to engine speed. #5 cylinder plug was dry black fouled while all other plugs were good.

Car has done 110,000 kms and has not had any major work from what I can tell. 8:1 compression engine.

I have:
done a compression test - all cyclinders 170 psi +/- 3 psi when hot
replaced plugs and leads - no different
had a look at the rotor button and cap, don't look bad but don't really know what I am looking for
checked timing, around 0° btdc as per manual.
checked earth strap to the ignition coil, was perfect both ends
replaced ignition coil

Does anyone have any ideas? I think i will have to pull the heads and check out the cam, which I am not real keen on doing.

Thanks

Dave

Tighten the exhaust manifold bolts. These work loose over time and can cause an almost metallic choofing sound.

If this isn't fixed by doing this, check for soot or get a piece of hose and run it around the exhaust ports on the head where they meet the manifold while holding close to your ear.

Don't put it in your ear, or you could be in the market for a new eardrum if you do find a leak.

Yep I should check my manifold bolts. Have had a good look around and can't see any black soot, so i figured that everything was good.

Doesn't explain why #5 is fouled. Am using injector cleaner, doubt it will do any good though.

Thanks

DJ

On the fouled plug, does it miss a bit? Lead could be a dud.

The choofing noise doesn't really make too much sense tho. Do try the listening test for the manifold before you move to the next bit.

Is it fouled as in wet, or a bit carboned (is that a word) up

Thought it could be a lead too, replaced leads and plugs and no better.

Fouled is dry black carbon powder, not wet at all.

Thanks

DJ

Does not miss a beat, car still has plenty of power and doesn't miss when in nuetral. Could be missing a bit when being worked (which is when then choofing happens).

Change the plug with another cylinder?

Might have been faulty from new or the install could have cracked the ceramic post.

You may have a leaking valve stem seal. I know on my Commodore the seals have pretty much gone (225 000 badly treated k's). It was running quite bad recently (missing on at least 2 cylindes) so we pulled the plugs out and gave them a clean and now its running like a dream...hopefully for about a month, before the carbon deposits will build up again.

This may be the problem. Does it blow smoke when its worked hard? The commodore also does this, its just burning oil and when the plugs are covered in the carbon deposits I suspect its also blowing out lots of unburnt fuel.

If the seals have just gone hard a bottle of valve rejuivinator (spelling?) from wynnes or something may help in the short term by softening and expanding all the seals.

Hope this helps.