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Title: Red Hot
Description: Exhaut query


JSeaman - March 27, 2007 08:30 AM (GMT)

After some 'spirited' driving my exhaust was glowing red hot where the 4 runners meet from the manifold. Is this common or are my EGTs likely to be through the roof?!

Andy S - March 27, 2007 10:04 PM (GMT)

EGT'sway off - running to lean or timing is off.

Check valve clearances as well.

Cheers

Andrew

JSeaman - March 28, 2007 08:30 AM (GMT)

That's the way I figured it - valve clearances have just been done.

I think timing-went to check it last night and found myself confused!!

On the distributor side of the crank pulley there are 4 white lines and marks on the crank pulley. Two close together, 1 with about an inch gap and another one about 3 inches further away. No marking on them and not what I was expecting but hooking a timing light on #1 lead showed I'm somewhere around the two that are close together (which I expect to be right).

This morning I found on the OTHER side of the pulley are 4 marks close together (what I was looking for) and a second metal bit sticking out to line up the timing marks. Again, no marks though - I'm guessing TDC, 2, 4, 6 but not certain. If anyone can shed some light it'd be great!

I've also found conflicting static timing values - Sierra manual says 8 degrees and Cortina (which the engine is from) says 4 degrees but there's also unleaded fuel thrown into the mix - any thoughts?

JSeaman - March 29, 2007 08:47 AM (GMT)

OK clearances are good, timing is bang on 6deg btdc and I have a red exhaust! It's the 4-1 join and it goes red just as the car starts to warm up and doesn't change no matter how much I cane it

Andy S - March 29, 2007 09:22 AM (GMT)

What's the timing doing at 3500? - and remember that the timing is only correct if the mixture is correct.

With all sorts of notches and marks on the crankpully I would double check TDC with a gauge on top of the piston through the plug hole. Also the timing will depend on the compression ratio - so if this has been rasied the timing will need to be different.

Cheers

Andrew


JSeaman - March 29, 2007 10:13 AM (GMT)

Only done the static timing so far - going to check the vac/mechanical advance out tonight if I can

I need to test the afrs but haven't got a method at the mo - I'm pretty sure it's on the rich side from the behvaiour of the car but I'm going to have to either get it to someone with a wideband, have a go with one of those weird ColorTune things or go a bit old shool and advance the timing until the spark plugs turn white - really can't get into this method of tuning, I'm used to precision so would prefer the wideband route!

I did the TDC by hand last night and it lined up with the 4 marks which I was expecting to see perfectly. The other marks look like they are 2, 4, 6 degrees and it was on the 6.

Anyone know a decent tuner in Derbyshire? It's a tiny job with the right equipment but I don't have all I need

JSeaman - March 30, 2007 08:21 AM (GMT)

OK done my advance check and both mechanical and vac advance are working as they should. The only two things left are whether the timing should be different from the norm with the cam that's in and the potentially altered compression ratio and whether or not my AFRs are OK.

I've been told that 'Colour Tune' devices should let me have a stab at AFRs and I know my plugs looked OK when I took them out so I'll give that a whirl first.

Need a local Pinto dude still to check the timing out-no ideas??

Andy S - March 30, 2007 11:29 AM (GMT)
Advance the timimg to 10 degrees before and see what happens - running hot like that is normally a sign that the gas is still burning when the exhaust valve opens - advancing he spark makes sure that all the combustion happens inside the cylinder.

May also indicate a weak mixture - weak mixtures take longer to burn and need more advance.

Cheers

Andrew

JSeaman - March 30, 2007 12:01 PM (GMT)

Advancing the timing without knowing what's going on is something I didn't really want to play with - I'll try and get one of those colour tune things before I fiddle with the timing

I've no idea where my AFRs are and tweaking the timing could make things worse

Thanks for the input




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