Thanks for the great tips. Here's a little more info. This car doesn't
seem to have the horsepower the last 1500 Midget I had did, but that one had
higher compression pistons in it. This one appears to be an original engine
in a California car, so it would have the really low compression engine.
When I left the shop, the idle speed was about 900-1000 RPM, but now has
dropped to below 500 RPM. It misses and bucks subtly at steady speed
cruising in the 2500 RPM range, like during in-town driving. Disconnecting
the EGR valve improved this but didn't cure it. Advancing the timing seemed
to make the Cat run cooler, but still way hotter than it seems like it
should. I'm parking it until I can look into this more. Seems like the
summary of advise has been:
Check exhaust valve clearance
Check canister vacuum leaks
Check mixture (again)--I have a colortune, but have never used it. Looks
like this might be a good time to learn.
If these still fail to bring about cooler exhaust, gut the converter.
David Riker
74 Midget
78 Midget
63 Falcon
http://personalweb.sunset.net/~davidr
----- Original Message -----
From <Thecarguru at aol.com>
To: <davidr@sunset.net>
Sent: Wednesday, January 19, 2000 7:12 AM
Subject: Glowing Catalyst
> Generally speaking, anything that burns or is still burning when it
reaches
> the converter will just burn hotter. Hydrocarbon (raw gas) is the big one.
> What do the spark plugs look like? Is the engine running too lean now?
Have
> the valves been adjusted? I dont even want to look at the two (junk)
cylinder
> heads in my shop right now. Both have cracks in the exhaust seats, and one
of
> them came off a running engine! And with the 1500's ability to burn
exhaust
> valves in the blink of an eye... well... start easy. Pull the valve cover
and
> check the exhaust valve clearances. I run mine around .018 without
problems.
> The clearances do close up with heat, and if the engine is running a bit
lean
> the valves will get hotter and expand more, so tight valve clearances will
> become too tight after running a bit and hold valves open letting raw gas
out
> on the compression stroke. Makes for big red converters and smoking
carpets
> etc. Same goes for screwy ignition advance and secondary ignition failure.
> Any missing ? Is this engine running smooth and strong?
>
> Gary
> 75 Midget daily driver non catalyst weber equipped and passes smog in a
> heartbeat (but they dont inspect under the hood here)
> 75 Midget project car that looks like it will probably NOT get another
> Triumph 1500
>
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