erik69&85

iTrader: (1)

At the end of the driving season last year, I had a high flow cat and larger pipes added to the exhaust. Went from 2.5" to 2.75" and replaced the flowmaster muffler with the same. Ever since then, the exhaust gets very hot whenever i drive it. I am guessing that it is running lean. Guessing I need to change rods.

I also had to reset the timing afterwards.

Anyone else had a similar experience? I like to get an idea before I start messing with the carb. Everything else on the engine is stock.

five7kid

iTrader: (14)

When does this problem crop up?

If you are referring to the rods on the hanger outside the carb, those only affect the secondaries.

erik69&85

iTrader: (1)

It is just a general thing. I take the car out for a drive, come back and park it in the garage. You can just feel the heat off the pipe and there is a distinct smell. Even the guys who helped put it in said that it was running hot and it did not do that before the exhaust work

The engine does not show signs of overheating though. Go figure.

five7kid

iTrader: (14)

You may have a problem with the carb that isn't allowing it to properly richen the mixture. Might want to do a kit rebuild, clean it all up, re-adjust everything, and see if that helps.

erik69&85

iTrader: (1)

Just did a total rebuild on it last year at this time. The carb rebuild has about 2000 miles on it. Still spanky clean. Go figure.

Hodge

A higher flowing exhaust can change many of the airflow characteristics of an engine. Even on the intake side of things.

you may be pulling in more air or pulling different vaccuum. It may like more or less timing now etc.

Start with the carb, get that right and then see if it likes different timing.

83_1/2 L69

One of the quickest ways to kill an O2 sensor is to bang on the exhaust.
I'll bet that the mechanic accidentally killed your O2 sensor.

Here is how a non-Canadian LG4 works (at part throttle):
Air:Fuel ratio is controlled by the Carb
Carb is controlled by the Computer
Computer uses O2 sensor to determine A:F.
Bad O2 sensor=Bad A:F

Saigon_Bob

iTrader: (2)

id say do waht you can to get rid of the computer. i have an 88 305 of which block i dunno. this engine didnt come with the car, soo i realized that nothing on the car is controlled by the computer which means one less varible to work with

83_1/2 L69

Actually, if you keep the computer and the sensors functioning, the Carb is always correctly tuned. This leaves zero variables to deal with. Changing an O2 sensor every few years is better then tuning a manual carb every time the weather changes.

Saigon_Bob

iTrader: (2)

general tuning gets you pretty far if u only drive it for a daily driver