EGR mess (1 Viewer)

[YukonCruisers]

I have started tinkering in the background of my 55 build and started in last night on my 40. I have sealed up the tank and can get it to run as it sits. I will order a carb kit later today from Kurt, but the EGR was hacked by the PO. Once I rebuild the carb, is it as simple as ensuring I have no vacuum leaks and checking the timing or are the other bits I need to do here, my other 40s didn't have EGR. Other option is to reconnect everything, but again, not somehting I've done before...

I will try and avoid modifying this one too much, its a bit of a survivor (dash, floor jump seats all in great shape, just really needs the rear sill area repaired and rear leaf replaced plus the usual going over).

Side note, the vehicle was originally purchased new here in the Yukon, Canada, where there were no smog requirements at the time, it's a 75 with the carb stamped for April of that year. My other 40s were from further south, but had no smog equipment - wierd that this one has it up here.

 

[1911]

... the EGR was hacked by the PO. Once I rebuild the carb, is it as simple as ensuring I have no vacuum leaks and checking the timing or are the other bits I need to do here, my other 40s didn't have EGR. Other option is to reconnect everything, but again, not somehting I've done before...

Unless you're aiming for a true restoration, there's no upside in reconnecting the EGR in my opinion - just take the rest of it off and plug where necessary.

 

[charliemeyer007]

Pulling the fumes and blowby out of the engine is good environmentally - trying to reuse exhaust is stupid unless you need some carb heat due to icing.

 

[WildernessRimFab]

Im with @1911 on this one.
Pull that stuff off.

Try not to break the EGR parts on removal, some of them may have value to those who live in emissions testing areas.

 

[YukonCruisers]

Yeah, that's kinda where my head was at too. Building this one to keep around and light trail use, it's not going to be a full resto, but I will try and not do any permanent harm in case the next owner wants tto take it further - I'll pull the EGR bits and put them in a box at the back of the seacan.

 

[Grayscale]

This is only my understanding, I'm not an engineer. EGR allows for CO2 and H2O-vapor to modify the combustion chamber environment. When EGR is running, you get the same heat from the gas-combustion, but it is performed at a lower temperature. It is the temperature that burns up valves. The system results in volumetric efficiency, as you also have more air being compressed and more air pressure driving the pistons. The stoichiometric ratio, or a balanced air/fuel ratio can't go too lean without depreciating the engine. With a piped-in oxygen source, gasoline has been used in place of acetylene to cut and weld metal. EGR allows engineers to design motors with higher compression ratios. It goes well beyond exhaust pipe emissions, or fuel tank range, pre-ignition, or knock, is not good. Knock-sensors are now normal, octane is expensive, and the cylinder's peak-pressure makes its most power when the piston is at an optimal position to turn the crank (leverage of the connecting rod).

So, nothing too critical on an F or 2F; it is older technology. The problem is EGR valves and plumbing eventually fails. Inside, you get rust (they are usually cast iron) or the diaphragm that operates it wears out. The fittings freeze due to corrosion. I'm running EGR on the other rig, and it gets awesome mpg, better than EPA-spec on the highway, and at high-altitude.

I have bigger issues with the early 2F stock manifold than EGR. The heat-riser is a serious problem, for both inake and exhaust manifolds. Also, capping off the stock manifold at the EGR is not supported by any plug, that I'm aware of.