Hot Rods Does a 305 Engine HAVE TO HAVE an EGR ?

still dont know what the timing is, or the compression ratio, or what gas he's running, or gearing, or any of the other variables that make engines ping

 

Didn't see what year 305.

Centerbolt.TBI era ones can be 9.5:1, and were equipped with a knock sensor.

 

The water trick will knock the carbon off the top of the pistons just as pouring part of a quart of ATF down the carb at about 2500 rpm and then running up the road until the smoke clears. I used to do that on my grandfather's Dodge about every two months and the guy who owns all the old cars down the road from me will probably tell you that I filled his yard with smoke a few times.
I don't think carbon on the piston tops is the issue here but total state of tune is. That may take some effort to get the timing squared away all across the rpm range and the carb set so it gives the right mixture across the same range.

 

Go back to your other thread and read it too. It says the same thing.

 

What it actually needs without the theory: Much less vac advance. I am pulling these numbers out of the air since I am not near my iron library to read the numbers off of old Chevy parts, but they are approxilutely correct.
Pre-EGR Chevies used vac advance around 10, EGR ones will show numbers somewhat over that.
This could be killed off several ways but easiest is to just go to NAPA and order a vac advance can for a hypothetical one ton Chevy truck V8 of same age as your motor. I'm pretty sure all p***enger SBC HEIs use the EGR type advance.
I think all Chevy and many aftermarket ones have degrees of vac advance stamped on the mount that affixes the vac can to the HEI body.
We aren't tuning yet, just getting rid of a part that is only usable with the missing EGR valve.
Plenty of other stuff remains to quarrel over...vac advance manifold or from upstairs? Lighter springs for the centrifugal advance and higher starting point? Aftermarket offers a whole zoo of ways to tinker!

 

MORE INFO - here is some info I left out of this post

1980's Era 305
3 degrees Advanced --- when timing set at factory specs it pings worse and has no power
Engine set at TDC Dizzy is not off a tooth
Edelbrock Carb & Manifold


Questions * will hotter plugs help ?
* Still got mixed comments from replies if we need to replace manifold with one with EGR

We are also thinking - Carb came with this used engine we bought might check guts to see if re jetted
and running too Lean ????

 

Sure, but the goal was to reduce NOX emissions.

While not the only pollutant from a gasoline engine, when NOX is exposed to sunlight, it reacts and turns to a reddish-brown haze seen over large cities. EFI or carburetor, doesn't make any difference as far as that goes. In fact, NOX emissions might actually be a bit worse with EFI now that I think about it. NOX levels spike at peak power/efficiency.

They severely detuned the motors at that time which really hurt performance and economy, by lowering compression, retarding ignition timing, etc, all of which lower NOX emissions (at the expense of HC and CO) and near as I can figure, now they needed an afterburner in the exhaust (catalyst) to dispose of all the wasted fuel out the tailpipe.

 

Start by checking the timing at other RPM than idle, and also see how far the timing changes when the vacuum advance operates.

We still don't know what distributor it has, what condition the distributor is in, what the timing curve looks like, or whether or not it has vacuum advance, and how that's set up. This might be stuff you don't understand, but it's vital to making it work right.
also still dont know what you're using for fuel, etc.

 

Many times folks get tunnel vision and cant see the big picture. The fact is internal combustion engines that did not ping where around for about a 100 years before a EGR was even thought of.

 

About a year ago I researched half-lives of the pollutants legislation was aimed at. If I remember right CO and HC had half-lives in the weeks to months. NOx was in the hours. All that was about getting to the critical rate of production below which these emissions really don't matter, in response to some who claim that such a critical rate doesn't exist. If I can show half-lives, it obviously exists.

The upshot of that was, if the half-life of NOx is a matter of hours, then going to a lot of trouble to reduce NOx isn't so much about improving air quality as enabling levels of traffic congestion to be maintained and even increased. NOx was always a problem of too much traffic, or at least too many boring grocery-getters and proportionally too few interesting things. The option of breaking down the reigning mobility deficit was never even on the table.