my 1977 Regal (350 2 barrel for now) has been my Daily Driver for a 1 1/2, but until a few months ago, that was no big deal, but now, driving 60 miles a day...I am having some issues. Just noticed my vacuum advance is shot. It was pinging slightly, but last week or so, it has gotten worse, even with a slight increase in throttle. Even with premium its pinging. so, I started looking into just getting a new Vacuum advance ( I have replaced them before, but only on points distributors, not fancy modern HEI units ) back in the day, if you points distributor seemed worn out, you just got another one for like $40. and I forgot who it was, Advance, O'Reillys, I only saw one vacuum advance, the ACCEL adjustable one for around $30. My Car has 103,000 when the odometer stopped a few days ago(posted about that too) at least. Starting to wonder even though a 93 Y.O. had it, if it really was 103,000, not 203,00o. and I was wondering if I should just replace the whole Unit...reading up here and checking some youtube clips, I am more confused...one guy on youtube made it sound like there are a lot of crappy cheap HEI's from China... have read lots of folks here talking about going with lighter weights, and other mods on the original unit. I have little experience with messing with distributors, beyond points, condenser, rotor....I am just a barely average shadetree mechanic (I can rebuild a Q-jet though!)with a bad back, and I am honestly fearful about messing with one, but curious to see what performance and more importantly, economy improvements I can make. so, long story very long, should I get a new , hopefully decent distributor, (any and all suggestions appreciated!) just grab a new vacuum advance (bad back, should I try to replace with the distributor off? going to take awhile to get to?) I should have a bit more time to work on my daily driver in a week or two, but worry about driving it this way, I know with another Buick 20+ years ago (My Dad's 1968 Wildcat) til we found out what was causing the over heating issues, it was pinging a lot, and running hot, and got terrible mileage (I'm getting 14 MPH with 2 barrel, bleh) sorry this is so long.... thanks!
Whenever you get pinging, the first thing you should do is check the timing. The vacuum advance will add timing, so if it was shot, your timing would be retarded at virtually all RPM. That explains your bad mileage, but not the pinging. Pinging can be over advanced timing, or it can also be caused by a defective EGR valve. An engine calibrated to run with EGR will frequently ping without it. Replacing the vacuum advance unit could not be easier. It is 2 screws holding it in. Rockauto has them cheap. https://www.rockauto.com/en/catalog...9977,ignition,distributor+vacuum+advance,7232
Thanks Larry, had not thought about the EGR valve! my Dad had a 68 Wildcat with the 430, and perhaps it was even before going to a 4 core radiator (that was used with 455s) but his aftermarket gauges did show it was running hotter, about 20 degrees more, but then again compression was much higher on that car, so perhaps that's why it pinged much more? Ok, only car I have had with EGR's before this one was a 73 Mark lV, and my Dad has one one his 79 Lincoln, we were able to clean those instead of replacing them, but looking at pics online, I assume you have to replace the EGR? Shop manual says you can't clean them, but they often error on the side of caution. Oh, if I replace nothing else on the distributor but the vacuum advance, will having an adjustable advance be that useful? thanks
I believe you can test the EGR valve by applying vacuum to them and see if they open. I have seen some where you can stick your fingers in and operate them manually. I had a friend with a Buick V6 that would ping if you put it in gear and power braked it a bit. Had a bad EGR valve. I could actually reach in and open the valve and it would stop as soon as I did that. If the vacuum advance is adjustable for the amount of advance, yes that would be beneficial.
I was wrong, but...it's my Dad's fault. I was driving home and he had read the shop manual, Dad said, or meant to say you couldn't clean the EGR valve...with solvents. You can tap them with a hammer, but theres a gasket that will no doubt be destroyed, so I guess I will have to by an new one (good grief, just like vacuum advances, the prices vary wildly, with Rock auto being much cheaper, saw $61 at one place online) that's interesting that merely squeezing the diaphragm stopped it. Fuzzy memories of all the crap that was underneath I think my Dad's 400 Lincoln EGR valve, bet there is a lot of soot here too. oh, are the EGR's for 350's all basically the same? Since theory at some point I will be putting a 4 barrel on, I could just swap this one to the other intake?
The problem I believe is the carburetors for EGR are lean. That may be why they need EGR to lower peak combustion temperature to prevent pinging. If you put a carburetor with richer mixtures, and pay attention to the ignition timing, you won't need EGR. The 4bbl intake you have may not even have EGR.
Ok, I made the mistake of ordering parts online from Advance (save some money, EGR Valve not in stores anyways) and heard so much pinging, decided not to wait til Friday night to attempt removing the old one. now after having a lot of trouble getting the old one out (barely enough room to get an open end wrench on it) I now find the 2 EGRs look NOTHING like each other.... looks like it would match up boltwise, but the vacuum port is tiny in the new one, and there is some sort of brass fitting that is on the old one, that isn't on the new one.... hopefully the pic will upload.... you can't search EGR here...1 letter too few...so, should I even bother trying the new one? I have read about blocking the openings, granted, this is a 2 barrel. likely to be lean.... any suggestions before I have to go to work in the early am/?? thanks... EDIT, wow is that blurry....the block hole is where the brass fitting is...you just can't see it
thanks... well, the BWD part # is EGR1209 (V17079) which I don't see on rock auto the part # on the original EGR pulls up this one, https://www.ebay.com/p/NOS-1978-81-...itm=263505665207&_trksid=p2047675.c100623.m-1 which looks like the one on my car, do you guys think someone put a Chevy EGR on this car? Does it matter? I just worry about the extreme differences (the new one has a very tiny orifice opening , the original is huge)and that brass piece that the new one doesn't have.... here is a clearer pic comparing them
