so i got a miss at 1500-1800 rpm. New points set at 29 degrees. New plugs, no plug wire arcing, 21 inches vacuum at idle. Vacuum stable all through rpm range. Timing 8 btc, cant move it anymore its stuck in the block and wont rotate anymore. 18 deg vacuum advance. Total timing 31 deg. Edelbrock 1406 just been cleaned and gone over. 5 psi fuel pressure. The car has sat for 20 years for all i know it may have some weak valve springs on the cylinders that were in the compressed position. I don’t really want to stat changing part unless im confident they are bad. Any thoughts ?
Try running Marvel's in both the gas tank and the crankcase according to the directions on the can. If engine sat for 20 years there may be carbon and gum varnish build up, sticky valves, lifters, rings etc. Can't hurt and may help, and will work right away if it's going to.
Truck 64. I thought about marvel. My dad put that in everything. Its worth a try. If i put in the crank case do i need to change oil soon ? Only driving to car cruises minimal mileage.
I see you use a vacuum gauge,,,,very smart man! Sounds like you have covered most of the bases,,,,,have you done a compression test? Could be a number of things,,,since it has sat so long. I would suspect the carb more than anything else,,,they can act quirky sometimes. But,, I don’t suspect the valve springs,,,,a miss that low should not be a spring on a 350. Did it just recently acquire the miss,,,,or did it have it since being brought back to life? And yes,,,,Marvel can be ran all the time in the engine or fuel system. Tommy
155 to 160 psi all cylinders. I bought it early spring from a family member. Due to life changes the was parked. Theres 2300 miles on the engine since it was built
Sorry. I was editing my response while you were posting here. Lol. Compression sounds okay,,,on the lower side but very even. Not many miles,,,,did it sit that long after your relative built it? Or was it built by a third party,,,and maybe never was straightened out from before? It is a beautiful ride through,,,looks fantastic!!
Thanks. It is a good lookin car. It was built then sold to family. Ran great, no issues. So after 20 yrs i got it and I guess i got some growing pains getting it back to normal. Hopefully i can get the distributor freed up and replace it or have it checked. Over 2000 rpm no issues.
Could any thing be sticking in the distributor,,like the advance weights? You say the vacuum advance is working properly? It still reminds me of an old carb issue I had in the past. Good luck,,,,some guys a lot smarter than me will jump in to help you. A lot of experience on this site! Tommy
You got me thinkin about the carb. Im wondering if its a lean condition and maybe different metering rods would richen it up. They are definitely stock size rods and jets.
Mechanical advance moves easy by hand but i dont get full advance till 3500 rpm. Maybe i need a lighter spring on the advance to bring it all in earlier? Your right there is a lot of good knowledge on this site.
Full advance at 3500,,,,sounds kind of late? I could be wrong but I think most are in by 3000. If not by 2700-2800. Tommy
Do you know of anywhere that has a distributor test machine? Back in the day,,,they could tell you everything about it. Tommy
Run a leak down test , usually will tell you more than a compression test. alone ..clean out the idle air bleeds , pull the idle screws and blow through with carb cleaner ..
Nope. Replace 1 quart of motor oil with it. A full size oil filter is about a quart, so that's one way to do it, put on a fresh filter and pour a quart in. About 4 oz per 10 gallons of gas in the tank. Give it some time to work, but like I said it shouldn't take too long.
If you suspect the plug wires, crank it up in the dark, have somebody power brake it a little for some load. Look for arcs and sparks. Lots of little things to check. Good luck.
Did anyone ever have a vacuum can on distributor leak ? Could it be moving because of a leak. Car does feel like its surging if you hold it around 40 mph. I know,, go faster
First disconnect and plug vacuum advance and see that the timing moves smoothly up and down the balancer timing marks without sticking. See that it stops advancing where it should, maybe 34° BTDC or whatever. Then re-connect vacuum can and spool it up again. Now the timing should move pretty high, because there's no load on the engine. 45 or 50 wouldn't be out of line. The diaphragm needs to hold vacuum, if it doesn't you need a new can.
Yes, I have had them fail. Not so much a vacuum leak, but a definite fail to advance. Disconnect the line to the carb and plug the carb connection with a short piece of vacuum line and a 1/4 -20 bolt stuck in it. Apply vacuum to the dist with a MityVac tool, or the best way you can. You should hear the motor speed up. If it doesnt, the vacuum advance can is bad. You can buy a fixed one, they come in different ratings, or you can buy an adjustable one. Good Luck.
I’m betting you have found the issue by checking into the vacuum advance operation. This is a very needed part for smooth street driving operation . GM should be connected to full vacuum . Once you determine if yours is working and where to connect it , drive the wheels off your car and enjoy it , it’s a nice one
Surging could be a lean issue from a vacuum leak, though the numbers he listed don't sound like it, or excessive vacuum advance pulling in at cruise.
Got the car this spring and haven’t had it 100% yet. Much better but not right. Fuel tank and fuel line were contaminated from 20 years of sitting. Carb was also loaded with dirt,rust etc. as clean as it looks inside after cleaning and a rebuild kit im betting theres trash hidden somewhere causing problems. Just hate to buy a new carb and find out that wasn’t the problem. It idles great, over 2000 rpm runs great. Its in between thats bad. Im leaning towards a lean condition even tho its only getting 9mpg !
It looks as though the can is working. It advances ok but im not sure if its advancing too much or too little. Its a b1 can. I think its rated at 18 deg
I don’t have anything as far as helping you with your issue. But that sedan is just rad. Nice stance,wheels and color choice. Great looking car. Sent from my iPhone using H.A.M.B.
The Jalopy Journal
