1972 351C runs crap

[jbojo]

Which distributor are you using?

 

[Stanglover]

Okay... problem... the new fuel pump is doing great, filled the filter up almost instantly (with the old pump the filter was just about 1/4 filled).

But now i got absolutely no spark on any of the plugs!!

This is with my new HEI distributor.

I have steady 12V to the dist with the ignition on, but no spark at all.

The rotor is spinning as it should while cranking and i cant see anything wrong.

All new cables (8mm accel) and champion plugs.

Could the new distributor be faulty? :shootself::-/

Throwing in my 2 cents worth, Champion spark plugs, yuk!! Never had any good luck with Champions, not even in my lawn mower.

Just one more thought on your HEI distributor came to mind, that happened to a friend who has restored several Mach 1's. He too was having issues getting a '73 351C 4V to run, backfiring etc. etc. He bought a new HEI off eBay and why he didn't notice I don't know, but he installed it, tried to start it and it ran for about 30 seconds and quit. Close inspection showed that, even though it was labeled and sold for the 351C, it actually had the smaller 302 gear. Worth checking!!

Good luck sorting this issue out. This sort of thing is enough to make ones blood boil.

Geoff

 

[scarpent1]

Is the distributor wired up properly? Do you have 12V to the coil in the Start position? I know when we did an electronic ignition conversion on a Mopar we had it wired 12V at start but 0V at run so it would start but stall when the key was released. Could yours be the opposite?

 

[rocket366]

The chevy type HEI dist. for the 351C is a one wire hookup. If your tested 12v source wire is connected to

the correct terminal than yes there is an issue with the dist.

I put the HEI type dist. in my engine with no issues and love it after doing a mech. Adv. spring upgrade and I run no

vac. adv.

Paul

 

[jbojo]

The chevy type HEI dist. for the 351C is a one wire hookup. If your tested 12v source wire is connected to

the correct terminal than yes there is an issue with the dist.

I put the HEI type dist. in my engine with no issues and love it after doing a mech. Adv. spring upgrade and I run no

vac. adv.

Paul

Paul,

Just a question on Vac advance.

For peak engine performance, drivability, idle cooling and efficiency in a street-driven car don't you need vacuum advance in addition to mechanical? I hear a lot of different opinions on this subject so I'd like to know.

thx

 

[Odmark]

I think the dist is only called Thunder HEI. I ran the same type of distributor om my 1973 Oldsmobile and that workef perfectly.

I will try to run a separate cable from the battery directly to the dist and also a ground cable from the battery to the distributor housing.

If i dont get any spark then, the distributor is faulty.

I bet the return will be a PITA... bought it on ebay from a guy in the states.

As for the gear, i compared with the old one before installing and it looked the same.

 

[Odmark]

Okay spark problem solved, it was bad ground.

New problem: Carburator is flooding BADLY! Like 2 geysers on top of the carbs badly.

I have adjusted the floats according to edelbrocks instructions and as mentioned cleaned it and replaced all the gaskets.

One problem after the other.. sigh...

I have not done much carburator work, what else could cause this except badly adjusted floats?

 

[Jeff73Mach1]

Fuel pressure should be 6-8 pounds, if your pump is producing more than thet you will need a fuel pressure regulator/

 

[Odmark]

The pump is rated at 5.5-6.5 psi and should be a direct identical replacement to the stock pump.

 

[c9zx]

Assuming the floats are properly set and don't have a hole in them, and the fuel pressure is normal, about all that leaves is the needle and seat. Chuck

 

[Don C]

Don't rely on what the pump is supposed to put out. I have a pressure gauge on my feed line and it normally showed around 6 psi, one day it wouldn't run and the pressure was at 12 psi.

 

[Odmark]

I will start by checking the floats, needles and seats. Really should get a fuel pressure gauge, too bad they are expensive and im on quite a low budget.

Cleveland parts are expensive, was looking into buying the oil pan gasket, valve seals, head gaskets (even if i get it running i think i would like to lift the heads and intake for proper cleaning), valley pan and intake gaskets, exhaust manifold gaskets, valve covergaskets.

Only this will set me back about 210 dollars.

And then i would need new head bolts, another 140 dollars.

So 350 bucks just to clean the engine properly.

And full rebuild kit with flat top pistons and a street cam will cost me 300 bucks more on ebay including shipping.

I cant seem to fit the damn compression tester either. Tried the "push down" variant but that wont fit at all. And the threaded variant i have to bend so much to get down there so i cant thread it in...

And even if i got it in i still need the engine warm while testing...

 

[Odmark]

Another thing. Ive been told many times now that the issues the car is suffering most likely is caused by clogged fuel tank ventilation.

And stupid as i am i havent checked it out, how do i do this? :$

 

[vozaday]

Are you sure the carb isn't 180 degrees out? When I did my engine we originally had it 180 degrees out and the engine would run and idle. Very rough and would backfire and die but it would idle for a couple seconds. I even had flames out of the carb at one point.

 

[Odmark]

Vozaday i assume you mean the distributor? I triple checked that now and everything is set right.

I also noticed just now (and i know someone wrote this previously in the thread) that it does in fact have a 4V intake between its 2V heads.

Dont know if this is the problem though, since the previous owner (at least he said so) that he did not put the intake on the car and he has driven it.

Also cleaned out needles and seats (even though i couldnt see any crap there) but did not have time to start it up.

 

[Jeff73Mach1]

If you have a 4V intake for 4V heads on an engine with 2V heads, it is likely not sealing properly. The mating surfaces just don't line up well. but there are 4V intakes made for 2V heads. Do you have apart number off your intake? Prior owner statements are about as reliable as politicians' promises

 

[Odmark]

I dont have a part number right now, but the intake says "Performer 351 4V" behind the carb. I can check for part no. Tomorrow.

And the person who put the intake there used a LOT of blue silicone thats for sure.

Thats is very true, i do know his brother though so hopefully he was telling the truth.

Still no guarantees though.

 

[vozaday]

Vozaday i assume you mean the distributor? I triple checked that now and everything is set right.

I also noticed just now (and i know someone wrote this previously in the thread) that it does in fact have a 4V intake between its 2V heads.

Dont know if this is the problem though, since the previous owner (at least he said so) that he did not put the intake on the car and he has driven it.

Also cleaned out needles and seats (even though i couldnt see any crap there) but did not have time to start it up.

Yes, sorry was working nights. I really need to learn to double check my posts when I'm that tired.

I dont have a part number right now, but the intake says "Performer 351 4V" behind the carb. I can check for part no. Tomorrow.

And the person who put the intake there used a LOT of blue silicone thats for sure.

Thats is very true, i do know his brother though so hopefully he was telling the truth.

Still no guarantees though.

My intake says Edelbrock 351C 2V right on it. But a quick google search shows that it shouldn't make that huge of a difference, the ports are different sizes but they are in the correct location.

 

[Odmark]

Fired the car up today and absoluteley no difference. Maybe it idles longer but thats it.

But i noticed now that the rocker arm at cylinder 5 is barely moving at all compared to the other cylinders... and it looks like the pushrod just rotates.

Also i think some more rocker arms are not moving quite as they should. But not as badly as no. 5.

Could this be a worn out cam after all? I took the rod out and it was straight and not worn.

 

[Jeff73Mach1]

Sounds like worn cam lobes- that would explain your problems.