So, I've got a Q-jet carb running on an Edelbrock Performer RPM intake, and I have a few questions about the setup and the carb itself.

First off, My secondary air flaps do not seem to open. From what I have gathered, they are supposed to open with air flow. But mine does not. Now... I still have a few sections on the intake manifold that are pulling vacuum and not plugged off, but I have no idea what is supposed to be plugged into this hole.

This hole is behind the carb, and almost under the distributor. It has a rubber gasket surrounding it and is not a threaded hole. Anybody have any idea what is supposed to be plugged into this? And once I plug this hole off, will that cure the issue with the secondary air flaps?

Secondly.... I am losing coolant but I have no idea where to. I have noticed that almost every time I run the engine, the coolant level will drop to an almost specific level in the radiator which is about 1 liter under full.
I have no visible leaks, the oil level is not rising and does not look milky or foamy, and a recent compression test is not showing a blown head gasket. Where is this coolant going?

 

How are you determining that the secondary flaps are not opening? Are you running it without the filter or hood down the road? They probably will not open under parked conditions as the engine RPM will rise too quickly without the need for additional airflow due to the lack of load.

As far as vacuum lines, etc, it would help to know what you are driving. Vacuum diagrams very greatly given different emissions requirements for the region the vehicle was originally sold into. Your emissions sticker should list this information. But if things have changed, all bets are off. At that point, a picture of your engine and a few detailed pictures of your carb showing all of the vacuum ports will be necessary to get things sorted out.

On the coolant loss, it is possible that you have a leaking intake manifold gasket and the coolant is being sucked into the cylinder. If you pull your plugs, look for a nicely cleaned plug (white porcelain around the center electrode). This will lead you to the leak. You can run a radiator leak down test as well to verify that you actually have a leak in the cooling system which can also point you in the direction of where it is leaking. It definitely sounds like there is a leak inside the engine and from your description, it sounds like a leaking intake manifold gasket would be a likely culprit. Compare the plugs from cylinders 1, 2, 7, & 8 to the cylinders next to them. 1, 2, 7, & 8 are the closest to the coolant ports in the heads.

 

Well I'm driving a 79 K5 Jimmy, with an engine from an early 80's van, and a carb from....somewhere. So All bets are probably off on that one.

As for the coolant issue, while doing the compression test I removed every spark plug and they all looked the same. There was not one that was cleaner or more fouled than the rest.
And during the compression test, the lowest I got was 130psi, and the highest was 140. So there is no evidence through the compression test that i have a leak.

 

An intake manifold gasket leak will not show up on a compression test as it would be before the valve in the intake track.

Do you have any emissions equipment that uses engine vacuum? If not, then you likely only have the brake booster, the distributor, and a few vacuum pots on the carb itself. Like I said, a few pictures and I'm sure we can get it sorted out. Also, the #'s off the carb will help as well.

 

I do only have the brake booster, distributor, and a few vacuum ports I have learned, so the vacuum issue should no longer be a concern for me, but thank you for the help.

Yesterday I had spent a little time cleaning out the engine with a carb and combustion chamber cleaner. You use it with the engine running as you pour it in the throat of the carb. Anyways, after a long session of smoke from the exhaust, the engine did sound like it was running much better, but had soon started to backfire out of the carb and exhaust. I'll be checking the spark plugs today to see how fouled up they are.

So I checked my timing.... again. I set it once to +8 at the proper rpm as my repair book specifies. That was two weeks ago. I had then checked it a week later as I was having some issues again, and discovered that it was at -4. This time I could not get it back to +8 and had soon discovered that I had installed the distrubutor off by one cog wheel. So, after finding TDC and re-installing the distributor, i easily set it to +8.

I'll be checking it again today since I am backfiring again. I'm almost posotive that it is going to be off... yet again. I'm coming to the conclusion that my distributor might need to be fully replaced, as the top end of it is brand new.

And also, on an interesting note, after running the cleaner through the carb and letting the engine cool, I checked the coolant level. It had risen this time. There was no notification that any oil was in the coolant and vice versa. I know that the cleaner had nothing to do ith the coolant, but while using the cleaner, I had the engine running for a solid 20 minutes. I'm thinking that I might have just gotten the thermostat hot enough to open and moved the coolant around more. I think I might just have an air bubble.

I'll check back and post my results from todays work.

 

Are you disconnecting the vacuum advance when you are setting the base timing? If you are not, then you are not setting base timing, but the vacuum advance timing.

Also, in my experience with these engines (goes back a long while), it helps to have the distributor to a direct to intake vacuum port and not to a ported vacuum port. A ported vacuum port will not have vacuum when the throttle blades are closed. The problem is it is very difficult to know which port is ported and which is open all the time with the carb on. I can say that on most Q-jets, the vacuum port off of the base plate on the front left (when looking at the carb) is typically a ported vacuum source. The port on the front right is typically full vacuum. If you have your distributor vacuum advance connected to the front left port, try connecting it to the front right port and see how things go.

 

I am disconnecting the vacuum advance when setting the timing. And I did happen to find the correct port after a series of tries, but I have found the proper one.

As for how the day went..... I drank some beer tonight, and it was well needed.
I removed the distributor and took a good thorough look over it. I decided that I had a cleaner distributor with a better functioning vacuum advance on it. So I installed the new one, aligned it up with the markings I made from the previous one, dropped it in place and got ready to re-time the engine. I finished re wiring the distributor cap, and decided to double check the wiring.

I learned that if you want something done right, don't let your friends drink beer before the job is done. 2 wires were crossed on cylinder 5 & 7. This could have easily explained the rough running engine. Now... to start the engine.

It turns over... turns over... sounds like it seizes, hiccups once, and fires up. I had to look at the other side of the engine for my line on the hb. It took me forever to finally get that line near the right degree, and once it was there... the engine stalled. Setting the timing at about 24 degrees BTDC has the engine run alright.

I'm still not exactly sure how this could be possible. Before I took the distributor off, I marked where the rotor was pointing to on the firewall. I positioned the newish distributor to that line, and it perfectly dropped in. But at 8 degrees, the engine wants to stall, and I'm still getting the occasional hiccups and backfires. If I retard the timing anymore, the engine automatically backfires and stalls.

What the hell is going on with this engine?

Oh, coolant issue is fully solved. It was an air bubble. Coolant has not dropped for the last 2 days.

 

it could be that q-jet i ran in to that before and make sure your timing hasn't jumped don't forget the nylon gear pick up a timing set for a few bucks and see if you can get a edelbrock (even if it just to try from a buddy) and see if that helps