silverriff

Ugg, so I got a completely rebuilt Q-Jet for my 1972 455. I got it off EBay from this company called i-5 Components somewhere in California. It is a really nice piece, completely rebuilt, and painted with an electric choke upgrade. I slapped it on the engine, and after fiddling around with it for a few days, and ultimately exhausted all my little bit of carb knowledge, it was still not running right. So I took it down to my mechanic I have been going to for 15 years, and after he fiddled with it for a day, he is claiming that the carb has some sort of really bad vacuum leak that is keeping him from making any sort of adjustments to the speed/fuel mixture. He claims that he can turn the mixture screws all the way in and out without affecting the engine in any way. Besides that he can "hear" it has a really bad leak somewhere in the bowels of the carb. This company I got it from seems to be a pretty high quality rebuilder. Over 1,500 carbs sold with only 1 person saying he had issues with it.... am I one of the lucky ones to get another bad one? Or could there be something else wrong? I haven't tried the mixture screw adjustment yet, but if it is true that they are not "adjusting" anything, it should be pretty evident that something is wrong internally. I would greatly appreciate anybodies input because I WANT TO DRIVE THIS DAMN THING!!

Oldsguy

First, what does the company say in response to your problem? Second, if you do not get your solution with them and are still left with a problem contact Danny Sarvis (70Wcars) he rebuilds Q-jets and might be willing to help you out.

silverriff

Wow quick response! The gentleman I spoke said he is very surprised to hear that there would be something that drastically "wrong" with it because they take a lot of care in their rebuilding and testing, but all of the stuff they sell has a 6 month warranty so I just need to box it back up and ship it back. They will then send me back a replacement and break down the one I returned to see if or what was wrong with it. I just hate that it is going to be another 2 weeks to send it back and forth from Baltimore (me) to California (them). I trust this mechanic I took it to be adjusted, but for some reason I just have a weird feeling that it may be something other than a bad rebuild. I know working on these Q-Jets is an art unto itself, and they can be that tricky, but my Spidey sense is tingling alittle...

silverriff

Ok messed with it alittle, it has a really noticeably loud wirrling/whine that seems to be coming from the back of the pass. side near the top of the carb. That was after I rubbed all over the carb ( it liked it ), and the only time that whine was muffled was when I got over that back rear section on the pass. side. I even sprayed some Gumout on the back of the carb, and there was a noticable jump in the RPM. I put my hand over top of the choke after it was heated up, and it sucked my hand hard to the carb, jumped in RPM for a fraction of a second, then stalled. Anything??

leadfoot067

are the secondary throttle plates hitting the base gasket? causing them not to be closed all the way? is the base gasket correct? ive personally had both of these things happen causing the symptoms you describe...

silverriff

That was my first thought, the gasket. As did my mechanic. It is the one that has the 2 holes in front for the primaries, and the large oval in the back for the secondaries. It is the same one that came off my other 1972 q-jet, according to all the references he had, thats what was supposed to be on there. Is there any way to visually tell which is supposed to be on there? Is there only one way to put the gasket on? Or is there a "right side up"? It is too dark and cold to check it out anymore tonight, but I am going to take off the carb first thing tomorrow and see what I can see.

OLD SKL 69

I am pretty sure your model has a hot idle compensator on the back of the carb. Is it in place? If you take the carb off and remove the two screws, there is a round gasket behind the compensator. Take it out to see if it is there. If it is missing, you will have a vacuum leak. If that's not the case, can you take a picture of the back of the carb?

silverriff

Yeah I see what you mean. I took it off the back of my old carb I took off there, and see the little doughnut gasket. I did read somewhere else on the internet that that is a little, but critical piece that may be overlooked in a rebuild. I will be up bright and early in the 20 degree snow ripping that bastard off my engine to see. Either way I am going to take some nice detailed photos and post them up for all to enjoy.

silverriff

Ok finally got to taking the back apart the hot idle compensator on the back. Here are pics of what I found. I first noticed that on the screwed in plate itself, that little tab with the spring on it was bent and the spring was broken ON THE NEW non working one, where as the old one was straight and the spring pushed back if you pressed on it. Second was the little doughnut gasket on the inside. It was in the new one, but the hole on the inside of the gasket was quite a bit larger than the old one (new one is the top, older one is the bottom) I could see that if that gasket is supposed to seal up around that brass plunger on the H.I.C, the new one was way too big to do so. Could this be my issue? And if so, where do I get that little gasket at? Would I have to buy a whole rebuild kit for it?

OLD SKL 69

It definitely could be your issue. I don't think they come in a rebuild kit but I will see if I can find out more for you tomorrow on where to get one.

silverriff

I think if it isn't the gasket itself, the lack of spring tension from the broken spring/bent tab on the outside plate would prevent it from sealing properly. I am just going to use the old plate as it is in fine condition. As for the gasket, I have not been able to locate any sort of replacement, but it seems like something I could carefully make. But if anyone knows where I could get one, please let me know!

OLD SKL 69

I would use the old plate and reuse the old gasket to see if that makes a difference. I'm sure you could make a new one with a fine point exacto-knife and some gasket material.

silverriff

Well I am going to use the old plate, but the old gasket broke apart on removal. I just pieced it together for the picture I took. But I spoke to my buddy who works up at one of our local parts places, and he ordered me a carb number specific rebuild kit that after doing some research, he said he is 75% sure it comes with that little gasket. The kit was only $24.00 and it came with the baseplate and aircleaner gaskets I needed anyway, so I thought I would give it a shot. If not, or if the gasket seems alittle large like the one I had already in my rebuild, I will just make my own. Thanks for your help. I will post the results when I see what happens!

Texas Jim

W/ all the downtime you're having, you could have sent it back and gotten a new one, and use all that investigation time either w/ your lady or working on another part of your ride. And if another problem arises w/ that carb, and the warranty time is up, you eat it. IMO, send that one back and wait the 2 weeks. Better to be safe than sorry later. I'm only stating this because I don't want you to eat crap in the end. Only looking out. Good Luck.

Had a good friend who was from Baltimore when I was stationed at Ft. Bragg, N.C. in the mid-'70s ('75-'78). I used to drop him off on my way home to NYC f/ weekends, a trip a bunch of us used to make together often. I'd then pick him up, and usually two other guys, one from Brooklyn and one from Queens, on my way out of The City and back to Bragg on Sunday afternoon. That was during the "disco era," when, f/ a time, turning wrenches took a close second to clothes, girls and dancing. Still had to have a ride to get to the clubs. LOL!!!

Cecil Anderson

For what it's worth,, I think you are right TexasJim//the new one might just work fine problem solved. Andy

Texas Jim

The new one "BETTER" work just fine. Otherwise, it would be time f/ a "complaint" and questions as to why the company has such a great reputation.

But anyway, I hope this guy sends that carb back. Let the company deal w/ the problems and send a new one out, and this guy can get his ride on the road and running it.

silverriff

I appreciate everyone's concerns, but I am happy to report after replacing the little gasket and putting on the old HOC cover, everything is working as it should. I put in a new gasket even thought it looked just like the one I took out. I am pretty sure the issue was that bent tab with the broken spring. But I put it back on with a new base gasket, and after a few minutes of adjusting, it is idling beautifully. Took it for a quick spin and everything is gravy Thanks again for your help and concerns!

Texas Jim

I'm very glad that you got the carb right. My concern is that if indeed the carb you got was one of the "Friday at 4:28 p.m. lemons," there may be other problems down the road. I just don't want you to eat it later. Personally, if I pay f/ something that's supposed to be rebuilt, then that's what I expect. Good Luck w/ the carb, sincerely.

OLD SKL 69

Glad we could help you with your problem. Have fun driving her!