T.Wagner

I have an '83 Hurst/Olds and I think she is running a little too rich right now. I am looking for some information and/or write-ups on how to properly tune my carb. Thank you for the help!

oddball

Qjet tuning is neither fast nor easy.

If the engine is stock, then your best bet is getting the service manual, a rebuild kit from the parts store, and following the procedures in the manual. Get a gallon or two of Chem Dip also. Use with care! Wear thick chemical gloves and keep a water hose handy. That stuff burns.
You only need basic hand tools. An air compressor is a big help too.

If the engine is modified and you have to tune the carb to match, well, it's an adventure.
There are two good books if you want to get really deep into this. Doug Roe wrote the definitive book years ago. Cliff Ruggles wrote a book more recently that is better for the later year carbs and has some newer modifications. And better pictures.

joe_padavano

If you have the original CCC Qjet, you MUST follow the adjustment procedure in the Chassis Service Manual EXACTLY.

T.Wagner

The engine is stock besides I think an aftermarket intake manifold. I may have some vacuum lines that are missing so I may have to go through that first. The car runs good right now, but I think it could run better. The carb was rebuilt not too long ago so all that should be fine.

joe_padavano

If vacuum lines are missing or improperly connected, the system won't work right. If any of the sensors or actuators are bad, the system won't work right. If the rebuilt carb was not properly dialed in on the car per the CSM procedure, the system won't work right. The fact that it was rebuilt is no guarantee that it is correct. Few people had the training or patience to properly set up the CCC carbs when they were new. Virtually no one does now.

T.Wagner

Interesting... I guess I will have to go through everything to make sure it all is correct. I do agree that not everyone is qualified because I had the carb rebuilt once before and it just wasn't right. Now after getting it done again it is running much better.

I guess this will be a big ongoing project as I go through all the vacuum lines and everything to ensure it is all correct.

I believe I have all the service manuals for the car. How hard is it to rebuild the carb? It looks like it is only about $40 for a rebuild kit.

joe_padavano

Hopefully, you have this manual.



The carb rebuild is not difficult, but it DOES require extreme attention to detail and a lot of patience. You cannot force parts together. You must carefully adjust what needs to be adjusted. The CCC Qjet has the added wrinkle of the mixture control solenoid adjustment. This requires some special gauges and tools, unfortunately. The CSM provides the dimensions on the gauges and I was able to work around them by using a depth caliper in one case and by bending some welding wire to make a gauge in another. I've since acquired the factory tools. The bigger problem is that there are several parts on the carb that use a special "double d" wrenching feature (picture a cylinder with opposing flats). These are down in a cavity and require the special tool to remove and install them. These tools do show up on ebay frequently.

http://www.thexton.com/carb-tools-p-125.html

T.Wagner

Yes, I do have that manual. I have about 5 or 6 if I recall.

Since my carb was rebuilt would I really need to rebuild it, or would I be able to just take it off the engine and tune it? Or are the parts I need to adjust inside of the carb?

joe_padavano

The mixture control solenoid adjustment requires the air horn to come off the carb. Everything else is external. I suggest you review Chapters 6C and 6E in your CSM.

T.Wagner

Thanks for the reference. I'll take a look for sure.

olds 307 and 403

Do everything external first before going into the CCC Quadrajet. Replace and properly route any questionable or missing vacuum lines. Make sure your TPS is adjusted properly, O2 functioning etc. I would buy those tools Joe mentioned before you pull off the carb top. Our cars up here, other than the Hurst/Olds and 442 didn't get the CCC till 86. Only the Delta 88, 442, 88 Cutlass Supreme Classic, Chevy Caprice and Custom Cruiser got the Olds 307 from the factory in Canada.

joe_padavano

Sorry, but I disagree. The M/C solenoid stops MUST be set before doing any external adjustments.

T.Wagner

Are there any write-ups or better diagrams I could use for the vacuum lines? The little emissions thing on my fan shroud leaves a lot to the imagination. Does the service manual have a more in depth section? Also, where would I purchase the vacuum tube and the little fittings?

joe_padavano

Sadly, this is one area where the CSM just falls on it's face. There is no good consolidated vacuum routing diagram for these cars. The under hood sticker is unfortunately the best diagram there is, and it sucks. I've had four CCC 307 cars now, with the CSMs for each, and I think I've finally figured it all out, but it isn't easy. Not only do the diagrams suck, but components are described with different terminology depending on where it is talked about. GM's technical writers went straight in the toilet in the 1980s, and by the 90s the CSMs are horrible. The SIX VOLUME set for my 1999 Chevy truck is one of the most worthless documents I have. The schematics are impossible to follow, the illustrations are drawn in crayon with no detail, and the whole book is full of typos (which is really amazing considering that these trucks were pretty much unchanged since 1995).

Vacuum tubing and fittings are available at any auto parts store.

T.Wagner

Well that is something to look forward to

I guess I'll just have to stick around and ask you the questions then hahaha!

olds 307 and 403

What I am saying is, make sure there are no vacuum leaks, codes set and the ignition timing is set to spec. You can adjust the mixture control solenoid all you want, if the base timing is set a 5 degrees, being an Olds V8, it will run less than ideal. His "running rich" issue may lie elsewhere. Without the proper tools, no point in opening it up.