?? Q-Jet adusting ??

[Austrian455]

Ok, now my Buick runs not bad. It performs much better than with the orig. cast iron "smog" intake. But when I push the accelerator to the floor the engine can´t handle it. It fires back out of the carb once and when I don´t close the throttle a little bit it (keep it fully opened) the engine nearly goes out!
So I thought I should adjust that carb.
Can anyone tell me hoe to do this? I think some Buick specialists like Adam or Rick should know? ;)
Maybe you have a good link where I can read this, or maybe anyone can tell me. I don´t have a vacuum gauge here at home. Can I adjust it also with a tach?

[Smartin]

What is your timing set at?

[Austrian455]

Good question. If I havn´t got a timing light, I should be able to check it with no. 1 cyl. at top position with both valves closed, and read it from the timing mark.
Should be correct, or not?

[Smartin]

You will need a timing light to accurately read the timing.

[Austrian455]

Ok, I´ll drive to a friend of mine who has a timing light.
What settig should the timing have?
10 degree ?

[Austrian455]

Does anyone know what the timing settings should be ????
10 deg. @ 800 rpm ???
32 deg. @ 2500 rpm ??
I don´t know. I´m going to the shop today or tomorrow to have the timing checked.
What should I tell the guy at the shop to set the timing?

[The German]

Austrian, as you know I´m still a greenhorn in these things and so I would first look into my chassis service manual. I have a 1971 car and so it might be different from yours. Second fact is that in my manual there are different timings listed for different engines and distributors, which means it seems as if you have to get a copy of that special page of the 1972 manual to be able to choose the correct adjustment data for your engine !

Hope you will get a better specified answer from a 1972 car owner; perhaps he could scan the special page of the manual and post it here for you.

On the other hand I would recommend to buy such an manual; it´s not too expensive :
http://cgi.ebay.com/ebaymotors/_Manuals-Literature__1972-All-Buick-OEM-Shop-Service-Manual-Riviera-Electra_W0QQitemZ270282564627QQadnZManualsQ20Q26Q2 0LiteratureQQadiZ2872QQcmdZViewItem?hash=item27028 2564627&_trkparms=72%3A543%7C39%3A1%7C65%3A12%7C240%3A1318&_trksid=p4506.c0.m245
http://cgi.ebay.com/ebaymotors/_Manuals-Literature__1972-72-Buick-Service-Manual-GS-455-GSX-Stage-1-Skylark_W0QQitemZ130262389159QQadnZManualsQ20Q26Q2 0LiteratureQQadiZ2872QQcmdZViewItem?hash=item13026 2389159&_trkparms=72%3A543%7C39%3A1%7C65%3A12%7C240%3A1318&_trksid=p4506.c0.m245

Good luck !

[Austrian455]

I thought that maybe someone has a timing data for some performance advantage. I don´t know this for Buick engines. I only know for example that all the Fiero guys told to set the timing to 12 deg. at idle, not 10 like the stock setting.
Now I have the Performer intake on, K&N filter, dual exhaust, MSD Coil...
So I thought that someone can tell something like "set your timing to 12deg. @ idle, that performs better"
But it looks like I have to find out by my self.

[Austrian455]

But thanks for your reply, Rolf.

[73 Centurion]

In general Buick engines like a lot of initial timing. The best setting for you depends on the current combination, the fuel available, the weather and everything short of astrological charts.

What you need to do is advance the timing a bit at a time and drive it for a while. If your engine begins knocking you either have to buy higher octane gas or reduce the timing. I intentionally give up maximum performance so I can fill it with regular gas instead of premium. Your mileage may vary.

If you advance the timing too far the engine can be hard to start.

There are some great threads on the intricacies of timing on V8 Buick.com. The general agreement consensus is the following: There is initial timing and 2 forms of advance. The factory settings are conservative and don't give the maximum performance. You can find gains by increasing the initial timing but soon you'll need to limit the vacuum and mechanical advance so the engine doesn't get too far advanced. There are adjustable vacuum advances and you can get different springs and weights that adjust the mechanical advance. It takes trial and experimenting to find the optimal balance for your combination. You'll probably have to readjust each time you change a major component on the engine.

My advice is to buy a timing light and experiment with advancing the timing a degree or two at a time and seeing how the engine responds. Give each adjustment a good long test so you see many different conditions. Look for situations that cause the engine to knock. Pulling uphill from a standing start is a good one.

Engine knock is very bad, you need to know what it sounds like and your combination should not knock.

Good luck,

John

[Robroy]

There are some great threads on the intricacies of timing on V8 Buick.com.

Check out this thread. Btw, stock setting for a 455 is 4* (1973)

http://www.v8buick.com/showthread.php?t=63475&highlight=power+timing

[Austrian455]

Thanks for the reply.
I found that topic on v8buick.com
That explains everything perfect.
Thanks for the help.

http://www.v8buick.com/showthread.php?t=63475

[Gum,beest]

Hi Austrian 455
in my owners manual it says that the correct timing is 4° Before Top Dead Center with the vacuumadvance line disconnected and plugged

You can go higher than that if you are running a high octane fuel (95 or 98 )

For the adjustment of your Qjet
you can find a pictures or a PDF of a original service manual from Rochester at
http://www.carburetor.ca/carbs/tech/index.html
They offer great rebuild kits for your carb as well

Greetz Erik

[Austrian455]

Erik, thanks for your post.

I´m sure the carb manual will help me to make the car run like I want it to run.

Thanks