| Author |
Message |
Don McCormick (Dandy_don)
New member
Username: Dandy_don
Post Number: 30
Registered: 2-2002
| | Posted on Tuesday, July 16, 2002 - 1:40 pm: | |
Thanks Steve. I understand and your analysis is quite sound. Still, I am not sure where I will end up, but the info is much appreciated. Don |
Steve Magnusson (91tr)
Member
Username: 91tr
Post Number: 848
Registered: 1-2001
| | Posted on Tuesday, July 16, 2002 - 9:20 am: | |
Don -- it's a 50-50 decision IMO. A properly working R2/R1 set-up has some advantages -- e.g., making the carbs less tweaky (more airflow @ 1000 RPM idle speed), lessens plug fouling -- but the downside is complexity (there is nearly no performance penalty if the R2/R1 switchover occurs at low RPM). Over most of my ex-308 ownership I had easy access to a good independent F shop so I kept the R2/R1 stuff working (and it was remarkably reliable over 2 30K mile stints). At the end of my ownership (without easy access to a F shop with distributor machine) I went to the single-trigger Cranes. Still, I'd put a ~$1K premium on a 308 with a complete R2/R1 system vs a modified 308. |
Don McCormick (Dandy_don)
New member
Username: Dandy_don
Post Number: 29
Registered: 2-2002
| | Posted on Monday, July 15, 2002 - 9:05 pm: | |
Steve, I need to check to see whether I have the two sets of points R1 and R2. I got so excited when I moved the timing to 7 Degrees BTDC that I did not spend much time looking at anything else. If I find two sets of points, do I really need the R2 set of points as they just seem to retard the engine at idle. I don't need the retarded timing as we have no emissions testing here in KS. Looks as if I can set the R1 points at 7 degrees and leave it. Your thoughts???
Paul, what you describe is exactly what I found with mine. It idles when warm at about 1100-1200 rpm. I will try your fixes for the backfiring. Thanx
Dave, I think I have closed all of the exhaust leaks. But I will check again. Thanx for your help Don
|
Steve Magnusson (91tr)
Member
Username: 91tr
Post Number: 846
Registered: 1-2001
| | Posted on Monday, July 15, 2002 - 10:54 am: | |
Don -- If you've truly got the "original stock timing set-up, 2 distributors, etc." you should be dealing with 2 timing settings:
3 deg ATDC at idle with the R2 points active (throttle microswith closed), and
7 deg BTDC just off-idle with only the R1 points active (throttle microswitch open)
If your distributors only have the R1 points installed then set to the 7 deg BTDC ballpark. |
Paul Newman (Newman)
Member
Username: Newman
Post Number: 259
Registered: 12-2001
| | Posted on Monday, July 15, 2002 - 9:11 am: | |
Don, I also had backfiring at times. Two causes for mine. One on decell, it would pop and fart. The second at higher rpm under load. The first was corrected by increasing idle mixture with the screws on the carb bases. The second problem was corrected by cleaning the points and setting the gaps. When it returned again, I replaced the points and it hasnt come back yet. I have also been messing with my timing by setting it to 7 degrees BTDC. The only side affect is higher idle speeds. Im running between 1100-1200rpm now. I cant get it lower than that with the timing set where it is. If I adjust the timing back to 0, it idles where I want it to but I have a big lag or bog off idle, so its back to 7 again. Mine also has no smog but has a single euro distributor. |
David Jones (Dave)
Junior Member
Username: Dave
Post Number: 142
Registered: 4-2001
| | Posted on Monday, July 15, 2002 - 8:53 am: | |
Hi Don,
First question...
did the car backfire before you made any of the changes?
You might want to double check all the changes you made to the exhaust, ( test pipe, air injectors ) to see if you have an exhaust leak.
|
Don McCormick (Dandy_don)
New member
Username: Dandy_don
Post Number: 28
Registered: 2-2002
| | Posted on Sunday, July 14, 2002 - 11:18 pm: | |
Hi, I need some help with ignition timing.
I have removed the cats (installed a test pipe) and all of the air pump stuff (rails and injectors) The car has the original stock timing setup, 2 distributors, etc. I got the car with the ignition timing set at 3 ATDC and 1000 rpm for both distributors. I put in new sparkplugs (NGK BP6ES gapped at .024) I had quite a bit of backfiring when running at 4k and coming off the throttle. I did some research on previous posts and found that several people have set their timing at 1000 rpm to as much as 20 degrees BTDC but that seems very agressive and potentially could generate some problems. I looked in the workshop manual and saw that the static timing should be adjusted to 6 degrees BTDC presumably for Euro models?
Anyway I have adjusted both distributors to the flywheel mark denoted as AF 7 which I interpret as 7 degrees BTDC at 1000 rpm. The car runs much,much better now and only backfires a bit. It seems to be a different car. Also where I live there is no emission inspection and so I do not need the 3 degrees ATDC timing which I understand now was specified to have the engine run hot at idle to get a good burn of emissions.
Anyway my questions are: What is the best timing set up for a 79 308 without any emissions equipment? How can I get rid of the remaining backfiring that I still have? Will more or less advance tend to get rid of it? I have not tested the advance mechanism yet to see what advance I have at 5k and 8k rpm but will do so as soon as I figure out the best place to start. have not done anything to the Webers yet but really want to get the ignition set first and then do the carbs. I have not invested any real money yet in the ignition system as I may want to get Nick's direct fire system so I am trying to see how good I can get it with the stock setup Any and all thoughts would be appreciated. Don |