VCCA Home Forums TECHNICAL - 1945 AND NEWER 1946-1948 Need advice on 216 cu/in timing and carb settings

Need advice carb adjustment and ign timing

Got a 216 running with a Carter W-1 in combination of a Delco-Remy electronic ignition. Engine has higher compression similar to 235 engine. Carburetor metering rod is 67/46 with a 93 jet.

Car runs at idle a bit rough and fast acceleratiom either kills engine or big bangs in exhaust system.

1. Is there an alternative way to set metering rod without gauge?
2. Which timing adjustment is reccomended due to higher compression?
3. Should original 216 valve adjustment be used or other?
4. Which metering rod and jet is preffered?
5. Is advanced timing reccomended due to high compression and lead free fuel? (This besides the octane adjustment on distributor)

Any advice or info welcome.

Hi Torpaero. I'm not the best help, but I did go through similar issues while working on my '47 Chevy 216 and Cater W-1 last year. A few questions for you if you have a second...

*Is your W-1 rebuilt? How is the accelerator pump, is it a new leather one?

*You mention your engine has higher compression, is this known? Are there modified parts or a shaved cylinder head?

*What grade (octane rating) of fuel are you running in the Netherlands?


Hopefully some of the answers to those questions may lead to a thorough answer from some folks.

Here are some thoughts for your questions...

#1. Not sure on that one (carb guys can chime in)

#2. Regular timing should do fine unless there are significant modifications elsewhere such as a aftermarket grind cam, etc.

#3. Regular valve adjustment would also be suggested. I'd do it hot and then recheck after some miles.

#4. Yours should work unless there's higher ethanol in your
fuel in the Netherlands. Some US folks have run richer 66 / 50 to compensate for the increased ethanol, and there's a 68/49 combos. This page www.siegmundguitars.com/Techtips.htm has tips on W-1 tuning. Scroll down to "carburetion".

#5. Depends on your setup. It sounds like your timing is way too advanced already with the backfires out the exhaust. I would set the base timing using the distributor and the ball on the flywheel. Put the octane selector on your distributor at the -0- mark. Try starting it and driving it. If it runs OK but lacks power, advance it using the octane selector. Keep going until it feels & sounds right and you have the highest RPM at idle. I also found a vacuum gauge hooked to manifold vacuum also helped when setting timing (and idle mixture on the carb). Just look for the highest reading (for me it was about 17-18 inches on the gauge. Once that was achieved, you should be able to run it and drive it just fine as long as your vacuum advance unit on the distributor is functioning. That should get you up & running.

My hunch is that your rough idle is from valves that are out of adjustment and the timing is too far advanced. Again, there are many others out there who are more experienced than me, but I thought I'd start with the basics. Hope to hear back from you on how things go and share some pictures of your Chevy when you get a chance.

Cheers,

-D

Daryl,

Thanks for your explanation. The carburetor is rebuilt with a leather acc pump plunger. Seal is also replaced to replace the cork seal. Fuel used in The Netherlands is Euro 95 or Euro 98 octane. Engine is completely rebuilt with new parts and adapted to take higher octane fuel. I have read the part on siegmund guitars and is usefull information.

I do notice if I advance the distributor the engine runs much better. Throttle reaction is faster and engine does not stop due to fast throttle input. I hope this is allowed without damaging the engine. Don't want to advance too much.

Still need to check valve clearance, so this will be the next step. But due to a complete engine rebuilt I must assume this will be correct.

Can you give me an indication on the height between lower side of metering rod lever to top side of carburetor. This measured with throttle valve closed ( throttle screw turned away completely )?

Good deal, sounds like a few tweaks and you'll get there. You want to advance it until it pings and then back the timing off to make it drivable.

Euro 95/98 octane from what I've read is 91/93 US. That's higher than a stock 6.5:1 compression 216 needs. Most of us run 87 octane and its just fine for what its worth.

I can't advise on the adjustment of the rod, I can check when I get home if you'd like a ballpark. I know that the Carburetor Shop sells the adjustment tools.

http://www.thecarburetorshop.com/Carter_tools.htm


Good luck, perhaps some other folks can advise more info on carb tuning.

With the throttle plate centered and fully closed, the distance from the metering rod jet to the post on the pump arm and countershaft assembly should be 2.795".

With Euro 95 and a little higher compression you can have 8 to 12 degrees extra advance ignition timing.The best way to determine the advance is using a vacuum gage and see where you get the best vacuum reading at about 2000 R.P.M. ( know that as I am also using euro 95 for my 48 Fleetmaster). If your compression is higher as 8 to 1 you can better use euro 98.
I can not advice you with the W1 as my original carb is a Rochester.
A new rebuild engine needs the valves to be adjusted at the maximum gap that is mentioned in the manual for the first hours of operation.After the first 400 Km readjust the valves one more time at maximum gap again with the engine running and totally warmed up ( at-least 30 minutes of operation ). Again after 1500 Km adjust the valves to a mid value ( this is only for reducing valve train noise ).

Jianis