Rough, yes. Worse, no.

You can set the car up to run well cold, or run well hot-- it can't be both. Modern cars adjust timing, mixture, etc. based on complex algorithms that gather inputs from multiple sensors. Pre-ECU cars had chokes to artificially enrich the mixture when cold. Model Ts had a lever to adjust the spark advance.

Your car has none of these things, so you adjust things for something in between. My hot idle is at or above 1000 RPM, because this means I've got a 500 RPM idle until it gets really warmed up. If I had a way to adjust the timing, I'd put 4 or 5 more degrees in at idle when the engine is cold, and I could back some speed out. 

You can't really "warm it up" in cool-ish weather unless you are driving for an hour or more under a decent load. Once the temp needle come off the full-cold stop, it's at least got some heat in it. At that point, it should idle for 15-30 seconds (without stabbing the throttle), but it's likely not going to keep idling for minutes unless it's set up for a super-fast idle when it's hot.

The "loss of power" part makes me think there may be something wrong, because a carbureted car will never run better than when it's getting cool, dense air. My car runs like a scalded dog on a 50* night when I've got some heat in the engine. Yours should too.

Good luck. There's a learning curve to determine what's normal and what's not. You're on the front side of it, but if you stick around you'll get it.


Michael, welcome to our virtual garage and service center.

We offer remote evaluation and troubleshooting of air-cooled engines at very reasonable rates. We like to think that our advice is worth every penny you pay for it.

But it would help a lot if we knew more about your car and your history with it.

Is the car new to you? How long have you had it and how far have you driven it?

Has it always had these issues or did they just start? Does it drive well in warmer temperatures? When it’s first started?

What Stan says about tuning for a specific temperature range is true, but as your profile says you’re in San Diego, you certainly should be able to find a good compromise tune that will work well in any temperatures you’re likely to encounter.

Again, the more you can tell us about your driving experience with the car and the specifics of the problem, the more we can help.

 

Sacto Mitch posted:


Michael, welcome to our virtual garage and service center.

We offer remote evaluation and troubleshooting of air-cooled engines at very reasonable rates. We like to think that our advice is worth every penny you pay for it.

But it would help a lot if we knew more about your car and your history with it.

Is the car new to you? How long have you had it and how far have you driven it?

Has it always had these issues or did they just start? Does it drive well in warmer temperatures? When it’s first started?

What Stan says about tuning for a specific temperature range is true, but as your profile says you’re in San Diego, you certainly should be able to find a good compromise tune that will work well in any temperatures you’re likely to encounter.

Again, the engine is a new Bernie Bergman supposed 2270 cc engine 240 hp.  40 mm carbs.  Yesterday it los s a ton of power and ran really rough.  Just got it back from it’s 500 mile device for new rebuilt engine.  

more you can tell us about your driving experience with the car and the specifics of the problem, the more we can help.

 

 

Wait a minute - Something just caught my eye.  Michael wrote:

"Again, the engine is a new Bernie Bergman supposed 2270 cc engine 240 hp.  40 mm carbs.  Yesterday it los s a ton of power and ran really rough.  Just got it back from it’s 500 mile device (service?) for new rebuilt engine.  "

If it was just serviced and the mechanic was poking around in the engine bay, he might have bumped off a spark plug wire and that would make it run rough and lose a lot of power, too.  If the plug ends of the wires have "ball ends" that fit into the holes in the fan shroud they tend to fit pretty tight and sometimes they force themselves out by bumping them or just from vibration over time.  

Check to see if any plug wire is off and push it back on until you fell it "click" onto the plug.

 

(I'm guessing) @Michael Balastrieri wrote- "Again, the engine is a new Bernie Bergman supposed 2270 cc engine 240 hp.  40 mm carbs.  Yesterday it lost a ton of power and ran really rough.  Just got it back from it’s 500 mile device for new rebuilt engine. "

DannyP posted:

I'll tell you one thing for 100 percent certainty. It isn't 240hp. Probably not even 200. Most probably somewhere between 140 and 180. On a good day.

Sorry to break your bubble, Michael, but I agree with Danny. As I said in another thread, I believe the limit for 40 mm carbs- Webers, Dellortos, HPMX's or ? is about 160 hp. How high did it (or is it supposed to) rev with power? I'm also sorry to hear it's a Bernie Bergman engine. The quality of workmanship from his shop is questionable at best, and some of the things I've seen/read about coming out of there are downright scary. People have torn down his engines and found mismatched case halves, different heads from side to side, displacement not what it's supposed to be, camshaft different than what's spec'd (and the list goes on).

After making sure that it isn't a plugged idle jet (already suggested by Chris- it will run cleanly above 3,000 rpm if it is), check that the timing is right, ignition (including the coil) isn't acting up, plug wires are all firing properly, plugs are in tight and all firing, pushrods are straight and the ends aren't pounding in, valve adjustment hasn't changed, rockers and adjusters aren't broken, carbs are still synced, adjusted and functioning properly and there are no intake or exhaust leaks (have I missed anything?). If you noticed during valve adjustment that a couple of rockers (probably 1 on each side) were way out and it's still running crappy- drain the oil. A silver slurry  means a cam lobe (or 2) and the matching pair(s) of lifters are going south and it's time to take the engine back to it's maker.

Let's hope it's something simple like Gordon suggested- a plug wire off.   Al

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