update "engine running rough"

Hi Roger, I got a '69 beetle which runs fine at speed but stalls if left at idle for any time,ie come up to a set of lights and the engine just dies. I was convinced it was the timing but set that and the points all to no avail so tried to set the carb as in haynes but still no good.seems to run fine with top butterfly v/v (choke?) shut nearly all the way but this moves about of its own accord when driving so the problem just re -occurs! Am at end of my rope! any help appreciated!

paul.

bug '59 wrote:

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Dear Roger,

While the symptom of zero clearance can mean several things, none of them are good with an engine of that vintage, which was known for incompatibility problems between the cam & cam-followers.

The wiser course may be to park it while you line-up a replacement engine, then simply plug in the replacement.

-Bob Hoover

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Dear Bob,

indeed I don't think the engine will last another year. Not sure why, doom thinking maybe. And sometimes weird sounds in the back :) I've been thinking on replacing the engine. That or rebuilding it. Although rebuilding requires some skill and knowledge of engines which i have not or at least very little (but you might have guessed that already).

So my best bet is to drive it while purchasing a new one. Unfortunately; most likely time will pass before I actually put money where my mouth is. Hopefully not too late, or I will learn it the hard way, so i can try to rebuild this one for spare Again, thank you and others who have helped me before, I will need some more in the future. :o)

Roger

"muziksmig via CarKB.com" schreef in bericht news:704a347cf7254@uwe...

Hi Paul,

Before i've been pointed out to search outside the fuel delivery I've checked everything they mentioned in your original post. Also do a search on this topic at:

It is really not all that hard to rebuild the engines if you have a VW Beetle repair book... sort of like following a cook book recipe. If you find a machine shop to handle the heads, and maybe even somebody to re-ring it for you, it isn't bad at all. Otherwise, why put off the inevitable? If you drive it until it dies, you have a pile of junk that used to be the engine, and the stress if it siezes could mess up your drive train... towing at least.... lots of wasted $$! Get the engine NOW and then maybe some shade tree mechanic could rebuild the engine.

Besides, if it turns out that the current engine is the "original" one, then rebuilding it would DEFINITELY be good since you could have a "matched car".

I would recommend adjusting valves AFTER checking the torque of the lower cylinder head nuts. Run the engine for awhile and recheck the valve stem clearance. Of course you are checking the clearance when the engine is cold. ;-)

You might just need cylinder heads which you could replace in a day or two. Compression check might help determine what you are looking at doing to your engine.

that is usually a sign that you could have an intake air leak....

well it's not that hard to assemble an engine....but most hobbyists don't even have the proper tools for measuring and the know how to "build" a vw engine.... but the engine is amazingly forgiving, in stock/mild form... so lots of folks ride around with a big smile saying to themselves "it runs great and *I* rebuilt it".... or assembled, or whatever..

I had a similar problem and it turned out to be a vacuum leak at the carb throttle shaft (common for old stock carbs).

Use some carb cleaner or WD40 and spray around the carb throttle shaft ends while the engine is idling. I had to partially close my choke which opens the throttle up a bit and raises the idle. If you spray on/near a leak it will draw in the carb cleaner and richen then intake mixture for a moment. The engine rpm should rise. You can also spray around the base of the carb, the intake to end casting boots and the intake to head flange. If the rpm goes up while your spray these spots you have leak that needs to be fixed (new gasket/boot). Also check any hoses that run from the carb. If these are leaking you will have a vacuum leak as well. It doesn't take a big leak to affect the idle quality.

Alternatively, you could have some dirt in the idle circuit of the carb preventing fuel from flowing at low engine speeds. You might be able to clear this out by removing the mixture and bypass screws (not sure if your carb has both) and spraying them and flushing their holes w/ carb cleaner.

Good luck!

AshMan40

True. They are forgiving. This last time I wanted to do it right so I measured and weighed things. It was a bitch finding something to accurately weigh the connecting rods and pistons - finally dug out a balance beam baby scales my folks gave us when my kids were small (heck, they had used it on my siblings and me for that matter).... even then it was hard to eliminate all the "noise" in the weighing. I still chickened out on the heads and had someone with a shop do them for me.

would a postal scale work? Digital is even better. ;-)

the extra time spent on the details will pay large dividends in longevity and even power output....

accuracy is the main concern....

"KWW" schreef in bericht news:4616ec32$0$27113$ snipped-for-privacy@roadrunner.com...

Yes i know it is best to be ahead of problems and if needed buy a new one but... Time is in this case the reason. Better said, lack of time. I still have a 30 hp engine which I have to build in into my '59. It's sitting in the garage for about 2,5 years now :( I even have a discbrake kit which needs to be installed on my '73

Sigh, and the wife is complaining why I'm not finnishing the attick after 2 (!) years

Thanks for the advice all, I try to live up to it :) Roger

I had the craziest symptoms on my Type IV engine. As Bob H said, the engine tells the truth, but you have to figure out how to interpret what it's trying to tell you.

Engine would idle fine. Rev it, and the revs stay high for quite a while, then it drops again. Almost typical vacuum leak symptoms, except intermittent.

I eventually found out that it was sucking air through the dipstick tube (which is sealed on a T4 but wasn't in my setup) -- but only when the oil level was low enough.

So rev the engine, it pumps oil, oil level drops below the dipstick tube, crank is open to air, crank ventilation system leaks air into fool rejection system, fool rejection sees this and adds fuel, revs go up.

Sealed the dipstick tube and that problem went away :-)