Rough Running Engine

[NelsAnderson]

A few weeks ago my engine starting running rough and I have not been able to fix it so could use some help.

1963 Series IIA 109 Station Wagon
Turner 2.25 rebuild engine
Weber 34ICH carb

I first thought it was just an idle problem, so changed the inline fuel filter, removed and cleaned the idle jet and removed and cleaned the filter screen. No effect.

Actually, it runs rough at all speeds. It's not really noticeable just listening to the engine, but is obvious listening to the exhaust. There's also a noticeable lost of power when driving.

I have since done the following, all with no effect:

Removed and checked spark plugs: all nice and tan

Removed distributor cap, cleaned contacts, adjusted gap

Removed wires from coil, cleaned contacts

Opened top of carb, check bowl for sediment (nothing found), cleaned out bowl and blew carb cleaner through jets (though did not remove them...not sure how, do they just unscrew?)

Clamped off vacuum hoses to check for leaks

Sprayed carb cleaner around base of carb to try and detect vacuum leaks there

Tried clearing carb by putting hand over air intake and letting it suck until it almost stalls

None of this seemed to have any effect. I am not experienced on this kind of thing so it's possible I've just failed to notice something, but at this point I'm out of ideas. Any suggestions would be appreciated!

[Les Parker]

Have you checked the adv/retard vacuum unit on the distributor?
Try disconnecting it and see if it runs any different.

[NelsAnderson]

Does that mean simply removing the vacuum advance hose from the distributor? I haven't tried that but it sounds easy enough to do. Thanks!

[daveb]

I didn't see where you adjusted the valves. Adjust the valves and see if that helps.

A few weeks ago my engine starting running rough and I have not been able to fix it so could use some help.

[bmohan55]

Plug wires??? Switched mine out and it got rid of the "burp" in the exhaust.

Also an easy trick taught to me by an old mechanic is to hold a dollar bill (for a Series use a $20) and see if it gets intermittently sucked towards the exhust pipe, if so you've got a burnt valve.

[Les Parker]

Yes, just pull the pipe from the dist. vac. unit and plug with a small bolt.
See if it makes a difference, plus try the dollar bill burnt valve detector !

[NelsAnderson]

OK thanks everyone. Let me now follow up.

The spark plug wires are only two years old, a rather expensive set of Magnecor wires that are supposed to last forever, so I would hope that's not it.

I have not adjusted the valves. I've never done that before so I'm a bit reluctant, though maybe that is the logical next step?

I checked the distributor vacuum advance. If I understood right, the hose is removed from the distributor and a bolt stuck in the hose to plug the vacuum leak. I tried running that way, but did not notice any difference.

While it was running I tried the (twenty) dollar bill test. The bill flaps around in the exhaust which seems to always blow out, with each "puff" blowing a little harder. I really didn't want a burnt valve so I guess this is good news.

[graniterover]

Nels,

I'm 99% sure you have hardened valves.

Did this happen all of the sudden, or gradual?

Mark

OK thanks everyone. Let me now follow up.

The spark plug wires are only two years old, a rather expensive set of Magnecor wires that are supposed to last forever, so I would hope that's not it.

I have not adjusted the valves. I've never done that before so I'm a bit reluctant, though maybe that is the logical next step?

I checked the distributor vacuum advance. If I understood right, the hose is removed from the distributor and a bolt stuck in the hose to plug the vacuum leak. I tried running that way, but did not notice any difference.

While it was running I tried the (twenty) dollar bill test. The bill flaps around in the exhaust which seems to always blow out, with each "puff" blowing a little harder. I really didn't want a burnt valve so I guess this is good news.

[kevkon]

Do you buy your gas at the same station all of the time? Any change in fuel in the last couple of weeks?
If not;
While your engine is running pull the plug wire off one cylinder at a time. If one comes off and no change is noticed in the engine you have your culprit.

[willincalgary]

What's the dollar bill burnt valve detector?

Yes, just pull the pipe from the dist. vac. unit and plug with a small bolt.
See if it makes a difference, plus try the dollar bill burnt valve detector !

What's this dollar bill burnt valve detector? I had to use a five dollar bill as we don't do the one dollar bill up here. It flapped out and then smacked back against the tailpipe quite rhythmically. Diagnosis of test results anyone?

[Nium]

Also an easy trick taught to me by an old mechanic is to hold a dollar bill (for a Series use a $20) and see if it gets intermittently sucked towards the exhust pipe, if so you've got a burnt valve.

A compression test may be a good idea willincalgary.

[NelsAnderson]

Nels,

I'm 99% sure you have hardened valves.

Did this happen all of the sudden, or gradual?

Mark

I'm not sure I understand what you mean by "hardened valves".

For as long as I can remember, I've always heard the occasional "puff" from the exhaust. The current problem happened pretty suddenly though, one day running good, the next day running rough.

The engine (Turner high performance) was new in March 2005 and has only 14,500 miles on it so I wouldn't be expecting valve problems already.

[NelsAnderson]

Do you buy your gas at the same station all of the time? Any change in fuel in the last couple of weeks?
If not;
While your engine is running pull the plug wire off one cylinder at a time. If one comes off and no change is noticed in the engine you have your culprit.

I usually buy gas for all three of my vehicles at the same station down the street from my house, though I cannot say for sure that I remember if I did that on the last tank of gas in the Rover.

Is it safe to pull the plug wires like that? Pretty high voltages there.

[bmohan55]

What's this dollar bill burnt valve detector? I had to use a five dollar bill as we don't do the one dollar bill up here. It flapped out and then smacked back against the tailpipe quite rhythmically. Diagnosis of test results anyone?

Your exhust valve is either burnt or not sealing all the way due to carbon build-up, thus the "sucking" action during the piston's down stroke.

Compression test would confirm. BTW, DO NOT wade thru deep water with tail pipe sucking in...bad things happen!

Nels...in reading through your posts, if you have not adjusted the valves in 14K miles I would do so now. Here a good how-to

http://www.lrfaq.org/Series/FAQ.S.tuning_2.25l.html

[Nium]

Is it safe to pull the plug wires like that? Pretty high voltages there.

Not with your bare hand. You need to use some sort of insulating device, such as a pair of plug pliers, to keep the voltage from using your body as a conductor to ground. Plug pliers are made of non-conductive material and are available at auto-parts stores.