Noises and stutters...

[DjEep]

A couple of random ones here.

Sometimes, when going up a hill in fourth in the westy I hear a little crackle, kind of like crumpling tin foil. I try to avoid this sound as much as possible by letting of the gas at the same rate as the bus would decelerate anyway, and then shifting to third. But my girlfriends ear isn't as trained as mine so I hear it sometimes when she is driving too.

Detonation? Vibration rattling something? Little green gremlins?

Also, Navin, the tired-but-still-feisty '71 has developed a low-mid rpm hesitation, more so that the usual 009 spot. As in no oomph under 32 or so in third, 20 in second... worse when real cold or warm. Clogged jet or something perhaps? when sorta cold he's fine, so i was thinking the choke is richening it up a bit, but it leans out when warmed.

[Amskeptic]

Sometimes, when going up a hill in fourth in the westy I hear a little crackle, kind of like crumpling tin foil.

Sounds like either pinging or a sheetmetal rattle. Track it down.
Drive the car until it happens, so all other variables are erased, then pull over. Experiment by retarding the timing a few degrees and go find another hill. Noise gone? You might have carbon build-up or lousy gas in your area. Are your plugs black? Chronic rich will build up carbon as will worn oil control rings. Noise still there? Retard another few degrees and try again.
Noise still there? Reset timing to proper specs, and start investigating each piece of engine sheetmetal for rubbing, twittering, loose screws, and check heater control valves and whatnot underneath for contact points.

Navin has developed a low-mid rpm hesitation, more so that the usual 009 spot.

Tune up including valve adjustment, adjust plug gaps and inspect wires, adjust points, adjust idle timing (verify dynamic timing at 3,000 rpm), clean pilot jet/cut-off jet, then adjust mixture on warm engine. What now?
Colin

[hambone]

Not sure about the crackle, maybe CVs? Weird...try to isolate it if you can.
You might want to try some carb cleaner on the '71. And check your points/timing.
Ditch the 009. I resisted for years then finally got a used one for $30. The difference is quite remarkable, you won't believe it.

[hambone]

Hey cool, I think like Colin! Sort of...I'm more of a lacky 27th class.

[DjEep]

Last I checked the plugs were clean on the '69. I'll try to check for pinging, as I'm still not sure exactly what it would sound like, but I thought it might be that. The sheetmetal thing could be it. Certain vibration caused by mid-rpm loading are making it rattle, perhaps?

I do need to tune up old navin, maybe just jumped the gun a bit by tossing it in here. He's got a compufire, and I don't drive him tto much, so I don't think it's timing. I'll check the valves when I get a chance, and he could probably use some new plugs.

[bottomend]

Unfourtunatly, the best location I've found to hear "pinging" is directly above the center of the crankcase. The problem is, you're driveing way up in the front and you cant get back there to hear! I have a mid-century T4 ('74), so I have the hatch to look down/listen through. I dont think early bus's have that convience...

The first time I heard detonation and realized what it was, I also thought it would've been more aptly referred to as "crackle" than pinging.

My valve seat comming loose sounded like peanuts being shaken in a tin peanut can.

My head leak sounded like a flag flapping in the wind when I accelerated uphill.

My leaking head, on the otherhand, sounds like dripping blood hitting the cold cement floor.

[DjEep]

yes, that is how i disqualified rattly cabinets, by hearing it come from beneath and behind me while riding is the back.

It only seems to happen when going uphill in fourth at between 50-60.

[Amskeptic]

yes, that is how i disqualified rattly cabinets, by hearing it come from beneath and behind me while riding is the back.

It only seems to happen when going uphill in fourth at between 50-60.

An extremely good noise to avoid. Seriously avoid.
Colin

[DjEep]

That's what I figgered. Like I said, I always try to avoid it. Now to get my girly to be able to hear it, or just not try and take those hills in forth.

[Amskeptic]

That's what I figgered. Like I said, I always try to avoid it. Now to get my girly to be able to hear it, or just not try and take those hills in forth.

See if you can fix the problem.
Bentley has advance curves, tach/dwell and a timing light, and a vacuum gauge, should do it. You can also check to see if the rotor is stuck in an advanced direction, turn it smartly counterclockwise with the engine off, then clockwise. It should spring back to the fully counterclockwise spot. Also check vacuum advance unit, suck on the carburetor end of the hose to the nipple and watch vacuum plate it should move smoothly counterclockwise and spring back when you release.

If advance all checks out, then you may very well have carbon build-up.
I would pull the heads and clean clean clean, that's a weekend project only) maybe do a valve job if all else is good and you're flush.
Colin

[DjEep]

Did valves, points and timing today. And, well as mentioned in another thread, I'm finally ditching the 009. Ordering an SVDA today. So as of now, no vac can to check, and as for the stuck advance, I did notice a bit of a stick in the rotor today.

As for carbon, the heads where changed about 8mos/10k ago and there was a bit on the pistons, but not a ton. I scraped off any bigger pieces. Last time I changed plugs, a few weeks ago, the plugs were all a nice tan. I don't know if that is an indicator of carbon on the piston or not though.

[Amskeptic]

as for the stuck advance, I did notice a bit of a stick in the rotor today.

Make a note of that. . . the 8-months-ago work should have dry plugs at the outside perimeter that is exposed to the combustion chambers. If there is any evidence of an oily wetness at the perimeter, that may be a sign of less-than-optimal ring break-in which can build up carbon way too quick. But I am pinning my hopes on the distributor.
Colin

[DjEep]

Ok, hopefully the dizzy will be ordered today. Unless I can find a suitable muffler first. I will get back to youses on this one after it arrives, or pending further relevent events.