That's right. It's all a big scam. Just trying to make an alibi for where I was when....well, you'll find out.bottomend wrote:Hey Sluggo, I looked at the " travel" pics in your gallery. Nice Photoshop job with the Golden Gate Bridge. Except for getting the shadows backwards, it looks pretty convincing. So... when do you think you'll get the bus on the road for real?
Horrible Mileage - FIXED! 100%
- Sluggo
- Wishin' I was Fishin'
- Location: Portland, Or.
- Contact:
- Status: Offline
1977 Bus with Sunroof - "Lucky '77"
2000cc Type IV w/Dual Weber 36s,
Aircooled.net SVDA w/Compufire,
Redline Weber Fuel Pump,
Holley Regulator,
Half Ass Brush & Roller Rustoleum Paint Job,
Incomplete Custom Interior,
Dual Batteries,
Crunched Slider Door.
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- chitwnvw
- Resident Troublemaker
- Location: Chicago.
- Status: Offline
So how are you using it as a diagnostic tool? It might be showing everything is a-ok, when 2 barrels are lean and two rich...Sluggo wrote: You don't. At least not with one air fuel ratio monitor. If you wanted a reading for each barrel you'd need 4 monitors with four senders welded into each exhaust manifold. About $500 for all that not including having the bungs welded in for the sender.
- Amskeptic
- IAC "Help Desk"
- Status: Offline
Your engine goes through a natural lean-out after the chokes have shut off and before the manifolds have warmed up. During this spell, the manifolds will go through a condensation period where the incoming air chills the manifold walls more than the engine heat can overcome. This condensation period occurs in all climates and is the reason behind all that factory air-preheater engineering.Sluggo wrote:I think I'm just covering up an intermittent vac leak.
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles
- DurocShark
- IAC Addict!
- Location: A Mickey Mouse Town
- Contact:
- Status: Offline
And is the biggest reason that current manifolds for centermount carbs on type 4's aren't worth the metal they're made of.Amskeptic wrote:This condensation period occurs in all climates and is the reason behind all that factory air-preheater engineering.
Colin
If someone would friggin just market a manifold with heat, all those Pinto carbs out there might actually work decently on our busses!
- Sluggo
- Wishin' I was Fishin'
- Location: Portland, Or.
- Contact:
- Status: Offline
No chokes on the Webers. Plus, it will happen after I've been driving for a few hours too.Amskeptic wrote:Your engine goes through a natural lean-out after the chokes have shut off and before the manifolds have warmed up. During this spell, the manifolds will go through a condensation period where the incoming air chills the manifold walls more than the engine heat can overcome. This condensation period occurs in all climates and is the reason behind all that factory air-preheater engineering.Sluggo wrote:I think I'm just covering up an intermittent vac leak.
Colin
It will blip down on each cycle if one barrel is lean or blip up if one is rich. Which it does sometimes. This is why I think I have an intermittent vac leak.chitwnvw wrote:So how are you using it as a diagnostic tool? It might be showing everything is a-ok, when 2 barrels are lean and two rich...Sluggo wrote: You don't. At least not with one air fuel ratio monitor. If you wanted a reading for each barrel you'd need 4 monitors with four senders welded into each exhaust manifold. About $500 for all that not including having the bungs welded in for the sender.
1977 Bus with Sunroof - "Lucky '77"
2000cc Type IV w/Dual Weber 36s,
Aircooled.net SVDA w/Compufire,
Redline Weber Fuel Pump,
Holley Regulator,
Half Ass Brush & Roller Rustoleum Paint Job,
Incomplete Custom Interior,
Dual Batteries,
Crunched Slider Door.
------------------------------------------------------
- Sluggo
- Wishin' I was Fishin'
- Location: Portland, Or.
- Contact:
- Status: Offline
I thought that was just a problem with centermount Progressives? I have duals.DurocShark wrote:And is the biggest reason that current manifolds for centermount carbs on type 4's aren't worth the metal they're made of.Amskeptic wrote:This condensation period occurs in all climates and is the reason behind all that factory air-preheater engineering.
Colin
If someone would friggin just market a manifold with heat, all those Pinto carbs out there might actually work decently on our busses!
1977 Bus with Sunroof - "Lucky '77"
2000cc Type IV w/Dual Weber 36s,
Aircooled.net SVDA w/Compufire,
Redline Weber Fuel Pump,
Holley Regulator,
Half Ass Brush & Roller Rustoleum Paint Job,
Incomplete Custom Interior,
Dual Batteries,
Crunched Slider Door.
------------------------------------------------------
- DurocShark
- IAC Addict!
- Location: A Mickey Mouse Town
- Contact:
- Status: Offline
It can happen to any carb setup. It's just almost guaranteed on centermounts because of the long runner length.Sluggo wrote: I thought that was just a problem with centermount Progressives? I have duals.
With dual carbs, even if it happens, it's less noticeable because the intakes are (usually) so short. Plus they heat up faster. So as Colin said, that moment in time when the chokes just opened but the engine isn't fully warmed up is when it's most likely to happen. You don't have chokes, so it'll happen until fully warm.
If you have an IR thermometer you can watch it happening. Start the bus cold and take a reading of the intake just below the carb. Take readings until the engine is fully warmed up. You'll see lots of peaks and valleys. Possibly even some below freezing temps!
There are times when it'll happen no matter how warm your engine is. There was a good write up on a 280z site about this, but I lost my bookmarks when I got laid off so I have no idea where it was. It showed temp changes just past the carbs on a set of weber side drafts. The guy had graphed it with one minute resolution. I was really surprised.
- Amskeptic
- IAC "Help Desk"
- Status: Offline
Same difference. Feel your manifolds the next time you slip into lean mode. Are they cool? It will happen during driving for a few hours, or after it has shut off for a few minutes after driving for a few hours?Sluggo wrote:
No chokes on the Webers. Plus, it will happen after I've been driving for a few hours too.
If you ever see condensation on the outside of the manifolds, it will be happening on the inside too.
OK, so you are enthralled with this intermittant nature of a vacuum leak. . . what sort of vacuum leak can pull off intermittant symptom?
Colin
BobD - 78 Bus . . . 112,730 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles
Chloe - 70 bus . . . 217,593 miles
Naranja - 77 Westy . . . 142,970 miles
Pluck - 1973 Squareback . . . . . . 55,600 miles
Alexus - 91 Lexus LS400 . . . 96,675 miles
- Sluggo
- Wishin' I was Fishin'
- Location: Portland, Or.
- Contact:
- Status: Offline
My barely educated theory was that as things expand and contract leaks can happen in the intake manifolds and vacuum crossover pipe. But I didn't realize icing could happen with dual carbs. I thought it was purely a symptom of long intake runners. I do always have a slight up and down blip whether lean or normal. But I guess that could be attributed to the same thing.Amskeptic wrote:Same difference. Feel your manifolds the next time you slip into lean mode. Are they cool? It will happen during driving for a few hours, or after it has shut off for a few minutes after driving for a few hours?Sluggo wrote:
No chokes on the Webers. Plus, it will happen after I've been driving for a few hours too.
If you ever see condensation on the outside of the manifolds, it will be happening on the inside too.
OK, so you are enthralled with this intermittant nature of a vacuum leak. . . what sort of vacuum leak can pull off intermittant symptom?
Colin
1977 Bus with Sunroof - "Lucky '77"
2000cc Type IV w/Dual Weber 36s,
Aircooled.net SVDA w/Compufire,
Redline Weber Fuel Pump,
Holley Regulator,
Half Ass Brush & Roller Rustoleum Paint Job,
Incomplete Custom Interior,
Dual Batteries,
Crunched Slider Door.
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