|
700/900 Series General Forum for the Volvo 740, 760, 780, 940, 960 & S/V90 cars |
Information |
|
Webcon weber carb conversion?Views : 1733 Replies : 21Users Viewing This Thread : |
|
Thread Tools | Display Modes |
Apr 4th, 2021, 14:09 | #11 | |
No longer Volvoless
Last Online: May 22nd, 2022 09:00
Join Date: Nov 2015
Location: Wendover
|
Quote:
|
|
The Following User Says Thank You to Ross Slaughter For This Useful Post: |
Apr 4th, 2021, 14:09 | #12 | |
Premier Member
Last Online: Today 19:03
Join Date: May 2012
Location: Lakenheath
|
Quote:
I remember being a young autoelectrician and they had a 1.1 Fiesta that would flood out as soon as you tried accelerating. None of the others could sort it or even get near the problem. I asked if i could have a try - "Huh! What would you know about it, you're just the sparky!?!?!" Yeah, ok, have it your way, took it up the road, had a word with the Service Director (my immediate boss), told him my findings and asked if we had another carb i could try. "Borrowed" a carb off a 1.3 Escrot in for bodywork, took it for a spin and came back, gave the keys to the old boy that had scoffed and mocked me and simply said "Give that a try". Came back 10 minutes later with a look of total disbelief on his wrinkled face. Even more disbelief when i told him the problem which meant all along him and everyone else in the workshop had been looking in the wrong area for the fault!
__________________
Cheers Dave Next Door to Top-Gun with a Honda CR-V & S Type Jag Volvo gone but not forgotten........ |
|
The Following User Says Thank You to Laird Scooby For This Useful Post: |
Apr 4th, 2021, 15:02 | #13 |
Junior Member
Last Online: Mar 31st, 2024 12:53
Join Date: Feb 2007
Location: Staines
|
I think the carb in the photo has the air filter adaptor fitted so it looks a bit different to a Fiesta carb. The 38DGAS can suffer with a flat spot from idle to progression when fitted on other engines than the Essex, I ran a couple on Opel engines and the progression drillings in the carb body were causing the problem. One I cured by using the 32/36 progressive linkage and the other by filing the butterflies to change the progression timing. The progressive 38 worked well but lost some low end torque and the other with filed butterflies nearly but not quite solved the problem. I moved to fuel injection so never really solved the flat spot completely on those combinations.
|
The Following User Says Thank You to qscgyjl For This Useful Post: |
Apr 4th, 2021, 15:58 | #14 | |
Premier Member
Last Online: Today 19:03
Join Date: May 2012
Location: Lakenheath
|
Quote:
As for the 38DGAS, there was something wrong other than the carb, biggest cause of flat spots on the 2.0 CIH Opel engine was incorrect points dwell and also the 38DGAS needed a few degees more adavance at idle to make it run properly through the rev range. Shouldn't have needed to use the progressive 2-stage lnkage from a 32/36 and as you discovered, you lost low-end torque as a result of having to open the first butterfly more. I'm guessing you also had the 2.0 CIH lump, originally fitted with the GM Varajet-II bucket? The idle bypass is the screw that should control idle speed on them but too many people touch the throttle stop screw, completely messing the vacuum advance up. If that was the case and you went to a Weber without first getting the timing right because of messed up vac advance, you would have had incurable flat spots. If memory serves the ideal figure for the vacuum advance was 8" H20 @600rpm, to be set (very carefully) with a water manometer. Needed careful tweaking of the dizzy followed by careful tweaking of the throttle stop screw to get it right, especially if some muppet had played with the throttle stop screw instead of the idle bypass screw. Once the right amount of vacuum was on the advance line, the igniton timing could be reset to where it should be and the idle speed brought up with the idle bypass. First time i did mine took me a couple of hours and several episodes of drying the water off the plugs but it was worth it. Then i went for the 32/36DGEV, followed a short time later by the 38 DGAS, converted to a 38 DGEV using the same electric choke element and OE feed to the electric choke on the Varajet. No flat spots or progression problems, just power all the way to 7200rpm in all 4 gears. Fuel economy was also improved on the DGES over the DGEV, nudging 30mpg which for a hard-driven car was pretty good.
__________________
Cheers Dave Next Door to Top-Gun with a Honda CR-V & S Type Jag Volvo gone but not forgotten........ |
|
Apr 7th, 2021, 05:14 | #15 |
Junior Member
Last Online: Mar 31st, 2024 12:53
Join Date: Feb 2007
Location: Staines
|
Digging deep into the memories here! The engine was a 2ltr, the GM carb, inlet and head went in the bin and a fresh engine built with a 1.9 inlet, big valve head, new 38DGV and Piper cam. Ignition is hazy, there were a few combinations, most likely being Lumenition in a resprung 1.9 dizzy. A Holbay cam went in shortly after. The flat spot could be driven round easily, it was more of a hiccup. The progressive linkage was a trial that gave way to EFi then a V8. The other engine was a friends 2ltr with a Granada 38DGAS we filed the butterflies on to alter the progression timing. The joys of tuning on a budget!
Were you racing your CIH? |
The Following User Says Thank You to qscgyjl For This Useful Post: |
Apr 7th, 2021, 09:11 | #16 | |
Premier Member
Last Online: Today 19:03
Join Date: May 2012
Location: Lakenheath
|
Quote:
That started life as a 32/36DGAV but i converted it with a Weber electric choke, obtained the jettings for the standard conversion and the jets at cost from a mate who worked in a carb specialist/rolling road place as at that time my commute was fairly long and the unreliability of the Varajet and poor economy were painful on the wallet. I didn't set out to intentionally tune it, it was more that when bits wore i replaced them with tuning bits and the cam went next so in went a Piper Magnum 285/2 cam with solid lifters and a stepped plug in the head to increase the residual oil level, meaning the cam always had oil wash lubrication. The downpipe went next so a Jetex 2" downpipe went on merging into a 2.5" outlet then the rest of the system changed to a Janspeed 3" skidded system. Then the 32/36 didn't give enough flow especially at the top end so the 38DGAS was sourced, rejetted and converted to electric choke. Ignition was more or less standard but running at ~11deg BTDC instead of the standard 5deg BTDC. Get the ignition timing even half a degree out and it was flat as a fart and sounded like one as well. Get it spot on and changed into a snarling beast that happily left Manta 2.0 GT/Es standing and on one occasion, left a 3.0 CDi (12v) Senator floundering in the weeds. That was the closest i came to racing and the wrong car to do it with, underneath that solid blue paintwork lurked some disco lights! Never had it on the dyno but estimates from the guy i got my cam and other tuning bits from and my own experience suggested ~160-170bhp. Can't remember the full spec, think there were a couple of other bits thrown into the mix but it was a very quick beast.
__________________
Cheers Dave Next Door to Top-Gun with a Honda CR-V & S Type Jag Volvo gone but not forgotten........ |
|
The Following User Says Thank You to Laird Scooby For This Useful Post: |
Apr 7th, 2021, 18:19 | #17 |
Junior Member
Last Online: Mar 31st, 2024 12:53
Join Date: Feb 2007
Location: Staines
|
Do you still smile if you see a Cavalier/Manta or Ascona? I had a strange find on my first car, a low mileage bog standard Cavalier 1.9GL with a 28/36 Weber fitted in place of the Zenith 35/40 INAT. At first I was disappointed to find out the carb was smaller but it went well, in fact better than the Opel Manta I replaced it with that had the INAT!
I had some fun with that engine in two cars, the Ascona B it came in and a GTE Coupe. The Ascona had the Holbay cam and big valve head and would keep with 2.8i Capri's to well over 100 then the V6 torque had the legs. RS2000's were fun as I could keep with them and had a 5 speed Getrag so they ran out of gears about 115. The fuel injection went on the Ascona effectively making a 2.0E not sold in this country, then the engine and box went in a stolen recovered Manta GT/E Coupe less the big valve head. The Ascona was more fun though. I wasted a lot of money on CIH engines, a mild Rover V8 made a real nice road car with no weight gain and twice the Torque. I had the best of both cars with that one, a Mancona GT/E coupe. That was so much more fun. |
The Following User Says Thank You to qscgyjl For This Useful Post: |
Apr 7th, 2021, 19:21 | #18 |
Premier Member
Last Online: Today 19:03
Join Date: May 2012
Location: Lakenheath
|
The Weber was a standard fit on some Mantas - i'd lay bets it had over-riders on the bumpers from the factory? Usually they went hand-in-hand and were German built.
The Belgian built (mainly Asconas but some Mantas and Mk1 Cavaliers) usually didn't have the overriders but the 28/36 Weber gave better economy and performance than the horrible Solex thing, even if it had Zenith stamped on it! Can't remember the last time i saw a Mk1 Cav/Manta/Asona on the road or anywhere else for that matter. I remember having fun with 2.8i Capris, their faces in the rear view mirror said it all really! I'd previously had fun with them in a Mk3 Cortina, it was an N reg with the 1.6 box and back axle (slightly lower ratio than the 2.0) but ended up with a Capri 2.0 GT engine with a wild cam in it - not sure what cam it was but it went like stink, nicely helped by the back axle and lower ratio 1st and 2nd so Capri 2.8i's were eating my dust up to about 100 then mine ran out of legs and the Capri went past. I also had a few standard Datsuns that would eat Capri 2.8i's on both acceleration and top end, that was fun! PS - i like the Ascona fronted Manta, the reverse of what Vauxhall did to create the Cavalier!
__________________
Cheers Dave Next Door to Top-Gun with a Honda CR-V & S Type Jag Volvo gone but not forgotten........ Last edited by Laird Scooby; Apr 7th, 2021 at 19:23. Reason: PS..... |
Apr 8th, 2021, 19:50 | #19 |
No longer Volvoless
Last Online: May 22nd, 2022 09:00
Join Date: Nov 2015
Location: Wendover
|
Oh man total thread highjack 🤣
|
The Following User Says Thank You to Ross Slaughter For This Useful Post: |
Apr 8th, 2021, 21:00 | #20 |
Premier Member
Last Online: Today 19:03
Join Date: May 2012
Location: Lakenheath
|
Errrrrrrr, yeah, i was going to apologise for that! In fairness most of it was around Weber carbs but not neessarily Volvo ones!
__________________
Cheers Dave Next Door to Top-Gun with a Honda CR-V & S Type Jag Volvo gone but not forgotten........ |
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests) | |
|
|