B20A top speed

[Derek UK]

The Stromberg may well act the same as the SU when you partially raise the piston. When correct revs will rise and then settle back to normal. Your carb probably has a temp compensator on the side in a small rectangular box. This shouldn't be messed with but all should be working and clean inside. It's a bi metal strip that makes small adjustments to the mixture. Sophisticated by SU HS6 standards but there is probably something similar in the later alternate SU 44HIF. That carb may well work better than a Stromberg and doesn't suffer from spindle leak problems like the SU.

[classicswede]

Back to the original question
late 131 with B20A with only mod being a late recon head (same spec as E heads) would do just over 115MPH in 4th - no OD
140's with a 4 speed and exhaust typically about 110MPH flat out in top

My slow 145 Auto is slow past about 80 but eventually get to just over 100indicated but in real terms only 95 on GPS

The biggest restriction is the exhaust

[Burdekin]

Changed the diaphragm, got the carb piston working nicely, screwed in the mixture screw as far as it can go, new air filter, new coil, new spark plugs and leads, new fuel filter, new fuel pump, checked timing and went for a spin with my wife and dog. Well night and day, got to 60 and it just wanted to keep revving. Very windy and on a back road but up to 85 and was still going. Then a couple of times on the way home too on the dual carriageway way but wife wasn’t impressed so slowed down. She is no speed demon but much better. I still have a new needle and adjustable jet to fit.

[arcturus]

Did you have your ear plugs in?

[Burdekin]

It’s not too loud really.

[Uncle Benz]

Originally Posted by Khe Sanh

It’s not too loud really.

I think he means your wife

[Burdekin]

Originally Posted by Uncle Benz

I think he means your wife

Ha ha oh, no it was just the look and the tense silence. :-)

[arcturus]

You need to check speedo against GPS they can be anywhere between5% and 10% fast

[Burdekin]

Originally Posted by arcturus

You need to check speedo against GPS they can be anywhere between5% and 10% fast

I imagine it is now going like a good B20A should. I have a carb jet conversion and new new needle to install but that will be it for now with regard to the engine. The engine is running lovely; starts first go, idles and revs lovely. I wanted to know what sort of top speed could be expected so I could gauge if my engine was performing as it should. I was smiling on the weekend.

Did a compression test yesterday and all 150 apart from cylinder 1 which was between 145 and 150, so fine. Car has only done just over 70000m so should be a good amount of life left in the engine. There's a group of Amazon owners visiting later this year so will see how their cars/engines compare.

Next main job is to install the new and upgraded suspension and then renew the steering.

[amaz'in]

Originally Posted by Clan

To be honest you would be better off with the correct distributor , It will be accurate and more reliable if you use the genuine Bosch Points . The electronic is ok if programmed to the exact timing curve your engine needs and it will go on and on for a while until it fails stranding you . Has it got the vacuum advance unit ? The original Bosch Cap rotor and points were at the time the very best on the market and that's still true if you can find some. If i remember correctly the ignition timing is 17 to 19 degrees Before Top Dead Centre at 1500 rpm , with the vac pipe on the advance unit disconnected .

As always, an interesting comment there by Clan, namely relating to the 123 dizzy. I'm in Norfolk, close to the Norfolk/Suffolk border in fact which of course puts me in the promised land as far as four of the Amazon specialists are concerned, just 8/9/14 and 40 miles away from each with 40 being Simon at Ipswich, to think that the Guru Nick of the original Amazon cars was just down the road when he ran the business, smashing bloke but anyway I digress.

Well last year, my car went locally for the fitting of a 123 'tune' Dizzy, and it was after a 'LOT' of procrastination, my thinking that the original still worked perfectly (as much as I could tell) after 50 years but the lure of better running, smoother idling piqued my curiosity and finally got the better of me, note here, I didn't do it to avoid changing points, I actually thoroughly enjoy that.

To be entirely honest, did it idle a smidge smoother...yes and although you noticed, it was not night and day, could I tell any difference at any other road speed, not in the 100 miles use I had from it, yup you read that correctly, 100 miles.....it failed on me, and yes it was brand new, top model (123 Tune) and installed by the pro's, luckily I was on a back road and being a doubting Thomas had the original in the boot so managed to re-install it, and twist it backwards and forwards until she fired and for it to get me home.

I'm sure I was unlucky, although I have been told 'they do go wrong' (yes everything does) so I presume many of you may have them and have had no real issues, any of you racked up fairly decent mileages on one yet? Mine was sent off and returned as new but still not brave enough to trust it again at the present.