Amazon: engine upgrade

[131annika]

I have a B20A engine in my 69 Amazon. Its running a Weber D.O.N.F I also have a B20B cam, that i can fit will the Weber run better with this cam? I will fit a 2 mm head gasket instead of the 6 mm gasket do i need to use the B20B distributor and drive as i do have one. B20A has left hand points with vacuum advance. Where the B20B has vacuum retard, so can i connect the vacuum back to the Weber? Any help i would be grateful

[lukeball]

You mean Weber DCNF, right? Do you have a special manifold for that carb, and how does it run? I am no expert, but I thought that the float on the dcnf isn't properly located to be used on a Volvo without a special manifold.

[131annika]

Hi, yes it is a DCNF and is running with the right manifold on the car for the last year, runs well with out vacuum on thanks

[guitarman]

Interesting- don't know about this particular Weber. It's a side draught I imagine? The cam really doesnt have anything to do with the carb. Go for it- sounds like you have a ripper there. It may be something of a drinker though!

[guitarman]

btw- Id avoid vacuum Webers- all mechanical much better response.

[lukeball]

You don't have to use vacuum advance or retard as guitarman posted. You can modify the distributor to remove it. So all mechanical advance. It looks like the DCNF doesn't have a proper distributor vacuum port (based upon searching); most people drill a new hole above the throttle plate.

Thanks for posting this; I never considered a Weber DCNF. I am trying to decide between rebuilt SU HIF6 carbs or a reworked Weber 38/38 DGAS.

By the way, you could probably find a mechanical advance distributor in the sales/wants section of this forum.

To answer your last question: Yes, you could use the B20B cam and it would probably run well except that you might have to re-jet your carb. You could also try the K-cam; it was used in the Volvo GT tuning kit with a Weber 36/36 DCD with good results.

[swedishandgerman]

Originally Posted by lukeball

By the way, you could probably find a mechanical advance distributor in the sales/wants section of this forum.

You could just use a B20B distributor and leave the vacuum unit disconnected. Set the timing at about 35 degs at about 2,000rpm and make incremental adjustments until there is absolutely no pinking when you drive it under full load up a hill

If you want a fully mechanical advance distributor, you should look for one originally from a B18B with part numbers ending 003 or 009.

This distributor also works well with SU's which run richer than Strombergs, the latter needing more advance as they go weak at part throttle openings, the former going strong.

However, with the carb being discussed, I have no idea of what it does, so you could experiment with a B20A sourced (vacuum advance) distributor and make comparisons with a fully mechanical advance distributor. That way, you could find out which distributor type suits the carb. Bear in mind that with either type of distributor, you will get no difference in performance above about 2,000rpm when they all go to full advance; all you're doing with these distributors is changing low end throttle response.

If you stick with the A-cam, it kind of restricts the airflow, for want of a better description. If you go for the B-cam, it allows the valves to open more and consequently lets the engine reach higher rpm. Consequently, it extends the power band. Fuelling (jets/needles) for an A-cam would therefore be different than for a B-cam where you might find it goes weak at high rpm.

I advise you not to attach the vac pipe on a B20B (vacuum retard) distributor.

If you want a B18B distributor, I have one. Just bear in mind that although it's a great distributor, it has the fiddly 2 piece points

[tdz840]

Originally Posted by 131annika

I will fit a 2 mm head gasket instead of the 6 gasket.

6mm gasket, are you sure?
I thought they were typicaly 1.2mm but some of the high compression engines used 0.8mm?russ

[Volvo Canadian]

Hey guys, I propose a rule for new members:

NO PICTURES, NO RESPONSE!!

Okay, maybe a little strong. Got any pics there Mr. 131?? Curiosity may have killed the cat, but I'm not a cat.

[131annika]

Thanks for the replies This is my first thread so do not know how to put pic up yet whot pic do you wont to see ? 2mm head gasket is for the B20B engine two carbs. the 6-8mm gasket is for the B20A one carb