B20 Modifications

[jdean299]

Hi lads. Hoping to order a twin Weber manifold for a B20 this week but not sure about clearances on a RHD car. Does anyone know which manifold I need? Do I need the shortest 42mm? Also twin 40's or 45's? What are most people running?

We are just starting to do up a B20 as a replacement for the B18 in our Amazon. We have just rebored the B20 as the bores were pitted and while we were at it, we had the blocked skimmed. The head should be going to the machine shop next week to be skimmed and set up for larger valves. Also on the cards are a TT6 cam, 4-2-1 exhaust, heavy duty lifters and rods, double valve springs and 37mm exhaust valves. Any thoughts on these upgrades? I also intend to get an alloy cam gear and have already purchased an electronic ignition + coil etc...

Any help would be much appreciated. Thanks

[Burdekin]

Sorry don't know clearances with running webbers but what Hp are you wanting should decide on the size of carbs. At a guess without knowing how much head work and what the cam is I'd say 45s.

What's a TT6 cam?

What head are you starting with and what head work are you doing as 37mm isn't that extreme. Why the double valve springs? Unless you are planning some decent amount of head work and increasing the rev range single springs are better. What size exhaust manifold is it that you have? Is it matching the head work and cam? Steel cam gears are what I've got and not heard of alloy ones for the B20 but sound like a nice idea. Lightened flywheel is a good idea and upgrade as well.

Good luck and keep us informed how you get on.

[Derek UK]

TT6 = http://www.tinustuning.nl/1-onderdelen-nokkenassen.html

They look to have good modern design cams as well as other nice parts. Good tuning advice too.

Use Google or Bing translate.

[jimbo1593]

Regarding manifolds it might be worth speaking to Rob at Amazoncars...or at least looking at their website and reading the news section, as he writes up lots of interesting tuning stuff.

With regard to weber sizing there are various calculators. I'm no expert but often sizing come down to large chokes (34mm) in a 40DCOE or smaller chokes in a 45DCOE. It is my understanding that 40DCOEs never came with a choke larger than 32mm as standard to inherent restriction within the crab itself. 45DCOEs are a lot more expensive.

Good luck

[jdean299]

@mitch1971
150-160HPish would be nice. Yes the cam I was on about was the one above by TinusTuning. So, how big can I go with the valves? My head was a twin carb from a '71 140 and I dont have an exhaust yet but was thinking of this 4-2-1
Is it a good choice?

I was recommended to go for the double springs but if its not worth it then I suppose there's no point wasting money. I cant find a used or new steel cam gear anywhere and the alloy one is 145euro so might not bother. Yes, the flywheel will be getting lightened when the crank etc is getting balanced.

@jimbo1593
I spoke to Rob at Amazoncars a few weeks back and he made out that 45's were overkill unless you were going over 200HP. Although, everybody on the Volvo forums seem to use 45's and they seem easier come by.

Thanks for the help lads

[jdean299]

Here's the Amazon by the way

Untitled by jdean299, on Flickr

[classicswede]

Originally Posted by jdean299

@jimbo1593
I spoke to Rob at Amazoncars a few weeks back and he made out that 45's were overkill unless you were going over 200HP. Although, everybody on the Volvo forums seem to use 45's and they seem easier come by.

Thanks for the help lads

Wow, I'd only ever bother with 45's on a B20 or 48's for a serious engine. If going to B21 pistons + stroked crank then you might even want to use twin 50's!

Manifold for RHD can be a problem and we just make our own to ensure good fit and clearance.

[Burdekin]

Whoever you get your cam and parts from should tell you what you need to do for your goals otherwise I'd think twice about buying from them. You will need head work but the guys at Tinustuning should tell you what you need and what CR to run. 44 x 37mm valves should be about right. The cam from what I know seems about right for mid 150ish Hp but again ask. I would also ask about the carbs and inlet manifolds and any clearance problems. I would say 45s is about right for what you want but you could also stick with the SUs and ask them what needles you should use. The Swedish guys would recommend 48s for 200hp so 45s might be a tad large for 160hp but not too far out I reckon. You don't get too many guys posting their dyno results and I reckon there probably is a lot of guys overestimating their HP and 160hp is quite a good effort from a 8 valve B20. I doubt you need double springs for 150 to 160hp but depends on where your power will be and how much you will rev the engine. The exhaust you could use an injector B20 exhaust manifold but if going for a extractor ask the guys what size as you don't want one too large as that will hurt your bottom end power. Something like the KG stage 1 which I think aligns with the R-sport one but worth checking before you buy. Also have a chat to the Tinustuning guys about what valves to use and valve seat angles. Adding volume to the cylinders is good when making the engine flow on a street engine better as this helps keep low down power.

So before you buy anything talk to Tinustuning or KG Trimning and get all the information you need.

[jorzez]

Originally Posted by mitch1971

...... You don't get too many guys posting their dyno results and I reckon there probably is a lot of guys overestimating their HP .......

here is dyno test, disappointing comparing to the description made by previous owner -below (couldn't verify)
170 hp /? Nm
engine, gearbox and exhaust system
B20 built by Timo
Ported and flat top
Uppstrokad
KG-cam
Dual Weber 45
fuel pressure regulator
Extraktorgrenrör
Lightened flywheel
Gearbox M41
2 "original sports system

[jdean299]

@mitch1971
A lot of good info there man, thanks. Don't think we'll bother with the double springs in that case as we don't intend to rev it too hard. Just bought an exhaust from PerformanceParts.NL who I think are linked to Tinustuning. Do you think there is any real advantages in heavy duty lifters and rods? Or would that money be better spent on head work?

@jorzez
We would be very happy with a number like that. We originally intended to put a B230FT from a 940 we purchased into the car for some serious power but then decided not to as it would have involved modifying the bulk head etc.. which would have ruined the cars originality. I since blew the B230FT up so it was a wise decision haha