B20 build
 

Attachment 91858My big B20 build is now well under way. I secured a pass to put it together in the kitchen which at this time of year is very welcome. Last weeks challenge was to get hold of a new crank pulley as the guy balancing my bottom end components had a good laugh at the old steel one. A friend who runs a historic racing engineering company has been working over my b20 e head for me. We had it on the flow bench this morning and using his fancy computer programme we were able to put in figures for a whole range of cams. I'm going to opt for the KG10 from KG Trimning. The computer print out is predicting 140 horses with good low down torque being the thing I'm really interested in. I'm wondering whether any of you have any experience of using a vernier cam timing setup? Do aftermarket cams from companies such as Trimning come marked up so that you can make use of volvo's line the dots up on the gears approach?

Yes they do, the keyways match to TDC#1.
However as always put it together and use a DTI to accurately determine. It worked out that the dots were exactly in line.
Without teaching anyone to suck eggs but the dots on the gear wheels are not together at TDC#1, that is the power stroke #4.
I have a KG19 cam and Tom Airey (Airey Tuning) without knowing the origin commented on its smooth spread of power.
I would expect a KG10 to be even better low down.
A word of caution regarding aggressive cams, the vacuum is vey low and really not sufficient to assist the brake servo(>14"). I had 10"Hg at best, slightly more when coming off the power at high revs.
There are two solutions and I provide them in case you find yourself in a similar situation.
1. Add another check valve in the line between the brake servo and manifold. Arguably the best way to do this is with a vacuum reservoir with its own NRV. This will help in marginal situations
2. Delete completely the line from the manifold and fit a vacuum pump and vacuum switch. Works well but noisy.
Handily most diesels don't have sufficient vacuum for brake servos so tanks or pumps are a plenty on eBay.
I fitted a Audi A8 vacuum tank in the nose cone of the 1800, can't be seen and the brakes are transformed with a regular 15" and sometimes up to 20". Cost me a tenner.
I know I digressed but brakes are important!
Russ

Are you running option 1 Russ?

Out of interest, here are the graphs of power from a standard b20 cam and the kg10

Do you know what the flow difference between the standard E head and your worked head? What else are you doing to the engine.

Head flow is up 9%. We've taken a mm off the head and going for 10:1. The overbore is to 2130. Balanced bottom end. I'm sticking with SUs and have rebushed and rejetted them, steel timing gears and the sensible modern crank seal arrangement. I'm already running a 123 distributor and will go for an electric cooling fan. I am replacing the oil pump because the old one was only just within tolerances and it seemed a false economy not to. I'm running a Simons exhaust and standard twin down pipe manifold because at the end of the day they're pretty good. Getting to the nice bit now- screwing it all together

That sounds like a very good improvement to me. Good to have someone with a flowbench working on the head for you. Russ (tdz840) would be able to offer some advice as well I'm sure as he's done a lot of work on his engine and researched into the engines so maybe worth dropping him a PM.

Cool. Similar to my engine specs, will be a nice sensible engine but with a bit of extra go over the standard engine. Please let me know what needles you end up with once you get to that stage.

That's a nice increase in power and torque over standard. What was the difference(apart from the cam) between standard and modified?
What is nice is the optimum power and torque crossover happens near the top end of the graph whilst with standard torque is significantly dropping off. That may be due to the function of the headwork. Were the valve sizes changed?
My car was RR by Tom Airey but unfortunately no means of printing out the results. I recall the hp was 158.6hp and torque similar value. However the AFR still needs work and I have a 123Tune to fit and further optimise the ignition.
Once I have completed those two activities I plan to take it to a local RR which does have printouts.
Russ

Sounds mean with the side draft carbs too.