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Make a torquey B20/B30

L

Leon_pp

Member
Joined
Sep 3, 2006
Location
France (zip: 51330)
Hi,

My wife have the project to participate to a "Rally Raid" : Trophe Rose des Sables in oct. 2015.
We are bought in Volvo and she want me to prepare for here a C202 or a C303 Laplander.

I am allready in volvo tuning, have a 142 with a full track engine (B20@21, KG stage 5 head, KG5 cam, MS with edis .....) and a 242 Turbo for fast road, and other Volvo.

But here the problematic is different, we don't need as much HP as possible, but we need as much torque as possible.
I will prefere go with a C303, cause have far best portic axle, 38cm ground clearance and a B30 who made more torque than the B18/B20 in C202.

Have you some receipe for made a torquey pushrod engine?
Or simply made a B30ET (with a MS box) as the rules allow it? I think it could be the cheapeast and coolest answer
http://www.youtube.com/watch?v=2GLLtlGzm3o&feature=c4-overview-vl&list=PL87A281EBE65DC698
 
Last edited:
Thats cool a fiminim race. Tried to look up the rules but cant read in British. If you guys can run a turbo or a supercharger do it to the b30.
 
B30 - more pistons, valves, displacement = more power and torks.

KGTrimning sells big-bore B30 headgaskets (or did last time I checked) - so get 6 B21 pistons (these can be made to work on 6-bolt B30 rods, if you have an 8-bolt B30 they're direct swaps) and have the block bored to match it. An extra 300cc's will make a noticeable difference - even if you don't change anything else (more low end torque - making more high end power with the added displacement requires other supporting mods).

If you're going to boost it (supercharger or turbo) then don't bore out the block, leave it 3.0L, you'll want as much cylinder wall thickness as possible.

If you want it to rev higher (more power to go along with the more torque) - you'll need to increase the flow. Ye olde intake/head/cam/exhaust formula. Maybe think about a D-Jet hardware/Megasquirt setup to feed it, otherwise perhaps think about triple DCOE's? The stock twin carbed setup probably isn't going to make much more power than stock. I think B30 heads aren't quite as bad as B20 heads in terms of flow, but the exhaust ports could probably benefit from some porting, perhaps some bigger valves as well (it helps to start with an injected head). Cam selection gets down to what RPM you really want to make power at.

A 'C' cam was stock, it's probably fairly well suited to low rpm use. They dont' seem to list an 'A' cam, but they might have something similar in a military B30 - basically a tractor cam in B20 form.
http://kgtrimning.com/kamB30.htm

Vroomy zoomy cams:
http://kgtrimning.com/KGkamB30.htm

Might not be what you want.

KG also sells headers for B30's - feed into a nicely sized exhaust (2.5 at least, maybe 3?).
 
The B30 by itself is a torquey motor. I had a chance to see a build many years ago, a 1974 262GL w/ a balanced and blueprinted motor have 205 hp, 225 ft lb torque on D-jet (no turbo guys) Is that enough?

Get a set of timing gears and advance to 6 deg and a D cam. I did some work to an early 69 B30(2.8L IIRC, later one's are 3.0 L) and put on a set of SU HIF6 carbs in place along with the above and was getting 175 hp and it had loads of torque.

Also lots of static compression. Take it up to/above 11:1 and use race gas which I assume that's avilable and legal, For a street build this may not be your best choice, but the torque added by octane + compression is significant

You don't need a turbo to get torque, especially with a pushrod motor. One conversion I did with a buddy was to take a '69 Chevy 260 IL6 pushrod motor from a pickup truck and put it in a 1950 Chevy coupe that came with a similar but passenger spec IL6 motor. That car has so much torque that it pulls from 1100 rpm up, and had to change the rear diff so the gearing was useful, and a diff from a 87 Camaro V8 was the only kind that could handle the torque, somewhere around 300 ft-lbs.

Otherwise, I'd say get a IL6 turbodiesel from a truck and slap that in there. I hear those in the Russian Transporters are awesome, won the Dakar Rally a few times.
 
1st : Can't have a 11:1 CR due to poor fuel in Africa where the raid is.
2nd : vvpete, you have to explain me how do you advance cam in a B30 engine with a steel gear? never seen adjustable gear on B20/B30
3 : i don't think that with 11;1 CR you need race fuel, a 98 oct unlead fuel could be ok no?
 
Years ago Volvo used to sell the timing gear set from the R-Sport catalogue, they were alumnimum. IIRC you need to drill another spot for the keyway to be at 6 deg (or anthing other than 0 deg)

Yes, race fuel isn't as available as it was back in the day when I did a lot of this work. Could get the 110 octane CAM2 gas all over the place, incl airports, which now even is scarce and the EPA has made modern planes use bad gas like cars get.
If you are reffering to the euro spec 98 oct minus 5 points is equivalent to the US R+M/2 93 octane, and for the old B30 with stock 10 something to 1 compression is OK, but marginal. You could improve the resistance to knock by head work and decking for the 'tight squish' cc, but going up in compression needs octane.

Honestly here's where a turbodiesel gets the nod.
 
They use offset keys. Normal cam and gear, the key just scoots it over a little:
blrk.jpg
 
Sounds like fun. When building your truck I'd recommend focussing on reliability rather than max power/torque. Whatever you build make sure it is done properly and is well tested before heading to Africa, and it looks like you have plenty of time to do that.

Good to be aware of petrol quality too. Once away from the major cities in Morocco the quality can vary.
 
Hen said:
Sounds like fun.
Good to be aware of petrol quality too. Once away from the major cities in Morocco the quality can vary.
Click to expand...

I'd take a 5 gallon gas can with 1/3 Toluene, 1/3 Xylene, ~1/3 premimum fuel and a quart of Methanol for when you really need the octane. This is a concoction I used when I made several cross USA trips in a 68 144 back in the early 80's. It had a built B20 12:1 compression race motor SU HIF6's, sounded like a piper cub and could cruise 100+ all day long. A couple quarts of this mix for each tank and it will go. 47 hrs NY to SF ;-)

I saw a pristene condition Laplander w/B30 and Strombergs at a car show here in Albuquerque, NM last summer, they are great for backcountry romping. IIRC it was for sale.
 
I would either bore it out to take B21 pistons or go down the supercharger path. Fuel wise you need to decide on carbs or injection, go with what you feel most comfortable adjusting and using. Ignition will need something in the way of adjustable timing so either the 123 programmable system or something alone the lines of megjolt.

Keep everying else as close to stock as possible.

One other thing you could do is have the crank reground for a little extra stroke.
 
In case of supercharging, i have several set of B19A piston (in very good shape).
In europe it is a 2.0L engine with low comp, piston are dished to lower comp.

123tune could be a very good solution, but i think i going to use MS cause i HATE carbs, especially DCOE, and allready have a MS1 box @ home without use for moment.
And i think MS could be more realiable in desert than carbs especially for a feminine team, turn the key :)
 
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