Quote:
Originally Posted by redcar
PS. stage zero?!?!?!?
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What I call stage zero, sorry. Basically making sure you're starting with a sound engine. Checking piston to bore clearances, valve train etc. Check crank, big ends, etc if feasible. Might include new oil and water pumps, fuel pump, points, condensor, check distributor for play, make sure yr brakes, gearbox, clutch, cooling system etc are all healthy, and so on.
Its really easiest, and most satisfying, to start with the engine out of the car. maybe a good route would be to pick up a second-hand B20 ( best for making serious power) and slowly build it up. There's about a million different ways to skin this particular cat, budget will determine a lot of it.
Alternatively, if you're reasonably confident that your engine's healthy, pick up a late B18 D head off a P1800, check it over and fit new valves if necessary, but if the old ones are good, and everything's nice and tight, stick with them! Make sure the head's seating nice and flat, if not get it machined. Fit a D cam kit, a second-hand P1800-type twin-downpipe manifold, and get a set of SU's rebuilt.( you can do this yourself with a kit from Burlen). If funds will allow, go for the 123 ignition. Set it all up ( jetting, ignition etc) as per P1800/ 123GT specs. Get it right, and you'll have a nice reliable, strong engine. As and when the money allows,go for a nice free-flowing exhaust system ( including a 4-2-1 manifold) and overdrive, and you'll see much better top-end performance. Porting work to the head starts to become worthwhile at this point, but you're moving away from standard Volvo spec, and will need to make sure your ignition and carburetion are set up correctly, and this would also be the time to look at a more modern cam spec. If you get this far, your engine will now probably rev up to c.6500 quite easily, so you will want stronger valve springs as well ( and i would seriously recommend an accurate rev-counter!)
( BTW, If I were starting by going down the P1800 spec. route, I would probably begin by giving someone like Brian Gue at Amazonia a ring, and asking if he might have a P1800 head, carbs and both manifolds, suitable for rebuilding....)
In many ways, the B18, when correctly built, is a smoother and sweeter engine than the B20. They sound particularly nice with a 4 branch! But if you're seriously chasing big increases in bhp, sooner or later you'll probably be going to a B20. Hope this helps.