Amazon: tuning a b18a

[redcar]

gents,

i wonder if you can offer suggestion on the following?

i'm starting to put together a plan to uprate the engine on my '66 b18a.

i've been searching around on the web for the most appropriate jobs to do, and so far, i think,order to get up to about 130bhp, the things i might do are

engine:
1. twin SU HS6 1.75's plus inlet manifold
2. 4-2-1 exhaust manifold
3. simonz sport exhaust
4. k cam (i believe this is an improved d cam)
5. mill the cylinder head down 2mm (for more compression and maybe convert to unleaded whilst it's out.)

before i start collecting the parts for the Spring.. am i going the right way?

any tips, suggestions, advice greatfully appreciated..

ta,

Gareth

[Burdekin]

Hi Gareth,

I'm new to this but will give you a run down to what I know.

Good gains to be had with porting and polishing the head and I think getting the inlet and outlet flowing better is the best idea. You're doing some improvements to the exhaust which is good and a 4 2 1 manifold is a good choice for a road car. A mild porting job can be done yourself or if you are to go further best to get someone with experience with the engine. One suggestion is to bore the engine to a B20, stick in B20 pistons and put a port and polished B20E head on. The B20E head will give you the gains you're after or if you really want to modify the head go for a B20F head but you shouldn't need to to get 130bhp. I'd suggest bronze valve guides, and good quality stainless exhaust valves with hardened seats for running normal unleaded with a B20E head with the higher compression. If you want you could put in larger inlet valve and deshroud the valves which will increase combustion chamber volume and lower the compression ratio a bit. Best to get a experienced shop to do this.

You can make some improvements with the SU carbs, suggest buying; How to build and power tune SU carburettors and they will do the job for 130bhp.

Regarding the cam, don't discount the standard cam for road use. I'd suggest first decide on what head, carb and exhaust modifications you want to make and then speak to someone about a choice of cam. KG trimning or Sten Parner in Sweden are two companies that have helped me out. Also Simon at Brookhouse is a really helpful guy.

Mitch

[Clan]

regarding camshafts in the 140 B20 tuning kit , that had great top end power but getting up a slope from the garage to the road made it hard going you had to take a run at it ! Running under 3000 rpm with a sporty camshaft is going to drink fuel . You would be surprised how nice a standard B20E engine is ...

[Steve121]

Gareth, the list of mods sounds good.. much the same as I did to my B18A, though my head was gasflowed, as was the inlet manifold. To be honest, I've never been too impressed with my K cam, if I was doing it again I would try another cam, maybe the D cam as a previous amazon I owned had this and went better for everyday driving, though the K goes well at high revs. A 123 dizzy could be worth a go from what I've heard.

I did have twin Weber 42 DCOE carbs which gave bags more torque over the SU's, I'd like to try either a single 45DCOE or 4 bike carbs and a Bog Bros made manifold.

[PaulWphoto]

If you are thinking of changing the cam you should also consider changing the timing gear to steel rather than the fibre one. A bit noisier but much safer.

[B20F]

Remember that the original cams are designed some 40 years ago. The're modern camgrinds at the market which do much better then the D&K cam. A drawback is the costs, think about twice as much as the old cams. I really like the TT5 cam. Drove an amazon B18 with twin SU's and a 4-2-1. Very impressive torque in the low revs that kept on going and going till 5500rpm.
This TT5 set costs €225. If you choose for the original cams I would advice the D instead of the K. D has more torque in the lower revs, the K has more power in the higher revs but not that much. In every day use the D is more fun.
It's a pitty this dutch site isn't available in english;

http://www.tinustechniek.nl/1-onderdelen-motor-int.html