Engine modifications

Originally I had used the original type air cleaner from a Ford Capri that I had modified so it fitted my Holley carb. Now I changed the filter to an open type originally made for the Holley carb.

In the late summer of 1992 I was driving to my parents home in Karlstad in the west part of Sweden, a drive of about 320 km from Stockholm. While I was driving quite fast, racing a bit with an Alfa GTV the oil pressure suddenly almost disappered and a knocking sound could be heard from the engine, later I found that the bearing shells of one of the big end bearings had rotated in the con rod and that the crankshaft was badly scored, also the other bearing journals had bad scratches. As the crankshaft was already re grounded to the smallest possible size and one of the con rod where destroyed I decided to find another engine.

I was lucky! My brother who had helped me find the original engine had a friend at a breakers yard that had an Essex engine. We contacted him and he told us that the engine was actually an exchange unit that had been fitted to a Ford Granada for a customer in Denmark, this person had then, (just after the engine was fitted) gone on a holiday trip to Sweden where he had a severe traffic accident and rolled the car, the car was not possible to repair and my brothers friend bought the engine from the breakers.

Of course this sounded almost to good to be true but the engine looked good and I bought it for a good price. I decided to dismantle the engine to really see what condition it was. When I stripped down the engine I started to believe the story my brothers friend told us, it was clear that the engine was not used very much, all parts including bearing shells looked like new, for instance the honing marks was clearly seen in the cylinder bores and the inside of oil pump cover had almost no scratches at all! For me it is clear that this engine was probably only used for 2000 km as I was told.

An unusual thing about this engine was that Cosworth type con rod bolts was used.

I rebuilt the engine using the big valve cylinder heads and the camshaft from my old engine. I changed the carb for a new Weber 40 DFI that I bought in England. The performance with the new carb was much better and the engine was much smoother.

I installed a Lumenition opto-electronic ignition system and a rev limiter with full throttle gear shift. With the elecronic ignition the engine revs much easier especially above 5500 rpm. The rev limiter also includes a switch connected to the clutch so the engine speed is locked to what ever rpm it has when the clutch is engaged. It is now possible to make full throttle gear shifts without any risk of over revving, just press the clutch without lifting of the throttle.

Changed to Pipercross foam filter for better flow, this improved performance at high revs.

Changed to a full stainless steel exhaust system.

Changed to a modified distributor from Aldon, this improved performance at high revs.

Changed to Kent V63 cam with full steel cam drive gear and Burton full race heads, this improved performance even more.

I have now changed the manifold and carburetors to 3 double Webers. It took some time to find the necessary parts as production of both the manifold and the carbs have ceased. I was also a bit reluctant to go trough with this modification as I have heard a lot of stories that the car should be almost un-driveable in anything else than racing tune with this setup.

The installation took some time as some things didn't fit so easily, for instance so was it difficult to tighten 2 of the bolts for the manifold and the studs for the carb is a really tight fit and needed some modifications. I used professional parts for all things except the bracket for the gas wire that i did my self from 2mm sheet steel. The linkage to connect the 3 carbs together with chokes and jets I got from Pierce Manifolds.

Originally I used the following settings:
Part Size
Chokes 34mm
main jet 145
air corrector jet 210
Idle jet 55
Emulsion tube F25
Idle air jet 170, (this is fixed and can not be changed, but differs between different DCNF carbs with different part numbers)

Before I started the car first time I did a standard setting of the idle speed and idle mixture screws and also tried to make the carb open as even as possible.

The engine started real easy and the car was also driveable but really rough at low RPM. I let it warm up and then I synchronised the carbs using a synchroniser tool which was real easy and didn't took long time. After synchronisation the car run much better but still had some misfiring at low to middle RPM and backfire through the exhaust, a sign that the idle jets are to big so I changed these to size 50. With the new jets the engine became real smooth in the whole rev range and it seems that I gained a lot of torque and power compared to the 40DFI. I don't know if the main and air corrector jets are ideal as they are but I will do some testing later in order to find out.

This installation went very well and didn't take so much time either, (so far I spent around 20 hours in total) so I wonder why this triple Weber setup has such a bad reputation? The only disadvantage I can see is the cost, it is not cheap and it's doubtful if the increased performance is worth the cost if you compare with the Weber 40DFI on a standard modified manifold, it is of course a personal choice. However the power and torque at lower RPM is much better with the triple webers, as normally is the case with similar installations on other engines. I also believe that fuel consumption actually will be somewhat lower, the future will tell. For some pictures of the new setup see: Engine pictures

Update October 6, 2002

I have now fine tuned the carb installation as good as I can do by myself without a rolling road, the method I have used is to check spark plug colour after driving at steady speed and I have also roughly checked acceleration times.

As I expected the main jets was a bit to rich so I have now changed them to size 135. I first changed to 130 but it seems to be a bit lean, 135 gave better response and the plugs have good colour when driving at steady state motorway speeds. To check air corrector jets I drove the car at high speed, (~160 km/h) for about 30km and checked plug colour, with the original size 210 the plugs was a bit white so I changed them and now use size 180.
See table for current jetting.

Part Size
Chokes 34mm
main jet 135
air corrector jet 180
Idle jet 50
Emulsion tube F25
Idle air jet 170

Next step is to test the car at rolling road, I expect the power to be higher than before and it will be interesting to see if my carb jetting is close to optimum or not, hopefully it shouldn´t be too far out.

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Created on ... October 6, 2002