It's been a while but there has been much progress. At the engine shop (PHP Racengines in Wauconda, IL), the jackshaft was replaced. The distributor was converted to FAST electronic ignition and the Bean water pump went in along with the Mikuni carbs. The engine went on the Dyno and this was the key ingredient in the outcome. When the engine was originally built it made 134 HP at 6100 rpm and 128 lbs. torque at 4700 rpm with Strombergs rebuilt by Joe Curto.
The first Dyno run with the Mikunis on the repaired engine was not good. The engine ran very lean. The Mikunis were (pre-jetted) by Vintage performance before being shipped and extra jets were included, but the mixture was way too lean. So a complete set of main jets were ordered and tried. The engine ran so lean at idle the engine builder thought the engine was problematic. He found a miss on cylinders 1 and 4 which is unusual at idle, and swapped plugs, cap, wires, and then distributor. He couldn't find the miss and removed the engine from the Dyno and removed the head to check. The engine had only 500 miles before I dropped the screw in the distributor after his rebuild and he found nothing wrong. The engine looked perfect inside. So he put it back together and put it back on the Dyno.
The engine made power but the idle circuit was dangerously lean, and believed to be the cause of the miss, so now a complete set of idle jets were ordered. Also, the main jet tubes have five different grooves where the e-clip can be moved to raise or lower the tube to change the how the jet is exposed when the throttle opens. So after many runs and jet changes and checks on the air /fuel mixture gauge the optimum combination was found. The engine builder specializes in Ford race engines and Twin Cams. Built race engine are sent to him from all over the country for tuning. I guess I'm saying he really knows his stuff. He said the Mikunis seem to be very adjustable but they are not as easy to change jets as are the Webers. The Webers have all the jets on top. The Mikunis have jets on top and below in the float bowls so some time the bowls had to be drained and removed to change jets.
The end result was very good. 144 or so HP and 128 lbs. of Torque. I don't have the print out yet to see at what rpms the figures were reached. The engine builder was now happy. He showed me previous Twin Cam runs he had done with Weber carbureted engines and the Mikunis were right there. Most engines were between 140 - 145 HP. By the way, my engine is a 1700cc, plus or minus a few ccs and he showed me runs of similarly built engines.
I delivered the engine to the shop to be reinstalled. As is evident, after I did my chassis restoration, most of the work I have had done has been with my wallet. I don't have the ability or the equipment to go this deep into the car.
I will give an update again when things are back together.
But so far the stainless water transfer tubes are installed and the rear Spax shocks have been installed in the stock rear springs. The adjustable lower control arms from RD Enterprises will also be going in. The last and maybe next most expensive item to be done will be an hydraulic clutch system. This will also be tricky. I got photos of how the system goes together and bought the cylinders. The only problem is the system in the photos is from a Renault. The exhaust is different, the motor mounts are a little different, and the gear linkage maybe on the other side of the engine. The mechanic at the shop said he believes he can make it work, but it will take some more time to fabricate brackets for the slave cylinder.
I have confidence in his abilities. Their shop (Northshore Sportscars in Lake Bluff, IL) have been racing a Renault powered S2 for over twenty years and they win a lot of races at Road America, often time times with the fastest lap of the day. They have made many such modifications to their car over the years so I believe I am good hands.
In for a penny, in a for a pound. Oh boy!
