Wed 12th Feb 2014
I called Steve at Jaz on Tue 11th Feb to see how he was getting on after he’d picked-up the engine from Neil Bainbridge’s dyno the Saturday before. The good news was that the engine was “almost” in the car. The “almost” was due to bit of a problem with modifications to the oil cooling system – he suggested I visit the following day to see what was what.
My mate Stan and I headed up to Jaz on the 12th to find engine man Dave at work underneath the car which was up on one of the Jaz ramps. The engine was fully fitted and attached to the gearbox which had remained in the car whilst the engine rebuild was in progress.
Oil Pipe Problem
As they were attempting to mate the engine to the gearbox – Steve and Dave realised there was a problem caused by the upgraded oil cooling set-up. One of the oil outlet pipes on the underside of engine was snagging the clutch mechanism on the 901 gearbox.
This only came to light once the engine was back in the car and it’s caused by a new external oil cooler and associated pipes which were fitted some time back by Steve (Jaz) and Bruce (Sportwagen) in anticipation of the engine rebuild. It had of course never been connected up until the newly rebuilt engine was installed.
To prevent any risk of boiling my precious “new” engine a 3.2 Carrera oil cooler was mounted under the front driver’s side wheel arch (ahead of the front wheel) along with longitudinal oil pipes (outward & return) routed along the underside of the sill running between the engine bay and the oil cooler.
Steve had specified and ordered all of the necessary bits in line with his planned engine modifications and Bruce fitted the attachment brackets and tabs to the underside of the car. He also fitted the oil cooler and long pipes – blanked off for later connection.
Originally – the oil pipes on the 2.2S ran through the bodywork. Of course we didn’t want to hack the body around so external pipe work was used, as it was on the 2.7 RS and on race cars. Not surprisingly – exposure of the oil pipes to moving air adds to the cooling effect. In designing the additional oil cooling system for my car – Steve opted to use slightly larger diameter pipes and fittings (25mm instead of the 22mm originally used) to improve oil flow and cooling.
Anway, to cut a rambling story short, Steve now needs to get a flexible braided oil pipe specially made-up so that it can be routed from the underside of the engine, over the top of the gearbox rather than under it. This will prevent it from fouling the clutch mechanism. Holes also still need to be cut through the bulkhead into the rear driver’s side wheel arch to route oil pipes from the engine to the thermostat and onwards to the longitudinal oil pipes.
Once all of this is done – remaining bits and pieces can be replaced/fitted/sorted (e.g. fit the missing heat exchanger, replace the frayed clutch cable etc. etc.) and then the engine can be fired-up.
Can’t wait to hear it in the car as the dyno is a slightly alien environment. The engine was noisy before the rebuild but this might have been down to wear and general state of the engine. It’ll be interesting to compare the timbre and volume of the quite definitely knackered motor with that of a fresh and more powerful one. I’m guessing it’ll still be noisy but in a nicer way!
Engine Bay Chock-full of Engine
Now that the engine is finally ensconced in the steam cleaned engine bay it looks fantastic. It seems a shame to have it hidden under an air box but it has to be done.
Steve had previously advised that fancy foam air filters simply won’t do! His view is that whilst they might look better and they expose more of the engine gubbins, they do nothing to improve engine performance and they do everything to increase engine noise. Yet another example of the original Porsche design (in this case the air box and diagonal air tube) being the best option.
When pressed Dave did suggest that an 2.7RS pattern air box and air tube might provide even better engine breathing but it ain’t original and ain’t that important just now. I’ll stick with my “rare as hens teeth” 2.2S air box & air tube!
Even the underside of the engine looks good – albeit with one heat exchanger and the silencer removed to sort out the oil pipe connection problem.
Even with the air box fitted, the visible bits of the engine really gleam and it’s unrecognisable from the dirty old lump that came out of the car at the start of the rebuild.
It was interesting to compare my now shiny engine with a similar 2.2S engine tucked against the garage wall awaiting the Jaz treatment. This particular engine was removed from Steve’s own 2.2S before the body was shipped off to Bruce at Sportwagen to work his metalwork and paint magic.
Throttle & Distributor Tweaks
Dave pointed out that as he was re-fitting the engine – he’d spotted a minor problem with the throttle linkages which he’d already fixed but which might have prevented the throttles fully opening during the dyno test.
During the dyno test Steve had expressed some concerns about the distributor and he asked Neil Bainbridge to carry out some tweaking of distributor weights and springs. Picking up on this – Dave explained that whilst the distributor should be OK for the time being – I might have to consider getting it (the original Bosch distributor) rebuilt at some point in the future or alternatively I could replace it with a new Bosch replacement (exorbitantly expensive) or I could replace it with a more modern (but non original) programmable/programmed one.
Jaz have tried out the programmable version in a couple of cars and it’s delivered good results but rather than go for the expense of a fully reprogrammable one (it’s unlikely that I’d ever need to carry out further reprogramming) there’s also the option of having one set-up with the ideal but fixed advance curve for my engine (i.e. a single hit programming).
Dave concluded by saying that once I’d put some miles on the car – he expected the maximum power to be nearer to 190bhp rather than the 185bhp recorded on the dyno. I guess a rebuilt or new distributor might also contribute to an improvement but this is not an urgent priority.
Meanwhile, I just want to get the car started up and find a window in the uniformly wet UK weather to get the 911 out on non-flooded roads!