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The Sister Turbo, Silver 1986 RHD 951

Last Updated 3 Feb 2008

The new street 951. (Jun 07)

This Silver 1986 Right Hand Drive Porsche 944 Turbo was imported to Australia from the UK and has relatively low miles (160,000km). The car was purchased from QLD and we had it transported to SA in 2007. The overall appearance of the car is fair but exposure to salt on UK roads and a general lack of attention has taken its toll. However the key mechanical items and body were OK. As this car is the sister car to the 87 951 track car we use the nickname "Sister" to refer to it..

Initial Condition

Mechanical Condition. The main issue was a bad vibration at idle (bad motor mounts), brakes were poor (ineffective), and an annoying clunk every time the clutch pedal was pressed. The motor seemed OK, and boost was at stock level. The car was fine to start when cold but slow to start when warm. A/C was barely effective and made noise from the compressor (R134a). The car was unmodified other than the radio. It had had some odd mechanical work done to make it comply with Australian Design Rules such as incorporation of a new fuel filler neck - this may account for the fact that the car has no fuel smells when filled (a nice bonus). The car had oil leaks and audible exhaust leaks. Steering and suspension seemed reasonable.

Cosmetically the  car was fair to poor. The exterior had a few small dings, the hood was misaligned, the wheel paint was peeling and corroded and the metalwork of the car was encrusted with corrosion deposits like calcium build up on taps. The body paint was fair. The interior carpet and dash were OK but trim parts were missing and the shifter looked pretty ratty. Electrics were mainly not working.

Initial Work, South Australian Compliance.

My main short term goal was to get the car registered in South Australia, a state known to be one of the toughest on ensuring that imported cars are complianced with Australian Design Rules and are in roadworthy condition. This car had been complianced with ADRs in Queensland by the original Aussie owner but that wasn't good enough for the local authorities and it was required to undergo a detailed mechanical inspection. I repaired the obvious issues like broken mirrors, and non working indicators, replaced tyres that had good tread but a blister forming and fixed up the worst of the exhaust leaks. I also cleaned up the car cosmetically because it just had a neglected look, apart from interior and exterior cleaning I also scrubbed the visible parts of the engine bay to remove the corrosion and degreased the lower engine area and suspension immediately prior to taking the car for it's inspection. I also installed a completely clean and dry set of under trays to give the impression that there were no oil leaks. I also did the motor mounts and clunking clutch. The clutch noise turned out to be the pedal bracket mounting tab had broken so the entire bracket moved with each clutch depression. That was a complete PITA job and was eventually solved quite simply by installing a supplementary bolt through the existing bracket area.

The car failed the inspection and I was ordered to install rear seat belts complying with the latest ADRs, replace the rear brake hardlines (corrosion), repair one rear caliper (below braking effectiveness threshold), repair the windshield washer, replace the brake pedal rubber pad and install a vent line to the battery. Having to install new 3 point retractable seatbelts was a pain since the car never carries passengers but you have to do what you have to do. The metalwork of the car did not have brackets in the right places so I had to fabricate those and then buy appropriate inertia reel seat belts. I discovered that those have to be very specific to the application and the mounting angles otherwise the inertia sensing will lock the belts. That all worked out fine. The brake caliper issue turned out to be frozen pads caused by crud under the spring plates seriously locking the pads in place. Pads on every caliper had to be removed using a hammer and drift after removing the calipers from their mounts. I did them all since the brakes just did not have a reassuring feeling to them. The rear hard line corrosion was on the surface only but the authorities wanted them replaced and I had no choice. The corrosion on the ferrous parts was rapidly becoming the main issue for me. Thankfully the body work & frame was good but a lot of clean up work was required for the car and every nut and bolt was going to be a struggle. I manufactured new rear brake lines after purchasing an appropriate metric bubble flare tool to create the correct fittings. At least they are all easy to work on now.

As expected the car has had more than its fair share of frozen bolts and has left me with a couple of sheared bolts ( worst being a sheared brake caliper mount bolt) and broken my 11mm flare nut wrench - even the brake bleeder valves put up a fight!

LIST OF Initial Repairs & Updates (Jun 07)

Rear Seat Belts

Brake hardlines

Brake frozen calipers

Slave cylinder - Clutch

Hood misalign, hood badge

Clunking clutch pedal bracket repaired

Engine mounts

Electrical (lights, windows, trim)

Hood cable release lever replaced

Leaking rear

damaged mirrors inc electrical

Manual Boost control Install

Replace Coolant expansion tank

Install boost gauge & narrowband AFM.

Fixed electrical issues for rear demister.

Replaced Frozen rear wiper.

Install Momo steering wheel

Install fuel pressure gauge

Install new coil (Blaster)

Replaced starter solenoid

New front tyres (Falken)

Replaced leaking BOV.

Replaced hood liner.



Round 2, Jan 08 Fixes

Apart from the pressing issues listed above there were a number of other issues that needed looking into but which I decided to put off until the Christmas holidays. Mainly oil/fluid & exhaust leaks plus a slow start issue and battery that fails to hold a charge. To repair the leaks I decided to pull the motor out so I could get to all the seals properly as well as get the exhaust apart. Naturally since the engine is out I decided to address a number of other problems while I was in there. The car was off the road for a month while I worked weekends & nights to do the work. As I had found with the ferrous parts in the rear, most iron brackets etc had signs of corrosion so I spent a fair bit of time with the wire brushed & blasting gun to clean up parts for electroplating & powder coating. This was a good opportunity to clean up and make sure the car is easier to work on in future.

6 Jan 08



Leaks Galore:

Leaks were evident in quite a few spots


List of Fixes

Front Oil Seals

Rear Oil Seals (smoke Issues)

Top Oil seals

Lower Oil Seals

Repair AOS elbow oil leak

Clean all Earth Points on block & body

Clean Alternator terminals, Inc new Regulator

Supplementary earth lead

New Timing & balance belts inc rollers

Clean & re-powder coat or re-zinc plate steel brackets & components

Re=seal PS Rack

Re-seal PS pump

Replace damaged adjuster bars for AC/PS

Replace PS Reservoir leaking hoses

Replace damaged Tie rods

Replace Aircon Compressor & dryer inc faulty pressure switch (Lines & Condenser)

R & R Aircon lines, update with R-134a barrier hose

Replace Exhaust seals at both ends of crossover, plus thick gaskets for rear pipe & wastegate dump

Replace old wastegate with Tial

Venturi delete Mod (fix vacuum leaks)

Replace turbo coolant pump & IAC valves with newer components

replaced IAC isolation mounts

replaced Speed & reference sensors (Start Issues)

AFM R&R (Lean Issues)

Replace old struts with Koni suspension.

Throttle body R&R (vac leak replacement)

replaced hardware with stainless steel

Cleaned engine & bay area

Paint Cam Tower

Polish components

Replace Air Filter (Tuning)

Replace caster blocks with 968 components.

Replace sway bar mount rubbers and end rods.

Replace washer bottle (rectified leak), added backflow valve to washer line.

Clutch Master cylinder and flexible pipe to slave cylinder replaced

Swapped front brake lines for stainless braided lines.


Some of the After photos


10 Feb 08 - Back on the road.

As can be seen above the list of repairs in Jan 08 was pretty extensive so a lot of issues have been addressed and the car is a lot better of. Along the way I discovered a few nice surprises, the automatic belt tensioner was fitted to this car and the AC condenser had been replaced with a later technology aftermarket style to improve A/C performance.


The 86 951 will not go down the same upgrade path as the 97 951. The objective with the 86 is to minimise outlay and make changes that will maximise performance from the stock turbo (K26-6) and fuel delivery system.  Several of the parts used in the upgrade,  suspension) in particular, came from the 87 951 as it transitioned from a street-track car to a dedicated track car.

968 Caster Blocks

The caster blocks from the 968 use a lot less rubber to mount the back end of the control arm and that equates to less give and suspension change when the car is cornering. The original caster blocks weren't in too bad a shape but these 968 blocks of my 87 951 only have about 5000km on them. I also had them re-plated in yellow zinc.

Tial 38mm

The stock wastegate is well known for not being able to hold higher boost and I bought another TIAL 38mm for this car and SFR adapters to mount it as I have found the TIAL to be a good unit on my track car.
Manual Boost control Porsche designed boost roll-off (a characteristic of the KLR programming) is a great longevity design but doesn't do much for the fun factor. The KLR & cycling valve control has been eliminated  in favour of simple manual boost control.
Koni Suspension The Koni Yellows with 300lb hypercoils and an adjustable ride height kit made for a pretty decent street suspension setup so these have been relocated from my spares box onto the 86 951.
29mm Torsion Bars The 29mm Torsion bars will compliment the stiffer front springs. They are not yet installed.... will save that for the next big job and replace the rear fuel lines at the same time.


The stock Bosch BOV is not a particularly durable item. I replaced it with a Forge 006 which has tougher internals and unlikely to develop leaks. I used the BOV from the track car in the 86 so the pictured BOV will go into the track car now.
Stainless Brake lines I put these on because I had them and the rubber lines were somewhat shabby looking.
Borla 3" Exhaust This is the key area that will enable better results out of the K26-6. Combined with the Tial wastegate and slightly higher fixed boost, the 3" free flowing exhaust will facilitate a worthy improvement in performance from the lightly modified 86.
Chips Aftermarket chips take care of the boost limit and extra fuel needed to run slightly higher boost.
Air conditioning Since it gets plenty hot in South Australia I decided to upgrade components of the air conditioning system. The AC is fitted with an aftermarket condenser which increases condensing capacity over the original Porsche design. I also removed the AC lines and had them modified by removing the original permeable R-12 hose sections and replacing them with R-134a barrier hose. An R-134 pressure switch is also installed along with a new drier. The compressor is the refurbished ND unit I removed from my 87 951 and it has been drained of R-12 oil. With all the lines and components accessible whilst the engine is out, all the O-ring seals have been replaced.

Notes / Lessons

Power Steering The line between the rack and the PS pump was  different on my 86 RHD model vs my 87 951. The replacement part I ordered from the US still fit just fine on my RHD 951 since the PS pump and reservoir are in the same place.

Sadly the same cannot be said about the PS Rack seal kits. Although the US kits are annotated for "all 944" they do not suit RHD cars which have a different pinion housing and the seals from the US kit do not suit ( a few do but the important ones don't). A kit is available for the rack in Australia but expect to pay $180+ vice the $70 for the US kit. Alternatively the primary shaft seals can be purchased from CBC bearings in Australia.

Banjo bolts - I ordered replacement M10x1 banjo bolts which came with hex heads but these are no good for most of the PS rack connections. They are OK for the connections that use copper washers but the rest use O-rings and that is why the stock banjo bolts are wide circular allen head style because the wide circular head clamps down on the o-ring where a hex head banjo bolt would fail to seal correctly.

Power Steering Reservoir. The PS reservoir lid seal is available from Porsche but will cost about $8. Go to an alternative store and buy a $0.50 part. Take the lid to get the size right.

AC Replacing the permeable R-12 hose with barrier hose is kind of involved. The existing hose will need to be cut off and new barbed fittings will need to be welded onto the existing hard pipes. The barrier hose is then crimped to the hard pipes using the new barbed fittings. Obviously the angles are important. Take pics. Getting the AC lines out of the car is a pain and whilst it may be possible to do it with the engine in the car... I wasn't going to try it. Even with the engine out of the car I had to undo both the front and rear brake line connections from the Master Cylinder (one more job to do when it goes back together).
Polishing This is time consuming. I used an abrasive fibrous wheel on a drill to cut back the rough surface. Then I used 60/100/240/320/400 grit paper to remove the scratches. I would also use 800 but I didn't have any on hand. After sanding I used a regular bench grinder to do the polishing with a loose leaf calico mop / white buffing compound. It was not really necessary to use the stitched sisal mop and fast cut (gray) compound. I worked some of the nooks & crannies with a dremel with the small sanding drum  attachments or grinding stone attachments but the grinding stones tend to clog pretty quickly.
Clutch hose. Whilst the motor was out I found the clutch hose was fairly well deteriorated so I had it replaced using a custom manufactured hose at my local hydraulics outfit.  They re-used the existing fittings but welded on new barbs and replaced the rubber section with a braided SS section. $40. 45 minutes. Good result.
Removal of powder coating Let the powder coater do it. It will be faster & cheaper.
Removal of anodising. (Boost pipes) 500g of caustic soda crystals in 10litres of water in a bucket. Done in 3-5 hours. Don't leave it for too long or probably no more boost pipes. The pipes also have a lot of deep scratch marks from manufacturing. If you polish those out the pipes will be pretty thin.
Oil Line fittings For me they required extension tubes on the wrenches (main and counter wrench) but once I used the extension tubes the lines came undone pretty readily.
SFR Tial Wastegate adapter



First thing that crossed my mind was that the finish on the SFR Tial wastegate adapter for the Porsche 944 Turbo was not the typical high quality finish that I was expecting of SFR products. It's not so much that the adapters are not polished which is typically an extra charge, it was the fact that the adapters were just rough around the edges. It appears that the unit I received was drop shipped from a 3rd party exhaust component manufacturer (based on the labels on the box I received). A few minutes with the bench grinder put a slight chamfer on the edges and the wire wheel took care of the minor burrs. The kit did not come with washers (or instructions for that matter - so it was necessary to double check some references to get the orientation of the wastegate correct. Instructions would also have been handy to confirm that the threaded holes on one of the Tial flanges should be drilled out so that the bolt slips through the Tial flange and the threads bite into the SFR adapter (only). The Tial comes with 2 socket head bolts but you need 2 extras to mount to the SFR kit. You also need some washers of a suitable thickness so that the bolts do not protrude through the SFR adapter flange. If washers are not used the bolts will pass through the SFR adapter and contact the Porsche wastegate flange. This means the Tial will not be snugged tight to the SFR adapter. Other observations I made were that the adapter plat was not square to the Porsche flange and that one of the holes on the SFr flange did not line up real well with its corresponding hole on the Porsche flange - it was able to be tightened up but could make for a tougher removal in later years. Probably the most important 'discovery' (everything is a discovery when the item is delivered without instructions) - is that it was necessary to remove 10mm of the dump tube (the long section of pipe that bolts to the wastegate) so that the flanges line up correctly when the parts are installed in the car. The 10mm is cut from the end opposite to the flange end. This took me from a situation where the flanges weren't even remotely close to lining up to a situation where the flanges lined up comfortably and allowed me to rotate the tightened assembly sufficiently to achieve a 6mm gap between the wastegate and the torsion tube/housing.

I found the easiest install method was to bolt the wastegate, with both adapter flanges attached to the long dump tube  and put that in place in the car. The small pipe cam then be slipped onto the crossover pipe and rotated so that its flange lines up with its matching SFR flange which is already attached to the wastegate. Install & tighten the 4 bolts for the flange, then rotate the assembly to clear the torsion tube, then tighten the factory exhaust seal components to lock everything in place.

NB I did cut off the piece of the original flange that formed a support bracket. In the end I don't think it made much if any difference other than allowing a bit better access to the top of the wastegate. Cutting off that bracket could be troublesome due to its thickness and shape if you don't have the right tools.


Post fix stuff


As usual when the job is done there are a few things that need sorting out before the job is really finished. On this occasion there were 3 things that needed looking at. Two are simple fixes but the third may yet proved to be a significant issue.

1. At the end of the first 5 minute run some hissing at the back of the motor was evidence that there was a coolant leak somewhere. The culprit was an insufficiently tightened hose clamp to the heater valve.

2. I replaced one of the hoses to the power steering reservoir because it looked in poor shape. The other one I gave the benefit of the doubt since it would be an accessible fix if needed. As it turns out it was needed, attention anyway. I actually replaced the hose clamp as the original one was unable to be made smaller/tighter. This appears to have stopped the weep which became evident after the first post fix test drives.

3. As can be seen in the pic to the left there is an oil leak at the back of the engine. This is originating from the head gasket itself, probably the 2nd to last oil gallery passage. This area was wet with oil when the motor came out but the origin was higher up (rear cam cover gasket & cam housing) so if the head gasket was leaking originally it was masked by the leak above it. The pic shows oil that accumulated after the engine was first run. Now that the car has been driven a few short drives the oil has not accumulated at this spot again. Time will tell if this leak will persist or not. I hope not because the head will need to come off to repair this properly and I have plans for my next weekend or two.

NB Coolant bleeding. When I first tried the bleed the coolant system the heater valve leak created a condition where the bleeder valve only released steam instead of a stream of water. After fixing the heater valve leak I used my air compressor and a makeshift adapter to pressurize the coolant reservoir after I filled it. I then opened the coolant bleeder and it was only a few seconds before I had a good stream of water coming out of the bleeder screw. This was done about 45 minutes after the car had been run and the car was jacked on the header side.

MBC MBC line feeds top port of the Tial waste gate to counter boost signal going into side port of the Tial. With stock exhaust & AFM, full anticlockwise closes the MBC (ie no boost offset to top port) and Tial spring results in 8PSI boost. 4 Turns clockwise gives 15PSI - enough to hit over-boost cut off in 3rd.

During this rebuild effort more than any other I have been particularly glad I had an air compressor and impact gun.

Oz 951



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