Checking the ims bearing (c4s project)

[Harv]

I don't think so, matt black is better at transmitting heat thermally than any other colour.

Check out the back of your fridge or the SR71 Blackbird. Science seems to say that the central heating radiators in our homes would also benefit from being painted this colour but to the masses it's not aesthetically pleasing??!

 

[Chris_in_the_UK]

I suspect its unlikely, though it depends on what you mean by colour. There are three fundamental modes of heat transfer for any material, and only one of them is directly affected by colour.

Heat is transferred from the heat source to the heat sink, and from the heat sink to the air by conduction. Most heatsinks are made of copper (heavy, and relatively expensive) or aluminium - and copper is generally left natural, and aluminum either has a natural clear covering of AL2O3, or is anodised and coloured. For conduction material rather than colour is important.

Convection is the movement of heat through the movement of air. While passive cooling simply uses this, you can increase its efficiency by increasing surface area (which is why heatsinks are finned), or by forced convection - blowing air to carry heat away. While air is not a good conductor, convection in air is how everything from cars to heatsinks are cooled. This is very efficient, and dosen't really rely on the material properties of the heatsink, or on the colour.

Radiation is.. frankly awful at transferring heat unless you're in a vacuum(It also sucks in a vacuum, but conduction and convection cannot happen). It is affected by surface colour.

Practically speaking, a heatsink being coloured is entirely for looks, and will affect cooling less than surface area, airflow, material and the contact between the heat source and heat sink.

 

[Alex]

I've also read on some 'scientific' sites that bare metal is better than any coating.

Dury's still out for me. If black was best, why don't they all do them like that?

:?:

 

[Harv]

Time for an update as I managed to get some time to move things on:

Mesh grills cut to size from a card template, painted and fitted with small black tie straps to rear of front grills. These are easily removable if need be





Crankshaft front pulley seal had a slight leak so pulley removed and area cleaned up with brake cleaner. The seal was removed by drilling a small hole in its face and using a self tapping screw and puller.







My cam timing kit finally arrived so tappet housings, tappets, cams etc were cleaned and refitted using the workshop manual (thanks Infrasilver!). Rather than chance it I also replaced the inlet cam sprocket stretch bolts and all the seals in here (not all are included in the head rebuild kit). This whole process looks quite involved but is not too bad provided you stick to the manual, work methodically and double check as you go.





Cam covers were chemically cleaned with the cylinder heads and re-fitted with the Porsche approved sealant





The timing procedure involves locking the front pulley at a known point using the tool supplied in the timing kit (a bolt would also work) and then fitting the inlet and exhaust cams and locking the position using their end slots and the holding tool. The cam sprocket bolts are left loose and the front pulley locking pin removed and the crank is rotated in a clockwise direction until TDC is reached. At this point the cam sprocket bolts can be tightened and the timing is then set.
The crank then needs rotating 360 deg (or thereabouts) and the other cylinder bank can be done.

I found after doing this that both my exhaust cams were very slightly off when trying to refit the cam end plate tool (possibly as a result of initial chain slack) so I made some more adjustments to ensure it was exactly as it should be.

Low temp thermostat and new water pump fitted



More next time

:thumb:

 

[Chris_in_the_UK]

Looking good sir - love reading these threads!

 

[Alex]

Same here. Very interesting, inspiring and educational :thumb:

 

[infrasilver]

Great work, :thumb:

 

[wasz]

Good work - did you drop the engine just on one jack!?

 

[Harv]

Thanks :thumb:

It's all a learning curve... The 996 engine isn't pretty like the early air cooled ones are. I was hoping to give this one a degrease and scrub up before re-fitting but I doubt it will come up much cleaner.

I dropped it out with a single jack, but I'm looking for something to hire that's a bit more stout like a hydraulic scissor table for re-fitting. Any ideas??

:?:

 

[wasz]

Think I've seen people use "ATV" (quad bike) jacks before

 

[Harv]

I will have a look at quad bike jacks...

A quick local search turned up one of these for hire which I think will make life very easy

http://www.brandontoolhire.co.uk/en/material-handling-equipment/651-scissor-tables.html

 

[wasz]

I will have a look at quad bike jacks...

A quick local search turned up one of these for hire which I think will make life very easy

http://www.brandontoolhire.co.uk/en/material-handling-equipment/651-scissor-tables.html

You could buy this for that price: http://www.ebay.co.uk/itm/like/251200195105

Would ideally need to mount it on castors though. Not sure how much an M96+gearbox weighs

EDIT: Looks like it has castors.

 

[Alex]

I will have a look at quad bike jacks...

A quick local search turned up one of these for hire which I think will make life very easy

http://www.brandontoolhire.co.uk/en/material-handling-equipment/651-scissor-tables.html

You could buy this for that price: http://www.ebay.co.uk/itm/like/251200195105

Would ideally need to mount it on castors though. Not sure how much an M96+gearbox weighs

Would be fine. The car only weighs 1200kg and that jack does 680kg, should easy be capable of engine and gearbox.

 

[wasz]

Knew I'd seen it done somewhere:

http://www.oz951.com/public/enginedrop.htm

 

[Harv]

Few more jobs done in the last week.

I decided to remove the sump and have a look in the bottom end, specifically at the oil pump pickup. Happy to say nothing much found other than a small amount of sludge sediment. The windage tray was removed and then the entire sump area cleaned before refitting the cover with the approved sealant.





The windage tray is quite ingenious and is fitted with flaps that are forced shut during cornering to try and keep oil in the pickup area.



Moving onto the ancillaries I've given the fuel rails (which are prone to corrosion) a good clean and inspection and they are in great condition. Worth having a look at these if you have the engine out of the car.



The aluminium intake manifolds were very grubby but have cleaned up well. I noticed the sealing faces seemed to be suffering from surface corrosion so wet & dry on a flat surface has flatted them back. New gaskets will be needed.



As this engine had suffered a burnt exhaust valve and I did wonder if the injector on cylinder #5 was not performing so all injectors were sent away for ultrasonic cleaning and flow testing. No problems reported and they will be refitted into the fuel rails based upon their flow readings (higher flowing injectors will go furthest away from the fuel feed).

Does anyone have a source (or a spare set 12) for the fuel injector seals? Porsche want something like £8 a piece for these!!



Wheels are back from being refurbished, what a transformation!





:thumb: