944T Engine Rebuild
- Thread starter barks944
- Start date
OEM Rings seem to be the way to go, no need to file fit apparently as they come in a range of sizes so you get the right ring gap for your bore wear.
I'm still amazed by the crank wear, its still within new tolerances after 125K! Bottom end of these cars is bomb proof, I think the crank is about 50% of the weight of the entire engine!
I'm still amazed by the crank wear, its still within new tolerances after 125K! Bottom end of these cars is bomb proof, I think the crank is about 50% of the weight of the entire engine!
Man I can't measure the wear on these damn bores! I suck at using an internal micrometer. My rough measurements indicate less than 0.1mm across the diameter and they seem round all the way down. Really need a proper bore gauge but they are pretty damn expensive. I guess I need to take it to a proper workshop or something.
Ooh goodies!
Ooh goodies!
George Elliott
New member
Barks,
if you can find a local toolmakers, or engineering company who have a precision boring capability and tell them you need a few measurements with an internal micrometer they should help you.
Great to read of our good old "Made in W.Germany" engine quality, as opposed to the pampered FSH kettles with their cracked cylinders, scored bores, failed intermediate-shafts and leaking seals. Oh and useless warranties.
944's will go like 356's over the years, two a penny now, but the few good remaining ones will be appreciated in the future.
Good luck
George
if you can find a local toolmakers, or engineering company who have a precision boring capability and tell them you need a few measurements with an internal micrometer they should help you.
Great to read of our good old "Made in W.Germany" engine quality, as opposed to the pampered FSH kettles with their cracked cylinders, scored bores, failed intermediate-shafts and leaking seals. Oh and useless warranties.
944's will go like 356's over the years, two a penny now, but the few good remaining ones will be appreciated in the future.
Good luck
George
It's amazing how little wear there is. Its interesting to note that the middle two cylinders are more worn than the outer two. You can just feel a lip at the bottom of the bore on the middle two clyinders but there isn't one on the outer two. Possibly due to imbalances in the intake manifold or something.
Although the bores look great and I am sure that re-ringing the engine will work great, there is some wear and I am wondering about the option nikasil plate the bores. This can add anough material to bring the bores back to perfect spec. Its about 1K inc vat to do it. Would it add much value to the car? Can you keep re-plating with nikasil forever? Does it have better/worse wear rate than alusil?
sawood12
New member
I always thought that the introduction of Nikasil was due to Nikasil's improved temperature capability needed as combustion temps of cars got higher as leaner burn engines came in. It is usually the case that if you want to improve the high temperature characteristics of an alloy you add Nickel as it is a material that can withstand very high temperatures and retains its mechanical properties at higher temperatures better than other metals. However it is very expensive which is why it was probably not used from day 1. Nikasil is a very similar material to Alusil - both are high silicon content Aluminium alloy's but with the addition of Nickel to get Nikasil. At the end of the day since both materials achieve their hardness from exposing the large globular silicon structures within the material I would think Nikasil would have comparable hardness properties - you can't really get any harder than Silicon.
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