71 911 T Drivetrain Rebuild

[porschetub]

Originally Posted by Nigel_Aston

Hi all,

I've been talking too much and not posting enough pictures so here's a few.







Can you spot which cylinder is low on compression? Any thoughts on what the culprit is?


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Welcome to Pelican,I have the same engine going into a suitably converted and restored 914 ,sad to hear the recent rebuild didn't pan out,did you receive a list of work completed on the motor from the past owner?
Reason I ask is there is an amazing wealth of information from expert members on here that could assist better if you supplied that info....if you have it?
Feel free to email me and I can answer some of your questions,always happy to help out a fellow Kiwi,cheers.

[Nigel_Aston]

Hi,

The engine had a broken valve which damaged the piston therefore I believe they decided to completely rebuild the engine and carbs during 2009-2010. During that rebuild they all the heads machined for new valves and a piston was sourced. I'm not sure if the piston was new or 2nd hand. It also has the later style tensioners but not hydraulic and a later style oil pump. When I pull it apart I'm hoping it's the oil pump that a previous post has described.

I do have all the receipts on the engine build and photos during the build.

Hope that helps.

I have PMd you with my mobile so would be great to chat further.

Cheers


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[Nigel_Aston]

No major updates but I think I've decided to rebuild my Marelli distributor and recurve it for a Solex profile camshafts. Also I will get my T cams reground to Solex spec if I can.

Other than just been reading Wayne's book and living life..... Peace!



Interior pic before rebuild.



Would love this look for my 71!


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[porschetub]

[QUOTE=Nigel_Aston;8967346]No major updates but I think I've decided to rebuild my Marelli distributor and recurve it for a Solex profile camshafts. Also I will get my T cams reground to Solex spec if I can.

Other than just been reading Wayne's book and living life..... Peace!



Interior pic before rebuild.



Would love this look for my 71!

Sent you an email with my thoughts,take them or leave them,good luck cheers.

[Nigel_Aston]

Hi guys. Been caught up with life and the usual. However had some time to get stuck in and I have an update.

Spent the afternoon pulling apart the engine and I have the heads off. Whoop whoop. Will hopefully get the case seperate soon. I was quite surprised how easy this was however I suppose disassembly is easier than assembly.








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[Nigel_Aston]

Been a great summer here in NZ so the 911 hasn't been getting much love.

Had a few hours spare this weekend so got stuck in.

I was quite happy to see std/std bearings on the crank and it looks to be in great condition.






With this being number 55 of the 1971 year this must of missed the piston oil Squirters so will need to installed when the machine shop starts work on her.


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[Nigel_Aston]

Hi guys,

Has anyone changed the final drive ratio on an early 901/911 gearbox? I would like to change the ratio a little. Just looking for a bit more accel through the gears.

If someone can point me in a direction for suppliers for that. Much appreciated.

Thanks


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[Nigel_Aston]

Hi guys,

What are the benefits of having the nikasil plating? Should I bother with that?


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[Nigel_Aston]

I suppose nobody replying means it's been discussed a lot, however would be good if someone had some experience relevant my build...


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[Flieger]

You can have old iron cylinders bored and re-plated with Nikasil to bring them back, but it's better to buy new cylinders because the all-aluminum construction conducts heat out better. The benefit to Nikasil is less friction and better wear (the Nikasil is very hard, the rings are made softer to be the part that wears). On the 917 where it was first used they got a noticable power increase. I don't recall what it was but I think it was something like 5%.

[Nigel_Aston]

Thanks mate. I'm pretty keen on new cylinders and pistons but not sure if I should jump to nikasil coating. Also thinking about nickies. Hmmmmm decisions.....


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[Flieger]

Nikasil is reliable and considered the best to use, as a result it is very common. It is the standard type of cylinder to use, the only other option being Alusil. Nickies are nice but I don't think you need the extra strength and benefits of the billet cylinders vs. cast Mahles.

[Nigel_Aston]

It appears the 2.2s p&cs on the hosts store is not nikasil coated? I'm not sure how many options in NZ I have for nikasil coatings. Thanks mate. I'll look into it.


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[Flieger]

The original 2.2 cylinders would have been Biral I think. I think the 2.7RS was the frist application for a street motor but I could be wrong. But I'm pretty sure you can get the right bore for a 2.2 in nikasil now. They are the same bore as the 2.4.

[Nigel_Aston]

Excellent. Thanks mate


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[E Sully]

I would have the pistons and cylinders measured to see if they are still in spec. If there is too much gap in the piston ring lands then look into aftermarket. It depends on your budget and performance desires.
It looks like standard steel T cylinders. I believe the E and S engines used the Biral cylinders. Having them Nikasil plated might offer minor reduction in friction, but having the original T cylinders plated would probably offer minimal improvement in cooling compared to aluminum cylinders with nikasil plating.

[Nigel_Aston]

Cheers mate. Will look into it. Currently have the parts out and labeling it for the machine shop.

Current list for the machine shop is

1. Oil bypass mod
2. Piston squirters
3. Face cylinder bases
4. Face case mating areas
5. Line bore
6. Shuffle pin
7. Rebush rods and machine to suit
8. Heads opened up to s spec
9. Valve seats
10. Valve guides
11. Balancing rods etc

Not sure on
Crank knife edging

The above list is what I've discussed briefly with the machine shop. Can you gents think of anything else?


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[Flieger]

I wouldn't bother with knife-edging but then I wouldn't bother with shuffle-pinning either.

Our cranks are in a different world than a big V8 crank with big counterweights that spins in a wet sump.

[Nigel_Aston]

Cheers mate. Will think it over.


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[Nigel_Aston]

No new updates. Just the usual compromise with wishlist vs budget on the parts list. Been dealing with Henry at supertec who has been very helpful.


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