911 T 2.2 rebuild - 1971

[ErrieKruger]

After reading and enjoying this forum for a year , I decided to jump in and start a rebuild of my own. My time projection on this venture is 3 years , as I want to do as much of the work myself in my spare time.
I bought a 1968 912 roller - with the normal rust issues , and a 1971 2.2 T engine.
Wish me luck on this !!
I have started to take the engine apart , and will have a close look at everything , and take some parts to Ollie's to be refurbished.

[ErrieKruger]

Close examination of the case shows cracks - did this happen when the case was split , and can it be repaired ? It looks superficial , but I do not want to start with a flaw.

[Flat6pac]

That isnt cracks, thats casting from the pour. Its been there since the engine was cast.
Bruce

[ErrieKruger]

Bruce - just shows my ignorance. I am new to this , but plan to do everything according to the book ( many conflicting ) from the start.
Thanks for your help ! I will ask many stoooopid questions in the future.

[ErrieKruger]

I bought new JE pistons and cylinders ( 86 mm ) , although the original Mahle pistons and cast cylinders look to be in good condition. The engine was sold to me as redone , but stored for many years. To make sure I decided to split the case and evaluate everything.

[Grady Clay]

ErrieKruger,

Good question. Keep them coming.

I assume you have Wayne’s engine book and others.
Please list your ‘library’ so we can spot any critical omission.
You are correct, there is no ‘one source’ and there is occasional seemingly conflicting information.
This Forum can help you sort through everything.

It will be valuable for you to post a ‘plan’.
Take Wayne’s lists (appropriate for a CIS 2.7) and apply that to a 2.2T.
I would not buy any parts until you have a complete plan and posted it for ‘peer review’.

You have a nice engine to start with.
It will respond to a few up-dates and the knowledge gained from 40-year hindsight.

Your case should already have the piston squirters – good.
It is a mag case. Even with the relatively low stress of a 2.2T, most will recommend inserts for the cylinder head studs and a few other.
There is an ‘oil bypass’ mod that is important.

Critical is inspecting and measuring. Ollie’s and others can help.
What are the measurements on the crankshaft?
What are the measurements of the connecting rods?
What are the measurements on your 2.2T P&Cs?
How “redone” are the cylinder heads?

What is the condition of the Zenith carburetors?
Have the Marelli distributor run on a test machine to determine its condition.
What is the condition of the exhaust system?

I assume your 912 has a type 901 or 902 transmission.
You will not be able to use the 225 mm pull-type 2.2T clutch/flywheel assembly with that transmission.
You will need a complete set of 215 mm push-type parts from 1969 911 and earlier.

Assuming you have the original 2.2T engine oil cooler and the long engine oil out hose, you will need an oil tank from ’71 and earlier (somewhat hard to find good used).
If you use a later (’73->) oil tank, you will need to change the engine oil cooler and the oil-out plumbing.

It will be desirable to find a ’70 or later engine electrical panel with the 14-pin connector harness.
This will let you maintain your ’71 engine electrical wiring harness.

What alternator do you have?
You will need a compatible voltage regulator.

Please post good images of all the parts.
This will allow us to spot anything that may need attention or is missing.

Please post some images of your car.

Best,
Grady

[ErrieKruger]

Grady - you guys are the best !
I bought every book available , including Wayne's , and have watched Nick Fulljames and Peter Morgan's episodes on youtube.
Case does have squirters and oil-bypass is in the plan.
I will remeasure crankshaft and post results and photos.
Zenith carbs being rebuild by my physician , who is an european motorcycle ghuru.
Distributor will be tested , and no exhaust/heat exchangers present.
901 transmission will be redone , and all needed parts replaced to fit
1971 oil tank to be cleaned and tested.

I live one hour's drive from Havasu , and will have Ollie's do the needed machine work.

I will post pictures this afternoon -
Thanks !

[chiroracer]

When I buy my matching number 2.2 case back I will be rebuilding it but with 9 to 1 compression and E or solex cams.Subscribed! Steve

[ErrieKruger]

Crankshaft measurements without rods removed - reference to Wayne's rebuild book p204 :

d1 - 57.04/57.01/57.04/57.01/57.02/57.03/57.04.

d3 - 31.02

d4 - 65.02

d6 - 30.00

d3 Seems to be a problem.

[ErrieKruger]

[ErrieKruger]

Pitting on crankshaft prodruding end - d1 seems to be damaged in picture , but it is an optical illusion caused by oil - I wiped it of.

[ErrieKruger]

[BK911]

If it were me I would buy:

2.4 crank and rods
E cams
Bosch dizzy

You will not be disappointed.

[ErrieKruger]

Woman question - my loving wife of 30 years is starting to make strange noises.

I barely started on this rebuild , but have already heard that a crankshaft does not belong on the coffee table in the living room. Next to the cylinder heads.

Pressure washing parts on the pool patio leaves oil stains , blocks the pool filter , and the overspray will cause the daisies or something not to grow this summer.

Her Chihuahua does not like the decibels a 2.7 psi hose put out ( he will be clean for the next 2 months ).

Diesel jeans are for diesel only - not wiping 20W50 on them. I guess I was wrong on this one. I should have read the petrolium rating on the label first.

This is going to be a long trip - my plan is 3 more years.

[Grady Clay]

When measuring d1, it is useful to measure to 0.001 mm.
It is also important to measure around the perimeter and across the bearing surface.

I can see there is some effort of ‘kitchen table’ measurements.
Keep up the good work.

Best,
Grady

[ErrieKruger]

Grady - I will have the exact measurements take by a machine shop.

Thanks for your help.

PS - what would a difference of 100F ambient temp make on these within 0.001 mm measurements ? Co vz Az.

[ErrieKruger]

This forum is amazing - the only place where the quarterback will give advice to the fan in the cheap seats.

That is a motivation for me to do this perfect.

Thanks Grady !

[tom1394racing]

Here's an example of what to expect for the rod and main journals

Measurements need to be made with a precision micrometer and the crankshaft held firmly. I fixture the crank in the flywheel when making these measurements

[ErrieKruger]

Tom - I ordered a Mitotoyo micrometer . I have 3 micrometers , but the only one in the 0.001 mm range is limited to 25mm diameter.

I said before that a specialist will do the machine work , but I want this to be a hands-on project. If I just write checks and keep my hands clean , I miss the purpose of this venture.

It would have been much easier ( and less expensive ? ) to simply buy a Porsche.

This forum motivated me. At this stage I am spending 10% of my time doing something , and 90% reading.

[Grady Clay]

Originally Posted by ErrieKruger

Grady - PS - what would a difference of 100F ambient temp make on these within 0.001 mm measurements ? Co vz Az.

Only if you take the measurements outside

The crankshaft, the digital micrometer and all your ‘standards’ should all be at ambient (indoor) room temperature (mine are calibrated for 20C, ~68F).

It is absolutely critical to let the crank and instruments temperature stabilize – 12 hours should do, 24 is better.
Do not handle without gloves.
Do not re-clean with anything that evaporates (solvent, brake-clean, water, etc.)
Simply wipe your preservative oil (WD-40?) with a clean, dry lint-free cotton cloth.

Only handle the micrometer with gloves and on the insulating grip.
Only adjust the micrometer with the friction nurreled grip.

Make double-sure the micrometer and standards are at the exact same temperature.
I found it useful to also have some good gauge blocks either sides and around the Porsche limits that I was measuring.
Rectangular gauge blocks are much easer to use when checking the micrometer.

I recommend you only use the standards for checking the micrometer.
If out of spec (and new should not be), have a ‘professional’ do the adjustment.

You will find measuring a cylinder to 0.001 mm (0.000,039 inch) is not easy.
Even your breath temperature can change the reading.
It will take a lot of practice.
You will make a lot of measurements you will not use.








I’m sure there are some better instructions on the internet but….
Make sure the anvil and spindle are clean.
Never tighten with more than the force of the nurreled ratchet.
You want the micrometer to just barely slide with a bit of resistance across the diameter.
If you ‘cock’ the micrometer to either side of perpendicular, it will not slide.
You must be very careful ‘approaching’ the journal, the carbide ends of the micrometer are a LOT harder than the journal and can damage the journal.

Unless you get the really expensive ones, reading the 0.001 mm digit is with the vernier.
Practice makes perfect to avoid parallax variations.

You will find the journals will have a ‘high’ and ‘low’ around the perimeter.
You want to locate and record both.

You will occasionally find a ‘taper’ to the journal.
This is usually from a slightly bent connecting rod.

You are also going to want a good (minor division = 0.001 mm) large dial indicator.
You will use this for measuring the crankshaft ’run-out’.
More on that later.
You will also use it for many measurements in the transmission.

Visual inspection is also critical.
You want to find every flaw, scratch, dent, etc.
Of particular importance are the radiuses where each journal meet the ‘cheek’ of the journal.
They must be ‘flaw free’ or risk a broken crankshaft.
I use a little 10X hand microscope from Radio Shack.If you find something suspicious, you will want an expert ‘second opinion’ and then possibility ‘non-destructive testing’ (Magnaflux, Zyglo, etc.)


You will find it VERY valuable for the machine shop experts to realize YOU can measure at least as well as they can – or better.
You will get their best work.






Can you post all the numbers from the crankcase?
What is the engine number (green arrow below)?
It may be in the range: 6114001 on.


(Ignore yellow.)


Here is the type number and build number (red arrow above).





What is the engine type number?
It may be 911/07.

What is the engine ‘build number’?
It should be just below the type number.

What are the case-half mating numbers?
It is on top of the crankcase, at a center case bolt between the middle cylinders (#2 & #5).
Usually 2-3 digit matching numbers.

What are the two (different?) casting dates?
They are on the front (pulley) end of the case.
They are a circle with a 2-digit year (70 or 71) and a series of dots around the perimeter of the circle.

What are the two casting numbers on the lower sides of the crankcase.
You can’t miss them.
911.101.101.2R 911.101.102.3R or something similar.

Can you use your great photographic skills to post some really good images of these?

Best,
Grady