wondering if this can be done 2.2 & 2.4

[paul b]

Wondering if this can be done ?

I possess a 2.2T engine that needs to be rebuilt that is out of the car (70T)- At present in the car is a 2.4T engine with PMO's that runs remarkably well

Preferably I would like the original engine back in the car but wondered if I may possibly use any of the 2.4 parts e.g. the 2.4 barrels / pistons/carbs yet retain the
block with the original engine number on it. I also have no space to store a " spare engine " so if I could amalgamate , all the better ?

I would keep the unused 2.2 parts. If I am faced with rebuilding the 2.2 then I would like to rebuild as a 2.4 anyway and this led me to ask whether I can use anything from my good 2.4 engine.

I'm sure I may have overlooked a fundamental here so go easy !



Thanks



Paul

[356RS]

Paul, Most of the 2.4 parts are interchangeable with the 2.2 but the problem will be with the pistons/compression ratio. The 2.2 has a 66mm stroke and the 2.4 has the 70.4mm stroke. If you swap the pistons you will loose some compression and the 2.4 T only has 7.5:1 to begin with.

[paul b]

Mark

Thanks for replying and forgive me but with regards to compression is there therefore no way to actually merge these two engines ?

When faced with a bill for rebuilding the 2.2 I automatically would want to upgrade , either 2.2E spec or 2.4 something E or S

As I have the 2.4T as a layman with limited tech knowledge I figured I could do this

Thanks anyway

Paul

[andrew15]

You can use your 2.2 case with the 2.4 70.4mm crank and the 2.4 P&Cs this would retain your current 2.4 specs and allow you to keep your 2.2 66mm crank and P&Cs in storage.

Regards,
Andrew M

[paul b]

Thanks Andrew

Looks like I have the start of a plan to discuss with mechanic

Paul

[Grady Clay]

Good advice above.

OK, you have two complete engines:
1970 911T with Zenith carbs
and
1972 911T with PMO carbs.

First, inspect the sides (lower) of the 2.4 crankcase. If the casting number is 911.101.xxx.7R. Stop. That is the crankcase to use regardless of ‘matching numbers’. Just save the 2.2 case.

Another; what is the engine number and type number from the ’72 engine? It may be a 911TV-E type 911/57 or 911/67. This originally had Zenith carburetors, not MFI.

Assuming you don’t have a ‘7R’ case:

The most significant difference is the 2.2T has a cast steel, non-counterweight 66 mm stroke crankshaft and matching rods. The 2.4 has a forged steel, counterweighted 70.4 mm stroke crankshaft and matching rods. The rods do not interchange between crankshafts.

The 2.4 crank and rods can be made to fit in the 2.2T crankcase. There are some clearance issues between the rods and the crankcase. Easy to remedy.

The ’70 crankcase does not have the ‘piston squirters’ introduced in ’71. It is desirable to install them.

Both sets of Pistons and Cylinders (P&Cs) are cast (not forged) pistons and cast iron (not Biral or Nikasil) cylinders. If the P&Cs are still within spec, they will work well in a low (T) performance engine. You must keep the sets of P&Cs together. The ’70 pistons are 8.6:1 CR, the 911T-E (MFI) are 8.0:1 CR and the 911TV-E (originally Zenith carburetors) is 7.5:1 CR. Use the highest CR set. These are all 85 mm bore and relieved for 911T cams – not other.

If you find you must replace the P&Cs, I think the best bet is to buy a set of 90 mm Mahle Nikasil originally for the 2.7RS. These are extremely high quality and long lasting parts. They are readily available at acceptable cost. These are 8.5:1 CR with the 70.4 mm stroke crankshaft and have valve relief for the MFI 911S cams.

If you install 90 mm P&Cs, you must have the crankcase spigots bored for the larger cylinder diameter. A straightforward procedure.

You should have cylinder head stud inserts installed in both crankcases.

The 2.2T Zenith carburetors are original. The PMO carburetors will work better and be more serviceable. They are directly interchangeable. Inspect the manifolds for fit to the carb base and cylinder head.

Given the choice, use the steel air filter assembly and intake velocity stacks (never the plastic stacks).

While the flywheels and starter ring gear are the same, the clutch disc, pressure plate and clutch release (TO) bearing are unique to ’70 and ’72. Use new flywheel bolts.

You will need to use the 2.2 engine oil cooler with the ‘70T car as the ’72-only cooler (a very valuable part) will not adapt to your oil tank.

Needless to say, use the best heat exchangers, muffler and engine tin.

You may want to use the alternator from the 2.2T as it will match the voltage regulator. If you want, the ’72 may have a more powerful alternator but must match the correct voltage regulator.

The two engines use the same 3-pin Bosch CDI.

The instrument sending units are the same.

Neither of these carbureted engines need any auxiliary engine electrics.

The distributors will not interchange.

Your Type 911 transmission will handle anything you can build on these cases. This might be the opportunity to service and re-gear the transmission. Many like to convert to the earlier AFMSX gears, particularly if you change to an ‘E’ or ‘S’ cam.

Best,
Grady

[paul b]

Grady

Based on your price list in your signature I owe you a great deal !

Many thanks for your advice which I will need to use to investigate , ie 7R case etc etc.

At least it seems possible and I have one usable / partly rebuilt engine.

If in time it actually needs to be rebuilt I could then look at cams /pistons and moving the spec up.

Both engines run with clewett HPX system so no worries on electrics and I have both oil coolers too. Also changed flywheel bolts when engines swapped with a new clutch.

More than all of this I feel better that I can tick the box " got an answer from Grady " to one of my questions !!

Have read many of your posts - long may they continue

Thanks to all the replies thus far

Paul

[paul b]

Grady

Im not near car / engine but have found out that the engine no is:

6131196

The type was US 2.4TE - running MFI originally - no number from case though

Could this throw any light on best way forward ?

Thanks for your time

Paul

[BK911]

Without knowing condition of anything, I would try to use:

2.4T bottom end, including case. Put original case on shelf and KEEP safe.
2.2T top end
If you have an extra $300 get a set of E cams.

This will produce a ~8.5:1 compression 2.4E. Awesome engine which you will love. Will run well from idle to redline. Even with the T cams will run nice.

[Grady Clay]

Paul,

6131196 decodes as:

6 = Engine designation; 6-cylinder unit.
1 = 911T-E, MFI either type 911/57 or 911/67 (Sportomatic).
3 = Model year 1973.
1196 = Sequential number.

This is closer to being a ‘7R’ crankcase. What is it?

When you say you have “both oil coolers” are they both the engine coolers or do you have a front oil cooler set-up?


Probably the critical question is the condition of the P&Cs. Be sure to keep each piston matched with its cylinder and wrist pin.

The ’72 heads will have the provision for the MFI injection nozzles. The ’70 heads do not have the MFI ports. The ’70 heads are the easiest to work with as they have the most metal. They are very desirable for enlarging the ports and contouring the combustion chamber to match the pistons (90 mm RS?) you choose.

If you can retain the original P&Cs, everything bolts together.

If you retain the original pistons, be very careful if you change camshafts. Higher lift, different timing cams can have the valves contact the pistons with very bad results. Measure, measure, measure.

Is there any possibility you can find the original MFI system?

Best,
Grady

[paul b]

BK911 & Grady

Thanks for taking the time to answer.

Grady , there is not much hope of finding the MFI although " an " MFI set up could be found although expensive -

Initial thoughts now are that it may be as cost effective to keep the two engines !

I plan to investigate further and speak with a mechanic I trust here so lets see.

Again , many thanks for your time

Paul