Advice on 2.2E MFI build with 2.4/2.7 Crankshaft

[herman maire]

Hello

Could use some advice on my engine build for my 1970 911E.

A quick history, the original 2.2E crankshaft in the engine has some light scouring on some of the main bearing surfaces. Instead of dealing with trying to source oversized bearings and sending the crankshaft out for machining I decided to purchase a 2.4/2.7 crankshaft.

I sourced what should be a very nice STD/STD 2.4-2.7 crankshaft and just had a set of stock 2.7 connecting rods refurbished by Ollies.

My questions are-

Will the stock 2.2E MFI work with the 2.4-2.7 crankshaft with 2.2E pistons and cylinders?

Would it be possible to run S cams if I replace the space cam in the 2.2E MFI pump with a "S" space cam?

Do you recommend aftermarket connecting rod bolts or are factory bolts good sufficient?

I plan to run the stock engine case. It seems to be in nice condition, I was going to assemble and see if theres any resistance when spinning the crankshaft VS sending it to ollies for a line bore. Thoughts?

My case has no piston oil squirters.

Any opinions appreciated.

[cmcfaul]

oh goodness. 2.2 E mfi pump should work with a 2.4 engine. Going higher compression (9.5 is ideal for single plug) will be a nice performance improvement. With higher compression come the ability to run better cams. I believe the DC 30 is an ideal setup with higher compression pistons for a street engine.

Now the bad side. The MFI is calibrated by porsche to run specifically a certain cam and displacement. It can be adjusted to get close to ideal but will never be perfect. You will need to install an AFR meter and become an expert MFI tuner (small adjustments and keep track of them). You will also need 2.4 heads.

If you build the engine to a stock 2.4 S. You can have the pump rebuilt with the right space cam and all should be good.

Chris

73 E

[faapgar]

A simple build would be to use the 2.4 crank & rods.CR will be a little higher.Use the same E cam and leave the stock injection pump alone.It will run just fine with minimal fuss.Go to s cam and spend $7500 more for ported heads & throttle bodies with different space cam and then you have to figure out how to tune it.Simple is better.Ciao Fred

[herman maire]

Thank you for taking the time to help me out.

So just to clarify-

If I take my 2.2E engine , install the 2.4/2.7 crankshaft and rods .
With stock 2.2E pistons and cylinders. My stock 2.2E cams and MFI will work good with this set up?

[Flat6pac]

You have to trim the pistons to clear the counterbalance on the crank
Bruce

[Geneulm]

This should be a nice motor. I’d do something more like the recommended dc30 or solex, although an S would (and your Es) work too. 2.2 and 2.4 heads are the same. Crank/rods should drop right in without additional clearancing - but should check anyway. There is A LOT more adjustment in the mfi pumps than many people think. The recommended AFR meter is in your future; it’s not rocket science.

[356RS]

Originally Posted by herman maire

If I take my 2.2E engine , install the 2.4/2.7 crankshaft and rods .
With stock 2.2E pistons and cylinders. My stock 2.2E cams and MFI will work good with this set up?

Yes, This will work. Might have to slightly richen up the the pumps main rack and re-adjust the idle.

[herman maire]

Thank you 🙂, really appreciate all the help from such knowledgeable members.
This is great advice and really encouraging. I don’t have a big budget so
Being able to use what I have is exiting.

So my little build will consist of
- stock 2.2e case ( will try to assemble with no machining or line bore )
- 2.4/2.7 std/std crankshaft.
-2.4/2.7 connecting rods
- 2.2e mfi injection and pump
-2.2e camshafts
-stock 2.2e oil pump ( is this a bad idea? Should I look for a 3.0l pump? )

I’ll just try to keep this build as simple as possible.

Do you think if i had my cylinder heads modified for dual plug ignition I could possibly
Run higher compression pistons in the future or would the gains not be worth the effort
( I still need to figure out what compression ratio I will end up at With the 2.2e pistons with 2.4/2.7 crankshaft)

Thanks again.

[Trackrash]

I think you have a good basic plan. Using the 2,2 pistons will give you around 9.5 -1 CR, which should work well with the E cams. If you are looking for some "free" horse power, go to K&N air filters and a sport muffler.

I think you would see diminishing gains going higher in CR. To take full advantage of more compression you want to completely upgrade everything, like cams, heads, LARGER CYLINDERS, DUAL IGNITION, and the MFI.

You should also do the oil pump bypass modification.

I am assuming your pistons and cylinders are in good shape. If not you could easily increase to a 2,7.....

[faapgar]

Bruce is correct.You need to trim about 9mm off the bottom of the piston skirts of your 2.2 E pistons.Also check the top of the cylinder for a ridge in the cylinder wall for the top ring land.With the stroke increase the top ring will be traveling a little higher in the bore.Fred

[targa72e]

you should be fine with 2.2E pump. Here is the flow specs for 2.2E and 2.4E. they are very close. I run a 2,4T pump on my 2.4 with e cams. A little adjusting with wide band o2 sensor and it works great. They have a lot of adjustability without changing the space cam.





john

[herman maire]

Thank you all again, I will check the top of the cylinders for any ridges for the piston rings.
That chart is great, im happy to see how similar the 2.2e and 2.4e pump are.

Another question, shaving the skirt of the pistons. What is the best strategy to doing this ? Any suggestions for machine shops? Ollies ?