Question for the MFI people out there...

[Steve@Rennsport]

OT Question but related:

Where are the plastic (or metal) velocity stacks that are supposed to be at the tops of the stacks???

If those are the later plastic stacks mated to the early steel aircleaner assemblies,, the openings in the aircleaner housings should be opened up to unobstruct the radii at the top of these later stacks.

We've done extensive R&D on velocity stacks; both normal & full radius ones, and they make a very big difference in airflow.

[Grady Clay]

Steve,

Thanks for posting.

You noted that this application has the ’72-’73 MFI stacks and some PO has adapted the earlier (<-’71) steel air filter assembly. That is an interesting mod.

I like the mod but am (only slightly) concerned about the transition in the “bell-mouth” for the stacks. Part of the “tuning” for MFI and “S” cams is that transition. If someone were to add the earlier steel intake stacks, that would lengthen the intake stacks and change the resonance. The existing stack bell-mouth should be functional.

Listen to Steve.

Best,
Grady

[bbthomson]

Hey Guys,

Thanks for wirghing in Steve...you bring up some interesting points.

Grady: The case is a '70. Here is the build sheet:

2.2 S Case # 630 0653
Rebuilt to 2.4 performance specs
2.4 S 9.2-9.5 TO 1 compression JE pistons and Mahle cylinders
70 Std crank
Install case savers and street head studs
New main bearings
New rod bearings
New inter. shaft bearings
2.2 Liter oil pump [modified for max flow]
Turbo pump modification
New timing chains and ramps
Turbo chain tensioners with chain savers
Reconditioned rods w/ new bolts and ARP nuts
Mag and polished crank
Factory 911 “S” cams
Complete engine balance
Complete valve job w/ manganese-bronze guides
Stock valve springs and retainers
36 mm intake ports 35 mm exhaust ports
Powder coated valve covers and sheet metal
Turbo valve covers (lower)
Sonic clean and pressure test cooler
Rebuilt 55 amp alternator
Engine wiring for mechanical fuel injection
2.2 S Mechanical fuel injection
New plug wires, plugs, cap & rotor
Rebuilt distributor
Reconditioned stock exhaust, new muffler
Stock flywheel

To answer your question regarding the clamp. No I do not see one other than the rubber clamps that hold the fuel line...they are in good shape.

I have checked if the leak was there while the car was running but it did not appear to come from there. The lines are dry.

The leak is coming from just under the red engine cover at the back corner.

I have changed the injectors around and the leak is coming from the same place...?

At this point, I am trying to figure out all of the places that fuel could leak from...All fuel lines are new and their apears to be no leak.

Keep the suggestions coming...they are appreciated!

Thanks,

Brent

[Grady Clay]

Brent,

Henry delivers great engines and I’m sure this is one. I’ll go through each of your “build items” as if it were from an unknown builder.


”2.2 S Case # 630 0653”
Great – this is valuable in its own right.

”Rebuilt to 2.4 performance specs”
Well, it is a 2.2 (2195 cc) and not a 2.4 (2341 cc). Did this include the piston squirters that were standard from ’71 and all 2.4s?

”2.4 S 9.2-9.5 TO 1 compression JE pistons and Mahle cylinders”
Good. The issue with JEs is always the exact (measured) CR and the piston-to-cylinder clearance.

”70 Std crank”
Good. This tells you that you have a standard dimension 66 mm stroke, counterbalanced crank.

”Install case savers and street head stud”
Good. Every engine should have this. The “high-end” also are shuffle pinned.

”New main bearings
New rod bearings
New inter. shaft bearings”
Good. All normal rebuild stuff.

”2.2 Liter oil pump [modified for max flow]”
Good. The mod is to relieve the corners in the oil flow path. While this isn’t necessary unless the entire oil system is addressed, it is an indication of inspection of the oil pump internals.

”Turbo pump modification”
I think this may mean the ’77 oil bypass mod. Needs clarification.

”New timing chains and ramps
Turbo chain tensioners with chain savers”
Good. The question here is the idler arm up-dated?

”Reconditioned rods w/ new bolts and ARP nuts”
Good. The 2.2 rods are so robust that they withstand way over 8K without mods (so long as the pistons are light weight.)

”Mag and polished crank”
Good. Magniflux, Zyglow and other inspection is the sign of a proper rebuild. Every used crank should be polished and the dimensions noted.

”Factory 911 “S” cams”
Good. These probably were in the original engine. The issue always is to keep the rockers and cam lobes associated. Otherwise both need to be ground/polished to new specs. Of course the good rocker shafts are installed to have a fresh wear surface.

”Complete engine balance”
Good. That includes the rods overall and end-to-end, pistons & wrist pins, and the crank/flywheel/clutch assembly in sequence.

”Complete valve job w/ manganese-bronze guides
Stock valve springs and retainers
36 mm intake ports 35 mm exhaust ports”
Good. This is where you get performance and longevity. Proper tight fit between the valve stem and guide allows for a great and long lasting valve job. I am of the opinion to not use the best sealing exhaust valve stem seals to allow some oil to the exhaust guides. Knowing that you have stock 911S ports is important for future reference.

”Powder coated valve covers and sheet metal
Turbo valve covers (lower)”
Good. Nice touches make for a professional rebuild.

”Sonic clean and pressure test cooler”
Good. Even the cleanest engine can benefit.


”Rebuilt 55 amp alternator”
The 55 A alternator was standard form ’69 through ’74 (there were two larger alternators in ’75 before settling on 70 A in ’76). Since there were so many destroyed ’76-’77 engines, the larger alternator and requisite fan housing are readily available.

”Engine wiring for mechanical fuel injection”
Good. That is standard ’70-’72 E&S

”2.2 S Mechanical fuel injection ”
What is the Bosch number on your MFI pump? It appears you have ’72-’73 stacks and the requisite throttle bodies.

”New plug wires, plugs, cap & rotor
Rebuilt distributor”
Good. All normal for a professional rebuild.

Reconditioned stock exhaust, new muffler
Stock flywheel
Good. The stock exhaust will allow the MFI to run properly. The stock (cast steel) flywheel is appropriate for street use (and even some competition if lightened).


”The leak is coming from just under the red engine cover at the back corner.”
We need to find where.


Best,
Grady

[bbthomson]

Hey Grady,

I will get the answers to your other questions once Henry responds which he always does.

In the meantime, the numbers on the MFI pump are as follows;
90816107
0408 126 009

Thanks,

Brent

[Grady Clay]

Brent,

The Bosch 0408 126 009 MFI pump is for '70-'71 911S and appropriate for your 2.2S engine (probably origional). FYI, the Porsche part number is 911.110.222.00.

Best,
Grady

[Howard Taylor]

I have read numerous threads here regarding fuel starvation and I am in the process of doing a systematic elimination of possible causes. I have drained the fuel from the tank and removed the fuel sending unit so I could get a good look at the interior of the tank. This tank, from an SC, looks absolutely new inside with no signs of corrosion or gunk. Further inspection reveals that the outlet and return to the tank are connected to tubes that run internal to the tank. I cannot see where either of these tubes terminate and therefore cannot locate the outlet screen to check for blockage.
I want to eliminate the clogged screen theory before I move on.
HELP!

[Briana]

Grady,

I was the original person who spec'd this engine from Henry and then sold it to Brent. It is in fact a 2.4 liter engine. I request Henry to build an engine that would appear to be an original 2.2S engine (correct 630xxxx case and Bosch 009 MFI pump) but to use a 70.4mm crankshaft. So it is 2341cc.

[Bobboloo]

Originally posted by Grady Clay
Brent,

Henry delivers great engines and I’m sure this is one. I’ll go through each of your “build items” as if it were from an unknown builder.


”70 Std crank”
Good. This tells you that you have a standard dimension 66 mm stroke, counterbalanced crank.


Best,
Grady

I think he meant 70.4mm crank not the year 70.

The stacks by the way are 2.2 mag stacks painted black not the plastic ones from 72/73'. He just needs the velocity stacks to mount inside the airbox.


Brent,

Question. If this motor was a fresh rebuild from Henry maybe you should give him a call. Find out if he tests his motors before they ship. That info would be very helpful in determining where to look regarding the oil and fuel leaks.