Correct air cleaners for various MFI years

[speedo]

Yeah...boring stuff I know. I would appreciate being enlightened as to what years were plastic, and what years were metal. I was of the impression that 69 was metal and 70-73 were plastic. I know the difference (or one of the differences) between the MFI and carb air cleaners is the introduction of the small squirter line on the front side of the cleaner (most of which have been buggered up at this point). And while we are at it, how about some direction on the snouts (left dangle vs right dangle).So starting in 69...ending in 73, what am I looking for?

Thanks

Speedo

BTW...were there any air cleaners that were the same for both MFI and carbs?

[silverc4s]

My 70 S still has all metal MFI.. This includes the cast stacks as well as the all steel air cleaner assembly. Dangle is long and to the right, with a small dent to clear the deck lid bracing.

My guess is that this stayed the same until the 2,4 liter, which went to plastic stacks, plastic air cleaner, dangle to the left with some sort of hot air valve in the snout. Others will know more than I, Ed where are you, this sounds a lot like a question from your quiz..

[304065]

My 71 is plastic.
Snout dangles to the starboard side unless air conditioning was installed, in which case it dangles port.

[RSTarga]

Bill is correct IMHO 2.4 was the switch to all plastic and the thermovalve to the left.

[kentf14]

I also believe that the switch to plastic happened with the 2.4 cars.

[sithot]

All 2.4's were plastic, stack included. Although no engine fire is welcome it is even less so in these cars. More reason to make sure your cold start enrichment circuit is in top condition.

Tom

[edmayo]

I believe plastic started in 71. My 71 T has plastic. The parts books also seem to show plastic starting in 71, and from then on I believe plastic was the superceded part, which also required changing the buckets. or maybe it was just the clips. All snouts up through 71 went right, 72 started left facing snouts, as has been stated already. I can't swear to it, but I sorta think MFI and carbs used the same aircleaners.

[hesaputz]

I'ts a change in the buckets, as I'm discovering now. The clip spacing is different, and so is the top seal.

[Grady Clay]

Thanks Ed. I think we are getting closer.
Everyone, please correct my mistakes.

EDIT
Please don’t use ‘quote’ function as quoting will prevent my going back and editing the post.
I want to be able to have all the correct information in one post.G.


I don’t think the ’72-’73 plastic air filter assembly will (properly) fit the ’71 (or earlier) or vice versa.

The metal ’69 air filter assembly (at the air filter port) has a single (no-over-center) clip at the top. There are two over-center clips at ~120º and ~240º. This is the same as the earlier Weber carbureted cars.
The MFI air filter assembly has the cold-start spay pipe in each side, above the intakes. The ‘69T continued to use the prior air filter assembly.
Both of these have a single opening for the crankcase breather and a drain tube.

In ’70, the metal air filter assembly was changed to two (cad plated) metal wing-nuts holding the cover on the filter port at ~90º and ~270º.
The metal crankcase breather now has two openings – one from the oil tank and one from the charcoal canister evaporative emissions system.
There continues the drain pipe.
The 911E&S have the cold start pipes in the housing, supported by rubber grommets.
The 911T (carbs) has the same metal housing but with a rubber plug at the cold start pipe openings.

My recollection is that many early ‘71s continued ‘using up’ the inventory of metal air filter assemblies.

The plastic air filter assembly was introduced in ’71.
The filter port closure had two black plastic wing nuts with adjustable black plastic back-up nuts.
The clips on the intake buckets became longer to accommodate the distance to the lip on the plastic air filter assembly.
I think the intake buckets themselves remained the same as prior.
The 911E&S cold start pipes remained the same as prior.
The metal breather connection was free to rotate in the plastic housing. The breather had both openings as prior.
The metal drain pipe could turn also.
(These ‘free turning’ connections were a pita because it was more difficult to push-turning the hoses on & off.)

All of the intakes 1971 and earlier had the intake to the right with a ‘warm air’ hose from a heater duct in the RR chassis.
When A/C was installed, the intake was cut and angled to the left with a very long warm air hose.

1972 was a major change.
In addition to continuing with a plastic air filter assembly, the intake stacks were now plastic.
The really good news was the cold start port was now low on the sides of the intake stacks.
This lessened (but did not eliminate) intake fires.
My recollection is the surface where the air filter assembly seals to the stacks is different from the ’71 where it seals to the intake buckets.
The two can interchange but don’t seal properly.

The other big change was the introduction of the warm air control system on the 911T-E, 911E & 911S.
This used warm (hot) air from a separate heat exchanger on the left exhaust pipes. This system is worthy of its own thread.
The advantage of this ‘left-facing intake’ was that there no longer needed to be ‘special’ intake parts when A/C was installed.
The filter port attachment and breathers continued as in ’71.
Notable is the ’72 intakes this air at the inboard side of this auxiliary heat exchanger, just below the valve cover.

There is also the 1972 (&’73) 911TV with Zenith carbs.
This had a metal air filter assembly with a left-facing inlet.
I won’t claim to remember many of these so I’ll defer to anyone with experience.

In ’73, there were some changes.
The evaporative emissions connection, crankcase breather and drain were now cast plastic on the back & bottom of the air filter assembly.
The air intake for the auxiliary heat exchanger now had an aluminum foil tube from the heat exchanger to a grill opening in the left (cylinders 1-2-3) side tin.

I don’t think there were any outward changes from ‘73S to the later Carrera RS 2.7 and 3.0.
(The MFI on the 911SCRS is much different.)

The ’70 & ’71 914-6 had both steel and plastic versions, similar (but not identical) to the 911T of those years.

When looking at a plastic air filter assembly engine, the first thing to do is to inspect the underside of the assembly where it seals against the stacks or intake buckets.
This is commonly fire-damaged and not sealing correctly.

Speaking of intake fires, many (most?) ’71 & earlier engines came with plastic intake bells.
These should be saved for static displays as the melt and/or brake, sheading plastic (molten or broken) down the intake.
Metal only!

The ’72-’73 plastic stacks also have a fire-damage issue.
Carefully inspect every throat.

Now … this is all from my (lame) memory.
I’m sure there are errors.
Let’s correct the mistakes and have a good reference thread.

EDIT
Please don’t use ‘quote’ function as quoting will prevent my going back and editing the post.
I want to be able to have all the correct information in one post.
G.

Best,
Grady

[edmayo]

Don't have any issue with any of that Grady.