Stacks and TB ID

[knapmann]

What stacks and TBs are these?

1) The stacks appear to me to be 2.2S stacks based off the part number and the appearance (fat tubes) and the 42mm measurement at the top. You can see that there is a lip between the trumpet and the stack when you look down it, they arent 46mm 2.0S stacks by my eyes.

Stacks are 901 110 303 0R? (im not sure if that is a 0 or "1/" it doesnt look like the other zeros... it looks like two lines maybe) I cannot find any reference to this ...0R number but a lot of references to 901 110 303 1R as 2.2S stacks...





2) Throttle Bodies have P/N 911 110 101 0R, I have seen numerous references to these as 69S TBs but now im confused because I also read in many places 2.0 and 2.2 TB and stacks cannot be mixed and matched due to stud spacing. Is this correct? If so, these are either both 69 parts or both 70-71 parts.

[Bruce M]

The part number looks like it was cast with a raised blank digit and the number (1 in this case) was stamped after machining to spec. At least that’s how it looks to me?

[inaglasshouse]

2) I also read in many places 2.0 and 2.2 TB and stacks cannot be mixed and matched due to stud spacing. Is this correct? If so, these are either both 69 parts or both 70-71 parts.

True.

I think you have 1970 bits, but will go and have a look at mine to confirm...
On yours, what is the stud spacing of the TB-stack studs? That will settle the matter.

[Lightweight_911]

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I seem to remember that the 2.0 throttle bodies & stacks had '901' casting numbers ...

.

[inaglasshouse]

Just checked. Andy, yes, you are right as always. 69 stacks are p/n 901 110 309 0R. Incidentally their casting number is on the flat "web", not on the side of the cylindrical part.
So, knapmann, I believe you have a matching set of tbs and stacks from a 2.2. Others more expert than me can tell you, but I reckon they will work fine on your 2.0S. Although the 2.0S stacks have a larger bore at the top (as you note), and although the stud spacings are different (as you note), the bore of the tbs is the same 2.0 vs 2.2.

One thing you will want to carefully check is he condition of the tbs. The spindles tend to wear oval holes in the alloy "seats" (no bearing, they run in the casting), meaning that the spindle and butterfly jiggle up and down, leading to air leaks etc. The result is tuning frustration because nothing ever works properly except wide open throttle. Also a vicious circle, because once the wear has started the vibration accelerates the wear.
Well worth a close look, it's a common fault.

[knapmann]

Just checked. Andy, yes, you are right as always. 69 stacks are p/n 901 110 309 0R. Incidentally their casting number is on the flat "web", not on the side of the cylindrical part.
So, knapmann, I believe you have a matching set of tbs and stacks from a 2.2. Others more expert than me can tell you, but I reckon they will work fine on your 2.0S. Although the 2.0S stacks have a larger bore at the top (as you note), and although the stud spacings are different (as you note), the bore of the tbs is the same 2.0 vs 2.2.

One thing you will want to carefully check is he condition of the tbs. The spindles tend to wear oval holes in the alloy "seats" (no bearing, they run in the casting), meaning that the spindle and butterfly jiggle up and down, leading to air leaks etc. The result is tuning frustration because nothing ever works properly except wide open throttle. Also a vicious circle, because once the wear has started the vibration accelerates the wear.
Well worth a close look, it's a common fault.

I have read about this a lot, I am attempting to take my stacks and TBs off at the moment and I would like to evaluate them off the car if possible. I suppose the key thing is how much play is acceptable and how do you measure it? Is it possible to do without stripping down the TBs altogether i.e taking all the butterflies and shafts out? Or is it a case of just try them and see. I can see the wear is nothing ridiculous like 0.5mm or more but beyond that evaluating them might be difficult

On this note, how the hell do you get these nuts off the LHS throttle bodies? access to the front and rear nuts is basically impossible with any tools at all! Especially the rear nut (bottom of picture).


Also, what is this pipe for above the oil cooler, and what is the thing in the red square? It looks like it should have small diameter vaccuum pipe connected to it or something

I seem to remember that the 2.0 throttle bodies & stacks had '901' casting numbers ...

Yes im certain they are 2.2 parts now, Im sure they will work fine but would be nice if I could swap them for the correct units one day. Easier said than done though I bet!

[210bhp]

The pipe fits to the connector on the back of your air box. It’s to drain condensed oil vapour. Fits here.......


Regards
Mike

[Gary71]

The nuts on the manifolds looks similar to my carbs. You have to use an open ended spanner and gradually undo them all. As you go you can lift the manifold to give clearance to go a bit further up the thread. Hopefully once they are loose you can spin them off by hand to speed things up.

[inaglasshouse]

When replacing those nuts - a little pearl of wisdom imparted by a friend whose business is to prepare race cars:
Various suppliers offer trick "manifold nuts" which are smaller than standard for the thread size. From memory these studs are M8, and the manifold nuts I bought use a 10mm spanner. Having made the switch, I can do most of mine with a 10mm socket and long extension.
Crowfoot can also be useful.

[inaglasshouse]

How to measure TB status:

1) Start from the assumption that, unless they have been properly refurbed, they are going to need it... that spindle running directly in the mag alloy is a very weak design

2) Any rattle in the spindle- refurb

3) For one butterfly, disconnect linkage and very carefully adjust the stop until it looks like the throttle is closing perfectly (but not binding). Close the air bleed screw. Reconnect linkage (making sure it doesn't move the carefully closed throttle - adjust linkage if necessary. Start the engine and use a Synchrometer to look at the air flow when throttle is closed, and as it gradually opens. Air leak when closed, or wobbly weirdness as it opens, are indicative of problems. With decent flow and a worn spindle, you might also see / hear it rattle.
Repeat for others.

Number 2 can obviously be done on a running engine, but in the absence of one of those an amusing hillbilly test rig can be fabricated from a vacuum cleaner and bits of wood.

See this post and onwards for JohnM's test rig, and some refurb pics:
https://www.ddk-online.com/phpBB2/viewt ... 25#p605979

[Lightweight_911]

Also, what is this pipe for above the oil cooler, and what is the thing in the red square? It looks like it should have small diameter vaccuum pipe connected to it or something

The part in the red square is the internal oil thermostat.

That's not a tube on the top but a threaded adjuster stud (not that I've ever known anyone to 'adjust' their thermostat !) ...

.

[jwhillracer]

The pipe is the drain from the air cleaner housing. The cylinder that it feeds into should have a rubber “duck-bill” valve on the bottom of it.
JW

[johnM]

On this note, how the hell do you get these nuts off the LHS throttle bodies? access to the front and rear nuts is basically impossible with any tools at all! Especially the rear nut (bottom of picture).

[/quote]

The nuts should be 12mm spanner size not 13mm. I use a wibbly wobbly to get them undone.

https://www.amazon.co.uk/Urrea-5275MH-8 ... B00I6TE6FM

[knapmann]

On this note, how the hell do you get these nuts off the LHS throttle bodies? access to the front and rear nuts is basically impossible with any tools at all! Especially the rear nut (bottom of picture).

The nuts should be 12mm spanner size not 13mm. I use a wibbly wobbly to get them undone.

https://www.amazon.co.uk/Urrea-5275MH-8 ... B00I6TE6FM[/quote]I need to get me a set of these! 12mm mine were not!

Success! Just as well they weren't super tight though!

Next question all... what can I see inside under the breather? Can you see the crank or oil pump or squirters (if installed) I would like to see what I have inside if possible without taking the whole engine apart...

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