Another 3.2 Engine rebuild - lots of questions!

[GaryR]

I just started ripping into my first 3.2, got it from a reputable shop nearby needing a complete rebuild. It looks like it has been stored in a salt mine but was actually running at the track a month or so ago! Anyway, ordered the Bentley 3.2 manual for reference but until that arrives I figured I would liven up Pelican with some nasty engine pictures!

First, the anchor.. errr, engine as picked up -


How are these hose replacements normally handled? DIY, from our host?


And these -


What is this larger thing called, think i'll replace it just for looking nasty.. what does the small sensor do?


Are these lines necessary, small one looks cut, big one plugged?


Need a blockoff plate for this, seems bigger than what my 3.0 had on it... where can I get one?


I'm having Len do all new fuel lines including that tiny J line circled so that part is all good.

Thanks that's it for today!

[yelcab1]

You mention Len so that is a source for all your hoses. Good!

The funny nasty thing is called an Idle Valve.
Look in the used market for a block off plate, or backdate the heat.

[GaryR]

Forgot this, how she sits now, need to get tools for 12mm exhaust nuts and allen nuts, i'm used to dealing with headers!

[GaryR]

Originally Posted by yelcab1

You mention Len so that is a source for all your hoses. Good!

The funny nasty thing is called an Idle Valve.
Look in the used market for a block off plate, or backdate the heat.

Thanks Yelcab, no heat, will have M&K headers as it will be a race motor. I sent Len an email about all the air hoses as I would just as soon send him that one metal-to-rubber breather line for him to crimp a new fitting on when I send my other lines in. I'm going all new SS fuel lines, no point scrimping on safety in a race car!

[KTL]

No more carbs Gary? Welcome to the crank it up and go club of Motronic fuel injection!

Those plugged hoses are for the PCV valve (#31). The parts diagram calls it a "recirculating air valve. Just leave them plugged however you wish.




For that missing shroud area where the heater plenum used to be, you can use the old plastic piece by chopping it and fabricate a cover for it. Mine was really crude

Fan Shroud Blockoff Plate- Poor Man's 3.2 Version

Or there are fiberglass pieces for $70.

Porsche 911 & Carrera Engine Miscellaneous - Page 8

If you get a new idle air control valve, keep the old for a spare. The little "sensor" below it is actually a harness pigtail for the useless TDC sensor that is on top of the engine right over the flywheel. It's a diagnostic sensor that is never used. Just remove it.


The various hoses can be sourced new. Some you can make yourself with basic hose. On the straight sections I used some Aeroquip socketless hose. This hose is very thick and good for vaccuum usage. The crimp clamps are basic Oetiker clamps you can get from McMaster.

The hose that has a 180 degree bend can be had from Pelican. Part no. 999.181.068.41 It is a pre-formed hose that is the perfect replacement.

The short hose beneath the fuel pressure regulator is a must to replace. That sucker is always cracked and a hazard. Len can set you up with that no problem.

The best tool i've found for the exhaust hex nuts is a 13mm universal socket. The integrated kind with the 13mm socket built into the u-joint. Craftsman brand works just fine. For the barrel head nuts, use a fairly long 8mm hex key with the bend cut off. Then insert the key into your 3/8 drive 8mm socket.

I suspect you'll need to replace the DME reference sensors, as they're typically toast by now. Make sure to get the BMW part number that is 1/2 the Porsche price, despite it being the exact same Bosch sensor, just with a bit longer cable on it.

[yelcab1]

For the exhaust nuts on a 3.2L, I have used

1) long 8mm allen socket (I think it is 8mm)
2) Box and open ended 13mm wrench
3) Deep offset 13mm boxed end

and have never needed anything other than those.

[GaryR]

Thanks guys, the info is greatly appreciated and i'm adding the hoses to my project list. Very strange thing is, I have the 13mm U-joint socket but these nuts are 12mm... I shoved a 12mm open end wrench on them to double check. I'm buying a Mapp gas torch and borrowing the 12mm socket and 8mm allen from a friend today so will most likely get them off tonight. If Sears has a long 8mm and 10mm (good for the starter and head nuts) allen I can cut off and weld to a 3/8" socket i'll make my own..

As for the reference sensors, amazingly they were replaced somewhat recently and never-seized before installation so they slid right out. I planned on buying new ones and keeping these as spares also. Is there a BMW part for the CHT? That is rusted in, will have the machine shop remove it when I get the heads done and have them drill out the 12 broken 4mm(?) shroud bolts and replace every stud....

Carbs Kevin? That was waaay back on my RSR project! This engine replaces the 3.0L in my Stock D PCA race car, along with Carrera brakes and regearing, to move me into Stock E!

[GaryR]

Another few questions - I assume I will have to put an oxy sensor into my headers for this to run properly? Any specific one or just use the stock one (cable long enough?)?

The hoses to the IACV apparently are NLA... Just replace with straight hose?
93011066500
93011058902

As is this little tapered rubber check valve sleeve.. have to match something up?
930-207-243-01

[r-mm]

Great project. As you know, I'm around the corner and just wrapping up my 3.2 rebuild.

I was able to get at the trickier exhaust hex nuts but cutting / bending a sacrificial box wrench. maybe get a few at HF? Along with some MAPP and the 6T press, I was able to make an "s" tool. I also bought some low profile wobble sockets but they were almost as hard to use as the modified box wrench setup.

So far as I know there is no alternative to the CHT.

Don't see why you'd use any other oxygen sensor than the one the car came with. Bosch sells them both as "universal" = you wire it and "oem" = has pigtail on it.

Welcome to motronic indeed. In all my years of wrenching I have come to greatly appreciate this vintage of fuel injection. Simple, reliable, tunable, cheap sensors, not that much can go wrong!

[GaryR]

Originally Posted by r-mm

Great project. As you know, I'm around the corner and just wrapping up my 3.2 rebuild.

I was able to get at the trickier exhaust hex nuts but cutting / bending a sacrificial box wrench. maybe get a few at HF? Along with some MAPP and the 6T press, I was able to make an "s" tool. I also bought some low profile wobble sockets but they were almost as hard to use as the modified box wrench setup.

So far as I know there is no alternative to the CHT.

Don't see why you'd use any other oxygen sensor than the one the car came with. Bosch sells them both as "universal" = you wire it and "oem" = has pigtail on it.

Welcome to motronic indeed. In all my years of wrenching I have come to greatly appreciate this vintage of fuel injection. Simple, reliable, tunable, cheap sensors, not that much can go wrong!

I can go back and look, but what did you do about those hoses that are NLA, especially the tapered ones??

[r-mm]

RESCUE TAPE Self-Fusing Silicone Tape: Amazon.com: Industrial & Scientific

[KTL]

If the hoses to the ICV aren't cracked, i'd just reuse them. Otherwise, see if Len can get some pre-formed hose sections for you if you provide the dimensions to him?

Yep you need to use the O2 sensor if you stick with a typical USA ECU & chip programming. However if you were to have the Euro programming then the ECU/chip is such that the O2 is eliminated.

[r-mm]

Huh, out of curiosity if all things were equal, I wonder what would change in terms of HP, MPG, drivability when going from the O2 fed DME to the non O2 DME? I'm guessing it would not be that easy a comparison in real life since the Euro DME is tuned for higher comp, no cat, maybe other things?

[GaryR]

Originally Posted by KTL

If the hoses to the ICV aren't cracked, i'd just reuse them. Otherwise, see if Len can get some pre-formed hose sections for you if you provide the dimensions to him?

Yep you need to use the O2 sensor if you stick with a typical USA ECU & chip programming. However if you were to have the Euro programming then the ECU/chip is such that the O2 is eliminated.

Thx Kevin.

I think I may be able to match up some hoses here and elsewhere using silicone - HPS 1/2" 13mm 45 Degree Elbow Coupler Silicone Hose 4-Ply Reinforced High Temp black

Will need to get the right ID's and lengths first. I'll check the hoses that are on there but if they are like everything else I will want them replaced. I emailed Len about a complete "kit" for all rubber (except the long J hose and the straight pieces (that are not tapered). If anyone knows the ID's of these it would be a great help, else measure them I will...

[Mehoff]

FYI, that ridiculous mess of hoses in your second pic is just the brake vacuum; not utile at all in a race car. Just run a hose from the bottom of the intake to the MC (creates the necessary vacuum), plug the outlet at the back of the TB and you're good to go.

I did this out of necessity at the track (forgot to reinstall when putting the motor back in!), and as it turned out most of the 3.2 guys don't use it either.

[911pcars]

Originally Posted by r-mm

Great project. As you know, I'm around the corner and just wrapping up my 3.2 rebuild.

I was able to get at the trickier exhaust hex nuts but cutting / bending a sacrificial box wrench. maybe get a few at HF? Along with some MAPP and the 6T press, I was able to make an "s" tool. I also bought some low profile wobble sockets but they were almost as hard to use as the modified box wrench setup.

So far as I know there is no alternative to the CHT.

Don't see why you'd use any other oxygen sensor than the one the car came with. Bosch sells them both as "universal" = you wire it and "oem" = has pigtail on it.

Welcome to motronic indeed. In all my years of wrenching I have come to greatly appreciate this vintage of fuel injection. Simple, reliable, tunable, cheap sensors, not that much can go wrong!

To remove and replace the CHT sensor:
14mm deep socket with a slice down one side to clear the harness. Similar to a socket to R&R an O2 sensor.

Sherwood

[KTL]

I think the only key component of that wacky brake vaccuum assembly is the check valve. PMO has one that should work. So Mehoff is right that you could ditch that whole setup and just run a hose with a check valve in it.

14mm flare nut wrench (like the ones used for brake lines that I never use...) also works good on the CHT sensor.

[GaryR]

Originally Posted by KTL

I think the only key component of that wacky brake vaccuum assembly is the check valve. PMO has one that should work. So Mehoff is right that you could ditch that whole setup and just run a hose with a check valve in it.

14mm flare nut wrench (like the ones used for brake lines that I never use...) also works good on the CHT sensor.

CHT Sensor is rusted to the extreme, wire was cut as it will be replaced. I have had it soaking in Aero-Kroil and will give it a little tug after heating the head a bit but if it doesn't go easy i'll just add it to the list for the machine shop.. I've snapped enough bolts already!

[r-mm]

Originally Posted by GaryR

CHT Sensor is rusted to the extreme, wire was cut as it will be replaced. I have had it soaking in Aero-Kroil and will give it a little tug after heating the head a bit but if it doesn't go easy i'll just add it to the list for the machine shop.. I've snapped enough bolts already!

Wouldn't sweat it. Machine shop can handle it. Worse comes to worse, what would stop you from just leaving the old one in there and swapping the heads around since they all have the threaded boss?

[GaryR]

Originally Posted by KTL

I think the only key component of that wacky brake vaccuum assembly is the check valve. PMO has one that should work. So Mehoff is right that you could ditch that whole setup and just run a hose with a check valve in it.

I can use the one off a 78 motor I assume? My old 3.0 is being made ready to swap into a car now and i'm sure I can have the one off the junk motor it's replacing.