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75 911s 11-13-2017 05:55 AM

Born in 75's 3.2 build
Hello! Welcome to the thread of my 87 3.2 Carrera motor rebuild. As some of you know, I have a 1975 911S with a stock 2.7. I've done a lot to my car as documented in my build thread over at the tech forum.

My stock 2.7 has held up OK despite being a thermal reactor car, having no front cooler for the majority of it's life (and being in hot climates like so-Cal and Arizona) and generally leaking quite a bit. I've done everything I can do to it without a rebuild. When I started looking at costs and final results of the 2.7 and the notorious mag case, I began looking around for a 3.0 or 3.2 to build. Having a second core would allow me to drive my car for the year or so it would take me to build my new motor. I'll shelf the numbers matching 2.7 for posterity and a future rebuild.

The opportunity to get into a 3.2 core came up at a low price that I didn't think I would ever see again for a 3.2 that included the fan, tin, crossbar, yoke and dizzy. The low entry price will allow me to amortize my total build cost over several years since I will have to buy an intake and exhaust eventually. It may end up costing me more in the long run but will allow me to fully customize intake and exhaust and all other parts to my whim. Doing a lot of the work will help me keep the build costs reasonable. I felt like the motor was a good buy as I have personally seen this motor running recently. The car appeared to move well and didn't smoke when I followed the car around So-Cal last may when I went to Luft4. I know the PO and felt like I knew what I was getting into.

This is the engine before I got it. The PMOs on the left caught fire during a drive. The fire was extinguished before a major catastrophe ensued. The other PMOs and exhaust were removed before I received it. Before the fire, the motor had occasional smoke problem. As a result of the fire, the motor was tested for compression and #5 was found to be low on compression. Results for the other cylinders were good for compression and leakdown.

The PO bought the motor with his car (coincidentally also a 75) and I've noticed a lot of mods that tell me that who ever did the swap, used some items off his original 2.7.

One such item was the shroud. It appears the outside was painted black over the green gelcoat. I haven't seen any sign of fire on the shroud and the wiring harness is totally fine. I think the fire was high on top of the carbs and was killed before it got too far down.

Another was this 2.7 distributor that contained a petronix ignitor and the vacuum advance plugged off.

There's play in the shaft, and this is the wrong distributor as there is backlash in the gear drive when using a 2.7 distributor on a 3.2. So I'll be selling this core distributor or maybe I'll keep it for my 2.7 if I ever want to change the ignition.

A few nice surprises were: 1. The mexico blue highlights on the fan, housing, valve covers and cross brace are (I THINK) paint and not powder coated. I'll be taking them down to metal and maybe just clear coating or painting them black. 2. There appears to be a brand new alternator in the fan.

Once I got the shroud off, I could see the source of the occasional smoking problem and low compression on 5. Oil is blowing past the cylinder and making it's way out between the head and cylinder. Broken rings?

Here's another clue that PO was running 2.7 style SSI (thin flange) HEs. Short exhaust studs.

I have Thick flange SSI on my 2.7 and if I want to swap, I'll need to change these to long studs. But that's a minor issue in a sea of unknowns at this point. I would run them if I remained stock. As I've heard they are fine for low end torque on a stock 3.2.

I will most likely be changing out the P/Cs to either euro for higher compression, or to a 3.4 displacement.

I noticed a lot of leaks around the cam tower with the plugs and cam lines. Looks like someone was a fan of some kind of white sealant.

I removed the cooler before putting it on my hand me down engine stand.

I just ordered the Torin engine stand from Costco. It's got the two legs, folds down and holds up to 1250lbs. I had picked up a yoke last year. It's an ebay special yoke but fits fine. The only problem was that it didn't come with any holes so I had to drill holes in the steel pipe for the set pin- which was a major pain.

My goals for the project:

1. Have fun and challenge myself. I don't have a lot of engine building experience, but I grew up in my dad's shop watching and helping him build hot rods and engines. I've helped him assemble a few V-8s and do a variety of machine shop work.
2. Take my time but finish the project within a year.
3. Build either a stock 3.2 (find cheap used stock intake and cheap exhaust) and swap into my 75, OR Build a dream engine core, then phase two add dream intake (two year timeline) I imagine opening up the engine will tell me which direction to take.

I like the look of this recent build:

This is an EFI with Jenvey ITBs and 911R style shroud.

Follow along for faux pas and fun.

Trackrash 11-13-2017 10:27 AM

Looks like a fun project.

Too bad you can't get the other PMO. I can't imagine that it isn't repairable. You might want to see if one is available somewhere. What size is it?

Are the cams stock? With carbs you are free to go to aggressive cams.

I bet the problem with #5 is broken head studs.

Good luck with your build.

75 911s 11-13-2017 11:16 AM


Originally Posted by Trackrash (Post 9813188)
Looks like a fun project.

Too bad you can't get the other PMO. I can't imagine that it isn't repairable. You might want to see if one is available somewhere. What size is it?

Are the cams stock? With carbs you are free to go to aggressive cams.

I bet the problem with #5 is broken head studs.

Good luck with your build.

Unfortunately, the carbs were bought by the previous owners mechanic before I was offered the engine. The first picture was taken before I bought the engine and I received it sans intake and exhaust.

I actually just pulled the chain box off and the cam is marked 930 14710. I think that is a stock 3.2 cam right? All the head studs appear to be intact. I'm removing the nuts on the left bank currently, but I inspected the other side and they are all intact, but I didn't torque them. I am very curious what is causing the low compression on 5. We shall soon find out!

75 911s 11-14-2017 09:49 AM

More on the tear down. I ordered the QSC P9191 tool off ebay. I used it with an ordinary deep socket and just went slow with a lot of leverage so as not to mark the cam bolt. It was suprisingly easy and I was expecting it to be much harder. I didn't see anything out of the ordinary as far as the sprockets.

Looks like a stock 3.2 Cams are marked 930 14710 and 14810
Chain boxes came off easy using a rubber mallet and some light taps.

Some wear on the chain ramps as expected. Of course I'll replace with new. I bought some for my 2.7 that I didn't use...are they they same?

Next up were the head stud nuts. Wayne says to remove the whole head and cam tower assembly. I was a bit worried about snapping some head studs, but I shot them with PBblaster and did a turn, and then a slight turn back, then a turn, then a slight turn back. This way I was able to break them all free with no drama.

The removed heads and cam towers:

There was some kind of sealant all over that crumbled. and fell onto the cylinders. It was orange and very brittle. This large rock like thing was jammed into the middle of #5. Carbon?

Left side bank was all oily

Right side has a cracked exhaust valve on #6.

And problem child #5 exhaust valve looks like it is not seated (low compression cylinder)

Inspected #5, rings are intact and cylinder bore is clean AFAIK

I did see this dried glue/goop - what is it? Is that normal?

I can see an impact mark on #5 piston top from the exhaust valve. Out of picture space so I'll show that in the next post.

More to come...

Trackrash 11-14-2017 10:35 AM

No broken studs? Amazing.

Perhaps the #5 exhaust valve hit the piston? Weak valve spring? Usually an over rev will hit more than one valve. Probably should check and possibly replace all the exhaust valves.

Flat6pac 11-14-2017 12:13 PM

3.2/3.0 valves are way less expensive than the smaller mid year/ early motors.
Orange tends to be 574, looks like the builder liked to seal base gaskets with schillac

75 911s 11-16-2017 03:58 PM

Thanks Gordon and Bruce. I took the heads off on 4,5,6 today.

Rocker shafts pitted and scratched. Grooves on each end. RSR seals on all of them. Someone's been in here...
Rocker bushings not bad but I'll re-bush too..recommendations?

Cam on right side looks good. I'll probably resell them to cover cost of more aggressive cams.

So here's the weird thing I ran into...

Head 4 is marked 2 on the back and 4 on the outside.
Head 5 is marked 4 on the back and 5 on the outside.
Head 6 is marked 3 on the back and 6 on the outside.

Engine builders..why would they change them up like this?

Also, who can clean my cam tower and maybe machine the surfaces?

Thank you guys for all the help.

Flat6pac 11-16-2017 04:27 PM

The stampings might have been machinist markings so he keeps everything together.
I and probably you do not have a set of stamps
I mark my heads and my machinist stamps over my marks.

Trackrash 11-16-2017 04:44 PM

Those numbers could mean that the motor was gone through multiple times or not. That number stamping is not factory, I believe.

75 911s 11-16-2017 05:36 PM

Should have showed the other side, the outside, these numbers were correct for where they were.

So this one was marked with a 3 on the backside.

Don't have the machinist stamps, but I'm sending out the heads to be rebuilt by our forum guy Craig.

Trackrash 11-16-2017 08:15 PM

Was that the leaking cylinder? Doesn't look like the cylinder was seated on the head.

75 911s 11-16-2017 09:29 PM


Originally Posted by Trackrash (Post 9817720)
Was that the leaking cylinder? Doesn't look like the cylinder was seated on the head.

Here's the low compression #5. Best I can tell, it leaked at the cam tower. But I'm not sure, this area shows the cam tower at 5.

A close up:

This shows the head on cam side at area of heavy oil concentration on low compression cylinder.

this is the piston side of #5

Sad that whoever marked the heads, marked them on the mating surface. They left pecker tracks of the numbers on the cam tower.

Also, what do you make of this machined surface? It looks pretty rough to me. i also noticed the stud holes are beveled on the cam tower...will my cam tower survive?

pmax 11-17-2017 11:06 PM

Cylinder #6 also has the same oily stains (red arrow) and the marking imprint (circle). Does it have low compression too ?

75 911s 11-18-2017 06:10 AM

Only 5 did, and yes all 6 numbers were impressed upon the cam tower. These surfaces will likely be decked anyway, not that those marks would have caused the leaks...Low compression on others is a moot point anyway since I'll be boring the cylinders to 98mm and running CP, or JE 98mm pistons for a 3.4 build.

My ballpark plan for the build is:

EFI with ITB (which setup might be up to budget) With The xfactory/or clay Triumph ITB setup being an option.

3.4 using existing cylinders bored out to 98mm and Carrillo or JE Pistons. 10.3:1

Possibly dual spark COP pump gas 91

What do we know about Carrillo Pistons?

Trackrash 11-18-2017 06:27 AM

Looks to me like the oil return tubes were leaking.

75 911s 11-21-2017 05:20 AM


Originally Posted by Trackrash (Post 9819065)
Looks to me like the oil return tubes were leaking.

No doubt, and you're right - that's the wrong side of the cam carrier to identify the leak I was seeing at the top of five. After looking over the top side, I've come to the conclusion that it wasn't leaking at the head, but at the rocker shafts.

All the rocker shafts are in really poor shape. They show pitting, scratches and the cam carrier itself has wear marks from the rsr seals on the shafts. The rocker bushings themselves are all worn as well.

what's interesting is the grooves on the shafts and in the housing, it almost looks like the shafts spun in the bore...Maybe they got loose at some point?

What's the best practice on ensuring a leak free bore moving forward? I guess the bores cannot be machined out as the rocker shafts are only one size.Of course the shaft expands when torqued down. I'm hoping a clean bore, new shafts with seals and bushings will keep me leak free.

Trackrash 11-21-2017 09:01 AM

Yea, those shafts are showing wear. Hard to tell from the pic if the bores in the cam housings are bad. Can those grooves be felt, or are they just marks? There usually will be marks from the shafts which are usually not a problem.

Its hard to believe that with the RSR seals that much oil could be leaking from the rocker shafts. Were they tight in the bore?

KTL 11-22-2017 08:24 AM

You've got quite an autopsy going on this engine. Nice job so far!

Looks like somebody chose to seal the cylinders to the heads with the orange loctite 574 goop? That's not necessary...... Also no reason to use that white teflon paste goop anywhere in these engines.

I would consider replacing the rocker shafts since they show a lot of markings. When you consider the fit is such a close one, you don't have a lot of room for wear. Plus the shafts aren't that expensive and Pelican has two good alternatives (Mahle & Febi Bilstein) to the original Por$che part

The bores in the cam housing need to be cleaned up so your shafts will seal well. Need to be careful with what you use and not disturb the surface too much. Wrapping a socket with super fine grit sandpaper does a nice job of cleaning them without disturbing the precision fit. Or you could try a hone and be very gentle with it.

You can get a grape hone that is 5/8" size (the rocker shaft bore is 18mm which is 5.67/8ths) and rotate the hone by hand to clean up the crud. Be sure to lubricate the hone with some oil.

The cam housings are easily the most neglected and abused part in these engines. I have seen so many boogered up cam housings over the years and I just don't understand why. It's baffling to me that people don't treat them with more care, given how much influence this piece has on oil leaks. Let's think about it:

-Both valve cover gasket surfaces
-Oil return tubes
-Camshaft paper gasket surface (more on this later)
-Rocker shafts
-Head sealing surfaces
-Oil spray tube

All of those places I listed have a high chance of creating a leak and still people do crazy stuff like clean them up with a scotchbrite pad, stamp numbers in a machined surface, gouge them with tools, etc. Just don't understand why so much carelessness :confused:

Regarding that camshaft paper seal location. Make sure before you reinstall the housing, to flatten the gasket location on each housing and also flatten the gasket side of the thrust plate (the piece that bolts in from the chain box side) because you'll be surprised how NOT flat that area is. Especially on the cam housing. It's easy to do with some wet-sand paper and a flat surface like a pane of glass.

And when you mate the heads with the cam housing, you hardly need any sealant. Only the round areas near the valves and the stud holes need sealant. All the rest of the machined surface doesn't need anything. It's just a waste of sealant and makes for unnecessary cleanup work (removal of old sealant) the next time someone takes it apart.

I think the CP pistons are a nice alternative to the usual JE pistons that have been used for years. The CP pistons appear to have all the features JE offers, and many of them at no addtional cost. Like for instance the JE pistons cost a lot more if you want the reduced skirt (they call it FSR- Forged Side Relief) and CP pistons are standard that way with their X-forging. Plus the flyer below says their pistons include a piston pin circlip (wire lox) tool. SWEET! :D

75 911s 11-27-2017 08:40 AM


Thank you so much for the detailed info. That grape hone is a great idea. I'm thinking the 600 or 800 grit and to just lightly do it by hand with some oil.


Well over the long weekend, my pops came up from AZ and brought his vintage Snap-on "Made in U.S.A." stud puller! He said he had it since the early 70s I couldn't believe how easy it was with this tool. All 24 studs came out easy. The dilvar studs came out with very little effort. The steel studs squeeked a bit and required more force, but nothing crazy.

Give the stud a little tap to break the loc-tite, thread on the stud puller:

Tighten the collet and unscrew the stud, oil a bit as you go.

Super easy to use and took me less than an hour to do both sides. No heating required.

The studs are perfect (other than the exhaust studs being made of Dilvar) and I hope to resell the 12 intake studs. (any idea of price)

Then I moved onto splitting the case:

Removed the 11 through bolts-

Blue seals. I removed the seals and the through bolts dropped right out.

Removed the 23 case nuts and washers and 2 bolts, removed the nut and washer inside the chain housing.

On the top of the case (Yellow square) was a brace/clip. Anyone know what this is for?

Wiring harness clip maybe?

The case came apart easy with a few gentle and strategic taps from a rubber mallet.

Looks pretty good inside. I see a scrape on the #3 bearing

and here is the nose bearing. Looks a bit worn, not too bad though.


75 911s 11-27-2017 08:45 AM

Some other areas I found damage so far:

IMS gear? Oil drive gear has some small chewed up areas.

I think it's reusable. What do you think?

Also found that the this stud mount is broken off on the back of the engine where it connects to the trans. i think it's a engine tin mount hole.

I want to hot tank the case. What machine work do you think is necessary for the case?

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