First time engine removal questions
 

Next weekend I am going to drop the engine from my 911SC due to the usual head stud problem. I have four broken, and three completely missing which I suspect was from the previous owner!

I have a few questions which I am hoping somebody can help me with?

Firstly, I assume there is a vacuum pipe for the brake servo (booster). Where is this located on the engine?

Is there a wiring loom connection at the back of the engine? I have disconnected all the wiring on the left side but I have read that there is more behind the engine?

Is the engine earth strap the one that is actually attached to the front end of the gearbox just in front of the mounting cross beam?

If I raise the car and rest it on its wheels to take the engine out, I assume when the engine is released onto my home made supporting pallet, that the car will move upwards on the suspension? Does anyone have any experience of this happening?

Thanks in advance!

I ll handle the questions..
The booster is vacuumed from above the #3 runner, a large black vacuum hose with a pair of clamps right there.
If the car is a Lambda car, there is a plug in of a six or 12 pin connector.
The oxygen sensor is a connector below #3 spark plug hole coming through the sheet metal.
just in front of the mounting cross beam? and attaches to the body bolt there to the right side of center. Be sure you remove the black wire on the starter. Its the battery line to the starter. Be sure to undo the ground of the battery.
Take a 2x6 about 2 to 3 feet long under the floorpan just in front of the transmission and lift the whole car to clear the engine and you dont have to worry about wheel spring.
Bruce

Remove and Replace SC engine
 

Here is a check list that I made to use with my SC. Hope this helps!

http://forums.pelicanparts.com/uploa...1369747379.jpg

The "other" wiring harness is located behind the heater fan motor on the left side of the engine compartment, on the little shelf just to the right of the top of the left shock absorber fittings. It should be a 6 pin plug. Just pull it straight up to unplug. The wire will then lower with the engine. Also, be careful when you unplug the O2 sensor wire. The plugs become quite brittle and will crumble if not handled carefully. Also, there is a sensor mounted on the right side of the transmission near the axles that must be removed. This is the speedometer sensor. Loosen one 6mm bolt and push the retaining wire out of the way. Lift the sensor out and hang out of the way so that it won't be damaged. The reverse switch wires can come out with the engine/transaxle. When you disconnect the axles, cover the CV joints with a plastic bag to keep dirt out. You can use a piece of wire or string to tie the axles up and out of the way. Make certain that you have disconnected the shift coupler or you will risk bending the shifter input shaft.

Additional wiring connections for SC's.....
 

Keynsham1,

If your SC is a RoW car (no lambda), there would be no wiring connector at the back of the engine. However, if your car is a non-Euro or RoW car:

'78-'79...........................no extra connector at the back side.
'80................................there is a 6-pin connector for the ECU.
'81-'83...........................there is a 12-pin connector for the ECU.

After the removal of the engine, the rear end of the car will go up several inches due to the removal of the load (engine).

Tony

Today I did it! The engine and gearbox of my 1978 911SC are sitting on a trolley in my garage. Not the easiest task in the world I must admit. I had to grind off some bolts on the driveshafts to get them off the gearbox and despite reading all the books and manuals, I am sure not all connections are where you might expect. Still there it is. Now for the hard work to begin!

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I would put a couple bolts through the CV joint to keep it from falling apart...Falls apart, then you have a challange.
Bruce

The CV joints are covered in plastic bags now. The photo was taken just as I removed the engine!

Well done!!!
I will be watching to see how the head stud replacement goes, in preparation (tips & traps) for doing mine.

Good start!
 

Good job, getting the engine down safely! If you don't already have it, buy a copy of Wayne's book on 911 engine rebuilding. Lots of good info and tips there. Worth every penny spent!

When you go to remove the Dilivar studs, use a propane or Mapp gas torch to heat the block just inside the spigot next to the base of the stud. You might need to apply the heat more than once, but when it is warm enough, you should be able to turn the old studs out using a plumbers pipe (adjustable) wrench. Using this method, I was able to get all of the lower studs out of my SC engine without too much trouble. Once they are out, resist the urge to run a tap into the threads. Doing so will cut them larger than they are now and will cause the new studs to be a loose fit. I replaced the lower studs on my engine with the Porsche steel units. The Supertec or ARP studs are unquestionably better but are also quite a bit more expensive. Which you choose to use is your choice, but don't blame anyone else if you go the less expensive route! As you disassemble the engine, put parts that go together into labled plastic baggies. Make is much easier when doing the reassembling work!

Got to work this evening and removed the inlet and fuel injection system. Just undo twelve bolts...... If you have never done this then I can assure you that some of them are not easy to get at! There is also a lot of wiring connectors to label and a few other parts to remove to gain access. I am learning as I go with the help of three different manuals, which is the best way I think.

I am struggling to part the gearbox from the engine at the moment. The lower stud positioned below the starter motor, is corroded onto the hole and will not budge. Apart from that it is free so it is presently soaking in penetrating oil. I will get there eventually!

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You need to completely remove the clutch lever, the upper lever is an idler lever and should spin freely to allow the throw out bearing fingers to move off.
Some upper levers have a cross pin to hold it in place, some SC s dont. It needs to spin freely to work properly and they do freeze on the vertical shaft.

Bruce

More strip down today but still can't get the gearbox off. It is lose except for the stud below the starter motor which seems to be corroded into the hole. I just can't budge it and don't have a plan at present to sort the problem!

http://forums.pelicanparts.com/uploa...1370553605.jpg

Offending stud shown below.

http://forums.pelicanparts.com/uploa...1370553687.jpg

You mentioned that you are soaking that corroded stud in "penetrating oil". Not sure what you are using, but not all penetrating oils are equal! For instance if you are using WD 40 or similar, you are probably wasting your time. Try Kroil or some have used PB Blaster. My experience has been with Kroil which works very well. Only problem is that you can only get Kroil via the internet.

sadly, neither PB blaster or KR Oil are available in the UK as far as I can tell, and ordering them from the States is a bit time consuming (4-6 weeks!), so they are not really an option.

Find a pair of thin nuts and double nut that stud, then put a wrench on it and see if it will budge; perhaps just enough to break the corrosion at the gearbox or maybe all the way out of the engine case.

In Australia we are like you in UK - no Kroil or PB blaster - that I have ever seen for sale.
(Although I have used PB blaster in the tropics, out of OZ, & I found it was very good compared to WD40 )

You could try making up a homebrew penetrant, plenty of recipes on the web - they all seem to have half acetone and half light oil like ATF mix. Here is an example:

In this bottle mix a 50/50 mix of 100% acetone and dextron/mercron automatic transmission fluid. The two fluids will separate like oil and vinegar so you have to shake the bottle well before spraying.

I would try some local heat (heat gun?) to warm it up fist then spray on the cocktail and wait (Obviously remove the heat source first as you dont want a Molitov cocktail!!:eek:)
Good luck Peter

I have tried the double nut approach but it didn't work. I think my only real option is to file some flats on the stud and use vice grips to try and turn it. There is no way I am going to break the corrosion layer other than twisting as there is no way to pull the gearbox off with enough force to pull the stud out of the hole. I only need a small movement to break the corrosion layer and it will come apart. I will need to replace the stud afterwards of course.

Vice grips and stud extractor sockets have both failed to free off my gearbox stud. I have tried making some penetrating oil with acetone and ATF fluid. It looks good but whether it will work or not is anyone's guess. I am completely at a standstill now as until I can get the gearbox off, I cannot do any more work. Really beginning to be a problem. I haven't been beaten before by anything like this.

I wonder what a professional garage or mechanic would do? I am sure they wouldn't take weeks to get the gearbox off as the cost would get silly to the customer. I don't expect they would admit defeat either.

Any professionals out there with a good idea??

As a last resort you can drill out the stud to the depth that gets you down to engine. Start with a small diameter bit and do your best to center it. Using progressive bits open the hole as much as possible. And then use a small rotary file to machine away material. This process will eventually waste away enough of the stud to break it lose.

Thanks for the advice. I would have to cut the stud off flush with the hole, and use a right angle drill attachment as access is terrible, but it might be my only hope!

As a last resort you could consider Spark Erosion - this is what a workshop here would do if nothing else worked.
Actually this is a last resort for extracting head studs, but hopefully you wont have to end up doing that too!!
There are a lot of mobile spark erosion services here, sort of 'one man bands' so ask around you may be able to find a friend of a friend who could do it for mates rates?

As an example, here is a UK site I found on Google which explains:

Spark erosion or Spark eroding or electro disintegration on site mobile service

"Spark erosion can be carried out in house, or at your site, anywhere, subject to call out charge, and is perfect for removing broken taps, broken drills and broken extractors, as well as broken bolts and studs."

Have you tried any heat?

If the stud has been soaking in penetrant for a couple of days, try giving the stud a couple of good hits with a two pound hammer to break it loose. Then wash out all the flammables with carb cleaner and then dry with air. Once dry, use a heat source like a MEPS torch or a small oxygen-acetylene flame to heat the stud up while hitting the stud.

By the way, have you attempted to pry the tranny away from the engine?

So I have now devised a plan to remove my gearbox, and it involves cutting. I have now removed the engine oil cooler and can see the rear end of the offending stud, which is not actually in a blind hole, but in a fully tapped hole. In the next picture, the red arrow shows the nut end and the black arrow shows the engine end behind the (removed) oil cooler.

http://forums.pelicanparts.com/uploa...1370808877.jpg


My plan is to cut a slot, removing material from the bell housing only, across the interface between the engine and bellhousing, to a depth required to cut the stud into two. See red line arrowed on the next picture.

http://forums.pelicanparts.com/uploa...1370809088.jpg

This will allow me to remove the gearbox from the engine. It should then be a simple task to remove the remaining pieces of studs from the engine case and bell housing as there will be no access issues.

I will bond a washer to the bell housing to make up the material removed from sawing to allow proper clamp-up on reassembly.

I cannot think why this will not work. If anyone knows differently please let me know!

Hi,

Sorry I do not understand. You have the nut off the stud right? The transmission housing should be a clearance hole. Are you sure there isn't something else that is holding the transmission back?

Paul

Do not do it. Bad idea.

x1,000,000

Acetylene torch and a hammer.

None of the above ideas have worked. The stud is corroded into the hole and will not budge. I have tried heat, penetrating oil, shaking it about, and everything else I can think of. It will not come apart and I need it apart! The gearbox is completely free from the other studs and dowels apart from this one. It has been under the car for 36 years so a with steel stud in an unprotected aluminium hole it is not difficult to imagine corrosion setting in!

Just out of interest to Lapkritis, why is this a bad idea, you don't say? I agree is is not the ideal solution but I can't see why it will not work. All I will be left with is a slight gap about two inches long between the bell housing and the engine casing which I can fill with a bonded shim to allow clamp up. This isn't a sealing surface so this repair will work fine.

Braze a nut on the stud and unscrew the stud from the engine with an air impact hammer.

Paul

It'll come out without hacking the transmission bell housing. Would look like crap and show lack of patience and knowledge of proper techniques for extraction if you hacked it out. You have plenty of material to work with in the photos. If it won't come out for you take it to a pro.

Should also say when encountering corrosion weld wheels or engine/trans you can use a wooden wedge to split. Normally helps to employ a second set of hands to hold things square while driving the wedge.

You did follow Bruce' instruction, correct?

All clutch operating levers and mechanism are removed.

I'm guessing that a lot of advice is coming from people who are not familiar with the area and it's associated strength? The area of corrosion on the stud, considering it's length and diameter, is likely to require more force to shear it out (Pure shear as there is no peeling or torsion loading possible in this case) than the load required to break the engine casing itself, which if the two side were wedged apart would be a thin web in pure bending and would definitely crack under this type of loading.

There is no access for an air impact wrench, and I suspect even a brazed on nut would come off. Brazing is only a form of soldering after all (gluing rather than melting parent metal) and is not strong.

The end of the stud which is protruding is gradually breaking up because I have tried stud extractors and vice grips which just slip and damage the end. Even if I was to weld a nut on, I suspect the protruding end of the stud would shear off at the first thread (weakest point)

I don't intend heating an aluminium casing with an oxyacetylene torch.

Unless you knew it was there, it is unlikely that once I have finished, you would be able to tell it had been done, and it certainly won't "look like crap" and for the information of Lapkritis, I have resored more that a few cars in the past and this is the sort of work around that is often needed to get around difficult situations. If I took it to a pro, what do you think they would do that can't be done at home...please enlighten me?

You don't drive in a wedge willy nilly obviously. You would come in from the bottom where there is meat. You would be extremely hard pressed to destroy the case with a proper wooden wedge and handling.

If you're hell-bent on chopping away and not considering the advice of brazing nuts on, soaking in penetrant etc then you're just wasting time here. I would personally be digging at the corrosion with a pic tool, penetrant, air, heat and wedge pressure until it was free. 30 seconds with a cutoff wheel will also do the job for sure just not anything I would ever consider under any circumstance. Ever.

Yes, but I'm more than certain you have to rotate the shaft that the lever was on to disengage the arm/fork that is around the clutch throw out bearing before the gearbox can be removed from the engine. And that shaft is right there at that corner where things are stuck. Look through the casting "hole" on the top of the gearbox/bell housing and see if the fork is still on the throw out bearing.

Hi Lapkritis, I appreciate your comments, but you still haven't told me why this is a bad idea! In fairness this is a last resort. I have been heating, soaking rattling etc all week and it is having no effect at all. If I thought there was another way, I would go for it but I really don't think this is ever going to let go. The trouble with wedges is that you can only come in from the top and this puts the stud in bending not tension., If I could get a wedge in the bottom it might have been worth a go but there is nowhere to push one in as the casings are hard together.4


Anyway, I have just come in from my garage having separated the engine and gearbox.

The slot was made with a Dremel tool and doesn't penetrate the casing as you can see from the pictures below:

http://forums.pelicanparts.com/uploa...1370896026.jpg

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I still have to get the remaining parts of the stud out of course which I am not expecting to be easy. I tried drifting the part in the bell housing out and it really will not budge. I will have to drill it I expect, but at least I have got good access now.

As for the slot, I will fettle this to be perfectly parallel, bond in an aluminium packer and trim to match the outer casing shape. It will be invisible and structurally functional.

When you were applying heat, were you applying to the bolt or the bell housing? I would have gone cherry on the stud and driven a wedge simultaneously. If that did not free it I would allow it to cool fully and then heat the bell housing around the stud while continuing with the wedge. The helper would hold things square to prevent English on the stud. That would probably do the trick with some tugging and 4-letter words. I find "C U Next Tuesday" works as well as any penetrant.

You would have to be very careful as cherry red steel is around 1200 - 1400 deg.F and cast aluminium melts at around 1200 deg.F . Admittedly, the heat sink effect of the surrounding material should keep the casting way below that, but still it could become expensive!