Budget 3.2 head stud replacement project
 

A few weeks ago I was excitedly pulling the valve covers to do a valve adjustment as I finally was wrapping up the work on my newly acquired 911 SC (with 3.2) and getting ready to put it back on the road. After pulling the right side valve cover, my heart sank as the telltale ‘clank’ of metal parts falling on concrete greeted my ears and I looked down to find a chunk of head stud on the floor.

The car had excellent compression and leakdown numbers, and ran well on the 1500+ mile trip home from CA, so I’ve now embarked on a budget head stud replacement project. I REALLY don’t want this to turn into a full rebuild. It ran well, so I’m trying not to invite trouble or spend more than I really have to. Dropping a motor is really no big deal for me, so even things like the clutch are being ignored because it worked fine and it’s only a couple hours to drop the motor again when I need to change it. However, I don’t want to be excessively penny wise and pound foolish, so I’ve bit the bullet and bought the replacement fuel lines from Len to avoid burning this car to the ground with lines that are of unknown age.

High-level, here’s my shopping list and intentions:
- New steel coated head studs/nuts/washers
- New fuel lines
- All needed gaskets
- New hardware where needed (exhaust studs, some intake/cam tower barrel nuts, some rocker shaft hardware)
- Clean/sandblast/paint engine shrouds, valve covers, etc. Not going to be able to help myself here.
- Turbo oil return restrictors

Budget/scope limiting moves:
- No splitting of the case
- Pistons remain in cylinders throughout process
- No head rebuilds (Burned about ½ qt in 1000 miles, though I’ll throw new valve seals in just because)
- Not removing the center chain housing/main pulley
- Not replacing the tensioner oil lines - they weren’t leaking and they are fairly easy to get to again.


I’ll post up my progress so far a little later. I’m already torn down to the case and have most of my stuff ordered. Initial thoughts or big stupid things I’m missing?

Snowball resistance - good luck, I couldn't help myself once I started reading and inspecting and not wanting to go back in for another 10yrs. A lot of areas on these engines demand attention as "cheap insurance" which is all fine and dandy except there are so many cheap insurances that the aggregate is easily $3000-$5000 in parts and machine work. The end result, at least for me, is having something you now place more confidence in.

Inspect the timing chain ramps, chains, sprockets idlers and tensioners; anything out of alignment will chew through the sprockets and wear down the chain. Cracked, missing or gouged ramps should be replaced unless you want to go back in when they start slapping around. Check the cam lobes for wear/gouges, rocker contacts for wear/gouges, broken valve springs, valve seats for warping, valve guide wear(easy especially if you're doing the seals). Consider the RSR rocker seals for reinstall. ARP rod bolts without case split, Etc..

You should budget for a set of Supertec studs and new exhaust valveguides. Your valveguides might be ok, but I would not bet on that! In my 3.2 the exhaust valveguide was shoot after 30.000 miles... found that out after a head stud broke.

My cheapo DIY opinion having done a few top ends with good success.

Some suggestions for while you're in there that are cheap fixes.


>Internal t-stat o-ring. Easy replacement with engine already out.

>Oil pressure warning light switch. This often leaks at the crimp joint. Good insurance to replace if yours looks even questionable.

>Check case breather hose. If very firm/inflexible, should replace.

>Flatten/mill your intake insulators to make sure they seal well. 3.2 intake is notorious for leaking.

>Flush intake manifold with solvent. You'll be surprised how much oil you find in the sump of the manifold halves. It's because the oil tank is vented to the throttle body rubber boot and a full oil tank will puke some oil at high rpms, along with the buildup of general oil vapor.

>Flatten/mill your cam cover plates. You'll be surprised how NOT flat they are.

>Check your engine oil supply hose from the tank to the feed tube below the oil cooler. If hardened/showing cracks, replace. DO NOT buy a URO brand replacement!

Exhaust studs.........
 

IF, you should happen to break an exhaust stud while removing the exhaust system, and there is still a piece of the stud to grasp, some heat from a propane or mapp gas torch will allow a fairly easy removal of the remaining piece. Drilling would be needed only if the stud breaks flush with the head. Lots of penetrating oil and heat from a torch will go a long way towards avoiding a broken stud! Good luck!

Some excellent tips here, thank you. I will take them to heart and post some updates shortly.

My exhaust studs are in terrible shape, I managed to get the nuts off with heat and a cold chisel and didn't damage the studs further, but they are unuseable nonetheless. I tried heat (oxy/acetylene) , soaked them in Kroil for a week, etc.

On the one stud that I tried to remove, I welded a nut to it, heated the head, etc. and it still broke. Twice. I then drilled it 90% out and tried to gently use an easy-out to finish the job. Mistake! I have an easy out snapped off in the head now. I've dropped that head off at a machine shop that has an EDM machine to burn out the easy-out and the rest of the heads are at another machine shop that I've had good luck with in the past for stud removal.

I have just dropped my 3.0 SC engine for the same reason. Advice I was given was that as I wouldn't have dropped the engine except for the head studs, and everything else was OK, why mess with it? Some preventative maintenance is a good idea but as they say, if it ain't broke, don't fix it. Something to ponder over?

I am going to replace vacuum pipes, fuel pipes (possibly) and any damaged or worn nuts and bolts so if I need to take it all out again, it will come apart!

(And give it a damn good clean up of course).

Welllll, I rebuilt my engine two years ago but stopped at the case (did not split it). Did everything but the case. Well now its apart again. Should have gone the extra yard and did it all "while in there"

Just some food for thought.

Chris
73 911 E

Why did you have to tear it down again?

pulled a head stud :-(

Currently in a bazillion pieces in my garage. Big pieces come off tonight (heads, cooler, p/c's)

Chris
73 911 E

Engine pulled - Got to use my Corvair engine cart. :)
http://i1269.photobucket.com/albums/...ps445d778e.jpg

Torn down to the case -
http://i1269.photobucket.com/albums/...ps907e3599.jpg
http://i1269.photobucket.com/albums/...ps610d5bd2.jpg

The valves sounded good to me previously and the oil consumption seemed minimal. I'll bear in mind the warning on the seals...maybe I'll pull just one apart for inspection for committing to the rest.

I assume this is something that I'd have the machine shop do...that the 'sandpaper on glass' technique doesn't scale well to the cam tower size.

Engine pulled - Got to use my Corvair engine cart. :)
http://i1269.photobucket.com/albums/...ps445d778e.jpg

Torn down to the case -
http://i1269.photobucket.com/albums/...ps907e3599.jpg
http://i1269.photobucket.com/albums/...ps610d5bd2.jpg

The valves sounded good to me previously and the oil consumption seemed minimal. I'll bear in mind the warning on the seals...maybe I'll pull just one apart for inspection for committing to the rest.

I assume this is something that I'd have the machine shop do...that the 'sandpaper on glass' technique doesn't scale well to the cam tower size.

If you're set up to disassemble the heads (can rent a basic valve spring compressor from local auto parts store) then it's no big deal to check a few valves for wear. Usually #3 or #6 cyl are the worst so check one of those heads. Since your valves were quiet and oil consumption was low, that's certainly a good sign.

No need to machine the cam plates. Fine grit wetsand paper on glass works just fine. That's what I do. You can use a fine tooth file on the cam housing itself to knock down the ridges and check the flatness of the housing end. Color it with permanent marker and then do the file test. You'll be surprised how much marker remains as you work the file around the sealing surface of the cam bore

Nice job putting in work to get to this point. My suggestion is to clean everything 10x's. I wrapped my chains with plastic and tape to keep debris from them and stuffed the opening around them with clean rags. Red solo cups in the case spigot bores kept debris out of the case as well while cleaning. Paper towels in the oil tube and distributor holes. WD40 and brake clean, old soft bristle brush to get the slime off; no water.

Good time to replace the case through bolt o-rings with the Viton available from the host as well. You can do these one at a time without splitting the case.

Send out everything for sandblast and powder coat early - perimeter tins, cross bar and the like. Nothing like kicking butt on your end and running into a parts wait on a vendor or supplier.

I find it ASTONISHING that people (seen this before) don't clean the engine before stripping it down..... Specially when you are only doing a top end rebuild.

1. Pull engine
2. degrease and power wash
3. remove tins, shroud, exhaust
4. degrease and wash again.
then
5. strip down engine

My own taste but I don't using water on engines if I can help it. You can clean just as well/better with other methods and not worry about corrosion or phantom issues with water finding a way into harnesses/sensors etc.

Different strokes I suppose. I've seen enough running issues with moisture in harnesses to last a lifetime.

I'll take moisture in the harness over crud in the engine any day of the week....

But you don't have to hose down the harness and I'm not saying to do it once a week, just before engine rebuild....

But lets not high jack the thread anymore, was just an observation.

Cleanliness is next to godliness. I like everything as clean as possible. And demand it of my product.

http://forums.pelicanparts.com/uploa...1370475326.jpg

http://forums.pelicanparts.com/uploa...1370475356.jpg

The thought of taking a 3.2 this far down without splitting take case is penny wise and pound foolish.

I know, enough of the folksy wisdom.

I have seen quite a few 3.2, 3.3 and 3.6 engines fail shortly after a major repair simply because the true history of the engine is unknown.
The weak link in the 3.2-3.6 rod is the undersized rod bolt. A simple over-rev can make extended life a big question. There is also the issue of contamination while performing this monument task.
Some have suggested rod bolt / rod bearing replacement without splitting the case and although it can be done is rarely a good idea. Rod bolts fit differently and to replace a rod bolt (same brand or different) without rebuilding a rod with undetermined history is asking for trouble.
Split the case, rebuild and replace the poor quality factory bolts with ARP and buy a little peace of mind.

Find oil leak minor oil leak, rebuild entire engine. Typical snowball. Would have been better off to drive another 100k miles without looking down and only topping off the oil.

Thanks for the tips on how to keep the gunk from the inside of the case. Of course I have my own sandblaster as well, so that work still on my list.

Fair enough. I'm a pretty astonishing guy, really, when I think about it. ;)

I thought the same thing when I got down to the block. I actually know better than this, I essentially followed the steps you mention on the last couple of Subaru head gasket jobs I did. I just got excited about teardown in this case and was more nervous, not knowing the motor intimately, about where I'd get pressurized water and not know it when I wasn't planning to split the case.

Henry, I have great respect for your experience and expertise. I'm trying to balance the realities of likely failures on this future 99.98% street car vs. the likelihood that I will be in for another $5-8k because when I split the case, recon the rods, do bearings, etc., how could I justify not doing rings, P&C, rebuilt heads, etc? Right now the scales are tipping in the 'leave it alone' direction for me.

If I throw a rod in a couple years I'll eat my crow and take my lumps for it.