Most difficult engine building job........
 

Just curious, what do you guys see as the most difficult job when rebuilding a 911 engine? Assembling the block? Compressing piston rings to assemble pistons to cylinders? Assembling the heads? Cam timing? Or???

My personal choice would be installing the second piston pin circlip! Getting those strong clips to compress into place while working among the cylinder head studs is a real pain! Most likely, there is an assembly trick that I don't know!

I totaly agree on those damm circlips. There is a method to simplify it, maybe I'll try it on the next build. I am also going to worry more about the oil pump o rings after reading a couple of threads lately.

Using the Supertec head studs allows you the put the pistons in the cylinders on the bench, install the wrist pin on the rod, then install the head studs.
Crazy easy compared to all other methods.
http://forums.pelicanparts.com/uploa...1377467777.jpg

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CIRCLIP INJECTOR™

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Made myself one of those circlip injectors, did make life easier, for sure!

My vote goes to cam timing...not difficult, but ain't half fiddly, and frankly, tedious

Another one would be getting the head studs out - cue the back-bottom-puckering for a newbie. Was a job I was dreading, but after growing a pair and finding the knack, they all came out nicely - even got into a bit of a rhythm after 2 or 3.

When I m doing a stud replacement I ll leave the bottom studs out until the clips are in on the pistons. That gives me more room to use needle nose or circlip injector which actually needs the shock of a small hammer to complete installation.
Bruce

Measuring the cam sprockets alignment is pain in the butt. I had 1 mm difference and removed two shims, mesured again and still had 1mm difference. I ended up leaving the same number of shims it came with originally. It worked then and should work now, since I did not make any changes in the cam towers.

I am now able to do circlips by hand and used the Stomski alignment tool on the sprockets. I too found the number of shims remained the same.

But I am really struggling with cam timing on my 83 SC.

I found that putting the 2 case halves together without screwing something up is really hard. Everything else is easy.

Cleaning everything after disassembly is the worst.

Probably the single most difficult job of rebuild?...........







.....paying for it :D

Having unrecognizable parts drop into the catch tub the moment the halves split. I was called to help a guy who found seven 8mm ball bearings in the tub and had no idea where they came from.

I'm in agreement with you. Some engines are shamefully filthy. Not to mention over-use of sealant (or use of the wrong sealant like Permatex bloo RTV) makes things even worse. It also gets worse when you've had bearing failure!

Seeing what stupid damage motormeister did on a previous rebuild is the worst.

Fiddling with wrist pin clips is the biggest PITA to me, and usually results in puncture wounds, bleeding, swearing, and reaching for the extra clips I ordered.

Cleaning the grooves in the rocker shafts...all 24 of them...is mind-numbing.

Scrubbing & polishing the through-bolt bores and all of the other bosses & bores in the case of plaque and hardened sealant from the last build takes hours and uses up lots of handgun & rifle cleaning supplies.

Cleaning mating surfaces - nope, I discovered Roloc discs - life is good on this task now.

Re-seating the timing chains when they fall off the intermediate shaft sprockets before you have installed the cam sprockets - infuriating.

Fishing a Woodrfuff key out of the sealed block after it disappeared down the timing chain openings - without tearing the block apart again - brink of insanity (but I got it out after 3 days of fiddling!)

Agree that cleaning is the absolute worst. Cam sprocket alignment gave me the most trouble until I bought the Stomski tool, then it was a breeze.

DIY trick for under $20:

http://forums.pelicanparts.com/911-engine-rebuilding-forum/738419-specific-question-arp-head-studs-2-7-magnesium-case-insane-11.html#post7447215

Personally, the most difficult as in the greatest pita with my top-end and p/c replacement job was the cam timing. It took me awhile to get them to match... and I did the job a few times over because the back plate seals pooped out and KTL was nice enough to recommend I double-check them.

Add me to the list of those who found cleaning to be the toughest part. There's nothing particularly tricky about it, but it was the most labor-intensive and by far the messiest part of the project. A few of the other tasks were a little fiddly. Cam timing would've been easier if I installed all the rockers before attempting it. I did a practice cam-timing run prior to disassembly with all rockers in place, and nailed it on the first try on each side. Both sides were outside the window, probably due to chain wear.

Add me to the list on cleaning.....

My opinion of the most difficult part of a rebuild is CLEANING and KEEPING EVERYTHING CLEAN. I clean things, send them out and have to re-clean them upon return AGAIN.

Sure the piston pin circlips are a pain in my thumbs, but I can do them much more quickly than I can clean even simple parts. My final cleaning is with lint free wipes and alcohol until the wipes are cleaner than when pulled out of the package.

My experience is that DIRT is the enemy and can be the cause of premature wear and leaks. Then again I firmly believe that haste makes waste.

This is a very good point. Don't trust your parts that have been sent out for service/reconditioning to be suitably clean & ready reinstallation. Clean them again!

I had a set of rods rebuilt and neglected to take them apart and re-clean. When assembling one of the rods, I found the rod bolt felt "rough" when tightening. These rods are Pauter brand with bolts that thread into the rod body- no nuts. So you are tightening just the head.

Removed the offending bolt and found some grit around the shank of the bolt under the head. Leftover crud from the machine work. So I took all the rods and went thru them. Found more crud on others as well. Shame on me.