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

http://forums.pelicanparts.com/uploa...1377467807.jpg



CIRCLIP INJECTOR™

m, http://forums.pelicanparts.com/uploa...1377467157.jpg

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.

P/C install: Easy, install piston to cylinder on bench. Install clip using circlip injector with or without studs in place. The injector makes that the easy, fool proof part.

Hardest/worst part? Fixing stuff other people have screwed up in the past.....

Circlips are the worst! I have a factory tool for installing 964 circlips but for the other motors I have to do it the hard way.

I don't do it enough to get good at it. Every time I do circlips, I know that I figured it out the "trick" on the previous motor but I'm just senile enough that I can never remember *how* so I have to relearn the trick all over again.

When you remember/figure the trick for getting JE circlips out be sure to let me know.

Cleaning, followed by a couple of the rocker bolts (1 and 4 if I recall) I used a hemostat to put the wrist pin clips in. If you grab them in just the right spot, the tips fit into the notches in the piston and they slide right in. Not sure if all pistons have those notches though.

Get a circlip injector!!! Easy!!!! A couple of seconds to install each one. Saves you the trip to the ER for stiches like I did a few years ago.... (you can search for the pictures)

Chris, good see you back on the forums!

Getting them in with the injector is indeed a piece of cake. Getting them out is a study in frustration. Good tool to have is a STRONG pointy pick and some needle nose pliers

That said, I really don't understand why these clips can't be the internal retaining ring type that you can easily removing with retaining ring plies?

ID circlips have those little extra tabs which have mass.
If the clips are in the wrong position...as the piston goes up and down the weight of the tabs loosens the clip in the groove and lets the circlip fall out.
I prefer Spiralocks myself...yes they are a total B**ch to get in and out...but I have never had one pop out at the wrong time (even in an engine blow up).
Bob

Ah ha. Makes sense that at very high speeds the weight of those ID tabs can cause the circlip to flex. Thanks for satisfying my desire to have ID clips in my pistons Bob!

I removed one of the JE clips using a screw driver that I ground down (only had to take one out to go back a step in the assembly). The pick tools would flex and slip no matter how hard I pressed... I tried a half dozen before deciding I needed more lever due to the strength of the clip. I wonder if the JE techs have a tool or recommendation.

as others said, that cam sprocket alignment is really annoying. I also did not like the cam timing. I got mine right but I never really felt comfortable with the process.

circlips are the worst. Cleaning sucks a strong second.
Before I buy the circlip injector will someone confirm that it gets in the wrist pin hole with the cylinders over the studs? Cause they way im doin it now either results in blood in my motors or the need for a ton of extra clips. Ping!! there goes another one. gettin sick of that.

Scott - the home made circlip injector from Home Depot motorsports works perfectly over the deck. Makes the job a matter of seconds as they clip straight in. Link above... under $20.

Awesome. ill give that a try.

Installing piston circlips.......
 

I figured out a way to install the second clip when adding the piston/cylinder assembly to the block. Using some small gauge wire, I place a small screwdriver blade against the bottom of the circlip opening. Then, I engage the top side of the clip into the slot holding it in place with the index finger on my right hand and then use a second flat bladed screwdriver to slide the opposite side of the clip up the flat edge of the first screwdriver, using it as an inclined plane. This causes the clip to compress evenly and snap into place in the piston. Last step is to make certain that the clip is properly seated all the way around. The screwdriver that is used to push the clip into place has a small notch ground into the blade so that it won't slip off the clip and draw blood!

http://forums.pelicanparts.com/uploa...1377790527.jpg

http://forums.pelicanparts.com/uploa...1377790625.jpg

Actually, I had purchased a circlip injector tool from PP for this build, but it turned out that the Mahle pistons I had required 23mm pins instead of the 22mm ones. The 22mm tool will not work with the 23mm clips! I probably could have returned it for the other size, but the next engine just might need the 22mm one.

I too used the homemade circlip injector that I learned from Ed Hughes over on Rennlist. It is very easy then.

In terms of the job I found hardest, I would say it was assembling the case halves. Nothing specific about it was that hard, but it is a very time bound operation and you need to be really organized. There are many ways to make mistakes and you don't have a lot of time to "think" once you are on the sealant clock.

Everything else in an engine build can move as slowly as one needs/desires so you have the luxury of checking, pondering, re-checking and then re-checking again!

Cleaning was the least fun part.

+1 on CLEAN-UP.

I don't remember the circlip being that bad, have only done it once.
I grabbed one end of the circlip with pliers and engaged the other end in the grove and twisted it in pushing with a finger on it. If it slipped my finger would catch it.

Magnus, I'll bet you're talking about stock circlips. The JE clips are about twice the strength as a stock clip and far more difficult to install because they do not want to bend. Personally I don't think there's anything all that difficult with a 911 assembly; pretty standard fair. Cleaning the parts to what is deemed appropriate is the most time spent and a lot of it is over-kill. Clean is clean but making a part that you will never see again look new is over the top. I really like over the top.

Finding time to do the work. haha