TO Split or not to split

[adomakin]

dunno about the stud question but you might want to replace them with some new ones. problem is Rich, this is where it all starts. you bought an engine. you were JUST going to do the top end. you are now going to split the case 'while you are there' I would prepare yourself for a nice long drawn out project that may well end up being a more expensive but ultimately much more rewarding and a whole lot more reliable (and probably more powerfull!) than you first thought!

good luck

Andy

[emcon5]

Split the case. Replace the rod bolts with ARP/racewear. Replace the head studs with steel. Forget about it for a very long time.

Tom

[Wayne 962]

You're probably okay without splitting the case - just replace the rod bolts with ARP or RaceWare ones. If the studs are threaded all the way down, they are the later-style 993 ones, and should also be okay (these ones don't seem to break).

-Wayne

[Jim Richards]

Wayne, would you really buy an engine at a swap meet, without any documented history, and only rebuild the top end?

[Rich76_911s]

Again I appreciate all the input and opinions on this matter; I can't believe even the author of my favorite book got in on it. I'm not sure how this post got back up to the top of the list. After doing a little research, OK reading a couple chapters of Wayne's book and looking at the pictures, I came to the conclusion that I must have the 993 headstuds, non-magnetic, identical to the picture in the book, ect, one problem adverted! If I decided not to split the case how do you clean the mating surfaces where the cam housings, oil cooler, ect meet the case without getting debris into it? Still haven't made a 100% decision yet, but all opinions and advice has been noted.

Thanks,
Rich

[Superman]

I agonized over this decision also. And Wayne knows I have a tremendous respect for him in many ways. But I'm going to suggest splitting. The closer you get to the center, the simpler engines get. When you open the case halves, all you've got in there is a crank, and intermediate shaft with oil pump at one end, and a fistful of bearings. The bearings will probably be showing copper. So, minutes after splitting you'll be feeling justified in the decision. Measure everything.

Are you rebushing the wrist pin bores? If you don't split the case, and you don't rebush the wrist pin bores, you very likely could end up with an engine noise that is not dangerous, but you won't like it and you'll wonder what the noise is.

I did not have to scrape sealant. Don't have the crank "worked." Just measure it. You can be in and out of there very quickly, IMHO. If you do this, you're going to feel like you built a 250k mile engine.

[Wayne 962]

Originally posted by Jim Richards
Wayne, would you really buy an engine at a swap meet, without any documented history, and only rebuild the top end?

I didn't see the "swap meet" thing. Hmm, I thought this was a 65K documented engine. Might be best to go through the bottom end then, as you don't know what fools owned the engine in it's early life. At least take a close look at the rod bearings (you can remove and inspect the rods and bearings without undoing the bottom end). If they look perfect, then it might be safe to assume the rest of the bottom end is generally okay. These SC and Carrera motors are *very* durable on the bottom end, if they have been semi-well cared for.

-Wayne

[Wayne 962]

Originally posted by Rich76_911s
I can't believe even the author of my favorite book got in on it.

What, Tom Clancy's here in this forum?



I try to post answers to all the questions in this forum...

-Wayne

[Rich76_911s]

Well guys I decided to and exicuted the case split today. I've never seen the inside of an engine before pretty awesome. That said, I don't know what is supposed to be going on in there. I have what look like gouges from a single scrape of a screw or something in several places, and a couple small cracks on the inside of the case. The cracks don't go deep but you can feel and see them. What worried me the most is that there was about a dozen metal remanents at the bottom of the case near the oil pump screen. They look like what used to be on the case before those gouges took place. Is this normal and how could it have happened. I haven't seen anything that could presently do this damage. I have never forcfully turned the engine to the point were I think I could have done this damage. Right now my mind is spinning in 5th gear expecting the worst. It would make a good paper weight even in a hurricane though. I will try to post some photos tommorrow. Any information would be greatly appreciated.

Many Thanks and Happy Holidays
Rich

P.S. Clancy's books bring a couple hours of enjoyment, your books bring a lifetime supply. No competition!

[Wayne 962]

Add photos, and we'll give our opinion. I am confused though, as in a previous post, I thought you said you bought this engine at a swap meet, and you hadn't run it yet?

-Wayne

[Rich76_911s]

Wayne I appologize for the confusion. By turning it over I meant by hand. I found where all the metal pieces came from. The intermediate shaft drive gear has some fairly large pieces nocked off of it on the edge that is towards the flywheel. Here are the pictures that I promised sorry they are a little late. Enjoy your family's and the holidays everyone. I sure am glad I decided to split this case even if it is shot at least I didn't rebuild the top end to have a bottom end like this. There is a picture of the crack with a red arrow I am just pointing to where the crack continues into.

[Mr Beau]

Are you absolutely sure that is a crack? It looks like it might just be left over from the casting process, thus nothing to worry about.

[Rich76_911s]

NO way am I absolutely sure it is a crack, and if you are right Santa delivered me a present a day early. I really mean that I have never seen the inside of an engine before, and do not know what is normal wear and remanents of the casting process.

Rich

[cstreit]

That really looks like a casting remnant to me. I seriously doubt it's a crack... Looks raised, not recessed. Can you confirm?

First time I opened a 911 motor I was suprised at the amount of flashing and casting remnants that were on the case...

[Groovy911SC]

I split my 1980 911SC engine earlier this year. I have those "casting" marks in my case as well. My machinist said "no big deal". I did find metal in the oil pump sump screen, which was to be expected due to "spinning" the number 3 and 4 rod bearings. However, thay were flakes, not chunks.
Just as an FYI, I've spent 9 months rebuilding my engine. I've also collected a considerable number of specialty tools that were needed. With new JE Pistons and re-plated cylinders and all associated parts, I've spent around $6000.00. I could not be prouder of my work!

Competetion Engineering did my crank.... worth every penny!!!! I learned the hard way to not cut corners.... If you want to hear my sob story... just let me know!

[Wayne 962]

Looks sortof normal to me, but I would have someone knowledgeable inspect it...

-Wayne

[Rich76_911s]

Thanks for all your replies and opinions your help is greatly appreciated. Yeah the chuncks of metal are without a doubt parts of the intermediate drive gear, at least that is what I think it is called. What the heck would have caused that? First thought is a jumped chain or something. As a side note it is a 89 with the tensioner update. I am heading back to Philadelphia tuesday morning so work on the engine has come to an ubrupt halt. It is in Colorado at my parents house. Time to go back to work. I will certainly have everything checked out by someone professional. Probably in Pheonix, but I am not sure yet. Thanks again guys and I wish you all the best in the new year.
Rich

[Wayne 962]

Make sure you get a copy of the Engine Rebuild book, if you don't have it already...

-Wayne

[Rich76_911s]

Oh I have a very worn copy of the book. Probably should buy another copy. My reading comprehension is terrible. I've read most of the book probably 3 times. Inparticular the machinist chapter and the teardown chapter. Sorry if I am asking questions that are answered in the book.

[ChrisBennet]

I've seen the aluminum intermediate gears get chewed up by a jumped chain.
-Chris