Align Bore or Not?

[jjemg]

I getting ready to get my 914/6 going and wanted to go through the engine to check it all out. It is a 2.0 T. I am hoping someone here that done this a few times can look at the pics and can tell if this is necessary to have the case halves trimmed and align bored or if this will be OK. I will not put more than 1 or 2K a year on this car.. Int bearings and Thrust is the only ones showing copper.

Also I will be using pressure tensioner. Do I need to up the pump to SC or will the original do. I am afraid that the bigger pump will make the oil tank puke all over the fresh paint. Any thoughts?

Anything else that I might be missing? Any Help will be great!

[Flieger]

Most people find that once the Magnesium cases are un-bolted, they relax and must then be align-bored before reassembly. Have you done any measurements?

[cgarr]

You might get lucky since its a rather low hp motor, the 2.7 or hotter running engines no so much luck but check it out then you will know.

[Evans, Marv]

If it were me, and since you have the case split, for sure I'd take it to a machinist who knows what he's doing and have it checked. If it needs align boring, have it done. If the cylinder spigots need machining, have that done too. Maybe have some oil squirters installed. Your engine will thank you. When you reassemble it, you might weigh the pistons & rods and put them in to match for opposing weight as best you can to tune the balance. Sounds like you plan to keep it a long time, so why not spend a few bucks and do it right.

[jjemg]

Max
I have not done any measuring. Just took it apart this morning and trying to decide if I need to send it off. I took it apart and bolted the case halves up as quick as I could for that reason. Don't know if that helped or not?
That's what I was thinking Craig that the low HP might make it OK
Don't have any inside mics. That's one reason I was hitting you guys up.
I guess I will just get it done .I am on a limited budget and the machine work will kill me but I do want it right.
Any suggestions on who does great work on these engines at a great price?
I will need case halves ,heads, crank, and rods done
Ollie's is the only one that I am aware of.

[Zeke]

No way to tell by looking. You could get the new bearings, polish the crank and assemble only the crank and see how it spins. If it's bound, it will tell you and you can then shave the cases and do the align bore. You can check your clearances this way as well using plastigauge, but you can't do both at the same time. The plastigauge can't be turned. Check your rod bearing clearance when you check your crank. Use the old bolts when checking. Install new ones at final ass'y.

Get Wayne's book.

[tom1394racing]

I check these by first measuring the case bores with a dial bore gage. If they are within spec, I then take a straight, standard crank with a new set of main bearings, install the crank, torque down the case through bolts and see how the crank spins. If the crank spins freely and evenly, the line bore is good. If the crank won't spin or binds during rotation, the case needs to be resized.

[jjemg]

Tom, This is the engine that I got the pistons for. I think I will send it off to get pistons squirters and just check it all out since it is number matching.Do you know many machine shops that do really nice work on 911 engines that might be a little cheaper than Ollie's?

[T77911S]

look for pitting on the case where the #8 nose bearing sits. if it is pitted. it will leak oil.

[AlfonsoR]

Originally Posted by jjemg

Tom, This is the engine that I got the pistons for. I think I will send it off to get pistons squirters and just check it all out since it is number matching.Do you know many machine shops that do really nice work on 911 engines that might be a little cheaper than Ollie's?

Decisions are easy to make when a clearance is out of spec or when the crank just won't turn as Tom suggests, but when measurements are close or there is a certain feel that you look for, then that's where experience really comes into play. I understand trying to save money, but be careful what shop you take your case to. Align boring is a very critical procedure, just as any engine machining procedure is. You want someone that has good experience...maybe the best experience. Remember, this is the foundation of any engine. It's got to be right.

[Superman]

Originally Posted by Evans, Marv

If it were me, and since you have the case split, for sure I'd take it to a machinist who knows what he's doing and have it checked. If it needs align boring, have it done. If the cylinder spigots need machining, have that done too. Maybe have some oil squirters installed. Your engine will thank you. When you reassemble it, you might weigh the pistons & rods and put them in to match for opposing weight as best you can to tune the balance. Sounds like you plan to keep it a long time, so why not spend a few bucks and do it right.

Exactly.

[RoninLB]

"Competition Engineering - Expert Porsche machining for 45 years"


E-mail:
compeng-dsl@verizon.net



I used this shop for everything 10 years ago

Walt will talk you out of services you don't need for your use of engine and tell you things you should have as well as Steve Weiner from Rennsport. If you need parts for your home rebuild and others can suppy it cheaper he'll steer you there. Both are great

[RWebb]

a 2L is not in the same boat as a high powered 2.7L motor, BUT why not spend a little more now to avoid the risk?

[Peter Zimmermann]

Engine Machine Service, (310) 641-7019, Inglewood, CA. Truly exceptional work, give Bill and Dick a call, they will gladly fax you a price list. Of course, they can do everything that you need done.