Engine rebuild - Leaky case already?

[WydRyd]

Hi Gang,

It's now been 1200km's since my engine rebuild and it seems the cases are leaking oil already

What can cause this? Incorrect torquing of case nuts?

I have been driving this thing at under 4Krpm's religiously and the engine hasn't seen ANY load at all.

How can the case already be leaking oil?!?!

Can this be attributed to poor/dodgey workmanship?

[Rot 911]

Where is the case leaking? Seam, cam towers? If it is the seam, probably bad job cleaning the cases and incorrect application of case sealer.

[WydRyd]

Small leaks at the front and rear of the engine. I don't have the car in front of me as a mate is doin the service for me. Will ask him to get some snaps. He did say that it should be squeaky clean considering it was a ground up rebuild! He said in order for them to be fixed properly, the case would need to be split AGAIN!!! WTF???

[Wayne 962]

Did you follow all the cleaning and application (of 574) procedures in the Engine Rebuild Book?

-Wayne

[WydRyd]

Wayne, I didn't rebuild the engine, I had a professional Porsche engine building workshop do it.

[Jim Richards]

Originally posted by WydRyd
Small leaks at the front and rear of the engine.

Crankshaft pulley and flywheel seals?

[Shuie]

Did you get a warranty? Bring it back to the shop and ask them to take a look at it.

[garibaldi]

ground up rebuild, or did they just take the motor apart and do a high priced oil change?

What was done?

[Wayne 962]

Originally posted by WydRyd
Wayne, I didn't rebuild the engine, I had a professional Porsche engine building workshop do it.

That's too bad. Every 911 Engine Rebuilder should guarantee their work against oil leaks. If they don't, it's a sign that a lot of their engines leak, and you should go elsewhere.

This sounds like shoddy assembly, or more appropriately, shoddy cleaning. With some notable exceptions, most shops don't spend the time cleaning the parts and cases as well as they need to be cleaned. If you do it yourself, you are guaranteed that it will be "surgically clean." Budget about 20-30 hours to fully clean the case from top to bottom...

-Wayne

[WydRyd]

Well, this is what's been done:-

Split engine case
Upgrade to 964 Piston Squirters
Linish/balance crank
New bearings & bushings
Resize conrods
930 P&C's
0.5mm base cyliner shim
0.5mm C2T head gaskets
Machine barrels down to maintain 7.0:1 C/R
New 930 Rings
GT2-EVO CAMs
ARP Rod bolts
ARP head studs
Sodium filled valve guides
Titanium retainers
Turbo racing valve springs
PhosBr Valve Guides
Twin plug prep heads and rocker covers
New timing chains and chain guids
Re-assemble engine

I'm taking pictures of the leaks and will request that they be fixed at their cost, not mine. I'm not paying a cent more to fix this

[DonE]

20-30 hours to clean my case? Yow.... I am rebuilding my 930 and will take all the parts possible to a local shop for an ultrasound cleaning. I am told this will clean it extremely well. Do you think there will need to be additional cleaning done?

[garibaldi]

You need to have every oil gallery plug pulled from the case, and have the piston squirters removed, and pull the plugs from the crank, and the spray bars from the cam housing, etc and run brushes through the passages if you really want to get it clean, anything less than that then your playing with yourself, if you are going to do it , than do it right.

[cstreit]

Wayne,

None of the shops in the around here will guarantee no leaks after a rebuild (or so I've heard)... Maybe not right, but it all depends. I think they should if given complete control over the rebuild process, but(!) if a customer doesn't want to pay for a machine shop to measure everything, how could you guarantee anything? (In which case I would more than likely tell them to take it somewhere else.)

Christian,

Do you really feel that this level of cleaning is necessary? (As opposed to a good solvent dip/utrasonic cleaning.) Why? Is there that much sludge or dirt accumulation?

[garibaldi]

I dont risk not going that far, the motor is at risk if you are not sure if everything is out of it. Most engines I see, never have the plugs pulled from the case or all passages opened up so they can be flushed. Every motor I do has every plug pulled and passage scrubbed out, I could care less how much longer it takes, or how much it adds to the cost, at least I know that its all clean.

Here is a shot of the guts of a piston squirter from a 911 case that was just brought into me to machine, that already had all of the "machine work" and assembly done by another shop, and they had "thoroughly cleaned" the case.

[Wayne 962]

Originally posted by garibaldi
You need to have every oil gallery plug pulled from the case, and have the piston squirters removed, and pull the plugs from the crank, and the spray bars from the cam housing, etc and run brushes through the passages if you really want to get it clean, anything less than that then your playing with yourself, if you are going to do it , than do it right.

That's good in general, but a bit extreme in practice. I'm not saying it's not the right thing to do, but for most rebuilds (stock rebuilds, where the engine just wore out), it's unlikely that you'll need to remove the plugs on the crank and the case. I'd also be concerned with the reinstallation of the plugs in the crankshaft - if not done properly, then they can fall out (disaster).

-Wayne

[Wayne 962]

Originally posted by cstreit
None of the shops in the around here will guarantee no leaks after a rebuild (or so I've heard)... Maybe not right, but it all depends. I think they should if given complete control over the rebuild process, but(!) if a customer doesn't want to pay for a machine shop to measure everything, how could you guarantee anything? (In which case I would more than likely tell them to take it somewhere else.)

Tom Woodford (1-760-731-7535 - by appointment only) will guarantee no leaks, if you bring him the car. He will pull the engine and do everything *his* way and then reassemble, put the engine back in the car, drive it 500-1000 miles and break it in for you. When he hands you the keys back, the car is ready for redline at the track, and doesn't have any oil leaks. This is probably the best way to get your engine rebuilt, both for the customer and the shop.

-Wayne

[Shuie]

What kind of shops have an ultrasonic cleaning device large enough to fit an engine case in?

[viejopatron]

Soon I will be assembling a 3.0 case. The engine was stock and, aside from 3 broken cylinder studs (Dilivars on Exh-side), the mill was very clean on the inside.

To date, I have used scrapers, Scotchbrite and Crocus cloth to prepare all joining surfaces, ad Nauseum. Reading this thread, I'll keep wiping the surfaces plus confirm function on all squirters (Christian - your photo was convincing), plus flushing passages. I do not plan on disassembling any pressed joints unless absolutely necessary. Unless there's evidence of leakage, I won't touch them except maybe epoxy potting.

[garibaldi]

With all due respect, and I truly mean that- Pulling the plugs from the crank and case is not extreme in practice, it shoudl be standard practice. the only reason why it is deemed extreme is because most of the people out there doing engine rebuilds for $1.99 in two days are too lazy to do the detail work like that, they cut corners, and save time and money, so the "industry standard" has been brought to a level of **** by most places since everyone wants to cut corners and save money and not necessarily do it right. It all sounds good until the money comes into play and then people start backing out So little details like cleaning out the main oil galleries get passed over. They will pay to have the valve covers glass beaded, or the exterior of the case scrubbed, or the fan polished and all the sheet metal painted, but pull out main plugs, and pull all of the crud out of the passages that supply the most critical thing to the motor, nah- dont bother with that. People need to start being educated on how crucial these types of things are. Most of the people I hear talking about the engine rebuilds sure talk alot about how cool this looks, or how trick that is, and the pics they post are of a nicely painted engine looking all pretty- but I hardly ever see any pictures or details of what was done on the build. No hard numbers on ring gaps, main housing sizes and roundness, bearing clearances, REAL- not advertised compression ratios, valve clearances, etc- but everyone gets a hard on for a freshly polished case- which does absolutely nothing for the performance, and never mentions a thing about the hard facts of what was done on the build of the engine.

Im not trying to sound like an ass, and apologize if I do, I just get frustrated that there seems to be a huge gap in the awareness of most people that are trying to get work done on these cars, and are gettign taken to the cleaners simply becasue they do not know any better, and the title of this thread is evidence of that.

In all reality, to pull the gallery plugs out, clean the passages, and make new plugs and drive them in is no big moment, same goes for the crank, if the builder knows how to size the plugs, there is no reason they shoudl fall out, theres only what 90 psi roughly tops of oil pressure running through the motor at worst case, so if the interference is correct, those plugs shoudlnt move. Maybe its better that you leave the plug in, since the same guy that woudl think a high mileage motor doesnt need to have its case flushed out, with all the cooked up crap inside all the passages, woudl probably be the same guy who woudl nt know the correct way to size a plug back into the oil passage of a crankshaft- in other words, in either case, they are lacking competence.

i cant begin to tell you what kind of crap I have gotten out of the oil passages in motors. Maybe you get lucky and pull the plugs and they are relatively clean, but I think its better to know for sure rather than not and wonder why the bearing are shot so soon, why the cam lobes are wittled down to nothing along with the rockers, why the oil pressure is low, etc. But look how good the fan shroud came out!

I just dont think that it is smart to skimp on crucial stuff that can come back and bite you in the ass later no matter what kind of motor it is or what its intended use is.

[Wayne 962]

Originally posted by garibaldi

Im not trying to sound like an ass, and apologize if I do, I just get frustrated that there seems to be a huge gap in the awareness of most people that are trying to get work done on these cars, and are gettign taken to the cleaners simply becasue they do not know any better, and the title of this thread is evidence of that.

I hear you! It's really annoying to hear from some yahoos out there who tell me that my book is too conservative, and that you don't need to replace this, or don't need to clean that to get it right. Some yahoo on Amazon's reviews wrote that - he obviously doesn't know what he's talking about. Frustrates the heck out of me.

Perhaps John or Steve would like to weigh in on the case / crank plugs issue? Christian, perhaps you can post a pic or two of the crap that comes out of the plugs too? You might win more converts that way.

I'm not against pulling the plugs, but I have heard of them falling out when they weren't properly reinstalled!

-Wayne