964 Rebuild, let the fun begin...
11-29-2011, 12:02 AM
#32
Rennlist Member
Thread Starter
So after todays teardown and unable to find the source of a significant leak coming from anywhere on the case my father-in-law suggested that we leave the case alone and not split it. Just replace all the gaskets in the valves and timing chain covers and give the engine a good clening. He does not think resealing the case is going to yield any significant reduction in oil leaks and if anything, may result in more. I thought maybe the best thing would be for a total rebuild, but am now starting to agree with him. If I can reduce the oil leaks to about 90%, then I could live with a little oil sweat, any thoughts?
11-29-2011, 12:25 AM
#34
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Thread Starter
80k miles on the motor, but car did sit for about a year before I bought it 2/3 years ago. Florida car for most its life until i brought it to Canada. Went though two summers and one winter before I put away again from November 2010 to September 2011 when I decided to get the leak looked at.
11-29-2011, 06:20 AM
#35
The stupid thing with situations like this is that when opening things up all is well.....when deciding not to bother things start leaking as soon as the engine is assembled again;-)
More serious: ask yourself whether potentially having to perform the task of removing the engine again at some future stage to delve deeper into the engine is OK with you without loosing any sleep over it.
If the answer is that you want to be done with it once and for all, I'd dive deeper into the engine....going this route also be prepared to replace bearings and have the crank polished....the slippery slope begins:-)
More serious: ask yourself whether potentially having to perform the task of removing the engine again at some future stage to delve deeper into the engine is OK with you without loosing any sleep over it.
If the answer is that you want to be done with it once and for all, I'd dive deeper into the engine....going this route also be prepared to replace bearings and have the crank polished....the slippery slope begins:-)
11-29-2011, 09:03 AM
#36
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Given what I've read at 80k you ought not *need* to go deeper into the motor from the perspective of wear. Pulling it apart and resealing it seems like enough of a PITA and there's enough stuff that you really ought to address while it's apart that I wouldn't want to go there unless I had some overarching need to do so.
$0.02
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11-29-2011, 10:37 AM
#37
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I need to do the same thing to mine. Most of my leaks are now at the through bolts for the case. I would like to replace the seals there but the cylinders have to be removed to replace those seals.
11-29-2011, 02:23 PM
#38
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I second yellowducman's flag on through bolt seals. In another thread somewhere on this site a mechanic said that early Porsche's had problems with sticking thermostats. This led to overheating which led to leaking seals and cylinder heads. The through bolts are a common problem.
Did you do a leak down test prior to tear down? I have both oil leaks and a couple of cylinders down on the leak test. I'm considering dropping the engine to fix the oil leaks, but am also considering pulling the heads and cylinders for a valve job and installation of O-rings. At this point the through bolt seals can be replaced.
Adds more $$$ and time, but you'll cover all the bases.
Did you do a leak down test prior to tear down? I have both oil leaks and a couple of cylinders down on the leak test. I'm considering dropping the engine to fix the oil leaks, but am also considering pulling the heads and cylinders for a valve job and installation of O-rings. At this point the through bolt seals can be replaced.
Adds more $$$ and time, but you'll cover all the bases.
11-29-2011, 04:06 PM
#39
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Thread Starter
The stupid thing with situations like this is that when opening things up all is well.....when deciding not to bother things start leaking as soon as the engine is assembled again;-)
More serious: ask yourself whether potentially having to perform the task of removing the engine again at some future stage to delve deeper into the engine is OK with you without loosing any sleep over it.
If the answer is that you want to be done with it once and for all, I'd dive deeper into the engine....going this route also be prepared to replace bearings and have the crank polished....the slippery slope begins:-)
More serious: ask yourself whether potentially having to perform the task of removing the engine again at some future stage to delve deeper into the engine is OK with you without loosing any sleep over it.
If the answer is that you want to be done with it once and for all, I'd dive deeper into the engine....going this route also be prepared to replace bearings and have the crank polished....the slippery slope begins:-)
Did you do a leak down test prior to tear down? I have both oil leaks and a couple of cylinders down on the leak test. I'm considering dropping the engine to fix the oil leaks, but am also considering pulling the heads and cylinders for a valve job and installation of O-rings. At this point the through bolt seals can be replaced.
Adds more $$$ and time, but you'll cover all the bases.
Adds more $$$ and time, but you'll cover all the bases.
11-30-2011, 11:53 AM
#40
Very clear what to do in an ideal world. Being pragmatic on the positive side of stupid is the actual challenge that is to be faced given the time and budget constraints you're now facing.
Since you already went in this deep, I personally would press on and spend a little extra time to split the case. Set yourself a hard max $200,- contingency budget to cover potential urgent situations uncovered.
This means leaving the bearings as they are, be very clean and methodical as to mark their positions. They should be good up to 150K anyway.
Focus on properly sealing all mating faces / threads, and check/optimize things as much as you can along the route without just throwing a buch of new components at it. I think this way gives added piece of mind, as well as a much more secure upside on an already hefty investment of time.
Since you already went in this deep, I personally would press on and spend a little extra time to split the case. Set yourself a hard max $200,- contingency budget to cover potential urgent situations uncovered.
This means leaving the bearings as they are, be very clean and methodical as to mark their positions. They should be good up to 150K anyway.
Focus on properly sealing all mating faces / threads, and check/optimize things as much as you can along the route without just throwing a buch of new components at it. I think this way gives added piece of mind, as well as a much more secure upside on an already hefty investment of time.
11-30-2011, 10:13 PM
#42
Regular leaks
I doubt very much that your case is cracked. If the case was cracked, you would have a gusher while its running. It could be a through bolt, or case seam seepage, but it really looks like years accumumulation of the usuall suspects. If the beather hose cracks or comes off, it leaks pretty bad. Any leaks up there are usually slow, but they all blow all over the place.
You have to take the cam sprocket off to get to the likely leaks at the back of the cam tower/chain box. I personally would be in no hurry to split the case. Definately replace front and rear crank seals, I/M Shaft O-ring, chain box, gaskets and seals, tensioner gaskets and o-rings, distributer o-ring, breather gaskets, oil return tubes, and o-rings, valve cover gasket. Go with Viton seals whenever you can.
At 80k if the clutch, pressure plate, and bearings are original, you can't go wrong replacing them. I would just scuff up the old flywheel, and reuse it as long as it is the later Dual Mass. It all depends on your budget, and what you want to do with the car.
I know the feeling of piles of parts, and wondering if I'll ever figure out where it all goes. Its actually pretty intuitive on how it goes back together. The are plenty of picturers out there. Adrian's book has alot of great information, but misses some detail.
Good luck!
You have to take the cam sprocket off to get to the likely leaks at the back of the cam tower/chain box. I personally would be in no hurry to split the case. Definately replace front and rear crank seals, I/M Shaft O-ring, chain box, gaskets and seals, tensioner gaskets and o-rings, distributer o-ring, breather gaskets, oil return tubes, and o-rings, valve cover gasket. Go with Viton seals whenever you can.
At 80k if the clutch, pressure plate, and bearings are original, you can't go wrong replacing them. I would just scuff up the old flywheel, and reuse it as long as it is the later Dual Mass. It all depends on your budget, and what you want to do with the car.
I know the feeling of piles of parts, and wondering if I'll ever figure out where it all goes. Its actually pretty intuitive on how it goes back together. The are plenty of picturers out there. Adrian's book has alot of great information, but misses some detail.
Good luck!
80k miles on the motor, but car did sit for about a year before I bought it 2/3 years ago. Florida car for most its life until i brought it to Canada. Went though two summers and one winter before I put away again from November 2010 to September 2011 when I decided to get the leak looked at.
12-01-2011, 05:54 PM
#43
If you have the top end stripped down please do yourself a favour and get the through bolt seals replaced, they will be hard as **** and if they are not leaking now they soon will be.
12-01-2011, 11:15 PM
#45
Yup Yup
Everything but split the case. By that point you are in real deep, I'd split it to at least get a look at the mains and IM shaft bearings. Like some else said, clean it up, and be looking to reinstall the bearings.
A leakdown test would be a real helpfull tool.
A leakdown test would be a real helpfull tool.