Posted by Orso
I am currently finishing a rebuild of my 365GT engine, and of course I have run into lots of interesting difficulties.
For start, could anyone confirm, hand on Bible, that it is indeed possible to get the Colombo engine oil tight? -Mine started leaking even before it had got any oil in the sump...
Looking forward to your useful, and useless, hints.
Forza!
Orso
365 2-cam rebuild
Re: 365 2-cam rebuild
Posted by Tom
Hi Orso,
Yes it is possible (in a relative sense), even without gobs of silicone! In fact, you want to use this stuff sparingly to keep it out of the rest of the engine. Where are you leaking?
Tom
Hi Orso,
Yes it is possible (in a relative sense), even without gobs of silicone! In fact, you want to use this stuff sparingly to keep it out of the rest of the engine. Where are you leaking?
Tom
Re: 365 2-cam rebuild
Posted by zac
I am currently rebuilding two 365 engines and have built many others in the past with a good level of success stoping oil leaks for the most part. did you remember the o-rings on the exposed rear main cap? how about new o-rings on the tube between the block and the front cover? a very thin coat of grey form-a-gasket on the pan,sump,front cover,and vale cover gaskets. permatex or hylomar also work great but look like junk when the engine is all painted silver. one last place that is a real pain is the o-ring at the top of the front cover that goes between the cam covers and the chain cover. I have found the cutting the ring at a 45 degree right on top and putting some silcone in the grove and at the two ends works good try to use black silicone here so that it can't be seen when your done. and like Tom said a little goes a long ways the one inch gob sticking out doesn't do any good and is probably going to end up in the oil system and eventually in the bearings. one last note loctite makes a thread sealer that you can put on the studs that stick out the bottem and any where else those little suckers act just like wicks and will leak.
good luck
p.s. and remember there are 12 qts in the thing so whats a little oil leak  
I am currently rebuilding two 365 engines and have built many others in the past with a good level of success stoping oil leaks for the most part. did you remember the o-rings on the exposed rear main cap? how about new o-rings on the tube between the block and the front cover? a very thin coat of grey form-a-gasket on the pan,sump,front cover,and vale cover gaskets. permatex or hylomar also work great but look like junk when the engine is all painted silver. one last place that is a real pain is the o-ring at the top of the front cover that goes between the cam covers and the chain cover. I have found the cutting the ring at a 45 degree right on top and putting some silcone in the grove and at the two ends works good try to use black silicone here so that it can't be seen when your done. and like Tom said a little goes a long ways the one inch gob sticking out doesn't do any good and is probably going to end up in the oil system and eventually in the bearings. one last note loctite makes a thread sealer that you can put on the studs that stick out the bottem and any where else those little suckers act just like wicks and will leak.
good luck
p.s. and remember there are 12 qts in the thing so whats a little oil leak  
Re: 365 2-cam rebuild
Posted by Tom
Hi Zac,
Good tips! The first time I saw a V-12 apart, I understood exactly why they have a tendancy to leak! Getting the o rings to stay in place when putting it all together is really a trick! Remembering all of them is one as well!
Tom  
Hi Zac,
Good tips! The first time I saw a V-12 apart, I understood exactly why they have a tendancy to leak! Getting the o rings to stay in place when putting it all together is really a trick! Remembering all of them is one as well!
Tom  
Re: 365 2-cam rebuild
Posted by Tom
Hi Zac,
Good tips! The first time I saw a V-12 apart, I understood exactly why they have a tendancy to leak! Getting the o rings to stay in place when putting it all together is really a trick! Remembering all of them is one as well!
Tom  
Hi Zac,
Good tips! The first time I saw a V-12 apart, I understood exactly why they have a tendancy to leak! Getting the o rings to stay in place when putting it all together is really a trick! Remembering all of them is one as well!
Tom  
Re: 365 2-cam rebuild
Posted by Orso
Hi zac and Tom,
thanks for your tips. I will start the engine tomorrow in my home-made test rig, crawl around hunting for leaks. Hopefully my efforts since the first test a month ago have improved things..
Then I had leaks at both ends of the valve covers, and at various other places, for instance:
The oil filter unit leaked at the joint to the timing chain cover. I removed it but could find no sign of where the oil had found its way out. There are two oil passages from the filter unit to the timing cover. One for return oil to the sump from the oil pressure reducing vavle, and one for oil supply to the bearings etc. In the first the pressure is zero, it is sealed by an O-ring. The second one has full oil pressure, but no O-ring seal, just the the paper gasket..
I have now machined a seat and fitted an O-ring to this one as well. Also I got rid of the paper gasket, and used Loctite 574 flange sealant instead. To compensate for the thickness of the paper gasket, the water connection tube had to be cut accordingly. I have good hope this will cure this particular leakage.
Will report more after the test.
Orso
Hi zac and Tom,
thanks for your tips. I will start the engine tomorrow in my home-made test rig, crawl around hunting for leaks. Hopefully my efforts since the first test a month ago have improved things..
Then I had leaks at both ends of the valve covers, and at various other places, for instance:
The oil filter unit leaked at the joint to the timing chain cover. I removed it but could find no sign of where the oil had found its way out. There are two oil passages from the filter unit to the timing cover. One for return oil to the sump from the oil pressure reducing vavle, and one for oil supply to the bearings etc. In the first the pressure is zero, it is sealed by an O-ring. The second one has full oil pressure, but no O-ring seal, just the the paper gasket..
I have now machined a seat and fitted an O-ring to this one as well. Also I got rid of the paper gasket, and used Loctite 574 flange sealant instead. To compensate for the thickness of the paper gasket, the water connection tube had to be cut accordingly. I have good hope this will cure this particular leakage.
Will report more after the test.
Orso
Re: 365 2-cam rebuild
Posted by Orso
Hi zac and Tom,
thanks for your tips. I will start the engine tomorrow in my home-made test rig, crawl around hunting for leaks. Hopefully my efforts since the first test a month ago have improved things..
Then I had leaks at both ends of the valve covers, and at various other places, for instance:
The oil filter unit leaked at the joint to the timing chain cover. I removed it but could find no sign of where the oil had found its way out. There are two oil passages from the filter unit to the timing cover. One for return oil to the sump from the oil pressure reducing vavle, and one for oil supply to the bearings etc. In the first the pressure is zero, it is sealed by an O-ring. The second one has full oil pressure, but no O-ring seal, just the the paper gasket..
I have now machined a seat and fitted an O-ring to this one as well. Also I got rid of the paper gasket, and used Loctite 574 flange sealant instead. To compensate for the thickness of the paper gasket, the water connection tube had to be cut accordingly. I have good hope this will cure this particular leakage.
Will report more after the test.
Orso
Hi zac and Tom,
thanks for your tips. I will start the engine tomorrow in my home-made test rig, crawl around hunting for leaks. Hopefully my efforts since the first test a month ago have improved things..
Then I had leaks at both ends of the valve covers, and at various other places, for instance:
The oil filter unit leaked at the joint to the timing chain cover. I removed it but could find no sign of where the oil had found its way out. There are two oil passages from the filter unit to the timing cover. One for return oil to the sump from the oil pressure reducing vavle, and one for oil supply to the bearings etc. In the first the pressure is zero, it is sealed by an O-ring. The second one has full oil pressure, but no O-ring seal, just the the paper gasket..
I have now machined a seat and fitted an O-ring to this one as well. Also I got rid of the paper gasket, and used Loctite 574 flange sealant instead. To compensate for the thickness of the paper gasket, the water connection tube had to be cut accordingly. I have good hope this will cure this particular leakage.
Will report more after the test.
Orso
Re: 365 2-cam rebuild
Posted by Orso
Wroom, the engine has been running for another 20-30 minutes. The modified joint for the oil filter unit was a success, and the front end of the cam covers were reasonable oil tight too.
Unfortunately, there are new problems. Oil is seeping out from the head gaskets (!), both of them, at both ends and most at the outside of the heads. This is of course impossible, since only return oil at zero pressure is passing through the head gaskets, except the oil supply for the camshafts, at the rear end. Nevertheless, it is a fact. If anyone can explain this, I will be very happy.
In fact, the first time I ran the engine, I did see some traces of oil at the rear outer edge of one head, but then it was uncertain where it had come from. Since then I have retightened the cylinder head nuts, and now the leakage has gone worse..
I have no water leaks from the cooling system, except a few drops from the water pump drain hole, which I hope is nothing to get worried about.
Looking forward to your expert advice...
Orso
Wroom, the engine has been running for another 20-30 minutes. The modified joint for the oil filter unit was a success, and the front end of the cam covers were reasonable oil tight too.
Unfortunately, there are new problems. Oil is seeping out from the head gaskets (!), both of them, at both ends and most at the outside of the heads. This is of course impossible, since only return oil at zero pressure is passing through the head gaskets, except the oil supply for the camshafts, at the rear end. Nevertheless, it is a fact. If anyone can explain this, I will be very happy.
In fact, the first time I ran the engine, I did see some traces of oil at the rear outer edge of one head, but then it was uncertain where it had come from. Since then I have retightened the cylinder head nuts, and now the leakage has gone worse..
I have no water leaks from the cooling system, except a few drops from the water pump drain hole, which I hope is nothing to get worried about.
Looking forward to your expert advice...
Orso
Re: 365 2-cam rebuild
Posted by Orso
Wroom, the engine has been running for another 20-30 minutes. The modified joint for the oil filter unit was a success, and the front end of the cam covers were reasonable oil tight too.
Unfortunately, there are new problems. Oil is seeping out from the head gaskets (!), both of them, at both ends and most at the outside of the heads. This is of course impossible, since only return oil at zero pressure is passing through the head gaskets, except the oil supply for the camshafts, at the rear end. Nevertheless, it is a fact. If anyone can explain this, I will be very happy.
In fact, the first time I ran the engine, I did see some traces of oil at the rear outer edge of one head, but then it was uncertain where it had come from. Since then I have retightened the cylinder head nuts, and now the leakage has gone worse..
I have no water leaks from the cooling system, except a few drops from the water pump drain hole, which I hope is nothing to get worried about.
Looking forward to your expert advice...
Orso
Wroom, the engine has been running for another 20-30 minutes. The modified joint for the oil filter unit was a success, and the front end of the cam covers were reasonable oil tight too.
Unfortunately, there are new problems. Oil is seeping out from the head gaskets (!), both of them, at both ends and most at the outside of the heads. This is of course impossible, since only return oil at zero pressure is passing through the head gaskets, except the oil supply for the camshafts, at the rear end. Nevertheless, it is a fact. If anyone can explain this, I will be very happy.
In fact, the first time I ran the engine, I did see some traces of oil at the rear outer edge of one head, but then it was uncertain where it had come from. Since then I have retightened the cylinder head nuts, and now the leakage has gone worse..
I have no water leaks from the cooling system, except a few drops from the water pump drain hole, which I hope is nothing to get worried about.
Looking forward to your expert advice...
Orso
Re: 365 2-cam rebuild
Posted by Orso
Wroom, the engine has been running for another 20-30 minutes. The modified joint for the oil filter unit was a success, and the front end of the cam covers were reasonable oil tight too.
Unfortunately, there are new problems. Oil is seeping out from the head gaskets (!), both of them, at both ends and most at the outside of the heads. This is of course impossible, since only return oil at zero pressure is passing through the head gaskets, except the oil supply for the camshafts, at the rear end. Nevertheless, it is a fact. If anyone can explain this, I will be very happy.
In fact, the first time I ran the engine, I did see some traces of oil at the rear outer edge of one head, but then it was uncertain where it had come from. Since then I have retightened the cylinder head nuts, and now the leakage has gone worse..
I have no water leaks from the cooling system, except a few drops from the water pump drain hole, which I hope is nothing to get worried about.
Looking forward to your expert advice...
Orso
Wroom, the engine has been running for another 20-30 minutes. The modified joint for the oil filter unit was a success, and the front end of the cam covers were reasonable oil tight too.
Unfortunately, there are new problems. Oil is seeping out from the head gaskets (!), both of them, at both ends and most at the outside of the heads. This is of course impossible, since only return oil at zero pressure is passing through the head gaskets, except the oil supply for the camshafts, at the rear end. Nevertheless, it is a fact. If anyone can explain this, I will be very happy.
In fact, the first time I ran the engine, I did see some traces of oil at the rear outer edge of one head, but then it was uncertain where it had come from. Since then I have retightened the cylinder head nuts, and now the leakage has gone worse..
I have no water leaks from the cooling system, except a few drops from the water pump drain hole, which I hope is nothing to get worried about.
Looking forward to your expert advice...
Orso
Re: 365 2-cam rebuild
Posted by Tom
Orso,
I've printed out you last post and will try to get you some answers by next week.
Tom
Orso,
I've printed out you last post and will try to get you some answers by next week.
Tom
Re: 365 2-cam rebuild
Posted by Tom
Orso,
I've printed out you last post and will try to get you some answers by next week.
Tom
Orso,
I've printed out you last post and will try to get you some answers by next week.
Tom
Re: 365 2-cam rebuild
Posted by Tom
Orso,
I've printed out you last post and will try to get you some answers by next week.
Tom
Orso,
I've printed out you last post and will try to get you some answers by next week.
Tom
Re: 365 2-cam rebuild
Posted by zac
well here goes my best explaination for your dilema. this is actually still a problem on a lot of modern european cars BMW and mercedes in particular. did you have the block and cylinder heads checked for flatness? I am looking right at my engine block and heads as we speak and the oil returns run along the bottem edge of the block furthest form the head studs so if the head is even slightly cupped that's were its going to leak and the more you tighten the more you torque on the studs the worse it gets. If it were my car I would make real certain that is indeed your leak and that it is not the cam covers leaking and flowing down on the head gaskets. otherwise once oil has saturated the head gasket it has been my experience that its time for a new one.
sorry for the $500.00 bummer
zac
well here goes my best explaination for your dilema. this is actually still a problem on a lot of modern european cars BMW and mercedes in particular. did you have the block and cylinder heads checked for flatness? I am looking right at my engine block and heads as we speak and the oil returns run along the bottem edge of the block furthest form the head studs so if the head is even slightly cupped that's were its going to leak and the more you tighten the more you torque on the studs the worse it gets. If it were my car I would make real certain that is indeed your leak and that it is not the cam covers leaking and flowing down on the head gaskets. otherwise once oil has saturated the head gasket it has been my experience that its time for a new one.
sorry for the $500.00 bummer
zac
Re: 365 2-cam rebuild
Posted by zac
well here goes my best explaination for your dilema. this is actually still a problem on a lot of modern european cars BMW and mercedes in particular. did you have the block and cylinder heads checked for flatness? I am looking right at my engine block and heads as we speak and the oil returns run along the bottem edge of the block furthest form the head studs so if the head is even slightly cupped that's were its going to leak and the more you tighten the more you torque on the studs the worse it gets. If it were my car I would make real certain that is indeed your leak and that it is not the cam covers leaking and flowing down on the head gaskets. otherwise once oil has saturated the head gasket it has been my experience that its time for a new one.
sorry for the $500.00 bummer
zac
well here goes my best explaination for your dilema. this is actually still a problem on a lot of modern european cars BMW and mercedes in particular. did you have the block and cylinder heads checked for flatness? I am looking right at my engine block and heads as we speak and the oil returns run along the bottem edge of the block furthest form the head studs so if the head is even slightly cupped that's were its going to leak and the more you tighten the more you torque on the studs the worse it gets. If it were my car I would make real certain that is indeed your leak and that it is not the cam covers leaking and flowing down on the head gaskets. otherwise once oil has saturated the head gasket it has been my experience that its time for a new one.
sorry for the $500.00 bummer
zac