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Discussion Starter · #21 ·
..ok if I go that route Pete what do I need to remove below the car to remove the engine . Only the propshaft /flywheel bolts and the flywheel housing stud?
 

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If you enjoy rolling around on the floor the sump will come off quite easily with the engine in the car. Pete can speak for himself but I really don't understand why you wouldn't replace the rings at this stage. To me that would seem like a terrible short cut not to.
I have been in hotel quarantine for two weeks, the box I have been in is my hotel room. I get out tonight.
 

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Well the last engine I did, a motorcycle and admittedly I did not have a proper ball hone, I feel the rings never bedded in properly. And I'm also trying to limit the "while there, lets just replace everything" expense.

To me if you are going to replace the rings, rip the engine out and strip it and do a full rebuild. In this case there was nothing wrong with the bottom end, until the crankshaft was rotated with the liners not held ... I'm trying to get the PO back to that stage (but by installing the o-rings properly)

I understand not having the funds for an Alfa, i.e. family, etc. ... to purchase new rings and get somebody to prepare the liners would probably be, what?, a $500+ job ... AND I would still remove the pistons and install them the normal way. I cannot imagine trying to get an engine builder I have never worked with before to understand the tapering at the bottom so I can save 1 hours work of not having to remove the sump and undo the con rod bolts.

You don't worry about time working on Alfas, if it is going to take 40 hours to remove a sump, that is what it will take ... now at a race track with experienced mechanics like alfettaparts2, miracles can happen, but they don't in my shed. I've learnt to just suck it up, and once done I will get over it (or sell the car, like I did with the 156v6)
Pete
 

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All good points Pete. To be honest I know I could be a little more humble in my assessment of other peoples issues.
If I was in this situation I would have the car on the hoist, sump off in no time. I have had enough of rolling around on the floor so without a hoist swapping out the liners appeals to me.
This far into the job the OP already has his hands full and pockets empty. Would be a shame to put everything back together for a crappy result. Might just be because I never done it before but I wouldn't pull a liner and not do a ring job with all this effort. Because I say something doesn't make it so (slaps myself on the back of the head).
 

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The O-rings are made of Buna. Any movement of a liner in an engine that has been run for some years destroys them. If a liner has moved it will leak coolant- period. Been there and done that to many times. Most times in an original motor the O-ring cracks when disturbed.

Putting them on by rolling them down the liner would make me very nervous about stretching them beyond there ability to return to there original size.

For a 3.0 liter I have had some success using 1.5mm x 96mm O-rings for the 99mm diameter liner skirt. I have no notes on the 2.5 liter though, but a guess would be 3 mm smaller than the liner skirt. To be clear, that's a guess.

Greg
 
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Discussion Starter · #27 ·
Ok I guess you guys are right ..I'm sure my rings are ok because I did a compression test before stripping the engine and it reads 170psi on average but the thought of the o ring leaking due to a shortcut just doesn't make sense. I just need some confirmation from fellow alfistis to wake up and do things the right way. I will try to roll on the floor as a hoist looks unlikely and report further.
 

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..ok if I go that route Pete what do I need to remove below the car to remove the engine . Only the propshaft /flywheel bolts and the flywheel housing stud?
To answer your question it would be exhaust off, gear linkage off, tail shaft out. A lazy morning rolling around on the floor.
 

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Discussion Starter · #29 ·
Ok first piston and liner out .open sump and release conrod bolt and pull out ..piston and sleeve looks new ..will measure later ..the replacement ring is also too loose. .bought from eb spares uk. But the old one looks smaller ..so originally supplied like stretch ..not because I put it over the liner as I initially described .. just info for those who do it again ..check the o ring sizes
 

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Discussion Starter · #30 ·
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original old o ring fits right


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Eb spares new o ring

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My o ring shop seal 1.5 mm thickness but too big so going to get it changed.
 

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Discussion Starter · #32 ·
Hi gregsef

Can I know when you said you had some success with the 1.5mm thickness o ring does it mean you fitted them and it's ok ..because I noticed the 1.5 mm o ring doesn't sit properly in the groove section of the liner although I changed to one that can be tight
 

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Has it been mentioned here that this could have been avoided if the DS had used the proper liner hold-down tools? They are easily made with PVC pipe and large flat washers.
 

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Hi gregsef

Can I know when you said you had some success with the 1.5mm thickness o ring does it mean you fitted them and it's ok ..because I noticed the 1.5 mm o ring doesn't sit properly in the groove section of the liner although I changed to one that can be tight
The O-ring should not be loose on the liner skirt. perhaps the o-rings you bought are the ones for the 3.0 liter liners? I purchased mine from McMaster Carr. My notes from the 3.0 say the liner bore is 93mm and the liner skirt is 99mm. My notes say I used a 96mm o-ring. So the skirt wall should be 6mm or 3 a side. Measure your liner skirt. If it follows the same idea as the 3.0 the bore is 88mm and the skirt OD should be 6mm more, so that's 94mm. Metric O-rings are sized by their OD. So looking at McMasters website, a 93mm or 88mm OD would be the ones available (90 to 85mm ID). A range of sizes around the ID of 91 to 88 would work. The way I do it is to very lightly oil or grease the skirt OD up and work the O-ring on, making sure I don't get it twisted up. I don't use any sealers. I might if the blocks sealing surface is wasted, but you would be surprised on how bad the block can look and still seal.

This has worked for me but as with everything you need to verify it on your own.

But, next time, as soon as the head comes off, install the hold downs.

Greg
 

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Discussion Starter · #37 ·
Hi gregsef
The o rings I bought are for a 2.5 overhaul gasket set and I did measure the Liner skirt and it's a 94mm. The shops here don't sell the same thickness o ring but they do sell a 93 mm od x 1.5 mm thickness nbr o ring which seems to sit a little off the o ring groove on the liner skirt .manually measuring the o ring gives an indicative thickness of 1mm for the original or (eb spares) o ring and 1.2 or 1.3 for the 1.5 mm o ring which is why im asking whether this thickness can work since you did mentioned that you had some success using it .

I was surprised the so called
original o rings from the overhaul gasket set was so loose but the thickness is similar to the old existing one .

I was also worried about a thicker o ring affecting the liner height which will in turn affect the cylinder head gasket or am I being overly concern for nothing . It looks negligible but then all engineering specs look negligible if you know what I mean. ..

Please let me know .thanks
 

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Discussion Starter · #38 ·
Has it been mentioned here that this could have been avoided if the DS had used the proper liner hold-down tools? They are easily made with PVC pipe and large flat washers.
Ya noted ..I was surprised the liner came out so easily but then looking at the good condition of the head and linera I should have expected it ..

I did an overhaul of my alfa spider 105 some time ago and the liners were dead stuck requiring me to knock them out with some force so I never thought the gtv6 liners are so free moving ..hahahaha thanks for the advice

I assume the plastic pipes are wide enough to sit on the original studs and long enough to reach the thread to tighten down on the big washers ..is that how it works ?
 

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Yes. Cut the PVC to the proper length. Or stack deep well sockets. What ever it takes. And yes, sometimes the liners are stuck in the block and need to be persuaded to come out. I had one that was stuck to the head gasket and came up with the head.
 

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Discussion Starter · #40 ·
The O-ring should not be loose on the liner skirt. perhaps the o-rings you bought are the ones for the 3.0 liter liners? I purchased mine from McMaster Carr. My notes from the 3.0 say the liner bore is 93mm and the liner skirt is 99mm. My notes say I used a 96mm o-ring. So the skirt wall should be 6mm or 3 a side. Measure your liner skirt. If it follows the same idea as the 3.0 the bore is 88mm and the skirt OD should be 6mm more, so that's 94mm. Metric O-rings are sized by their OD. So looking at McMasters website, a 93mm or 88mm OD would be the ones available (90 to 85mm ID). A range of sizes around the ID of 91 to 88 would work. The way I do it is to very lightly oil or grease the skirt OD up and work the O-ring on, making sure I don't get it twisted up. I don't use any sealers. I might if the blocks sealing surface is wasted, but you would be surprised on how bad the block can look and still seal.

This has worked for me but as with everything you need to verify it on your own.

But, next time, as soon as the head comes off, install the hold downs.

Greg
Hi gregsef I hope you can help with the question of the 1.5 thickness o ring . Eb spares have confirmed they sent me the wrong o rings in a 2.5 gasket set but meanwhile I was wondering should I use the locally bought 1.5mm thick but snug fitting o rings.
 
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