| Author |
Message |
'75 308 GT4 (Peter)
Intermediate Member
Username: Peter
Post Number: 1914
Registered: 12-2000
| | Posted on Thursday, July 18, 2002 - 10:29 pm: | |
Ric and James:
GT4 WSM makes no mention of any weeping allowed
"-Proceed with checking the water sealing: for this close the water lines and introduce possibly warm water through the heads manifold at the pressure of 8 to 10 kg/cm^2. Make sure that there are no leaks from liners rubber seals. If the pressure keeps constant for approximately 5 to 10 min. the sealing is considered in order" (WSM pg. B31). |
Paul Newman (Newman)
Member
Username: Newman
Post Number: 274
Registered: 12-2001
| | Posted on Thursday, July 18, 2002 - 10:21 pm: | |
This might be a good lesson not to cheap out and buy aftermarket gaskets. I bought ferrari headgaskets for mine. Didnt machine either surface during the rebuild and no leaks after 3000kms. |
James Selevan (Jselevan)
New member
Username: Jselevan
Post Number: 43
Registered: 6-2002
| | Posted on Thursday, July 18, 2002 - 7:13 pm: | |
Ric - your memory serves you right. Quoting from the TR WSM,
"Hydraulic Test
- Fit two flanges ....
- Then introduce water until a pressure of 8-10 atm. is reached, and maintain it for 15 minutes.
- Check that the cylinder sealing rings do not leak. If the pressure remains constant for about 10 minutes the seal is efficient.
A slight sweating along the gasket outside perimeter is allowed.
- Blow compressed air through the spark plug holes and check that no water comes out."
Perhaps the key here is to hold this high pressure for 15 minutes. We are talking about 8 to 10 atmospheres - (147 psi if I assume 14.7 x 10). Mitchell is testing at 20 psi. At 147 psi, the real test will be presence of water in the cylinder, and more than a "sweating" along the edge.
Good memory.
Jim Selevan |
Ric Rainbolt (Ricrain)
Junior Member
Username: Ricrain
Post Number: 190
Registered: 2-2002
| | Posted on Thursday, July 18, 2002 - 5:55 pm: | |
I know for a fact that the Testarossa WSM even states something to the effect of "small leaks at the very edges of the head gaskets is considered normal" or some such language. I don't remember if the 308 WSM has that or not.
I've had a TR and a 308 motor leak tiny amounts (3-4 drops over a 2 minute period) and then "seal up" after being brought up to operating temp. The 308 motor went on to be a daily car for me, without any coolant leaks. So far the TR is still "in progress", but has also stopped leaking.
Of course, YMMV. |
Edward Gault (Irfgt)
Intermediate Member
Username: Irfgt
Post Number: 1587
Registered: 2-2001
| | Posted on Thursday, July 18, 2002 - 2:13 pm: | |
The fact that the gasket is leaking only in the area that does not have the sealer further lends evidence that there are some deep cuts in the head surface that are allowing coolant to escape. I had this happen on an AMC Jeep once. The machine shop resurfaced the head and I used stock steel head gaskets and as soon as I put coolant in it, it poured out. I went back again with an aftermarket softer fiber gasket and problem solved. There is no doubt in my mind that your leak is from crevices in the head surface. |
David Feinberg (Fastradio2)
Junior Member
Username: Fastradio2
Post Number: 106
Registered: 4-2002
| | Posted on Thursday, July 18, 2002 - 10:21 am: | |
Hmm...After much thought, as I enjoy solving difficult problems (life and F-related..)
That, being the lack of sealant around those upper coolant passages does seem a bit odd...particularly in that, in essence, the gasket will crush differently due to the liner protrusion from the block versus the deck surface.
I'd be curious to compare your elring to an OE Ferrari gasket...
The issue of paralellism is just one of extreme paranoid...and reaching a bit. Another thought, again on the verge of extreme...Are the head studs "bottoming" out in the nuts?
Onward...and best of luck with your adventure!
Regards,
David
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Mitchell Minh Le (Yelcab1)
Junior Member
Username: Yelcab1
Post Number: 238
Registered: 11-2001
| | Posted on Thursday, July 18, 2002 - 9:50 am: | |
Dave
I take everyone comments to be constructive, I asked for them.
All your comments are very wise and true. I am contacting GT Car Parts to see what is up with the gasket.
I follow the torque sequence you described, starting at 30 moving up 10 lbs a time. Waiting before the last torque sequence as well.
The liners protrusion is within specs which is 0.001 to 0.002".
The heads was machined by a very merticulous machinist who trued the deck very carefully. One thing I did not check for is the perpendicular of the block deck to the studs. I only cleaned the surfaces, checked for flatness and reused.
There is coolant passages along the intake side of the heads. And the liners do not have any sealant or any rings at the edge near the surface. What that means is the coolant can seep out the top of the liner and out to the edge of the gasket along the intake. I used Elring before on my BMW engines and they worked great, but this lack of sealant along the intake side of the gasket is very questionable and inferior, IMHO.
I too would like to get a fresh set of head gasket, I need to talk to GT Car Parts today.
It is fun, but I do not want to take the motor apart again. Now is the time to do it right |
David Feinberg (Fastradio2)
Junior Member
Username: Fastradio2
Post Number: 102
Registered: 4-2002
| | Posted on Thursday, July 18, 2002 - 5:33 am: | |
Mitchell,
With all due respect, please take my comments to be constructive...and to give you some perspective from someone who has been through at least 15 Ferrari engines and likely 100's of other marques...
There are several issues here, that I feel are worth mentioning. Some have been touched upon by others...and Jim certainly hit the nail on the head with his thoughts, as I too believe that something is not quite right here.
I am speaking from a perspective of having spent more than 20 years in the automotive industry with substantial exposure and hands-on experience with many types of exotic engines, including Ferrari.
Based on sound, tried and proven engine rebuilding practices...Here are my thoughts:
Head gaskets, once torqued... are not re-used. Re-using a head gasket, as �the engine has not being run� is sheer nonsense, and IMHO a guarantee that this motor will be apart again, very soon! Sealants, or snake oil applied to a head gasket�Never.
Liner protrusion...If it is truly "0", as you mentioned in your most recent post, indeed you'll have a near impossible time getting the head gasket(s) to seal properly. Wet liner motors, that are typical in Ferrari and Alfa engines, require particular attention to detail, precise machining tolerances and assembly cleanliness. This type of design, although not necessarily more troublesome to seal, can pose certain challenges to seal, if tolerances are not closely adhered to.
Cylinder head being flat...Not particularly meaningful, if the head surface was not machined precisely 90 degrees to the stud holes. Not necessarily a given, considering the previous pounding this engine was subject to�
Deck flatness-Again, parallelism is key. Measurements are required across all axis�s on the liners and block surface to ensure good sealing. As the head gasket must seal again the block and the liners...liner protrusion and parallelism is key here.
You had mentioned that there was no "sealant" along the top edge of the head gasket...along the intake side. If my memory serves me correctly, there is no reason for it, as the coolant passages are along the lower side near the exhaust. Hence, if that's where you're leaking, I would seriously question the installation procedures of the liner o-rings. IMHO, the o-rings should be installed without any sealants. Did you compare the old head gaskets you removed to the new elring ones you installed? Having recently done valve guides in a BB, and using the elring head gaskets, I found them to be far superior in design to the OEM gaskets, as they actually had a bead of sealant around the cooling passages, whereas the OE ones did not!
If someone, past or present was "paying" me to put my name of this motor...or to ensure its long-term durability, I'd start over...checking everything for flatness and particularly parallelism, replace the o-rings per the factory procedures...and replace the head gaskets. Furthermore, in that the case was line-bored, hence moving the centerline of the crankshaft, I�d want to be pretty confident that the piston top edges don�t extend over the liners. (Note: I�m not referring to the domes�)
When applying the initial torque to the head studs, I usually start at 30 lbs...Go through the factory prescribed tightening sequence and then bring each nut up to spec 10 lbs at a time in sequence. When you hit the final spec, wait 10 minutes or so...then go around again. Let the engine settle 12-24hrs, and then re-torque them. At that point, I would expect the heads to hold water pressure. At this point, maybe a tiny seep or air bubble along an edge might be seen, but heat cycling and a 1000 mile re-torque would cure any remaining ills�
Regards,
David
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Mitchell Minh Le (Yelcab1)
Junior Member
Username: Yelcab1
Post Number: 237
Registered: 11-2001
| | Posted on Wednesday, July 17, 2002 - 10:09 pm: | |
James,
Good advice, I am still trying to contact GT Carparts to see if they have seen the problem before with the Elring and to see if they will honor the gasket return. So far, have not even got to talk to the Man yet.
I saw the heads being ground and checked for flatness, they were absolutely flat. I checked the block myself with a straight edge, absolutely flat. The problem here is the lack of a bead of sealant along the intake side of the gasket that is not sealing well.
Yes, the Dino 308GT4 does have liners, and they are evenly pushed into the block without any protrusion. I checked when I removed the head before the second time I installed them.
I did ask some very good machinists, engine rebuilders, and one Ferrari mechanic and they all indicated that heat-cycling is necessary for the head gaskets to totally seat and seal. And, while everybody agrees that replacing the head-gasket is the "best," they also indicated that they believe the head gaskets can be retorqued especially since I have not even fired up the engine yet.
I have not given up on GT Car parts, I am chasing them tomorrow for sure. |
James Selevan (Jselevan)
New member
Username: Jselevan
Post Number: 39
Registered: 6-2002
| | Posted on Wednesday, July 17, 2002 - 9:18 pm: | |
Mitchell - I respectfully suggest that you take another vote. I have spoken with two experienced mechanics today concerning your situation, and both suggested that 1) no head gasket sealant or paint is recommended and 2) once crushed, don't reuse a head gasket. Finally, neither suggested that leakage at 20 psi is normal. They both suggested that you could pressurize the system to 100 psi and you should not experience any leakage. There is something wrong here. Whether the head is not parallel or not flat, something is not right in Peoria. I am sorry to complicate your life, but the alternative of completing assembly and installing the engine only to have an insidious problem of coolant depletion and overheating is worse. Investigate and fix now - not later.
As always - advice is worth what you pay for it.
ps - forgive me for asking this silly question, but does the 8 cylinder Dino of 1975 have liners? If so, could a liner be protruding thereby preventing the head from seating?
Jim Selevan |
Mitchell Minh Le (Yelcab1)
Junior Member
Username: Yelcab1
Post Number: 235
Registered: 11-2001
| | Posted on Wednesday, July 17, 2002 - 4:33 pm: | |
After letting it sit overnight, I filled up the block and heads water jacket with water and pressurized to 20 psi. No water leaks. Lower the water level so that the pressured air was hitting the gasket surface and saw some very minor bubbling. Everyone agrees that the heat and cold cycling will cure that, so I am moving on with twice torqued head-gasket.
Lesson learned: Next time, ask to see if there is the sealing beads all around the gasket. Elring is not a good make. |
'75 308 GT4 (Peter)
Intermediate Member
Username: Peter
Post Number: 1910
Registered: 12-2000
| | Posted on Wednesday, July 17, 2002 - 12:36 am: | |
Mitch, I used aftermarket head gaskets on my engine and I'm positive they had rubber sealing rings (like a squirt of sealant, but done by the factory by a machine) ON ALL PORT PASSAGES, BOTH SIDES. I don't know who manufactured my gaskets, but I got them from Dennis McCann, cheap too.
These type of gaskets are a one-shot deal, the metal rings for the cylinders are shaped into somewhat of a channel and are meant to compress to seal. Once compressed, they can't be anymore (kinda like the torque-to-yeild studs featured on other engines. First stretch: good, more stretch: bad...). |
Mitchell Minh Le (Yelcab1)
Junior Member
Username: Yelcab1
Post Number: 234
Registered: 11-2001
| | Posted on Tuesday, July 16, 2002 - 10:40 pm: | |
Ric
The first time tested, there was about 1 drop of water out of each leak (3 spots) every 15-30 seconds.
The second time, I think I did not fill it with enough water so there was not water leaking out. I sprayed some soapy water into the edges and found some bubbling but that is all. I will open it up, fill it with water tomorrow and see if there is anywater leaking out. Hope for the best tomorrow.
I was told that the rubber seal beading material on the head gasket melts with heat and seals better. True, except that along the leaks, there are no rubber seal beads to melt. They did not put it there.
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Mitchell Minh Le (Yelcab1)
Junior Member
Username: Yelcab1
Post Number: 233
Registered: 11-2001
| | Posted on Tuesday, July 16, 2002 - 10:33 pm: | |
I thought of the too-long studs theory and check them out. Found that 2 of 10 stick out a little longer than the other 8. But, these two studs were on the ... non leaking side of the heads. Checked for threads under the deck and there was sufficient thread there. Bad gasket, it must be. |
Ric Rainbolt (Ricrain)
Junior Member
Username: Ricrain
Post Number: 188
Registered: 2-2002
| | Posted on Tuesday, July 16, 2002 - 10:31 pm: | |
When you say it seeps, how much are we talking about. It is not unusual to have a small amount esp. near the corners. Normally, after one or two heat cycles the leaking goes away (assuming it's small to start with). |
Mitchell Minh Le (Yelcab1)
Junior Member
Username: Yelcab1
Post Number: 232
Registered: 11-2001
| | Posted on Tuesday, July 16, 2002 - 10:13 pm: | |
Well
Yes, visually inspect the studs and found no problems. Chased them all down with a die of the correct size (11mm x 1mm) right before each installation. Lubed with motor oil before torquing for a smooth even torque. Used a very expensive SnapOn 1/2 inch torque wrench so it is dead nuts on accurate. Retorqued 3 times so that the torque wrench clicked each time. I cannot think of anything else I could have done better.
I am leaning in the bad gasket decision myself. The point is, what to do next? Ask for a free replacement? Buy a new one. I hate to spend another $200 to replace a bad gasket that is not my fault in the first place. I will contact GT Car Parts tomorrow anyway to see what they want me to do.
With this engine, I am proceeding cautiously and testing my work every step of the way. I was gonna do a compression and leak down test next before I drop the transmission on the block. Now that is going to have to wait.
When I dissambled the engine, I noticed the previous mechanic did use copper gasket material sprayed onto the head gasket to form a seal. Having nothing to lose at this point, I might try that tomorrow if the head still does not seal overnight. I am leary at retorquing the head gasket the 3rd time ... |
Bill Sebestyen (Bill308)
Member
Username: Bill308
Post Number: 277
Registered: 5-2001
| | Posted on Tuesday, July 16, 2002 - 10:07 pm: | |
Good point James.
Mitchell, is there thread on the studs below the surface of the head? In other words, could you have bottomed out the nuts before the head was properly seated? What do the liner deck heights look like now?
There is a USA contact for Elring gaskets:
ElringKlinger Sealing Systems USA, Inc.
35955 Veronica
Livonia, MI 48150
Michigan/USA
Telefon +1-734-542-1522
Telefax +1-734-542-0179
E-Mail: [email protected]
|
James Selevan (Jselevan)
New member
Username: Jselevan
Post Number: 33
Registered: 6-2002
| | Posted on Tuesday, July 16, 2002 - 9:45 pm: | |
Mitchell - there is good news and bad news. The bad news is that I would be reluctant to complete assembly with "silver paint" sealing my head gasket. Furthermore, I would be reluctant re-torqueing for a third time a head gasket. (I would not reuse if torqued twice - they are made for one-time only). Finally, in the bad news category, there is something wrong. This is not rocket science. Head, gasket, and block are suppose to seal - first time, every time. The slightest hint of a leak calls for serious rethinking. While I have not built hundreds of engines (perhaps 10), I have never used any type of gasket sealant, paint, copper, belly button lint, spit, whatever. Just the gasket, Ma'am, just the gasket. With 75 foot-pounds all around, this sucker is tight. No need for sealant.
The good news is you tested it. Imagine your frustration had you installed the engine! I have never done what you did - pressure test before install. Perhaps I should start.
Sounds like a bad gasket. By the way - did you visually inspect the studs to make sure one was not stripped or fatiqued?
Hope this helps - not meant to depress you.
Jim Selevan
|
Mitchell Minh Le (Yelcab1)
Junior Member
Username: Yelcab1
Post Number: 231
Registered: 11-2001
| | Posted on Tuesday, July 16, 2002 - 8:58 pm: | |
These are Elring gaskets, not OEM. |
Bill Sebestyen (Bill308)
Member
Username: Bill308
Post Number: 276
Registered: 5-2001
| | Posted on Tuesday, July 16, 2002 - 7:52 pm: | |
Mitchell, are these OEM head gaskets? If not OEM, maybe you can contact the manufacturer and ask for his advice. |
Mitchell Minh Le (Yelcab1)
Junior Member
Username: Yelcab1
Post Number: 229
Registered: 11-2001
| | Posted on Tuesday, July 16, 2002 - 6:59 pm: | |
Well
I read that part on the WSM too, and avoided using any material on the head gaskets. One held, the other leaked. The heads are expertly surfaced, the block is straight and clean. It is leaking along the intake edge where there is no rubber bead sealant material on the head gasket itself. I am leaning in the direction of a bad head gasket, but ... this is a hard thing to get a replacement for, or a refund for. Bought it in a kit from GT Car parts and Bill is a good guy, but each head gasket is easily ... $200. Unsure if he is willing to just give me another one on my say so.
By the way, the aluminum head cannot be magnafluxed because it is not Ferrous. |
David Jones (Dave)
Junior Member
Username: Dave
Post Number: 147
Registered: 4-2001
| | Posted on Tuesday, July 16, 2002 - 6:31 pm: | |
Unless things have changed over the years,
my 308 engine reassembling manual says to place carefully the two head gaskets on the engine block, and avoid spreading the surfaces with any substance. |
James H. (Jamesh)
Junior Member
Username: Jamesh
Post Number: 118
Registered: 5-2001
| | Posted on Tuesday, July 16, 2002 - 6:09 pm: | |
I dont know if I would feel comfortable knowing the silver stuff sprayed on your head gasket was the fix for two of the leaks. Just dont know if that is a permanent fix. Wonder if the head gasket is bad. I understand those are pretty expensive too. Was the head magnaflux to check for cracks? Have anyone ever use silicone sealant (RTV) around the water jackets on the heads. We used to use it where the intake meets the heads at the water jackets on the small block chevys, but dont know if they have every been used with the head gaskets. |
Mitchell Minh Le (Yelcab1)
Junior Member
Username: Yelcab1
Post Number: 228
Registered: 11-2001
| | Posted on Tuesday, July 16, 2002 - 6:03 pm: | |
Steve
I do not mean the copper gasket material in a spray can. That is something I will probably try next. Although, that means the 3rd time torquing down on the head gasket and I am unsure as to the integrity of the head gasket by the 3rd time.
Ed, the finish on the head is not mirror like, but very very smooth. The deck of the block, however, is flat, but not polished at all. With all the studs sticking out, there was no way to "finish" the block.
It is puzzling to me why there is a bead of rubber seal on the gasket on the exhaust side, but not on the intake side where it is now leaking. |
Steve Magnusson (91tr)
Member
Username: 91tr
Post Number: 852
Registered: 1-2001
| | Posted on Tuesday, July 16, 2002 - 5:33 pm: | |
Glad to hear the bottom end of things are OK. When you say "silver paint" do you mean something like:
http://www.permatex.com/products/prodidx.asp?f_call=get_item&item_no=80696 |
Edward Gault (Irfgt)
Intermediate Member
Username: Irfgt
Post Number: 1579
Registered: 2-2001
| | Posted on Tuesday, July 16, 2002 - 5:32 pm: | |
The finish on the resurfaced head had better be like a mirror or leaks will occur. I had mine finished with an abrasive sander type machine with negligable material removed. |
Mitchell Minh Le (Yelcab1)
Junior Member
Username: Yelcab1
Post Number: 226
Registered: 11-2001
| | Posted on Tuesday, July 16, 2002 - 5:04 pm: | |
Hello all. I need some wisdom.
In the middle of my engine assembly, got to install the heads and did a pressure test of the coolant system. It leaks. Here is what I did.
1. Cleaned all studs and nuts with 11mm x 1mm tap and die
2. Cleaned all surfaces,
3. Torqued all to 75 lbs (~100 NM) with a Snap On torque wrench.
4. Poor some water in the block
5. Pressurize to 15 psi.
Notice some water seepage out along the head-gasket contact points along the intake manifold side of 1-4 head. This is the edge where there is no rubber seal bead along the head gasket, the other side (exhaust) there was a rubber bead.
This is what I have tried.
Retorquing all nuts again
Took off the head, cleaned all surfaces, spray painted the gasket with silver paint (2 coats) and reinstalled. 1 of 3 leaks went away. The other two are still seeping air, but no longer seeping water.
I have not tried copper gasket material. I used brand new Elring gasket bought from GT Car Parts.
Heads were surfaced on a professional grounding machine. The block was checked for flatness (it is) but was not machined.
Right now, I have retorqued everything, letting it sit overnight for the silver paint to settle and for the head to relax.
What is wrong and what can I do? |
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