Which Head Gasket for me?
10-29-2003, 11:29 PM
#76
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ARP makes a lot of different fasteners it wouldn't be the first time someone sells something as theirs that really isn't. ARP is also very reputable and customer oriented, if you have questions call them, I have.
10-29-2003, 11:29 PM
#77
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ARP makes a lot of different fasteners it wouldn't be the first time someone sells something as theirs that really isn't. ARP is also very reputable and customer oriented, if you have questions call them, I have.
10-29-2003, 11:29 PM
#78
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ARP makes a lot of different fasteners it wouldn't be the first time someone sells something as theirs that really isn't. ARP is also very reputable and customer oriented, if you have questions call them, I have.
10-30-2003, 12:22 AM
#79
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The guy at Performance developments the other day, was talking about some rivets or dimples that have to line up together. Can someone explain this? I'm pretty sure it will be clear once I see the gasket just looking for some info ahead of time. TIA
10-30-2003, 12:34 AM
#80
Maybe I can add something here as I know this Gasket quite well.
First there is a 106.00mm MLS Gasket made for the 968. PD has 100, 101.6, 103, 104 for the 944, and 101.6, 104, and 106 for the 968.
As for the rivets, the Gaskets layers are held together with 3 rivets. Installation care is required to be sure that the layers do not overlap when installing the Gasket. Very simple, but necessary. for the guy who had a failure at 200 miles, I amsure that there is something else wrong or there was an assembly problem not seen. There is absolutely no reason if everything was done correctly, that the Gasket would not work properly.
First there is a 106.00mm MLS Gasket made for the 968. PD has 100, 101.6, 103, 104 for the 944, and 101.6, 104, and 106 for the 968.
As for the rivets, the Gaskets layers are held together with 3 rivets. Installation care is required to be sure that the layers do not overlap when installing the Gasket. Very simple, but necessary. for the guy who had a failure at 200 miles, I amsure that there is something else wrong or there was an assembly problem not seen. There is absolutely no reason if everything was done correctly, that the Gasket would not work properly.
10-30-2003, 12:36 AM
#81
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Originally posted by Ski
The guy at Performance developments the other day, was talking about some rivets or dimples that have to line up together. Can someone explain this? I'm pretty sure it will be clear once I see the gasket just looking for some info ahead of time. TIA
The guy at Performance developments the other day, was talking about some rivets or dimples that have to line up together. Can someone explain this? I'm pretty sure it will be clear once I see the gasket just looking for some info ahead of time. TIA
Once you see the gasket you will know what he was saying, it is like a metal sandwich and the layers can be seperated a little, just need to make sure it is stacked all nice a neat when the head goes on.
10-30-2003, 12:46 AM
#82
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Originally posted by mochman
ARP makes a lot of different fasteners it wouldn't be the first time someone sells something as theirs that really isn't. ARP is also very reputable and customer oriented, if you have questions call them, I have.
ARP makes a lot of different fasteners it wouldn't be the first time someone sells something as theirs that really isn't. ARP is also very reputable and customer oriented, if you have questions call them, I have.
10-30-2003, 01:02 AM
#83
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First there is a 106.00mm MLS Gasket made for the 968. PD has 100, 101.6, 103, 104 for the 944, and 101.6, 104, and 106 for the 968.
I have about 5000 easy miles very few boosted runs and 15 psi max on my Guru gasket, which I think is the same as the PD gasket.
I do have some symptoms of a leaky headgasket, coolant level drop and gurgling after sutdown, could this be a problem with the gasket not sealing ??? will do a leakdown, maybe this will tell something
10-30-2003, 10:31 PM
#84
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Originally posted by Ski
Well....has everyone used the factory torque specs and sequences? David, Sean, Dan, ??? Anyone else.
Well....has everyone used the factory torque specs and sequences? David, Sean, Dan, ??? Anyone else.
10-31-2003, 10:36 AM
#85
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AFter blowing my head gasket the other day, as stated, I have the Cometic one on the way, along with a set of factory studs. I am probably going to get raceware since Paragon has those in stock. Question: for those of you that have pulled and installed the studs, which Loctite did you go back with; red - perm. or blue semi perm, or maybe just a small dab of red?
10-31-2003, 12:19 PM
#86
The issue here is:
How many of you have a SLEEVED motor, such as the Anderson 106mm, or some darton sleeves (which may go in differently), and have the MLS gasket?
Of those, how many had an issue?
A very important point to make is that with an aluminum head, VERY RARELY can someone take the head off after some sort of issue with gaskets, slap a new gasket on of any sort, and simply rebolt the head down without so much as a resurface or anything of the sort.
I think some here may agree with the fact that, for all intents and purposes, a block should be planed, and a head surfaced when you are replacing a head gasket.
Others may not of course. I'm over here because I will probably be getting an MLS gasket for my 89 928S4, and it will be sleeved with 106mm sleeves. I will then be running up to 18lbs of boost through this motor with an intercooled Vortech, and the computer will be a DTA.
Suffice to say, I am interested in finding out more about what gaskets are working with you boostards. Are there any Wide fire gaskets for 106? Are these usually custom made?
How many of you have a SLEEVED motor, such as the Anderson 106mm, or some darton sleeves (which may go in differently), and have the MLS gasket?
Of those, how many had an issue?
A very important point to make is that with an aluminum head, VERY RARELY can someone take the head off after some sort of issue with gaskets, slap a new gasket on of any sort, and simply rebolt the head down without so much as a resurface or anything of the sort.
I think some here may agree with the fact that, for all intents and purposes, a block should be planed, and a head surfaced when you are replacing a head gasket.
Others may not of course. I'm over here because I will probably be getting an MLS gasket for my 89 928S4, and it will be sleeved with 106mm sleeves. I will then be running up to 18lbs of boost through this motor with an intercooled Vortech, and the computer will be a DTA.
Suffice to say, I am interested in finding out more about what gaskets are working with you boostards. Are there any Wide fire gaskets for 106? Are these usually custom made?
10-31-2003, 12:37 PM
#87
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Ski, as to the head studs, I would really suggest ARP as they don't require or even suggest a retorque is necessary. As to torque specs the factory recommends a 90 degree process, but ARP recommends using staged torque values. I guess if you stay with the factory studs and nuts use the factory torque specs. If you go with Raceware, use their reommendation, if ARP use their spec. By the way I was very impressed by the quality look of the ARP product.
As to Loctite, I got several different suggestions, ARP said use red, so I used red, but didn't glob it on. I did run a tap through the block threads and then flushed the threads clean with degreaser and air, with the block upside down. As you commented there are several versions of red and I chose to use the red just past the blue. Also be sure to set the stud height as per the manual.
When you get the MLS take a look at the ridges built into the top and bottom layer. Make sure they are all of equal height and shape. If not I wouldn't proceed as these ridges are key to creating the seal against the head and block. If any are less prominent then you will have less of a contact point seal at that areaa. How much variation is allowable I don't know but PD or Cometic could probably tell you.
As to Loctite, I got several different suggestions, ARP said use red, so I used red, but didn't glob it on. I did run a tap through the block threads and then flushed the threads clean with degreaser and air, with the block upside down. As you commented there are several versions of red and I chose to use the red just past the blue. Also be sure to set the stud height as per the manual.
When you get the MLS take a look at the ridges built into the top and bottom layer. Make sure they are all of equal height and shape. If not I wouldn't proceed as these ridges are key to creating the seal against the head and block. If any are less prominent then you will have less of a contact point seal at that areaa. How much variation is allowable I don't know but PD or Cometic could probably tell you.
10-31-2003, 01:29 PM
#88
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Anytime you hear torque specs using "degrees" rather than force, you know that the torque spec is for a "stretch" bolt or "stretch stud". That's the only time you will hear "degrees" used on torqueing.
The factory studs are stretch studs, so they will retain the proper tension when things heat up and cool down.
The ARP/Raceware are not stretch studs, and therefore should be retorqued after a full heat cycle.
Personally, I think the factory has it right in their selection of stretch studs rather than non-stretch. But I can't stand the thought of not using the stongest hardware available, and thus I use the Raceware. The thought of a stud breaking off in the block is just too much....
Concerning the metal head gaskets leaking...
Make sure you have the correct version of the head gasket. There is a version for people with "O" ringed heads, and there is a version for people with "non-0" ringed heads. If you use a version for a non "O" ringed head on a application with the head/block being "O" ringed, you will have leakage big time.
The factory studs are stretch studs, so they will retain the proper tension when things heat up and cool down.
The ARP/Raceware are not stretch studs, and therefore should be retorqued after a full heat cycle.
Personally, I think the factory has it right in their selection of stretch studs rather than non-stretch. But I can't stand the thought of not using the stongest hardware available, and thus I use the Raceware. The thought of a stud breaking off in the block is just too much....
Concerning the metal head gaskets leaking...
Make sure you have the correct version of the head gasket. There is a version for people with "O" ringed heads, and there is a version for people with "non-0" ringed heads. If you use a version for a non "O" ringed head on a application with the head/block being "O" ringed, you will have leakage big time.
10-31-2003, 02:36 PM
#89
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Originally posted by dand86951
Just another data point, I put a MLS headgasket on my freshly rebuilt engine which has Darton liners....<snip>
Lots of discussions and having machinists check the head and flatness of the blockand conclusion was that nothing was wrong. So instead of going back together with MLS gasket I put a WFHG and 2300 miles later no blown headgasket.
Just another data point, I put a MLS headgasket on my freshly rebuilt engine which has Darton liners....<snip>
Lots of discussions and having machinists check the head and flatness of the blockand conclusion was that nothing was wrong. So instead of going back together with MLS gasket I put a WFHG and 2300 miles later no blown headgasket.
What size bore are running?
Sean
10-31-2003, 02:46 PM
#90
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I noticed a discprepancy in this thread... I was wondering about this as I was building my motor as well. Here's the discrepency:
- The factory turbo manual doesn't specify torquing the studs to a stretch value.
- The newer factory 944 engine manual specifies torquing the studs to a stretch value.
Anyone have a definitive answer on this, with supporting material?... Like a Porsche tech bulletin or something similiar?
I'd really like to know what the right procedure is... On my current headgasket, I ended up going with the the torque procedure in the turbo manual.
Thanks,
Sean
- The factory turbo manual doesn't specify torquing the studs to a stretch value.
- The newer factory 944 engine manual specifies torquing the studs to a stretch value.
Anyone have a definitive answer on this, with supporting material?... Like a Porsche tech bulletin or something similiar?
I'd really like to know what the right procedure is... On my current headgasket, I ended up going with the the torque procedure in the turbo manual.
Thanks,
Sean