Show full size 924Board.org
Discussion Forum of 924.org
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
 Technical FAQ924 FAQ (Technical)   Technical924 Technical Section   Jump to 924.org924.org   Jump to PCA 924 Registry924 Registry

Stage Next...
Goto page Previous  1, 2, 3, 4, 5, 6, 7, 8, 9  Next
 
Post new topic   Reply to topic    924Board.org Forum Index -> Performance Upgrades
View previous topic :: View next topic  
Author Message
Kenodog  



Joined: 25 Jun 2003
Posts: 2439
Location: Vancouver,B.C.

PostPosted: Fri Jan 20, 2017 8:56 am    Post subject: Reply with quote

I had the block on my old 931 motor o-ringed and ran a stock head gasket. The car was intercooled and had a TurboSmart 2-stage boost controller set to 12 & 15 psi respectively. Never had an issue and I drove it hard and fast.




Me
_________________
1979 Euro 931, Olive
1981 931, Sabine
2014 Mazda CX-5 (Kid's limo)
2008 GS500
1996 Dodge Caravan (DJV)
Back to top
View user's profile Send private message Send e-mail MSN Messenger
Carrera RSR  



Joined: 08 Jan 2010
Posts: 1565
Location: Somerset, UK

PostPosted: Fri Jan 20, 2017 7:52 pm    Post subject: Reply with quote

Issue is, once o-ringed you never have the future option of goung from stock HG to MLS. With stock HG circa £50 and an MLS at £100, it makes sense if you are not planning on opening the motor in the next few years then play safe and go MLS. Too many cases of stock HG failing and such a small premium for the MLS. In addition you can use the MLS to fine tune your CR.

As for ARP, I have re used 3 times now. Make sure you use the ARP grease on the threads. Don't follow the ARP instructions in putting in the studs finger tight. Use a small amount of torque and get them more than finger tight. They can back out of the block.
_________________
1980 931 - forged pistons, Piper cam, CGT turbo, 951 ducted FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife LSD
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252
Back to top
View user's profile Send private message
ideola  



Joined: 01 Oct 2004
Posts: 15503
Location: Woodstock IL

PostPosted: Fri Jan 20, 2017 11:10 pm    Post subject: Reply with quote

Carrera RSR wrote:
Issue is, once o-ringed you never have the future option of goung from stock HG to MLS. With stock HG circa £50 and an MLS at £100, it makes sense if you are not planning on opening the motor in the next few years then play safe and go MLS. Too many cases of stock HG failing and such a small premium for the MLS. In addition you can use the MLS to fine tune your CR.

As for ARP, I have re used 3 times now. Make sure you use the ARP grease on the threads. Don't follow the ARP instructions in putting in the studs finger tight. Use a small amount of torque and get them more than finger tight. They can back out of the block.


+1 to all of that.

On the ARP studs, I had that happen on club sport motor. I have since been applying 15# of torque on the studs, and that seems to do the trick.

On the o-ringing, I blew two OEM headgaskets because the o-ring crimped the fire ring in the gasket, which lead to the fire ring failing in a very short time. After pulling the head twice, the third head gasket was a Cometic copper gasket. So far, that has held up well (all this also on the club sport motor).

Leigh, I would be interested to know if your o-ringed setup was standard 86.5mm bore. Mine was 87.5mm, and that might have been enough of a difference to cause the fire ring crimping I discovered on mine.
_________________
15 981 GTS | 88 924S SE | 82 931 Holbert | 82 931 Rallye | 81 937 | 81 Euro 931 | 81 Weissach | 80 US 928 | 80 US 931 '941' | 80 US 931 | 80 931 GTR | 79 Sebring | 78 D-Prod Replica | 78 w/D-Prod kit | 78 Poli-Form | 78 Limited Edition | 77 Martini
Back to top
View user's profile Send private message
Cédric  



Joined: 27 Aug 2004
Posts: 1734
Location: Sweden

PostPosted: Fri Jan 20, 2017 11:55 pm    Post subject: Reply with quote

ideola wrote:
Carrera RSR wrote:
Issue is, once o-ringed you never have the future option of goung from stock HG to MLS. With stock HG circa £50 and an MLS at £100, it makes sense if you are not planning on opening the motor in the next few years then play safe and go MLS. Too many cases of stock HG failing and such a small premium for the MLS. In addition you can use the MLS to fine tune your CR.

As for ARP, I have re used 3 times now. Make sure you use the ARP grease on the threads. Don't follow the ARP instructions in putting in the studs finger tight. Use a small amount of torque and get them more than finger tight. They can back out of the block.


+1 to all of that.

On the ARP studs, I had that happen on club sport motor. I have since been applying 15# of torque on the studs, and that seems to do the trick.

On the o-ringing, I blew two OEM headgaskets because the o-ring crimped the fire ring in the gasket, which lead to the fire ring failing in a very short time. After pulling the head twice, the third head gasket was a Cometic copper gasket. So far, that has held up well (all this also on the club sport motor).

Leigh, I would be interested to know if your o-ringed setup was standard 86.5mm bore. Mine was 87.5mm, and that might have been enough of a difference to cause the fire ring crimping I discovered on mine.


OT: Looking at MLS gaskets in your webshop, which is the one that replicates OEM compressrion ratio? I think CR8,5 will do for some higher horsepower aswell...
_________________
´79 924
http://www.garaget.org/show.php?car=211
´80 924 Turbo
http://www.garaget.org/?car=160275
Back to top
View user's profile Send private message MSN Messenger
ideola  



Joined: 01 Oct 2004
Posts: 15503
Location: Woodstock IL

PostPosted: Sat Jan 21, 2017 12:04 am    Post subject: Reply with quote

Stock head gasket is .046" compressed. However, I usually recommend .051" for a rebuild targeting OEM specs, for the simple fact that a rebuild should involve at least mild decking of both the head and the block. The .051" is therefore more likely to maintain original compression ratio.

I have all of the OEM configurations pre-loaded in my CR calculator, and you can play with the numbers to see how the different gasket thicknesses...in combination with other mods...will affect final static CR.
http://garage.ideola.com/top-DL-CompressionRatioCalc.html
_________________
15 981 GTS | 88 924S SE | 82 931 Holbert | 82 931 Rallye | 81 937 | 81 Euro 931 | 81 Weissach | 80 US 928 | 80 US 931 '941' | 80 US 931 | 80 931 GTR | 79 Sebring | 78 D-Prod Replica | 78 w/D-Prod kit | 78 Poli-Form | 78 Limited Edition | 77 Martini
Back to top
View user's profile Send private message
Kenodog  



Joined: 25 Jun 2003
Posts: 2439
Location: Vancouver,B.C.

PostPosted: Sat Jan 21, 2017 12:49 am    Post subject: Reply with quote

Dan, the pistons were 86.75. I did it for 2 reasons, fist because the MLS wasn't out yet and second because blocks are a dime a dozen so if I need a new one in a few years who cares. My point wasthat the factory hg is fine if you have the block ringed properly. And for some people that are modifying, and therefore repetedly removing the head, it is cheaper to buy new factory gaskets then to spend double everytime on the MLS.





Me
_________________
1979 Euro 931, Olive
1981 931, Sabine
2014 Mazda CX-5 (Kid's limo)
2008 GS500
1996 Dodge Caravan (DJV)
Back to top
View user's profile Send private message Send e-mail MSN Messenger
ideola  



Joined: 01 Oct 2004
Posts: 15503
Location: Woodstock IL

PostPosted: Sat Jan 21, 2017 12:57 am    Post subject: Reply with quote

Kenodog wrote:
Dan, the pistons were 86.75. I did it for 2 reasons, fist because the MLS wasn't out yet and second because blocks are a dime a dozen so if I need a new one in a few years who cares. My point wasthat the factory hg is fine if you have the block ringed properly. And for some people that are modifying, and therefore repetedly removing the head, it is cheaper to buy new factory gaskets then to spend double everytime on the MLS.


Thanks for the confirmation on the bore.

Yeah, I o-ringed my block for the same reason (MLS wasn't available then). But personally, I will *never* do it again after the repeated failures I experienced.
_________________
15 981 GTS | 88 924S SE | 82 931 Holbert | 82 931 Rallye | 81 937 | 81 Euro 931 | 81 Weissach | 80 US 928 | 80 US 931 '941' | 80 US 931 | 80 931 GTR | 79 Sebring | 78 D-Prod Replica | 78 w/D-Prod kit | 78 Poli-Form | 78 Limited Edition | 77 Martini
Back to top
View user's profile Send private message
Kenodog  



Joined: 25 Jun 2003
Posts: 2439
Location: Vancouver,B.C.

PostPosted: Sat Jan 21, 2017 3:01 am    Post subject: Reply with quote

No offense to your machinist but that's just a bad o-ring job, not the fault of the gasket. Like I mentioned I had my boost set to a regular 12 psi with lots of 'fun' driving at 15 psi and never had an issue. And trust me when I say this but here in the land of the free we drive hard and fast ALL the time because speed enforcement is almost nil.

Last good run in my old 931 was from Hinton, Alberta to my house in Richmond, B.C. in 7 hours, 10 minutes flat. Look that up on Google, it's autobahn fast for 7 straight hours in the late June heat. Rocked through Jasper Park's 40 kph zone at 110 MPH. Scared the shit out of some Elk chewing their early morning cud in the middle of the road....





Me
_________________
1979 Euro 931, Olive
1981 931, Sabine
2014 Mazda CX-5 (Kid's limo)
2008 GS500
1996 Dodge Caravan (DJV)
Back to top
View user's profile Send private message Send e-mail MSN Messenger
ideola  



Joined: 01 Oct 2004
Posts: 15503
Location: Woodstock IL

PostPosted: Sat Jan 21, 2017 3:29 am    Post subject: Reply with quote

Kenodog wrote:
No offense to your machinist but that's just a bad o-ring job, not the fault of the gasket.


I disagree. I can see no way with the bore diameter I had that the o-ring wouldn't impinge on the fire ring, causing the fire ring to be pinched and compromised.
_________________
15 981 GTS | 88 924S SE | 82 931 Holbert | 82 931 Rallye | 81 937 | 81 Euro 931 | 81 Weissach | 80 US 928 | 80 US 931 '941' | 80 US 931 | 80 931 GTR | 79 Sebring | 78 D-Prod Replica | 78 w/D-Prod kit | 78 Poli-Form | 78 Limited Edition | 77 Martini
Back to top
View user's profile Send private message
Kenodog  



Joined: 25 Jun 2003
Posts: 2439
Location: Vancouver,B.C.

PostPosted: Sat Jan 21, 2017 4:03 am    Post subject: Reply with quote

Well we can agree to disagree then. Seems odd that mine ran perfectly with double the factory boost levels for MANY thousands of miles and was perfect until the day I parted it.

Guess the car gods love me more. Just sayin'....




Me
_________________
1979 Euro 931, Olive
1981 931, Sabine
2014 Mazda CX-5 (Kid's limo)
2008 GS500
1996 Dodge Caravan (DJV)
Back to top
View user's profile Send private message Send e-mail MSN Messenger
ideola  



Joined: 01 Oct 2004
Posts: 15503
Location: Woodstock IL

PostPosted: Sat Jan 21, 2017 4:19 am    Post subject: Reply with quote

Well, all we have is anecdotal evidence...only two anecdotes I know of with o-ringed blocks. So certainly not scientific. I bring it up merely to share my experience, not invalidate yours, so that others can make informed decision about whether they want to consider o-ring, MLS, copper, etc.

Now that MLS is available, in my opinion, it is the far less risky alternative. MLS is reusable, the money you save on o-ringing the block can be put toward the MLS gasket, and you don't have an o-ring in your block that will dig into the head surface. My advice for anyone considering o-ringing is to NOT use an OEM gasket but to use a copper gasket.
_________________
15 981 GTS | 88 924S SE | 82 931 Holbert | 82 931 Rallye | 81 937 | 81 Euro 931 | 81 Weissach | 80 US 928 | 80 US 931 '941' | 80 US 931 | 80 931 GTR | 79 Sebring | 78 D-Prod Replica | 78 w/D-Prod kit | 78 Poli-Form | 78 Limited Edition | 77 Martini
Back to top
View user's profile Send private message
Fasteddie313  



Joined: 29 Sep 2013
Posts: 1556
Location: MI

PostPosted: Sat Jan 21, 2017 7:25 am    Post subject: Reply with quote

Good info guys thanks..
Good debate is a great way to bring out the supporting evidence of any and all sides..
It should be plain to see why I am conflicted and hesitant to go with some method of upgraded headgasket at this time..

I'm not wanting to get into any machine work at this time so I thought going with the best quality OEM style gasket will do for now..

The MLS being confirmed reusable is a pro but if my block and/or head end up in a machine shop Oringing at that time would be simple while your at it thing to do..

I think I should also decide what pistons and CR I will use before deciding what HG I should use.. Need to choose a whole system before I can decide which components to go in that system so the organs all get along..
Bunch of related thinking to do around the HG before I choose..

If you want to chat about internals then what do you think about going..
1. Low compression(7-8:1), non-interfearance, no squish..
VS..
2. High compression (8-10:1), full interfearance, All of the squish..

Do you think maybe it should depend on how accurate/safe I can keep AFRs? As to if high accuracy is possible maybe high compressions is the way to go and if not then low compression for added safety?
High compression less boost VS low compression silly boost?
Ported head lower boost VS standard head higher boost?
Do we care about lightweight pistons and rods for high RPM or not?
Light high RPM HP low boost VS heavy low RPM Torque silly boost?
Deisel direction VS F1 direction?

Then I can worry about what kind of HG would go best with that type of system..

Right now, I just want to get the controllable virtually unlimited fuel supply figured out so the sky is the limit..

I don't think my turbo is big enough for that much boost anyway, yet..
Plan very far ahead..
_________________
80 Turbo - Slightly Modified


Last edited by Fasteddie313 on Sat Jan 21, 2017 7:59 am; edited 1 time in total
Back to top
View user's profile Send private message Yahoo Messenger
Kenodog  



Joined: 25 Jun 2003
Posts: 2439
Location: Vancouver,B.C.

PostPosted: Sat Jan 21, 2017 7:30 am    Post subject: Reply with quote

Indeed Freddie. Measured, civilized debate is what separates us from the unwashed, heathen masses.






Me
_________________
1979 Euro 931, Olive
1981 931, Sabine
2014 Mazda CX-5 (Kid's limo)
2008 GS500
1996 Dodge Caravan (DJV)
Back to top
View user's profile Send private message Send e-mail MSN Messenger
Fasteddie313  



Joined: 29 Sep 2013
Posts: 1556
Location: MI

PostPosted: Mon Feb 13, 2017 9:59 am    Post subject: Reply with quote

I needed to keep my injector lines low for hood clearance and concentrated to clear the pop up lights crank arm right there..

Here you can see my external system pressure regulator tucked down behind the headlight, and to clear that swinging stop bracket on the headlight, plumbed fits good..

Arm clears..
BTW that 3 pin connector there on that side is the metering plate position sensor, it has some whiskers that wipe across a thing when the axle turns as the plate goes up and down.. You can log it to see what it's up to but it's pretty useless other than that.. The one that means business is the 2 pronger over toward the inner fender, the DPR..

This area here above the headlight torsion arm drive shaft thing is a pretty free space and where all of my fuel line connections will go, the siamese magic if it ever arrives in the mail Lost my package, reshipped..

And there on the mount tab of the lower airbox housing where you see the lines ziptied I am going to make like a little mount for that group of lines to mount there to that tab.. Their is 4 in the bundle but may be 5 if I figure out wether or not I need or want to keep the cold start injector.. I'm not sure yet if it stays or goes..

Fuel line routing toward the engine..

Through there..

Looks good to me..
What I think I am going to do with these lines as of this moment...
I'm going to buy a ton of fire retardent shrink tubing because it's so much more cost effective to but an almost lifetime supply vs smaller amounts it's a no brainer, then I wont have wiring excuses anymore either..
I think what I'll do is shrink wrap every one of the injector lines individually all the way from my siamese splitter fitting all the way to the injector, and then where they are in a good bundle I will shrink wrap them all together into a bundle as far as I can keep them in a bundle, maybe double especially across the flexible portion..
The cohlone there is good, I'm not going to replace it.. Shrink wrap em all to protect them from themselves and other things, maybe a little steel shimstock shield section on them under the 2nd layer of shrink just by the cam pulley just incase.. I could slightly tether them to the thermostat housing so they cannot reach the cam pulley.. We shall see..

Here we get thinking about how to connect the big hole to the top of the airbox somehow.. Maybe like the GTS is done I am contemplating..

I guess mine is a little offset unlike the GTS whick is in pretty direct line..

The AFM opening is pretty high, it will have to come out and then back down into the airbox..

Trying to get like a sightline of how much hoodroom I have to work with, I think that if I keep everything lower than a line from the blue cap on the washer bottle to the airbox top then I should be good..

Crap pic..

From the top of the blue cap to the top of the airbox headroom..

Little lower..

Plenty of wires.. Surplus..

Megasquirt connector end, I think I will put my computers and related fueses/relays on the back side of the passengers seat kick panel and leave enough wire so I can put the whole panel in my lap sitting in the passengers seat to work on it, and put it back under the dash with a ouple screws when I'm done..

Also you can see I ot my wideband in the gauge plate and installed except the old O2 left its threads in the downpipe bung so I have to find an O2 thread chaser similar to the one I sold not too long ago, imagine that..

The 3 firewall holes there...
The bottom one is that drain tube from the wiper motor area, the top 2 are the old AC line holes, this is obviously where my wires come out..

And they are plenty long even with the computer connector end on the passengers seat..


Instead of trying to screw around with sheathing on my wires I will just shrink wrap them all the way from the sensors to the firewall and then bigger shrink wrap over groups as I can get them to flow together into a harness bundle.. That fire retardant shrink wrap..

I need wiring supplies to get going on making connections but I plan to use the wires to their full length and then pull them back inside the car and tie the extra into a little nest way up under the dash, so when I screw it up I'll have more wire..
I put all the wires through the firewall and for the ones that need to be inside the car I plan to pull out of the harness from inside the car 1 by 1 when I want them..
If it doesn't work and I should put them through the firewall 1 by 1 then I'll just call it a doover..

Need to tap the intake for the IAT, going to put it right in the WUR spot for some meat, was thinking the big old BOV hole under runner 1 but then though oil might fill in my sensor and screw it up so I better put it somewhere that isn't a low spot where oil can pool.. It's GM so 3/8 NPT and pretty big.
Some BMW closed element temp sensor fit the old thermotime switch hole perfect so that's where that went..
BTW dan that intake cleaned up pretty nice with SOS pads and that fitting fits a copper line compression that fits my boost gauge so I guess I'll use it..
3 bar GM MAP just goes on a rubber vac line..
No TPS plan yet..
The AAV and Decel valve get ditched in favor of a Bosch rotary idle valve that works on a duty cycle along with the WUR, frequency valve, lambda system from the throttle switches to the brain and o2, harness, etc..

I have pretty much an entire 931 fuel system and lambda system in great working condition, half of it has made its way to separate plastic baggies for safe keeping.. All I need now is another 931 project to put all these known good parts on right?

Debating on wether or not to shoot the 931 FD full of engine fogger before storing it or maybe some 2stroke oil to keep it from rusting up and setting up whatever..
_________________
80 Turbo - Slightly Modified
Back to top
View user's profile Send private message Yahoo Messenger
Fasteddie313  



Joined: 29 Sep 2013
Posts: 1556
Location: MI

PostPosted: Wed Feb 15, 2017 2:35 am    Post subject: Reply with quote

So after all that work it turns out my feed and return lines are bassackwards..

I hooked up my feed line and ran my pumps and the thing wouldn't do nothin.. Tripped me all out..

Note, the external system pressure regulator goes on the fuel return line, not the feed line, it basically trapps X pressure in the whole system all the way up to the return line..

This mistake really discouraged me and put my mood in a bad place for a while but it's a new day, and all I really have to do is swap the cohline hardline barb ends on the distributor side feed/return, big/small, so it's really not that big of a deal..

And on these mysterious cohline barbs that are "precision" and you can't scratch or you ruin them and need special tools to put them on..
Fogetaboudit..

The machining on these barbs, looks like a toddler did it, they are far from some pieces of German machining perfection.. I'm still not going to scratch them but I expected something snazzy under there and found the opposite.. Standard air compressor line barbs are twice as precision perfection looking than cohline barbs..

I was also able to install cohline onto its barb by hand outside in the winter by doing nothing more than applying a bit of heat to the barb itself with a lighter to maybe 150f to where I could still handle it no problem.. Put a little heat in the metal and push it on some, let it transfer to the line, little more heat into the barb metal, push it on a bit more..
easy easy and didn't leak a sniff much less a drop..
_________________
80 Turbo - Slightly Modified
Back to top
View user's profile Send private message Yahoo Messenger
Display posts from previous:   
Post new topic   Reply to topic    924Board.org Forum Index -> Performance Upgrades All times are GMT + 11 Hours
Goto page Previous  1, 2, 3, 4, 5, 6, 7, 8, 9  Next
Page 3 of 9

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group