8 snapped head studs - help please??

aussie993gt-faux · 07-08-2009, 01:13 PM

Hey ppl, will appreciate any advise.

I recently received my 3.6L from Japan. I was stripping this for cleaning prior to install and have found 8 snapped head studs (now this was only out of three heads - the exhaust is still in the way of the fourth so I havent checked there) so there may be several more!

I knew these engines do snap a stud or two over time but at least 8?????

What is wrong, is this indicative of a more serious issue?
The car probably did a lot of idling and stand still in Japan so maybe ran hot?

Anyway is it a big issue. or just a matter of taking heads off maybe skimming and replacing with high tensile studs??

I would really appreciate some advice.

Thanks.

aussie993gt-faux · 07-08-2009, 01:23 PM

I should add that the snapped studs were both from top and bottom heads ie the dilivar and non-dilivar studs (they are snapped) not pulled.

im hoping theres no cylinder head or piston damage from heat over time...any experiences.. i was just blown away by 8 studs and there will be more!

springer3 · 07-08-2009, 03:34 PM

Sorry, no clue. But 8 broken studs in just 3 heads? At 4 per head, there are only 12 total. How could the engine even run?

I check my head studs each time I adjust the valves. So far all are tight. Engine is original. It was my understanding that snapped head studs were rare. I suspect that after the first one breaks, the others soon follow, as the neighbors of the broken stud start to carry its load. Perhaps the engine was driven long after the popping noises started, or perhaps it was run after the fan belt broke, and all the damage occured in one event. Any warranty?

aussie993gt-faux · 07-08-2009, 11:34 PM

No warranty.

The only thing i can do is split this engine open and see if there is any damage.
from an overheat?

I actually have 2 3.6s now as the first one i bought was accident damaged so they replaced it with this one.

Maybe between the two I can sort something out.

This must be the only 3.6 in the world with 8+ snapped head studs...lucky me

Oracle · 07-08-2009, 11:51 PM

I know that Japanese cars sit for long periods and the island is very humid, I've been told that Porsche from Japan usually require much more work than from NA.
Anyway, good luck and use this opportunity for a good engine overhaul

aussie993gt-faux · 07-09-2009, 05:57 AM

what could the damage to the cylinder head be?

darth · 07-09-2009, 06:36 AM

any corrosion on the broken studs? Once the heads are off check for large amounts of carbon buildup which could raise the C/R.

aussie993gt-faux · 07-09-2009, 07:11 AM

darth, yes it seems the divilar coating had worn off that leaving them exposed to corrosion and they snapped.

Im more concerned that this may have occured in 1 overheating event as springer suggested or even if it was a gradual snapping of study heat may have got into the cylinder head and damaged it.

darth · 07-09-2009, 07:37 AM

Snapped studs are caused by increased stress on the stud (i.e. due to higher than normal compression)or a weakening of the stud (ie. due to corrosion or fatigue) beyond what the stud is spec'd out to handle. If your concern is a heat issue, you'll find out once the the pistons are removed and you,re able to see the cylinders/piston walls for signs of scouring. Heat will expand the size of the pistons beyond the clearance specified between the piston/cylinder wall and in the worst case a seized engine will occur.

Bill
90C2

springer3 · 07-09-2009, 08:45 AM

Quote:

Originally Posted by aussie993gt-faux

what could the damage to the cylinder head be?

Anything from zero to destroyed. Depends on what happened. If the car was driven a lot after the studs got loose, the loose parts hammer each time the cylinder fires. Things can get pretty banged up and the seals can get flame-cut. If the studs broke in a single over-temperature event, the heads could be OK - but get a valve job and new seals sure.

07-08-2009, 01:13 PM	#1
aussie993gt-faux User Join Date: Dec 2008 Posts: 24	8 snapped head studs - help please?? Hey ppl, will appreciate any advise. I recently received my 3.6L from Japan. I was stripping this for cleaning prior to install and have found 8 snapped head studs (now this was only out of three heads - the exhaust is still in the way of the fourth so I havent checked there) so there may be several more! I knew these engines do snap a stud or two over time but at least 8????? What is wrong, is this indicative of a more serious issue? The car probably did a lot of idling and stand still in Japan so maybe ran hot? Anyway is it a big issue. or just a matter of taking heads off maybe skimming and replacing with high tensile studs?? I would really appreciate some advice. Thanks.

07-08-2009, 01:23 PM	#2
aussie993gt-faux User Join Date: Dec 2008 Posts: 24	I should add that the snapped studs were both from top and bottom heads ie the dilivar and non-dilivar studs (they are snapped) not pulled. im hoping theres no cylinder head or piston damage from heat over time...any experiences.. i was just blown away by 8 studs and there will be more! Last edited by aussie993gt-faux; 07-08-2009 at 02:03 PM. Reason: ino

07-08-2009, 03:34 PM	#3
springer3 Addict Rennlist Member Join Date: Jul 2003 Location: Atlanta Posts: 2,195	Sorry, no clue. But 8 broken studs in just 3 heads? At 4 per head, there are only 12 total. How could the engine even run? I check my head studs each time I adjust the valves. So far all are tight. Engine is original. It was my understanding that snapped head studs were rare. I suspect that after the first one breaks, the others soon follow, as the neighbors of the broken stud start to carry its load. Perhaps the engine was driven long after the popping noises started, or perhaps it was run after the fan belt broke, and all the damage occured in one event. Any warranty? __________________ 1992 White/Tan C2

07-08-2009, 11:34 PM	#4
aussie993gt-faux User Join Date: Dec 2008 Posts: 24	No warranty. The only thing i can do is split this engine open and see if there is any damage. from an overheat? I actually have 2 3.6s now as the first one i bought was accident damaged so they replaced it with this one. Maybe between the two I can sort something out. This must be the only 3.6 in the world with 8+ snapped head studs...lucky me

07-08-2009, 11:51 PM	#5
Oracle User Join Date: Oct 2003 Location: Calgary, Alberta. CANADA Posts: 400	I know that Japanese cars sit for long periods and the island is very humid, I've been told that Porsche from Japan usually require much more work than from NA. Anyway, good luck and use this opportunity for a good engine overhaul

07-09-2009, 05:57 AM	#6
aussie993gt-faux User Join Date: Dec 2008 Posts: 24	what could the damage to the cylinder head be?

07-09-2009, 06:36 AM	#7
darth Addict Rennlist Member Join Date: Feb 2003 Posts: 640	any corrosion on the broken studs? Once the heads are off check for large amounts of carbon buildup which could raise the C/R.

07-09-2009, 07:11 AM	#8
aussie993gt-faux User Join Date: Dec 2008 Posts: 24	darth, yes it seems the divilar coating had worn off that leaving them exposed to corrosion and they snapped. Im more concerned that this may have occured in 1 overheating event as springer suggested or even if it was a gradual snapping of study heat may have got into the cylinder head and damaged it.

07-09-2009, 07:37 AM	#9
darth Addict Rennlist Member Join Date: Feb 2003 Posts: 640	Snapped studs are caused by increased stress on the stud (i.e. due to higher than normal compression)or a weakening of the stud (ie. due to corrosion or fatigue) beyond what the stud is spec'd out to handle. If your concern is a heat issue, you'll find out once the the pistons are removed and you,re able to see the cylinders/piston walls for signs of scouring. Heat will expand the size of the pistons beyond the clearance specified between the piston/cylinder wall and in the worst case a seized engine will occur. Bill 90C2