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FYI on 4ZE1 head gasket... #449605 05/13/04 04:34 AM
Anonymous
Unregistered
After my guy at Sanels told me that my head (for the truck) is in excellent shape (he did a beautiful job), he showed me a report from AERA dated 1994 I believe. Apparently these engines are noted for having the head bolts loosen. I was fortunate in that as soon as it happened I stopped driving it and prevented any further damage but what a sucky thing ha? Now I'm gonna always think of that. I got conflicting advice from everyone I talked to about whether I should replace the head bolts or not but in the end I went with my guy at Sanels who said "If it was me, I would". Good enough for me...the guys a genious in the shop.

Re: FYI on 4ZE1 head gasket... #449606 05/13/04 02:50 PM
Joined: Apr 2003
Posts: 898
litnin Offline
Rock Warrior
Why don't you ask someone who knows more about Isuzu's that anyone. Send Jerry Lemond at jlemond@bellsouth.net a note.
He's a factory Isuzu guy who has been working with Isuzu's since they came to this country in '81. I'm sure he'll be able to tell you if that is a fact or fiction and give you advice on how to keep things right as you get it back together.


1995 Trooper LS auto 3.2 DOHC /w SOHC intake
1989 Trooper 2.6 auto
1989 I-Mark RS DOHC 1.6
1991 Stylus XS DOHC 1.8
Re: FYI on 4ZE1 head gasket... #449607 05/13/04 04:01 PM
Joined: Oct 2001
Posts: 4,016
strawmyers Offline
Isuzu Moderator
The head pins are stretch to torque. I would always put new ones in if the head is off anyway (might as well). Also, don't forget to chase out the holes they thread into with a tap. Junk stuck in there can lead to improper torque readings. JMHO


Sean Strawmyer
Back and ready to rock...... crawl.

From Indiana or surrounding states and interested in wheelin'? Check out www.mwior.com

Re: FYI on 4ZE1 head gasket... [Re: strawmyers] #449608 05/13/04 04:55 PM
Joined: Nov 2003
Posts: 78
L
lowflying90 Offline
Getting the Wheeling Fever
i was told isuzu did not use yield to torque head bolts.

Jeff

Last edited by lowflying90; 05/13/04 04:56 PM.
Re: FYI on 4ZE1 head gasket... [Re: lowflying90] #449609 05/13/04 11:36 PM
Joined: Apr 2003
Posts: 898
litnin Offline
Rock Warrior
2.6 is NOT Torque to Yield head bolts.


1995 Trooper LS auto 3.2 DOHC /w SOHC intake
1989 Trooper 2.6 auto
1989 I-Mark RS DOHC 1.6
1991 Stylus XS DOHC 1.8
Re: FYI on 4ZE1 head gasket... [Re: litnin] #449610 05/14/04 12:28 AM
Joined: Oct 2003
Posts: 1,318
chasespeed Offline
Body Damage is Cool
Here is a thought, if you havent bought the head bolts yet, and knowing there are issues with the head gaskets in these motors, I think it would be worth it to stud the top end while you are in there, but this is just MY HUMBLE OPINION, I dotn even know if there ae studs for this motor..but hey..

My 2 cents
Chase


Chase




Re: FYI on 4ZE1 head gasket... [Re: chasespeed] #449611 05/14/04 01:50 AM
Joined: Jun 2001
Posts: 846
pucci Offline
Rock Warrior
Quote
knowing there are issues with the head gaskets in these motors, I think it would be worth it to stud the top end while you are in there


My thoughts exactly. Being that I've yet to deal with a 2.6 head r&r, maybe there are fitment issues or something to prevent this from being a viable option, I dunno.

It is common with head bolt equipped import motors being tuned for performance to switch over to a stud/nut set up. A brief explanation on the reasoning behind it: http://www.sdpc2000.com/faq/kbhowto.asp?mt_node=34

I don't believe there are any Isuzu specific stud kits, but I wouldn't be suprised if there is something with the correct length/thread pitch available. Best bet would be to talk to someone at ARP if interested in this route.


2.6 Trooper
2.0 Impulse Turbo
Re: FYI on 4ZE1 head gasket... [Re: litnin] #449612 05/14/04 04:33 AM
Joined: Mar 2002
Posts: 198
doby/reddevil Offline
Wheeler
Quote
2.6 is NOT Torque to Yield head bolts.

2.8L are


89 trooper SAS/SOA v8 on 35s
locked f/r




my site:http://members.fortunecity.com/dobyreddevil
Re: FYI on 4ZE1 head gasket... [Re: doby/reddevil] #449613 05/15/04 01:56 PM
Anonymous
Unregistered
Thanks again guys. I will check out all the links. I did go ahead and purchase new head bolts and a tap for the block. I figured...why not? I've also decided to change the timing belt and water pump. I've put 50K + on it since I've owned it and figure that I should do these things while it is torn apart. I've also decided to drop the oil pan and really clean the block out as best I can cuz some debree did get down in there. My old head gasket looks as if something chewed a portion of the metal ring (on the gasket)around the number 4 piston. Not a pretty sight. I'm diappointed cuz I thought I would be putting it back together by now but I would rather put the time and effort into doing whatever needs to be done in order to make sure she's a happy picki when I turn that key again.

trooperless for now....
dawn...

Re: FYI on 4ZE1 head gasket... [Re: litnin] #449614 05/18/04 01:53 PM
Anonymous
Unregistered
Thanks litnin...I did contact jlemond and he was kind enough to reply and explain things to me. All those who've said the 2.6 does not use "torque to yield" head bolts are correct but the torque requirements are different depending on whether you are using old bolts or new ones. I opted for the new ones....I figure at this point in this job, I will take no chances and along with new head bolts, I have purchased a water pump, timing belt, oil pump, all new seals, plugs (of course), and more....It's already in pieces and everything is easy to get to right now and it's probably time to do them anyways. I've put over 50K since I've owned it and who knows what the previous owners did for routine maintenance and such. But thanks again litnin...as usual, you all are a great source of info and help....Below is the email reply from jlemond.

HI DAWN ,WELL THERE IS A REASON THE HEAD BOLT BACKED OFF , THE HEAD GASKET WHEN IT BLEW RELIEVED THE TENSION ON THE BOLT AND AS A RESULT IT LOOSENED UP , VERY COMMON ESP WITH AN AFTER MARKET HEAD GSKT, AS LONG AS THE OLD HEAD BOLTS ARE IN GOOD SHAPE , NOT PITTED ON THE SHANKS OR THE TOP OF THE BOLT IS NOT ROUNDED OUT WHERE THE HEX HEAD WRENCH GOES IN , THE BOLTS ARE FINE TO USE , JUST MAKE SURE THAT THE THREADS IN THE BLOCK AND ON THE BOLTS ARE NOT ROUGH, TAKE A CLOSE LOOK AT THE THREADS OF THE BOLTS , AND SEE IF YOY CAN SEE ANY PITTINGS IN THE THREADS , IF SO THEN REPLACE THEM, THESE ARE NOT TORQUE TO YEILD BOLTS ON THIS ENG AND CAN BE REUSED , IN FACT THE SHOP MANUAL EVEN LISTS THE TORQUE SETTING WITH NEW AND USED BOLTS , LIGHTLY OIL THE THREADS AND THE BLOCK THREADS AND MAYBE RUN A TAP IN THE BLOCK THREADA AND YOU WILL BE FINE , AALSO PUT A BIT OF OIL UNDER THE WASHER ON THE HEAD BOLT SO IT IT IS NOT TURNING AGAINST DRY ALUMINUM TORUQ THE BOLTS IN A CENTER TO END CIRCULAR SEQUENCE, FIRST STEP TO 55 FT LBS AND THE SECOND STEP TO 80 FT LBS, AND INSIST ON A FACTORY HEAD GSKT, AND DON,T USE ANY TYPE OF GSKT COATING , THESE FACTORY GSKTS ARE GRAFITE COSTED, MAKE SURE THE HEAD AND BLOCK ARE AS SMOOTH AS POSSIABLE , THE SLICKER THE BETTER ON THE ALUMINUM, THESE GSKTS ARE DESIGNED TO LET THE HEAD MOVE WHEN HEATING AND COOLING , ONLY TALKING LESS THAN1/2 OF 1 TEN THOUSEANDTH, BUT IT MUST MOVE OR IT WILL EVENTUALLY LEAK, WE HAVE SEEN MANY TIMES WHERE A MACHINE SHOP WILL SURFACE THE HEAD AND THE SURFACE WILL BE TOO ROUGH AND IN A BOUT A YEAR GSKT BLOWS AGAIN , AND OF COURSE IT IS ALWAYS THE BAD ISUZU DESIGN, HOWEVER IN THE 21 YEARS I HAVE WORKED ON THESE THINGS I HAVE SEEN MANY MANY OF THEM GO 200000 MILES AND THEN OVERHEAT BECAUSE OF A BAD WTR PMP RAD, OR WHAT EVER AND THE GSKT STILL BE IN CONTACT .. HOPE THIS HELPS SOME JERRY








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