Broken timing belt

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JoeIsuzu
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Location: Germantown (next to Elvistown), TN
Isuzu vehicle(s): Original owner, '83 LS Diesel, 5-spd, 2wd, Long Bed, restoration in progress!

Re: Broken timing belt

Postby JoeIsuzu » Sat Jul 07, 2018 1:44 pm

makaraft wrote:I’m ordering a rocker arm assy, push rods and a new tensioner bearing.

Really? From where? The only source I know of for rocker arms and pushrods is the used/salvage market.

Jack

dorf
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Joined: Sun Jul 17, 2011 1:03 pm
Location: N. Central Arkansas 81 LUV 4x4

Re: Broken timing belt

Postby dorf » Sat Jul 07, 2018 2:49 pm

Looking back...I guess I've done 5 belt changes on my 81

Always used NAPA belts...never a problem and used the same book as yours

Good luck...I mean that sincerely

Just my 2 cents

makaraft
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Location: Utah
Isuzu vehicle(s): '81 Chevy Luv Diesel

Re: Broken timing belt

Postby makaraft » Sat Jul 07, 2018 3:38 pm

Update: I found the cam sprocket had a small amount of play forward and aft, tried unscrewing the bolt and it seems like it’s spun off in the cam. I know it had a key way so I know the sprocket didn’t spin, but perhaps the forward and aft play messed up the belt as it spun. I’ll try to get the bolt out and replace it.

FiatSpider2
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Location: Sunny Tampa Bay Florida

Re: Broken timing belt

Postby FiatSpider2 » Sat Jul 07, 2018 9:20 pm

Did you check the timing marks before you started disassembling things? If the cam sprocket did not spin it would indicate a lot of thrust was put against it potentially from having the thrust bushing out of place.

How accurate is your torque wrench? Clickers are notorious for slipping the setting or jamming and over-torquing things. I am at the point where I trust my old beam and pointer over the clickers.
FiatSpider2 (4FB1 Isuzu Diesel powered 1978 Fiat Spider)

makaraft
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Location: Utah
Isuzu vehicle(s): '81 Chevy Luv Diesel

Re: Broken timing belt

Postby makaraft » Sun Jul 08, 2018 10:56 pm

JoeIsuzu wrote:
makaraft wrote:I’m ordering a rocker arm assy, push rods and a new tensioner bearing.

Really? From where? The only source I know of for rocker arms and pushrods is the used/salvage market.

Jack



They're all used, I found someone with some spare parts on the forum.

makaraft
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Posts: 18
Joined: Mon Jan 16, 2017 1:15 am
Location: Utah
Isuzu vehicle(s): '81 Chevy Luv Diesel

Re: Broken timing belt

Postby makaraft » Sat Jul 21, 2018 5:52 pm

Update: got all new parts installed and redid the timing procedure properly. Everything is running, but now I’m paying attention to the temp gauge. It’s not cooling itself properly, temp keeps climbing and never stabilizes. I’ll try taking the thermostat out to see if that’s what the issue is.

That may have been my original issue; overheating and then seizing the cam/crank, then as it cooled it was able to move again. I do have all new temp sensors on top of the thermostat housing (ordered off rock auto). I’ll post once I have the chance to do more trouble shooting.

dorf
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Posts: 333
Joined: Sun Jul 17, 2011 1:03 pm
Location: N. Central Arkansas 81 LUV 4x4

Re: Broken timing belt

Postby dorf » Sat Jul 21, 2018 6:38 pm

I had similar problem ...installed 180 degree thermo from GM 350 cu inch engine

ALSO PUT springs in all radiator hoses to prevent collapsing hoses

No more problems ...runs in center of gage now...if extended climb .....the fan engages at the top of gage marking

makaraft
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Posts: 18
Joined: Mon Jan 16, 2017 1:15 am
Location: Utah
Isuzu vehicle(s): '81 Chevy Luv Diesel

Re: Broken timing belt

Postby makaraft » Sat Jul 21, 2018 7:18 pm

My fan is set up to run all of the time, just mounted on the water pump pulley. I hadn’t thought about it being engaged or not until now.

makaraft
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Posts: 18
Joined: Mon Jan 16, 2017 1:15 am
Location: Utah
Isuzu vehicle(s): '81 Chevy Luv Diesel

Re: Broken timing belt

Postby makaraft » Sat Jul 21, 2018 8:10 pm

Yeah, took the fan off and spun the water pump pulley while looking in the thermostat housing, no fluid movement. I may be in the market for a pump here shortly.


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