98 2.2 Isuzu Hombre 0 Compression after new head - S-10 Forum
 
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post #1 of 24 Old 10-30-2011, 06:12 PM Thread Starter
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98 2.2 Isuzu Hombre 0 Compression after new head

Hello,

This 98 Isuzu Hombre overheated and blew the head gasket. The head ended up being warped and was replaced with a rebuilt one. Cylinders and pistons looked in decent condition.

I turned over by hand and it went smooth. After I buttoned her all up, I tried to start, and it cranked with no abnormal sounds except no firing. Fuel and spark where there so I did a compression check and found ~0psi on all 4. I had not messed with the timing and the head was bolted down to haynes torque specs.

what could be the cause of 0 on all 4? Im thinking timing, but after searching I can not find a definitive answer as to how many teeth it could have jumped to cause 0 compression and yet not have valve damage.

any help will be greatly appreciated, I just want to finish this thing for my buddy and get it out of my garage....

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post #2 of 24 Old 10-30-2011, 06:26 PM
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Re: 98 2.2 Isuzu Hombre 0 Compression after new head

Well, you could pull the valve cover to confirm the valves are moving, or remove the timing cover.

its not "common" for the chain to snap, but it does happen, skips teeth too. but for sure timing related it sounds like.

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post #3 of 24 Old 10-30-2011, 06:30 PM Thread Starter
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Re: 98 2.2 Isuzu Hombre 0 Compression after new head

valves are definitly moving, before I bolted down the valve cover, I turned it over by hand to make sure they were all in good order, which leads me to think timing... my lack of experience tells me that skipping 1 tooth wouldnt cause 0 compression, maybe low, but not 0.. but i really dont know.
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post #4 of 24 Old 10-30-2011, 07:31 PM
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Re: 98 2.2 Isuzu Hombre 0 Compression after new head

You did align the timing marks on the gears right? There is usually a big hole in the cam gear and a little mark on one of the teeth on the crank gear that have to align, see attached pic. If you did go through that process, it is unlikely that timing is the problem. The problem could be rings not sealing because they are stuck in the pistons caused by the overheating.
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File Type: pdf Cam Timing.pdf (19.7 KB, 86 views)

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post #5 of 24 Old 10-30-2011, 10:16 PM Thread Starter
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Re: 98 2.2 Isuzu Hombre 0 Compression after new head

I just finished checking the timing, and it is spot on...

I am at a complete loss....

I guess the next step is to try a leak down test and see where it is leaking....
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post #6 of 24 Old 10-31-2011, 11:47 PM
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Re: 98 2.2 Isuzu Hombre 0 Compression after new head

I just had the same problem. How did you tighten down your rocker arms? Just because they are moving doesnt mean they are right. loosen all your rocker arms to just a little wiggle, start the motor and then tighten till quiet plus a quarter turn for each valve
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post #7 of 24 Old 11-01-2011, 01:09 AM
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Re: 98 2.2 Isuzu Hombre 0 Compression after new head

The rings on these things don't like to be overheated. They tend to gunk up as well, contributing to oil consumption.
Speaking of which, try spraying some oil into each cylinder. It will cling around the piston and assist with initial compression, if the rings sticking is the problem that is.
Are you positive you got the right gasket for your engine? Small variations can cause a lot of problems, including compression loss and cooling system leaks.
Just asking, don't be upset..
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post #8 of 24 Old 11-01-2011, 11:53 AM Thread Starter
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Re: 98 2.2 Isuzu Hombre 0 Compression after new head

I am 99% sure that the gasket kit I got was the correct one, it was from AutoZone and was specific for the 2.2 98 Isuzu Hombre, not just an s10.

Also, I tightened the rocker arms to 22 ft-lbs as per the Haynes manual.
Obviously I am at a loss as to why this is happening, so anything is possible... when you readjusted the rocker arms and pushrods did this solve your problem?

On these engines I was under the impression that you did not have to adjust for valve lash. Im I correct?

Thanks guys!
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post #9 of 24 Old 11-01-2011, 12:51 PM
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Re: 98 2.2 Isuzu Hombre 0 Compression after new head

i think i have read a case or two here on the forum where the rocker arms were tightened too much after a rebuild, even when they said they followed the manual...

wouldnt hurt to loosen them and try it.

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post #10 of 24 Old 11-01-2011, 01:03 PM
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Re: 98 2.2 Isuzu Hombre 0 Compression after new head

22ft lbs in the manual is wrong. Trust me I been there. Take your valvecover off and I guarantee you have bent your pushrods.
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post #11 of 24 Old 11-01-2011, 01:16 PM
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Re: 98 2.2 Isuzu Hombre 0 Compression after new head

sorry that last post was from my iphone, now im by the comp. You don't have to adjust for valve lash, but the correct way to tighten your rocker arms on the 2.2 is how i stated in post #6. That haynes manual screwed me up big time. I ended up bending 3 pushrods, lucky i had a couple lying around because i couldnt find at any the parts store
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post #12 of 24 Old 11-01-2011, 06:08 PM Thread Starter
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Re: 98 2.2 Isuzu Hombre 0 Compression after new head

Ok I will check on this now.

Thanks for all your input guys, I hope you are right. Ill let you know soon.
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post #13 of 24 Old 11-01-2011, 07:59 PM
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Re: 98 2.2 Isuzu Hombre 0 Compression after new head

The 98 2.2 is a net lash valve train that is not designed for adjustment, at least the S10 isn't. I'm not sure you can treat these as adjustable, what would stop the rocker bolt from just backing off? Something sounds wrong here.

To get to the bottom of this, I would set the piston to TDC on the compression stroke and then see how many turns on the rocker bolt is needed to bottom out after the slop is taken out....spin the push rod while tightening to find this point. It should not take much more than a turn or so. If it does, then is seems that is what could be causing the valves to not close (if that's the problem). If you have a dial indicator, you can do this more accurately. In the old v8s we used to use shims or different push rod lengths to get them adjusted.

If I'm wrong on this, then let's get it out there.

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post #14 of 24 Old 11-01-2011, 08:17 PM
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Re: 98 2.2 Isuzu Hombre 0 Compression after new head

Yeah you are wrong.... the ways these 2.2 rocker arms are set is the way that i explained. The rocker nuts are lock nuts, they wont back off. your only meant to use them once. Your right that it is a none adjustable system. Start the engine up with the cover off and the rocker arms chattering. tighten one at a time to silent plus a quarter turn.
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post #15 of 24 Old 11-01-2011, 09:54 PM
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Re: 98 2.2 Isuzu Hombre 0 Compression after new head

Yup, just read the Haynes manual, it's wrong. *sigh*
Tighten to zero lash, then a quarter to a half turns more. This is based on a "cold" engine.
New lock nuts are relatively cheap, so replace the old ones as an insurance measure against them backing off. IMO.
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post #16 of 24 Old 11-02-2011, 03:54 PM
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Re: 98 2.2 Isuzu Hombre 0 Compression after new head

If you re-read your manual, it says "inch" pounds, not "foot". A lot of difference..

Quote:
Originally Posted by mugency View Post
I am 99% sure that the gasket kit I got was the correct one, it was from AutoZone and was specific for the 2.2 98 Isuzu Hombre, not just an s10.

Also, I tightened the rocker arms to 22 ft-lbs as per the Haynes manual.
Obviously I am at a loss as to why this is happening, so anything is possible... when you readjusted the rocker arms and pushrods did this solve your problem?

On these engines I was under the impression that you did not have to adjust for valve lash. Im I correct?

Thanks guys!
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post #17 of 24 Old 11-02-2011, 04:10 PM
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Re: 98 2.2 Isuzu Hombre 0 Compression after new head

my manual says foot lbs
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post #18 of 24 Old 11-02-2011, 11:22 PM
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Re: 98 2.2 Isuzu Hombre 0 Compression after new head

I'll be darned! Well, entries can be wrong can't they! LOL.
I'll stick with zero plus 1/4 to 1/2 turns more. Enough for hydrolic action, but not enough to prevent closing. Just based on experience of course, you can do as you like..
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post #19 of 24 Old 11-02-2011, 11:50 PM
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Re: 98 2.2 Isuzu Hombre 0 Compression after new head

on 98+ just tighten the rocker arms nuts to spec. as said before, they are net lash, there is no way to make adjustments. On 94-97 rockers are similiar to old style SBC chevy design in the way they need to be adjusted for lash.

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Re: 98 2.2 Isuzu Hombre 0 Compression after new head

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on 98+ just tighten the rocker arms nuts to spec. as said before, they are net lash, there is no way to make adjustments. On 94-97 rockers are similiar to old style SBC chevy design in the way they need to be adjusted for lash.
you are right but I think you have the years wrong. I've done it that way on my 97 and it runs perfectly fine.

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post #21 of 24 Old 11-07-2011, 09:13 PM
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Re: 98 2.2 Isuzu Hombre 0 Compression after new head

well, on the 98+ heads have a key-way for the rocker to sit in so you just tighten them to the torque specs and your done, on the 94-97 valvetrain is similiar to the SBC design like I said so I believe you have to adjust them, I could be mistaken though, they may be set up for net lash as well but the rocker arms are of an older design so it makes sense they need an adjustment of some sorts

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Re: 98 2.2 Isuzu Hombre 0 Compression after new head

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well, on the 98+ heads have a key-way for the rocker to sit in so you just tighten them to the torque specs and your done, on the 94-97 valvetrain is similiar to the SBC design like I said so I believe you have to adjust them, I could be mistaken though, they may be set up for net lash as well but the rocker arms are of an older design so it makes sense they need an adjustment of some sorts
are you thinking of the guide plates for the pushrods? the 97 has them too.
I've never seen a "keyway" for rocker arms for any other engine that doesn't have a valve lash adjustment.

I can tell you with 100% certain the 97 doesn't have a valve lash adjustment. I bought a new engine for mine and the booklet says to tighten the rocker arm nuts to 22 ft/lbs.

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post #23 of 24 Old 11-11-2011, 09:06 AM
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Re: 98 2.2 Isuzu Hombre 0 Compression after new head

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are you thinking of the guide plates for the pushrods? the 97 has them too.
I've never seen a "keyway" for rocker arms for any other engine that doesn't have a valve lash adjustment.

I can tell you with 100% certain the 97 doesn't have a valve lash adjustment. I bought a new engine for mine and the booklet says to tighten the rocker arm nuts to 22 ft/lbs.
check out a newer style head like 98 -2003 theres a groove in the rocker boss that the rocker sets into assuring alignment , and you just tighten to spec , no valve lash setting and i believe if you are a little heavy or light on torque it wont affect valve ive seen them taken off and put back on on edge of road with no adjustment
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Re: 98 2.2 Isuzu Hombre 0 Compression after new head

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Originally Posted by screamncj View Post
check out a newer style head like 98 -2003 theres a groove in the rocker boss that the rocker sets into assuring alignment , and you just tighten to spec , no valve lash setting and i believe if you are a little heavy or light on torque it wont affect valve ive seen them taken off and put back on on edge of road with no adjustment
yeah it's only for rocker arm alignment. has no effect on valve lash.
I think some of these guys are confused as to what valve lash actually is.

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