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Post by JustinW on Jul 13, 2007 22:12:39 GMT 11
OK the rebuild has started tonight. Three hours exactly from drive in garage to engine sitting on floor. Will pull the head off it tomorrow and see how bad it is.
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Post by isuzumudman on Jul 13, 2007 22:44:11 GMT 11
Thinkin of U. How come? What went wrong?
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mattmurdoch
Isuzu Junior
when the going gets rough..
Posts: 68
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Post by mattmurdoch on Jul 14, 2007 11:19:42 GMT 11
im looking at doing the same. my rear crank seal is leaking so is the front. iv noticed some bad blow-by as well so im goin to take it out pull the head off check the valves, then do the piston rings awell, and while im at it have a look at both crank seals..
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Post by JustinW on Jul 16, 2007 12:40:57 GMT 11
Overheated it coming up Bombay Hill at full noise. Temp Gauge at 3/4 about 2/3 of way up hill, boiled (and seized) at top. Drove it using oil and smoking for the next couple of weeks.
Pulled it to bits on Saturday.
The head is cracked in three places (just by looking at it not crack testing). New head ordered.
Liner in #1 is cracked
Liner in #1 is badly scored as is the piston
Big end and main bearings and crank are mint
While getting the engine out found the joint at the bottom of the turbo dump pipe was loose, undid the nuts with my fingers. The front end of the exhaust system has been replaced recently. The oil cooler was covered in exhaust soot, so maybe the viscous fan getting lazy was not the only cause of the overheat.
Talked to the engine reconditioners that are going to put the new liners in and they recommend not using the Isuzu chrome liners as they have heat transfer problems, especially when towing (or thrashing it on big tyres!). They recommend cast iron liners, so thats what is going in.
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mattmurdoch
Isuzu Junior
when the going gets rough..
Posts: 68
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Post by mattmurdoch on Jul 16, 2007 19:00:30 GMT 11
one word *ouch*
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Post by geeves on Jul 16, 2007 19:02:52 GMT 11
I would be crack testing the block at the same time. It could be money well spent. Ive heard the recomendation about the chrome liners before but not because of heat It was because you cant hone them so if the bore isnt completly true the rings wont seat properly causeing bad blowby.
James had this problem with his reconed 2.8.
Strange to have no 1 bore as the bad one This normaly gets the best cooling. Did the cracked head cause everything else or was it all the same cause?
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Post by JustinW on Jul 17, 2007 11:28:08 GMT 11
Here is a photo of the cracked liner  |
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Post by JustinW on Jul 25, 2007 16:30:09 GMT 11
Update
Got a new head and have given it to the engine machinists that are doing the block to cut the valves in. Did you know there are two sizes of inlet valves. Gave the engine machinists the cleaned valves out of my "spare" engine and they rang me later in the day to say they were too small. The uncleaned ones out of my engine were about 3mm larger in diameter and will fit with a bit of machining. The exhaust valves out of both engines were the same.
The new liners went into the block today and they skimmed the exhaust manifold so I'll get a good seal when it goes back togeather.
The injectors needed new nozzles at about $120 each so I had the injectors out of the spare engine checked and they are OK. Bearings, seals etc ordered today so hopefully every thing will be ready to put back togeather on Friday night, engine back in and running on Saturday!
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Post by geeves on Jul 25, 2007 19:31:32 GMT 11
Why muck around with old valves They cant be that expensive in the grand scheme of things. I would be very cautious machineing valves. Most modern valves are have heavily case hardened surfaces
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Post by JustinW on Jul 25, 2007 20:11:24 GMT 11
Yeah, bit of brain fade on my part. Machinists didn't raise any concerns so not too worried
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Post by superturbocompound on Jul 27, 2007 12:53:13 GMT 11
if you are going to install cast iron liners,are you going to use the original rings?base on the feed back i got here,i was recommeded to do that to,but apparently the original rings might wear prematurely beacuse its only compatible with cast iron liners.as for the bigger valves,direct injection requires alot of air speed going into the combustion chamber,making the valves bigger would slow it down,i think this will lead to the knocking sound when idling more apparent....
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Post by superturbocompound on Jul 27, 2007 12:55:58 GMT 11
aahhh sorry,yours is a indirect injection,in the case of the bigger valves that would be a good idea.(didn't get much sleep last night)
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Post by geeves on Jul 27, 2007 17:38:47 GMT 11
re rings They must be a different material to the liner ie one chrome the other iron. This is to prevent the molecular structures trying to interlock causeing extreme wear.
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Post by superturbocompound on Jul 28, 2007 1:32:14 GMT 11
"base on the feed back i got here,i was recommeded to do that to,but apparently the original rings might wear prematurely beacuse its only compatible with cast iron liners"
what i was meant to say was that the "rings are only compatible with crome liners."(must get more sleep,all this office paper work is making mad)
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Post by Roger on Jul 28, 2007 11:32:28 GMT 11
Update Got a new head and have given it to the engine machinists that are doing the block to cut the valves in. Did you know there are two sizes of inlet valves. Gave the engine machinists the cleaned valves out of my "spare" engine and they rang me later in the day to say they were too small. The uncleaned ones out of my engine were about 3mm larger in diameter and will fit with a bit of machining. The exhaust valves out of both engines were the same. That's interesting. I'm curious of the age difference between your two engines. If the bigger valves came from an engine built after 8/95, and the smaller ones before that, it might explain something for me. If not, then  |
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Post by JustinW on Aug 9, 2007 11:46:22 GMT 11
Well it's all back togeather and running with the intercooler fitted.  Haven't cut the hole in the bonnet yet, so don't know if it's made a difference. I've got a horrible harmonic vibration at about cruise revs that I'm going to have to find before it drives me insane. Roger - my engine is 97, I think the "spare" was pre 95. It was in worse condition than my one! We took it to bits to take the aluminuim out of it and it had no rings! Note of interest, electronic 4JG2s don't run very well with only one of the three! control plugs plugged in. |
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beau
Isuzu Baby
green just doesn't cut it
Posts: 37
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Post by beau on Aug 11, 2007 13:35:42 GMT 11
im looking at doing the same. my rear crank seal is leaking so is the front. iv noticed some bad blow-by as well so im goin to take it out pull the head off check the valves, then do the piston rings awell, and while im at it have a look at both crank seals.. i dont want to sound all doom and gloom but leaking crank seals are a sign of lateral movement in the crankshaft. worn bottom end, bearings is the norm in this situation however not as common but can be an issue is the locator. this bearing and sleeve is different from the other four as it's job is also to stop lateral movement as well. valves dont have much to do with blow by, thats the job of the piston rings when mine was rebuilt you could move the piston around in the bore (455000kms) it required a rebore and oversize pistons. |
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Post by Roger on Aug 15, 2007 17:59:05 GMT 11
Roger - my engine is 97, I think the "spare" was pre 95. It was in worse condition than my one! We took it to bits to take the aluminuim out of it and it had no rings! Thanks for letting me know about the valves. I think it explains why my MU used to be slightly quicker than my friend Joe's MU. My MU is a 95 update and his is a 94 model. |
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Post by JustinW on Aug 30, 2007 11:12:47 GMT 11
OK next stage has been done, scoop has been fitted. First photo is the point of no return  Second photo cutting the ribs out  Will post completed view when the scoop has been repainted, it got a single coat the night we put it on. |
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Post by JustinW on Aug 31, 2007 13:19:21 GMT 11
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