8070 troubles
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=192810
Printed Date: 15 Nov 2024 at 7:54pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: 8070 troubles
Posted By: cowkicker
Subject: 8070 troubles
Date Posted: 08 Jan 2023 at 5:42pm
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My 8070 is getting compression in the radiator, any ideas how to figure out where it is coming from. In case it is liner trouble, are there any tools out there to put air in each cylinder one at a time to see if I can get the water to bubble. Trying to narrow things down a bit. Hour meter not working but probably 2000 hrs on overhaul. Any help appreciated.
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Replies:
Posted By: DrAllis
Date Posted: 08 Jan 2023 at 5:47pm
Posted By: DMiller
Date Posted: 08 Jan 2023 at 5:48pm
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Not likely a sleeve unless not ever kept up on coolant changes or additives. Most Likely Head gasket or more typically often Nozzle Sleeve seal to head.
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Posted By: bigal121892
Date Posted: 08 Jan 2023 at 6:06pm
Head gasket, the 426's, don't have the injector nozzle sleeves.
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Posted By: cowkicker
Date Posted: 08 Jan 2023 at 6:41pm
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I took the head off yesterday and see no sign of any issues with the gasket, head, or block. I was going to pressure check the head today but the valve stem on my sealing plate is broken, hope to have time to get one tomorrow. But anyway, my air compressor only puts out 150 psi, is that enough pressure? I thought if I don't find any head trouble I might set the head back on, add water and put some air pressure to it. Hate to put it back completely back together until I find something kinda wrong. The head gasket rings on top of each cylinder look good, no signs of blackening or cuts. The only thing that looked a bit odd was on the bottom side of the gasket next to one of the rings. It was black and looked sort of burnt looking. Could compression get past gasket sealing ring without distorting or changing the looks of the ring itself? I sure wish I could send pictures.
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Posted By: DrAllis
Date Posted: 08 Jan 2023 at 7:07pm
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Were the head bolts retorqued after the engine was put together ?? I always would run the engine a couple of hrs at full throttle, dyno for a 1/2 hr full load, let the engine sit overnite and retorque to 165 ft lbs from 150 ft lbs when assembled. Head bolt holes cleaned with a tap and compressed air. Gun grease lightly on head bolt threads. I've experienced far more head gasket issues on engines with Bosch inj pump than Roosa Masters. That's why the engine rattles all the time....Bosch start of injection always the same. End of injection is variable. Roosa Master is the other way around.
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Posted By: cowkicker
Date Posted: 08 Jan 2023 at 7:10pm
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Head bolts were not retorqued.
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Posted By: SteveM C/IL
Date Posted: 08 Jan 2023 at 7:55pm
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Question...to retorque a head,do you just pull from where they set or do you start in sequence and slightly loosen then go tight? I'm sure I didn't retorque my 8070 head 200hrs ago after putting it back together. Now I'm concerned.
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Posted By: Ed (Ont)
Date Posted: 08 Jan 2023 at 8:00pm
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Just retorque all to spec. Do not loosen or you have to do twice again. Same as retorque on truck or car wheels.
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Posted By: DrAllis
Date Posted: 08 Jan 2023 at 8:00pm
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I torque to 150. Do my run time. Retorque COLD to the 165 max number. Remember, I have clean head bolt holes and light gun grease on the head bolt threads.
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Posted By: SteveM C/IL
Date Posted: 08 Jan 2023 at 8:13pm
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Well,memory isn't great these days but I know I washed and blew the holes clean while sleeves were out. Don't remember using a tap. Would have used my service manual for instruction on install. I'll have to go read it but doubt it says grease on threads.More likely engine oil? Maybe should have used the Cat bolt lube. LOL
Guess I'm not out much to try retorquing but I'd bet I went to 165 the first time so may not move.
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Posted By: Kevin in WA
Date Posted: 08 Jan 2023 at 10:15pm
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My guess is the sleeve protrusion above the block is low, I like to see .004 to .005 otherwise the block gets surfaced and counterbored to correct the situation.
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Posted By: injpumpEd
Date Posted: 09 Jan 2023 at 8:05am
Any discoloration on the gasket indicates an internal leak. It will likely be the side the pushrods are on. The AC procedure called for the special tool to torque the bolts under the rocker assy, but it flexes too much. Might be fine on a lower hp engine, but the upper end of the 426 hp levels and way beyond like we do, it just doesn't clamp the head down enough. Once the long ones through the rocker stands are torqued, the short ones nearby end up loose, so to speak. A good friend once told me how he torques the AC 426 head, so I do it that way and tell everyone I know. Get 6 spare of the short head bolts. Now, go through the sequence for all 26 like they show after the rocker assy is installed, but leave it off and use the 6 spare bolts in place of the long ones. Now go through all the steps, I go in 25# increments, until I get to the final 165. After going over them several times still at 165, once they quit moving, I then take out the 6 spares, and carefully install the rocker assy, moving the stands around to get the end rockers aligned properly, while ensuring the pushrods are all still in the rocker adjusting screws, a drop of clean oil in the pushrod cups helps them stick. Then final torque the 6 long head bolts through the stands, and finally adjust the rockers. Since I went to studs on my puller, I use 6 spare rocker stands instead. I've had guys tell me they have a short socket that will fit under the rocker shaft to direct torque the bolts with it installed, but I don't. It's a little extra work, but well worth the effort, and clamping the head down even is key, as long as everything is right like mentioned above, clean bolt holes, sleeve height etc.
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210 "too hot to farm" puller, part of the "insane pumpkin posse". Owner of Guenther Heritage Diesel, specializing in fuel injection systems on heritage era tractors. stock rebuilds to all out pullers!
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