My '89 9670 build


For you lovers of the Class 8's and bigger.

Golden Jubilee
Golden Jubilee

Posts: 4576

Joined: Thu Nov 29, 2012 9:28 pm

Location: Lyman, IA

Post Wed Feb 05, 2020 7:46 pm

Re: My '89 9670 build

A week or so ago I was climbing Bozeman pass when the turbo hose popped half way up the hill. I didn't recognize it for what it was, it sounded like a tire. limped over the hill and got a new hose at a shop on the Livingston side.
Fast forward to this Monday, I just got loaded to go back to Montana, I was pulling out of town and when I got on the high side of the Roadranger, I put some fuel to it and I popped a head gasket!. Not sure if the two failures are related, they happened so far apart.
Limped the loaded trailer to my Bosses house and bobtailed home. When I raised the cab, there were two broken headbolts staring me in the face.
So the '89 is parked until I can get the head off and the stub of the bolts out. I spent today getting the '83 back legal with the state.

Site Admin
Site Admin

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Joined: Thu Nov 29, 2012 9:10 am

Location: Nampa, Idaho

Post Wed Feb 05, 2020 11:13 pm

Re: My '89 9670 build

Hope not to difficult to get it back on the road. Really puts a crimp in things when on the road. My Son still has a vehicle sitting about 200 miles away from home. Hopefully it was only a head, but he planned on an in frame rebuild once he gets it back home. Never ends and still have to work to get the money for the work needing done. Be Safe on the Road!

Golden Jubilee
Golden Jubilee

Posts: 4576

Joined: Thu Nov 29, 2012 9:28 pm

Location: Lyman, IA

Post Sun Aug 16, 2020 3:29 pm

Re: My '89 9670 build

After looking around and asking about at shops, finding no one who wanted to take on the job, I pulled the head myself. Found a total of three head bolts snapped. On right under the head of the bolt, one right at the block surface and one 1 1/2" below the deck. 1st one came out with vice grips once the head was removed, 2nd I was able to turn with a punch and hammer, after 3 turns, enough was proud of the block that I could grab with vice grips and get it rest of the way out.
The last on was going to a bitch and I asked around at the best welder in the area but couldn't get someone to come and get it out.
An old Cummins mechanic told me to to take a valve push rod and cut a section out of the tube and put it down the hole and weld it to the stub. The Pushrod tube is a good fit and about the same size as the bolt.
I went to town and got some fresh 7018 rod. It took three tries for me to get it. 1st I had the current too high and blew through the side of the tube, 2nd had the current too low and it didn't hold, 3rd time wasn't great but it held and I was able to back the stub out.
I got my headbolt tap to chase the threads, and it went in hard. Taps don't last forever and depending on the hardness of what they are cutting can wear in as little as 10 holes. My hadbolt tap has done a few engines with over 30 headbolts per, it is time for a new tap. Two steps forward one back. After being successful in getting the stub of the headbolt out, it would be height of stupidity to snap a tap off in the hole because I was in a hurry or too cheap to get another tap.
The headbolts are 11/16x 16 TPI so is not a tap you are going to find at the local hardware store.
I ordered a new tap and pushrod to replace the one I sacrificed to the headbolt removal. I think I am going to frame that stub and tube, not because how hard it was to get out, but the confidence it took to try. When the best welder in the area didn't want to attempt, I was on my own, and if I was going to loose the engine, I am glad I wasn't paying someone to ruin it for me.
Once I chase all the bolt holes, drop a new head gasket on the block and get the head back on, it should go smooth.
There is some cracks on the piston crown not sure if they are from climbing the hill when the hose blew, or from before I owned the engine, but I am not going to inframe the engine now. I would burn some oil between oil changes before all this happened, and I suspect the cracks have been there for some time. Cummins allows for some cracking on the lands between the valve reliefs, which is where these cracks are.
If I were going to overhaul (which I am not) I would have it machined for lower press fit liners and then it would be a fairly bullet-proof engine. I just don't see me putting enough miles on to go through all the work.

Golden Jubilee
Golden Jubilee

Posts: 8297

Joined: Thu Dec 27, 2012 12:45 pm

Location: Canada's left Coast

Post Sun Aug 16, 2020 5:02 pm

Re: My '89 9670 build

https://youtu.be/tL_oLlnMh6k
My Dad used to use this broken bolt removal method back in the 1950s.
I have had to remove a few broken studs. I bought a left-hand drillbit set from the SnapOn truck guy. This has worked, for me, so far.
I would rather have tools I do not need than to need tools I do not have
“Never argue with stupid people, they will drag you down to their level and then beat you with experience.
Mark Twain

Golden Jubilee
Golden Jubilee

Posts: 4576

Joined: Thu Nov 29, 2012 9:28 pm

Location: Lyman, IA

Post Sun Aug 16, 2020 5:41 pm

Re: My '89 9670 build

Headbolts in the 855 are HARD, HHS drills will not touch it. Carbide would have been required, With that you need a mag drill and coolant to drill it out, and it is a blind hole in the block.
Push rod tube is thick enough and just the right size.
It just took the confidence to have at it.

Golden Jubilee
Golden Jubilee

Posts: 4576

Joined: Thu Nov 29, 2012 9:28 pm

Location: Lyman, IA

Post Fri Sep 18, 2020 6:38 pm

Re: My '89 9670 build

Its been a month, and I finely got it out for its first spin on the road. So far everything seams good. Monday its off to town for an inspection to keep the insurance company happy. I am a fully qualified inspector, I have been through the CVSA course and have more then the required experience, Both are more than enough for the DOT but not for the insurance company! For them, anyone other than myself is preferable.
The bigger bunk and the exhaust exiting further back, it is alot quieter than the shorter cabover.

Golden Jubilee
Golden Jubilee

Posts: 4576

Joined: Thu Nov 29, 2012 9:28 pm

Location: Lyman, IA

Post Fri Oct 09, 2020 9:58 am

Re: My '89 9670 build

I took the truck on its first trip in 9 months. It did fairly well but had a few things "shake out" on the trip. First was the thermocouple for the Pyro, the fitting in the exh stripped but I was able to dress the threads and re-insert the fitting.
2nd was the A/C quit, when I got home for the bolt the holds the belt in tension had snapped, so that was an easy fix.
3rd was it melted the wiring harness to the remote voltage regulator after two long pulls. The exh reached 1000 deg after the turbo on those pulls. The harness and the hoses for the heater run under the turbo, not that close, in my opinion, but I guess at 25 mph there isn't enough airflow to get the heat away. Turbo must be dull red hot on those pulls. I'll be making up a two layer heat shield to shield the harness and the heater hoses. Fortunately, I could "unplug" the remote regulator and run on the internal to get home.
This truck is now 31 years old and I have owned it for all but the first 6 years. I am wearing out things than normally don't wear out. The dipstick tube is in the "wheel wash" from the right steer tire, and has rotted out. IHC wants between $250 and $300 plus shipping depending on who I source it from. I am making one from stainless steel tubing that should outlast my needs.
The next problem is the Tractor protection valve. It sits between the false floor under the drivers feet. It started leaking slowly. When I pulled up the floor it still had the metal tag on it and the IHC part number, so likely the original, I know I have never replaced it and it is unlikely it was done so in the 1st 6 years of the truck life. The part has been superseded by Midland, and I ordered one, but also found a OEM rebuild kit for $12 so ordered that at the same time. The kit will be here today and the valve will not until later next week. So it looks like I'll rebuild what I have.
Last I noticed a small amount of play in the drag link. I have one coming from Michigan Truck Spring.
What is kind of annoying is that a week before I had to pay someone to do an annual inspection of the truck. You'd think some of these problems (not all) would have been obvious at that time. My Insurance company will not accept an inspection that I do, even though I am a full qualified inspector.

Golden Jubilee
Golden Jubilee

Posts: 4576

Joined: Thu Nov 29, 2012 9:28 pm

Location: Lyman, IA

Post Sat Oct 10, 2020 6:09 pm

Re: My '89 9670 build

Made a new dipstick tube from 304 stainless. I thought the bell-mouth end of the tube was formed on the tube itself, but after cleaning I found it was a separate piece, I was able to remove from the old tube and braise onto the stainless new one. 1st one lasted 30 years, it was plain steel, this one should outlast the truck.
Without pictures it never happened.
Attachments
dipstick.jpg
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