Rebuild time!

The place to discuss problems and routine maintenance questions and tips. This is for topics that are specifically diesel-related.
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Halden
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Location: Everertt, WA
Isuzu vehicle(s): 1983 Diesel LS Long Bed 4x4

Piston Knurling?

Postby Halden » Mon Mar 25, 2019 4:28 pm

I was wondering what thoughts on piston knurling are? With that taper I have I am wondering if that could possibly help take up the slop and reduce piston slap... Any thoughts or input?

Thanks

Halden
It's not pronounced "Ih-soo-zoo", it's pronounced "It-screws-you"
83 LS Long Bed Diesel
64 Chevy C20 w/ 283 & 4 speed.
05 Sonata with a standard
At work: 2000 Blue Bird TC2000 w/ 5.9

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Paul
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Location: Central Calif Coast

Re: Rebuild time!

Postby Paul » Mon Mar 25, 2019 8:24 pm

Halden - -

When overhauling the engine I previously mentioned to you with 3 1/2 thou of taper I did knurl the pistons. There are some photos below.

I was able to borrow a Versnick manual knurling tool from a friend. He also gave some advice: ie, knurl the crap out of them and then use a flat file to bring them to the desired clearance. I did this and the engine is running OK, no oil consumption and no piston slap. This is a turbo engine.

If you just knurl them a little to get a new dimension, the peaks of the knurl will wear off right away and you will have no lasting effect. With the heavy knurl and file routine, you get some expanded flat areas to carry the thrust and some valleys in between to carry some oil.

The photo is of a piston knurled but not yet filed.

Another thing you may want to take a look at is the upper ring groove wear/clearance. Our upper grooves were worn to 'very sloppy'. We fixed this by turning the groove out enough to accommodate an upper ring groove spacer. These are installed above the new piston ring. Problem may be to find the spacers. These used to be very common but not so much now. An alternative is to use part of an oil ring for the upper spacer, not quite as wide as a genuine spacer but more available.

You can see the top ring groove spacer in the photo.

Piston 1 left.jpg


Piston 2 on Versnick knurler 2 .jpg


Piston 2 on Versnick knurler 3 .jpg
'84 P'UP 2 wd diesel, 5 spd with 0.78 fifth gear and differential back to 3.73.

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Paul
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Re: Rebuild time!

Postby Paul » Mon Mar 25, 2019 10:58 pm

Halden - -

There is a Versnick on ebay right now: https://www.ebay.com/itm/Vintage-Piston ... Swl1FcP95e

Paul
'84 P'UP 2 wd diesel, 5 spd with 0.78 fifth gear and differential back to 3.73.

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Halden
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Isuzu vehicle(s): 1983 Diesel LS Long Bed 4x4

Re: Rebuild time!

Postby Halden » Tue Mar 26, 2019 8:46 am

Thanks for the input, Paul. Whew that is one expensive tool. Pretty expensive for one time use. I'll look into seeing if any machine shops in the area do this or something. Would like to eliminate some slop. I'm done running this thing hard. Time to sit back and relax. I imagine some knurling would last quite a while with that attitude

Yes that is the key, you need more surface area so the knurl does not wear too quickly. Jerry Lemond mentioned to me I should be okay with that much taper just throwing new pistons in there. Mine had some kiss marks from the valves and some scuffing on the side. Wondering if high engine speeds for long extended periods of time caused that. We're talking danger zone/ketchup territory. Things get a little sketchy up there.
It's not pronounced "Ih-soo-zoo", it's pronounced "It-screws-you"
83 LS Long Bed Diesel
64 Chevy C20 w/ 283 & 4 speed.
05 Sonata with a standard
At work: 2000 Blue Bird TC2000 w/ 5.9

Red Truck
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Re: Rebuild time!

Postby Red Truck » Tue Mar 26, 2019 11:57 am

For the knurling, I suggest Bud's Machine Shop out of Lakewood, WA (budsmachine.com). Some friends get a lot of their racing engine work from them, and if they don't do it, I'm sure they'll recommend someone who does. Very friendly and cordial staff there.
'87 Isuzu pickup 2.3 gas, 5spd, 4WD

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Halden
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Postby Halden » Sun Apr 07, 2019 10:15 pm

Always a pleasure to start getting parts from JLEMOND. Love seeing "ISUZU GENUINE PARTS"

First of 2 or 3 boxes.
Bronze Valve Guides
stainless int and exh valves.
Stem seals.
4x4 oil pump
Wrist Pin bushings.
Bearings and thrust washers
Cam bearings
Block plugs
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20190407_195945.jpg
It's not pronounced "Ih-soo-zoo", it's pronounced "It-screws-you"
83 LS Long Bed Diesel
64 Chevy C20 w/ 283 & 4 speed.
05 Sonata with a standard
At work: 2000 Blue Bird TC2000 w/ 5.9

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puttputtinpup
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Re: Rebuild time!

Postby puttputtinpup » Mon Apr 08, 2019 5:56 am

It's like Christmas, isn't it?

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Halden
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Isuzu vehicle(s): 1983 Diesel LS Long Bed 4x4

Re: Rebuild time!

Postby Halden » Mon Apr 08, 2019 11:35 am

Pressure testing oil cooler. Great success! 50psi no leaks.

Get a couple plugs. A pressure regulator. And a way to attach a quick connect to a plug. Give it some pressure in a bucket of water.
Attachments
20190408_091946.jpg
It's not pronounced "Ih-soo-zoo", it's pronounced "It-screws-you"
83 LS Long Bed Diesel
64 Chevy C20 w/ 283 & 4 speed.
05 Sonata with a standard
At work: 2000 Blue Bird TC2000 w/ 5.9

User avatar
puttputtinpup
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Joined: Sat Oct 08, 2005 5:18 am
Location: Winston Salem, NC

Re: Rebuild time!

Postby puttputtinpup » Mon Apr 08, 2019 12:20 pm

That's good! Looks like the old style cooler. Is it? I was never sure which year they changed over. Probably been told, just forgot

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Halden
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Re: Rebuild time!

Postby Halden » Mon Apr 08, 2019 3:21 pm

It's an 83. I'm not sure what the differences between the years are.

Yes it's definitely like Christmas

Took my rad to a good shop today. Evaluation was it's not worth saving unless painted into a corner. Had a hunch since you can see some oxidizing and leaking all around it. Need to replace it.
It's not pronounced "Ih-soo-zoo", it's pronounced "It-screws-you"
83 LS Long Bed Diesel
64 Chevy C20 w/ 283 & 4 speed.
05 Sonata with a standard
At work: 2000 Blue Bird TC2000 w/ 5.9

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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: Rebuild time!

Postby JoeIsuzu » Mon Apr 08, 2019 8:35 pm

puttputtinpup wrote:That's good! Looks like the old style cooler. Is it? I was never sure which year they changed over. Probably been told, just forgot

The cooler changed with the '84 model. '84 and up require a different filter.

Jack

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puttputtinpup
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Re: Rebuild time!

Postby puttputtinpup » Tue Apr 09, 2019 1:38 am

JoeIsuzu wrote:
puttputtinpup wrote:That's good! Looks like the old style cooler. Is it? I was never sure which year they changed over. Probably been told, just forgot

The cooler changed with the '84 model. '84 and up require a different filter.

Jack

I've owned 82 (old cooler-small filter) and an 84 (lg 2-stage filter). I wasn't quite sure what the 83 had

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Halden
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Joined: Thu Mar 29, 2012 5:20 pm
Location: Everertt, WA
Isuzu vehicle(s): 1983 Diesel LS Long Bed 4x4

Re: Rebuild time!

Postby Halden » Tue Apr 09, 2019 8:40 am

puttputtinpup wrote:I've owned 82 (old cooler-small filter) and an 84 (lg 2-stage filter). I wasn't quite sure what the 83 had


I've thought about installing a bypass filter. Would like to just add some fun mods... Also a coolant filter sometime...
It's not pronounced "Ih-soo-zoo", it's pronounced "It-screws-you"
83 LS Long Bed Diesel
64 Chevy C20 w/ 283 & 4 speed.
05 Sonata with a standard
At work: 2000 Blue Bird TC2000 w/ 5.9

User avatar
Halden
Regular Member
Posts: 2898
Joined: Thu Mar 29, 2012 5:20 pm
Location: Everertt, WA
Isuzu vehicle(s): 1983 Diesel LS Long Bed 4x4

POP testing

Postby Halden » Thu Apr 11, 2019 2:27 pm

Tested my injectors. All popped low. Should pop at 1500 (actual spec is 1493 PSI). They were all popping around 1200. Spray patterns were not good. For precup engines they should atomize the fuel in a nice cone shape without streams

I raised the pressure to spec on a couple of them to see if it helped. Perhaps it did marginally. Then I cranked one above 2000 PSI. Seemed to help. Obviously you would not want to run that. Though It did eliminate all dripping

Here is some super slow motion footage.

You can see the spray pattern is not so good. You can see it's not crisp pop and some dribble occurs. They all shot the fuel in streams. This would explain the black smoke my truck produced under load.

You should also here a nice clean crisp pop. When testing. I'll string some other footage together and upload it to YouTube.

A couple of them just sort of peed the fuel out for lack of a better term

Ignore the stupid music. My phone adds that to these videos
Attachments

[ Play Quicktime file ] 20190411_092811_001.mp4 [ 5.69 MiB | Viewed 191 times ]

It's not pronounced "Ih-soo-zoo", it's pronounced "It-screws-you"
83 LS Long Bed Diesel
64 Chevy C20 w/ 283 & 4 speed.
05 Sonata with a standard
At work: 2000 Blue Bird TC2000 w/ 5.9

User avatar
Halden
Regular Member
Posts: 2898
Joined: Thu Mar 29, 2012 5:20 pm
Location: Everertt, WA
Isuzu vehicle(s): 1983 Diesel LS Long Bed 4x4

Re: Rebuild time!

Postby Halden » Sun Apr 14, 2019 9:09 pm

Los pistonés

It's like Christmas getting packages from Jerry Lemond.
Attachments
20190413_202537.jpg
It's not pronounced "Ih-soo-zoo", it's pronounced "It-screws-you"
83 LS Long Bed Diesel
64 Chevy C20 w/ 283 & 4 speed.
05 Sonata with a standard
At work: 2000 Blue Bird TC2000 w/ 5.9