Replace or rebuild? ‘90 L98
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
I'd throw out there that it's more about the "back and forth, than it is about force. You need some force, but in the one I did, oil and back and forth worked fast than simply trying to force the rings through the rust.
Pro
Joined: Jan 2022
Posts: 689
Likes: 245
From: Spokane Wa.
That has been my experience also. The crust in the cylinder can build up if you start forcing it in one direction and actually prevent further movement in that direction. Back and forth gives it a chance to dissipate some and for the oil to get into the area that was just uncovered allowing it to soften the crust underneath.
Thread Starter
Instructor
Joined: Jul 2021
Posts: 238
Likes: 66
From: Frederick, MD
Tried to pry on it a little bit today, but no luck. The flywheel turner tool doesn't arrive until tomorrow, so time to focus on other issues for today (instrument panel display is acting weird, and I want to see the mileage).
Thread Starter
Instructor
Joined: Jul 2021
Posts: 238
Likes: 66
From: Frederick, MD
Got the instrument panel display to work properly last night, basically by just taking it out, inspecting, and reinstalling. Loose connection?
Mileage is confirmed at 120730 - I was close! That also means it went down in summer of 2018 (maybe a hot AZ day of 100+ contributed to overheating).
Also an aside, the DIC buttons weren’t working properly, so I repeated the process of desoldering and replacing the little button switches on that board, a process which I did previously to my ‘91. Luckily I still had a pile of those switches, so one less thing to worry about! After this the CCM is throwing a code 13 which mean there’s still some wiring issue there - connector didn’t seem very snug so maybe that’s it.
It’s also throwing a code 41 (ECM serial data), and the ECM isn’t responding to diagnostic mode, so either I have a bad ECM or another wiring issue to track down.
NOT a fan of electrical diagnosis but at least the FSM has great diagnostic charts.
Flywheel tool is coming this evening so back to that later.
Mileage is confirmed at 120730 - I was close! That also means it went down in summer of 2018 (maybe a hot AZ day of 100+ contributed to overheating).
Also an aside, the DIC buttons weren’t working properly, so I repeated the process of desoldering and replacing the little button switches on that board, a process which I did previously to my ‘91. Luckily I still had a pile of those switches, so one less thing to worry about! After this the CCM is throwing a code 13 which mean there’s still some wiring issue there - connector didn’t seem very snug so maybe that’s it.
It’s also throwing a code 41 (ECM serial data), and the ECM isn’t responding to diagnostic mode, so either I have a bad ECM or another wiring issue to track down.
NOT a fan of electrical diagnosis but at least the FSM has great diagnostic charts.
Flywheel tool is coming this evening so back to that later.
Oil Producer
Joined: Apr 2014
Posts: 9,371
Likes: 2,736
For those who have done this, im curious.
in this situation, where head gasket perforation is suspected, if you pulled the heads and used a piece of say 1x1x 6” long, could you shock each cylinder by bonking it with a 2lb sledge on the end of the wood? or would that just wreck stuff? to shock/break things loose i mean
in this situation, where head gasket perforation is suspected, if you pulled the heads and used a piece of say 1x1x 6” long, could you shock each cylinder by bonking it with a 2lb sledge on the end of the wood? or would that just wreck stuff? to shock/break things loose i mean
Last edited by VikingTrad3r; Apr 26, 2023 at 05:09 PM.
Pro
Joined: Jan 2022
Posts: 689
Likes: 245
From: Spokane Wa.
For those who have done this, im curious.
in this situation, where head gasket perforation is suspected, if you pulled the heads and used a piece of say 1x1x 6” long, could you shock each cylinder by bonking it with a 2lb sledge on the end of the wood? or would that just wreck stuff?
in this situation, where head gasket perforation is suspected, if you pulled the heads and used a piece of say 1x1x 6” long, could you shock each cylinder by bonking it with a 2lb sledge on the end of the wood? or would that just wreck stuff?
Oil Producer
Joined: Apr 2014
Posts: 9,371
Likes: 2,736
I would say that is a next step if tools/ lubricants don't get it free. You would't do any harm that way as the ignition of the charge when firing would put a lot more force to the piston then you are going to be applying that way so I don't see you doing any more damage to it. That is as long as you aren't applying it to a very small area of the top of the piston. A block of hardwood that will fit down into the cylinder with a mallet to drive with should work just fine.
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Thread Starter
Instructor
Joined: Jul 2021
Posts: 238
Likes: 66
From: Frederick, MD
I would say that is a next step if tools/ lubricants don't get it free. You would't do any harm that way as the ignition of the charge when firing would put a lot more force to the piston then you are going to be applying that way so I don't see you doing any more damage to it. That is as long as you aren't applying it to a very small area of the top of the piston. A block of hardwood that will fit down into the cylinder with a mallet to drive with should work just fine.
And then if even THAT doesn't help, I'll move to take the pan off and see what it looks like underneath. For all I know there is a bent rod or worse which ends going down this path.
Pro
Joined: Jan 2022
Posts: 689
Likes: 245
From: Spokane Wa.
Yeah, I can see myself going down that road. I think it will have to wait until I get my country place with more shop room. I'm looking all the time but haven't found that one that makes the wife as happy as it makes me happy. For some reason she gets this idea that a nice kitchen is as important as a big shop is. I will say that as I love to eat good food as much as she likes making it that one that meets both needs will have to be found.
Advanced
Joined: Apr 2023
Posts: 99
Likes: 14
From: Erie Pa.
Im rooting for you to get it unstuck. I have broken a few motors loose doing what you are doing. Dont get up the hope. tbh, the pulling the head is a good idea. See what you are dealing with. Could be (I hope not) so bad that you will never break it loose. But never know until you go there. If you pull the heads, and it looks decent, keep soaking.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
For those who have done this, im curious.
in this situation, where head gasket perforation is suspected, if you pulled the heads and used a piece of say 1x1x 6” long, could you shock each cylinder by bonking it with a 2lb sledge on the end of the wood? or would that just wreck stuff? to shock/break things loose i mean
in this situation, where head gasket perforation is suspected, if you pulled the heads and used a piece of say 1x1x 6” long, could you shock each cylinder by bonking it with a 2lb sledge on the end of the wood? or would that just wreck stuff? to shock/break things loose i mean
I used a round log rather than a 2x4, so as to spread the load around to the edges of the piston and not inadvertently cave in the top of the piston.
Thread Starter
Instructor
Joined: Jul 2021
Posts: 238
Likes: 66
From: Frederick, MD
It’s hard to see in the pics, but there’s a serious layer of rust on the cylinder walls and it’s really hard. I did bang with a mallet on all four pistons and they seem pretty solidly stuck.
If there’s any chance this thing will move I will need to remove the other head and do the same thing. But I’m starting to wonder if it’s a worthwhile exercise. I will try to clean up the accessible rust with some solvent and a nylon brush, and take a closer look at the cylinder walls. But if they are pitted badly, will it recover enough once it’s firing to last any significant amount of time?
Thread Starter
Instructor
Joined: Jul 2021
Posts: 238
Likes: 66
From: Frederick, MD
The used ones that are relatively close to me are in Phoenix, and between $2500 and 2900 depending on mileage (70k to 160k miles). The good thing about those is they are run tested (with video) and include harness, ECM, intake, etc. and it would be good to have the spare components. Anyway does that cost seem reasonable?
Pro
Joined: Dec 2021
Posts: 547
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At this point I'd pull the engine and disassemble it. Ball-hone the cyls, remove the rings and clean the pistons. Evaluate the crankshaft bearing condition. Check the heads and decks for flatness. (Something caused the gaskets to let go again after the previous repair. ). Evaluate what you have. If this is going to be a patch-job, new rings, bearings, and a hand job valve lapping may get it running again with minimum expense.
Re #3: I think the water damage is going to be pretty deep and extensive. If the other 7 bores clean up satisfactorily, and the pistons clean up, are free on the pin, etc, consider having #3 sleeved to restore the bore to std size for the original piston.
Cheers.
Re #3: I think the water damage is going to be pretty deep and extensive. If the other 7 bores clean up satisfactorily, and the pistons clean up, are free on the pin, etc, consider having #3 sleeved to restore the bore to std size for the original piston.
Cheers.