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crd 2.8 mystery motor teardown
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=89134		 Page 1 of 1
Author:  pulsenpal [ Thu Aug 16, 2018 10:02 pm ]
Post subject:  crd 2.8 mystery motor teardown
so I bought this 2.8 crd off ebay--no history from a super dealer in Waco--
checked compression by hand crank and am concerned about cylinder 3

mounted unit in headstock stand and pulled head today--all looks good --cross hatching in all cylinders

nothing obvious in lifters-rockers will pull valves tomorrow
planning on installing rings

will plastigage rod journals

anyone have cross referrence for domestic cross match on ring sets?

pulsenpal

https://plus.google.com/u/0/b/105038664 ... K_VnY-B8wE
Author:  rancherman [ Thu Aug 16, 2018 10:37 pm ]
Post subject:  Re: crd 2.8 mystery motor teardown
pulsenpal wrote:
so I bought this 2.8 crd off ebay--no history from a super dealer in Waco--
checked compression by hand crank and am concerned about cylinder 3

mounted unit in headstock stand and pulled head today--all looks good --cross hatching in all cylinders

nothing obvious in lifters-rockers will pull valves tomorrow
planning on installing rings

will plastigage rod journals

anyone have cross referrence for domestic cross match on ring sets?

pulsenpal

https://plus.google.com/u/0/b/105038664 ... K_VnY-B8wE


Been there, done that, w/finding replacement rings. 'No Longer Available'.. Nor serviced by aftermarket.
The only way to put fresh rings in that engine, is to either get a custom set built.. or buy the 'late version' pistons and rings. Top ring on the early piston is .125 inch wide, top ring on the late and replacement piston is .095 wide. The second ring is also proportionally narrower on the newer piston.
Oil control appears to be the same between the two styles.

The "Keystone" ring, *top ring, isn't the easiest ring to build, and there are very few who do.
Grant piston ring, out of Anaheim Ca. http://www.grantpistonrings.com/ showed interest in working with me on a set. Mine cleaned up so they are getting re installed.

edit.. I didn't see your pics until now. Looks like some nice compression 'escape paths' headed toward the water port around that end cylinder. Make sure it cleans up!!! it looks 'deep'. But pics are misleading too.

When you say 'hand cranked' for compression testing, what was it doing on your #3? no resistance, wheezing?

When I see that much corrosion in the block water jacket.. (pretty crusty) that engine's been bleeding compression gas into the coolant for some time. Hopefully it's just a matter of cleaning up the surfaces, and a new headgasket/fasteners.. and not dealing with a cracked liner, sunk liner... etc.
Author:  pulsenpal [ Fri Aug 17, 2018 12:04 am ]
Post subject:  Re: crd 2.8 mystery motor teardown
thanks Rancher

bummer about rings--raises questions about extent of restoration

compression was checked with breaker bar turning crank with rubber glove finger obstructing glow plug port

more soon
Author:  rancherman [ Fri Aug 17, 2018 9:08 am ]
Post subject:  Re: crd 2.8 mystery motor teardown
pulsenpal wrote:
thanks Rancher

bummer about rings--raises questions about extent of restoration

compression was checked with breaker bar turning crank with rubber glove finger obstructing glow plug port

more soon



Gets pricey just to 'freshen up' real quick! If you are looking to build an engine for your long term vehicle, it's probably justifiable. but to 'fix up' a vehicle for resale purposes, y ou are going to 'work' for free.

Love the repurposing of your headstock!! That is a monster!! Left over oil field repair equipment??? Mine is a spare irrigation tower gear box Use whatcha got!!
;Image
Author:  Mountainman [ Fri Aug 17, 2018 12:57 pm ]
Post subject:  Re: crd 2.8 mystery motor teardown
Those rings are good for 500k+ so I wouldn't worry much unless you have wiped bearings or other signs of oil starvation. It's rare to see one of these engines to be beyond 250k miles currently, and the bottom end is almost always in great shape still unless it ate a valve.
Build the top and cross your fingers that the bearings are good, or you can check them all, but I don't know how you'll set the front of the crank up properly without the factory tools ($$$$)
Author:  pulsenpal [ Fri Aug 17, 2018 1:18 pm ]
Post subject:  Re: crd 2.8 mystery motor teardown
headstock came off lathe I bought 20 years ago and never powered up--machine came out of shipyard on east coast

beefy looking worm drive assembly spinner--Rancher--I like


Mountainman---not sure I understand comment on setting up front of crank--what is needed?
Author:  Mountainman [ Fri Aug 17, 2018 2:08 pm ]
Post subject:  Re: crd 2.8 mystery motor teardown
pulsenpal wrote:
headstock came off lathe I bought 20 years ago and never powered up--machine came out of shipyard on east coast

beefy looking worm drive assembly spinner--Rancher--I like


Mountainman---not sure I understand comment on setting up front of crank--what is needed?


There's specific spacing (depth) required when you install the front seal, and the tool helps. Oil leaks likely otherwise
Author:  Mountainman [ Fri Aug 17, 2018 2:38 pm ]
Post subject:  Re: crd 2.8 mystery motor teardown
Actually, I'd have to look at the tool, but I think the rear main seal tool also isn't just a flush fit, if so, the depth is critical. Let me know if you want me to check.
It's easy to fab many of the tools, but I don't know about the front seal puller or installer.
Author:  pulsenpal [ Fri Aug 17, 2018 11:10 pm ]
Post subject:  Re: crd 2.8 mystery motor teardown
thanks for guidance on assembly

plan now is to reassemble with least cost and run--if performance is good enough I will pull a second time and spend additional to correct leaks etc---head gasket kit ordered today

pulled injectors and valves today

all valves look good but injector pockets were packed with fine dust which hardened into soft cement
found definite failed seal between copper washer and mating aluminum seat in head--the likely cause of poor compression on #3

pics soon
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