What do you replace when you're inside the engine?

[Emit]

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Car has been sitting for an unknown amount of time, at least ten years, it started and ran after rebuilding the fuel system without serious problems, I'm doing a frame off restoration as there is frame/everything rot.
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I've the engine in my garage on a stand, I'm committed to doing the heads (snapped bolts that need professional removing, want to do the headgaskets/check valves and there is a snapped "easy" out stuck in a spark plug). The lower carrier/crankcase must be replaced as the mounts are rotted off.

If I've got all that out then I have a serious case of "while-I'm-there-itis", I guess I'll be doing the bearing shells, but should I do the piston rings too, it that the kind of thing that you do if you're looking at them? I wasn't able to compression test the engine because of the snapped spark plug, but it wasn't smoking when I got it running.

Should I change the liners if I change the rings?

[David T]

It might be more economical to consider just replacing the whole motor. Used ones are available or you could consider a Stage II from DMCH for more power. The PRV is a very durable little motor and even a high mileage one could be in good shape.

[Emit]

It might be more economical to consider just replacing the whole motor. Used ones are available or you could consider a Stage II from DMCH for more power. The PRV is a very durable little motor and even a high mileage one could be in good shape.

It had crossed my mind, but I've already purchased the crankcase, I'll be doing the work, and I figure that the cost of gettiing a replacement engine would be a lot more than the service parts of what I'm looking at here.

Bearings, rings, maybe a few liners if they are looking bad. And I guess that's my question, what should I replace as a matter of course inside the engine? Odo shows 27000miles

[David T]

It had crossed my mind, but I've already purchased the crankcase, I'll be doing the work, and I figure that the cost of getting a replacement engine would be a lot more than the service parts of what I'm looking at here.

Bearings, rings, maybe a few liners if they are looking bad. And I guess that's my question, what should I replace as a matter of course inside the engine? Odo shows 27000miles

At 27K miles, unless the motor was never serviced (no oil changes, wrong oil, not enough oil) and parts are damaged, all you should need to do is clean everything up and use new gaskets and seals. The bottom end of the PRV is almost bulletproof. Inspect the upper case in the valleys for corrosion. When reinstalling the liners the protrusion (nip) is critical to get right and follow the torquing procedure for the cylinder heads. Before you go buying parts see what's out there now for a whole "lump". The one cost that may determine if it is cheap enough is if you can find one close by so you can pick it up yourself and save the shipping. Unless the motor was overheated or the upper case corroded through in the valleys, it didn't need to be disassembled. The motor is the most durable thing in a Delorean.

[dn010]

At 27K miles, unless the motor was never serviced (no oil changes, wrong oil, not enough oil) and parts are damaged, all you should need to do is clean everything up and use new gaskets and seals. The bottom end of the PRV is almost bulletproof. Inspect the upper case in the valleys for corrosion. When reinstalling the liners the protrusion (nip) is critical to get right and follow the torquing procedure for the cylinder heads. Before you go buying parts see what's out there now for a whole "lump". The one cost that may determine if it is cheap enough is if you can find one close by so you can pick it up yourself and save the shipping. Unless the motor was overheated or the upper case corroded through in the valleys, it didn't need to be disassembled. The motor is the most durable thing in a Delorean.

Perhaps you missed his first post where he indicated the motor mount section of his lower crankcase was rotten and he already bought a replacement?

You shouldn't need to replace any liners or rings at 27K unless you really want to, there should be very little wear on them and it's easier to leave those alone - removing them means you'll need new seals and sealant. You don't have to change liners if you put new rings in. If you're doing bearings, I have new in box deloreango connection rod bearings if you're interested in them. I'd replace the timing cover seal and the rear main as well regardless of mileage. Check the plastic timing guides while you're in there but those should also have very little wear. This is all assuming the engine was maintained. IF not then all bets are off.

[Emit]

Thanks all, so my takeaway is that at 27k miles the engine should be fine and I don't need to do rings/bearings/liners if my inspection doesn't show anything drastic, as I'd just be doing extra work with the possibility of messing it up. But if I was feeling adventurous I could do the rings and the bearings as I'm there already (making sure to clamp the liners in place so they don't move at all).

I'll see what I find when I pull the heads, the oil had a lot of horrible sludge in the pan and a little bit of clear liquid, but I suspect/hope that was from fuel when I was trying to start it as the injectors were stuck open, certainly smelled like old gas/varnish... I understood that all bets are off if the engine is in trouble.

Thanks very much for the offer of the bearings, but I'm too far away from you and hopefully I may not need them.

[dn010]

Even with liner locks, I'd still be concerned about a liner moving with removing and installing pistons - I want to know for sure it's sealed. If a re-ring was really necessary, I'd be removing the liners (which will allow you to see what all that anti-freeze did to your aluminum block from all the years sitting in the water jacket), giving the liners a quick hone, re-ring, get the pistons back in the liners and install them as an assembly.

While I am sure there are people who do follow the instructions on the "critical" sleeve protrusion and torque that David mentions above, all I've been doing is slapping .15mm STEEL shims on all cylinder liners with hylomar and using the 25-50-75 torque procedure. No failures yet.

[dmc4087]

Agree with this, my block looked ok until I removed the liners. The aluminium below just disintegrated


Even with liner locks, I'd still be concerned about a liner moving with removing and installing pistons - I want to know for sure it's sealed. If a re-ring was really necessary, I'd be removing the liners (which will allow you to see what all that anti-freeze did to your aluminum block from all the years sitting in the water jacket), giving the liners a quick hone, re-ring, get the pistons back in the liners and install them as an assembly.

While I am sure there are people who do follow the instructions on the "critical" sleeve protrusion and torque that David mentions above, all I've been doing is slapping .15mm STEEL shims on all cylinder liners with hylomar and using the 25-50-75 torque procedure. No failures yet.

[Emit]

Little update:

I've taken off the heads, lower crankcase, crankshaft, liners with the pistons. Block looks ok once I cleaned out all the sludge, no rot around the edge of the liners.

All bearings look good, so I'm on the fence about replacing them, I'm all for changing them if I'm in there as long as it doesn't make things worse! Input appreciated :)

I'll re-ring the pistons, hone the liners, stick in the shims and done.

70995

[dn010]

If you have new bearings, pop them in - you're already in there. Don't forget to use assembly lube.

[David T]

If you have new bearings, pop them in - you're already in there. Don't forget to use assembly lube.

I would use Plastigauge to measure the old and new bearings but if you have new ones you might just as well put them in. The rings should not be necessary to replace either but it is also worth it to measure them for wear. At this point it sounds like all of the "hard parts" should be alright but of course replace all of the seals, shims, hoses, and gaskets. Cut open the oil filter and inspect it for any metal. If you don't see any metal there should be no need to replace any "hard" parts. The main thing to look for is any signs of the motor being overheated or the block rotting under the intake manifold. You should also have the heads cleaned up and the valves and valve seats touched up and lap the valves in. For break-in add a quart of Marvel Mystery Oil and change the oil and filter after 500 miles. If the car is a 5 speed, inspect the clutch but consider replacing it, the T/O bearing and the pilot bearing. Replacing the clutch slave cylinder is also a good idea now and probably also the master (and the plastic hose if it still has it). Have the injectors cleaned and tested, replace the spark plugs, ignition wires, O2 sensor, cap and rotor. The water pump is also easy to replace now. On a car that has been "sitting" you don't know how old any of this stuff is, it could be original and shortly after getting it to run all of the old stuff will start to fail. Now is the time to replace it all while it is all apart. If you still have the original plastic header tank replace it too along with the radiator if it is the original with the plastic end tanks. As you can figure, reviving and old car can get expensive.

[dn010]

Maybe it's just the picture, but it looks like your timing chain guides have more than 27K miles of wear on them- looks more like 127K miles on them. Those are pretty cheap to replace, I'd change those out while it is opened up. Did the liners have any ridge at the top?

[Emit]

Maybe it's just the picture, but it looks like your timing chain guides have more than 27K miles of wear on them- looks more like 127K miles on them. Those are pretty cheap to replace, I'd change those out while it is opened up. Did the liners have any ridge at the top?

Thanks for the heads-up, I thought the grooves in the guides were supposed to be there, I'll change them. is there a method to check the timing chain?



71009

No ridges in the liners, or shiny spots, appear to be alright.

[Delorean Industries]

Quality internals are no longer being manufactured. Everything is the lowest bid overseas junk. Supplied and distributed by a singular kingpin with personalized branding when required. Perfect example:

https://store.delorean.com/102620-piston-liner-assy.html

If anyone thinks quality internals can be produced, imported, marketed, and have a known company-wide minimum profit margin at that price point. Hope you haven't discarded your stock components. This goes for everything on the market currently for internal application on the PRV for owner installation.

[Emit]

Quality internals are no longer being manufactured. Everything is the lowest bid overseas junk. Supplied and distributed by a singular kingpin with personalized branding when required. .

I'm a bit lost on this comment, do you mean I should be keeping my existing guides because the quality of all replacement parts is subpar? Or that they come from other countries and I can get guides from the right countries? Maybe I misunderstood something.

[Delorean Industries]

Yes, keep your stock guides; if they are worn, the nylon wear strips can easily be replaced with a suitable material. The reproductions will fail before break-in is completed.