1993 Sundance Engine Repair Questions

Summer weather is here now, and I want to get my 1993 Sundance put back together and running. It has sat in my carport since 2018, and I pulled the motor and transmission in early 2019, which are the 2.5L NA 4-cylinder, and 3-speed automatic transmission.

I already have all the parts needed: a new set of standard-size bearings, new oil pump, new gasket set, new set of brass freeze plugs, new motor mounts, etc.

I have some questions about the planned DIY engine rebuild.

  1. What engine assembly lube should I use? What sealant to use on the freeze plugs? Do you roughen up the freeze plugs and the hole in the engine block with sandcloth before installing?

  2. I am replacing the crankshaft with a used crankshaft that does not appear to have any wear to the bearing surfaces. I do not plan to do any measuring, other than check for gross excess clearances. How long does it generally take to notice if that will be a problem? For example, if the engine runs fine for 10,000 miles, can I reasonably assume that it will run fine for many more years?

  3. When reassembling the connecting rods with new bearing inserts, the service manual says to label which cylinder the end cap is from, and to not mix them up. Unfortunately, I labeled them with a permanent marker, and the labeling has been lost. How important is it to use the correct end cap for each cylinder, when using a different crankshaft?

  4. The connecting rod for the cylinder which was knocking has visible discoloration and pitting on the inside of the bearing surface. I would like to replace it, but that would require removing this piston from the cylinder bore. If I do that, can I get away with reusing the same piston and rings, or is that likely to result in problems? It appears that replacing the pistons and/or rings requires a lot of measuring, which I’d rather avoid.

  5. Once I put this back together and fill the engine with oil, how do I get a new oil pump to pump oil? I believe the oil pump on this engine is driven by the intermediate shaft, which also runs the distributor.

  6. A previous owner removed the balance shaft assy, which was a popular modification to increase horsepower, and this is what likely led to the loss of oil pressure and ruined bearing and crankshaft in the first place. I got another balance shaft assy from a scrap engine, but had to cut the timing chain to remove it. Is it sufficient to reinstall the balance shaft assy without the timing chain, just to prevent oil pressure loss and to act as a baffle in the oil pan?

  7. If repairing this engine is going to be too difficult, or I am unable to put it back together properly, where can I get another used engine that runs for a reasonable cost? The junkyards here generally crush cars this old, and don’t bother to sell parts from them, even if the car was in good running condition.

I’ve always used Permatex engine assembly lube.

The bearing clearance can easily be check using Plastigage before assembly.

I don’t use a sealant on freeze plugs. I just make sure the holes in the block are clean before installing.

To prime the engine with oil. with the distributor removed, find a tool that will chuck into a drill and drive the oil pump shaft.

Bearing caps are matched to the rods. Should have used hand stamps to identify the caps

image

The rest of your questions would require seeing the engine/parts.

Tester.

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Note: I am not a mechanic.
Testor gave you good advice.
IMO, as long as rhe engine is out, replace all the rings on all the pistons. I may well be wrong, but if you replace the one connecting rod, the weight of the new rod would need to be the same as the old rod.
You will need a piston ring compressor tool. I don’t know if the pistons can be done from the bottom or must come out from the top.
Just seems to me an awful lot of labor involved to not do a complete job.
Just my opinion.
The real mechanics can give you more advice.

Connecting rods and caps are matched to each other and to tne correct direction. If you have lost that reference, the only solution is to remove each rod, try to match the caps and then take them to a machine shop to have them resized on the big end. The shop can then stamp them so you don’t mix tnem again. That knocking rod really needs this anyway since the big end is no longer round.

You can reuse the pistons and the rings but only in the same bores. Remove the head and the pistons come out the top. New head gasket of course. Check the valve seal in the head. Use brake clean into each intake and exhause to see if it leaks past the valve seat.

Suggest to take replacement crankshaft to the local auto-machine shop and ask them to measure it for you then. There’s no sense having to put it together, only to find its knocking, won’t hold oil pressure, etc. No need re-invent the wheel in other words, just for the saving the cost to pay an expert to measure the crankshaft bearing journals.

I expect you’re concerned that you’ll get caught up the common car restoration problem, a never-ending “if you are doing that, you might as well do this too” and you never finish anything. But you should still seek expert assistance when needed, and otherwise ignore the perfectionists’ recommendations .

I think if I were contemplating this job myself … hmm … I’d be inclined to ditch the original engine b/c it probably has a complicated electronic-controlled carburetor, a configuration that is very difficult to diagnose problems. Instead I’d install an OBD I electronic fuel injected engine. OBD I engines of that era are golden, all the good stuff, very little of the unnecessary stuff (e.g, this sort of engine, while it would have electronic computer controlled fuel injection, would be unlikely to have a complicated obd II style evap system). I’d also probably switch to a manual transmission, which would allow me to use a slightly smaller displacement engine. But a 2.5 L obd I with 3 speed auto should prove quite serviceable too, if you prefer to keep the transmission.

A machine shop can’t measure bearing clearances unless you bring the block, rods, bearings and crank in. And it’s not cheap.

Plastigage can give you the same answer for a lot less.

Tester

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No, they’re MACHINED as a set. This ensures the big end is perfectly sized and round. Mixing the rods and caps destroys that relationship, and the rod no longer fits the crank correctly. The correct resolution is to have all the rods/caps resized at a machine shop. Anything less invites disaster.

But that means they are still matched, so Yes. Which is why I said this;

The exception would be sintered rods which are cracked after machining and cannot be resized. But I doubt the Chryco 2.5 has these.

https://mgaguru.com/mgtech/engine/cs207.htm

Tester

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I understand your point. But would it be useful to first have a machine shop measure the crankshaft journals? To make sure the diameter matches the new bearing shells? To make sure the journals are round, not elliptical? to make sure the journals are the same diameter along their entire length? Or is it just easier as a practical method to just figure all that out when installing the crankshaft, & checking clearances using plastiguage?

If all the machine shop did was measure the journals for those parameters, maybe OP could do it themselves using a good caliper tool?

Odds of used crank being turned .010 already? On a 93-Sundance? Very very slim. Or, put a bearing set on a journal and see how it feels.

What do you folks think about this idea? I’d want to restore the engine to the original oem configuration, meaning to replace the balance shaft and timing chain to working order. Or is this being too much of a perfectionist given what the OP is trying to accomplish, get the car back to drivable condition?

If the balance shaft oil journals having no shaft could lead to no oil pressure then the former owner would have found out quick.

How does anyone know how long the car ran after the shaft was removed? Unknown history.

Unless the oil passages to the balance shaft bearings were plugged up, those passages would kill the oil pressure causing a bearing knock.

Understanding the oil path through the engine is critical to answering #6

And every professional engine builder out there that read the OP is cringing, grabbing there chest and gasping for air right now…

What about any oil sludge, carbon that was left in the oil gallery’s is probably rock hard and not coming loose with brake cleaner… The rings left open to the humidity (depending on where you live) and cylinder walls could be trashed, did the crank journals have any rust on them, if so probably pitted now… The cylinder walls need to be checked for taper, crankshaft that does not appear to have any wear to the bearing surfaces could look like that cause it has already been turned once possibly… You are probably screwed on the rod cap mistake…
On #5 you said in #6 that it was already removed, how was it working at that point then?? #6 should answer #5

You need a machine shop to check this thing out and from the sound of it probably just have them assembly it also… They might even have an engine run stand to run it on and make sure it test OK before you pick it up…

I aways used plastigage to double check the machine shop and or during disassembly to know what to expect when the machine shop called with the outcome of there check…

Now what is the condition of the camshaft and it’s followers, rust pitting, worn or flat lobes etc??

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Every Plymouth Sundance, 1986 - 1994 has a fuel injected engine. For an older 2.2 liter engine, it wouldn’t be necessary to replace the engine to add fuel injection.

Yesterday you and Bing had a discussion about training the homeless to rebuild carburetors, seems you feel carburetor work is so complicated that you would rather replace the engine. Training program canceled already?

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OP’s engine is fuel injected? Ok, I see what happened, my mistake. I was thinking by “NA” , OP meant the engine is carbureted. Presumably all that means is the engine has no turbo or supercharger.

NA means “normally aspirated”

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Is “NA” equivalent to saying “no turbo or supercharger”? Or is it more complicated than that?

It must be for you .

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