Engine swap opinions

macleanflood

I break sh!t
Original poster
Supporting Member
Ride of the Month Winner
Joined
Jul 24, 2021
Messages
11,890
Location
Fall Creek, OR
Bearings look bad...no oil pressure at warm idle...here are my options as I see it...let me know your thoughts and opinions!

1. Oil dial gauge arriving Friday...it's going to verify that either the original and replacement sender were wrong and I have oil pressure at warm idle...either way...roll in new crank bearings and check everything with Plasti gauge.

2. Reman engine...

https://portland.craigslist.org/mlt/pts/d/portland-40-jeep-engine-rebuilt/7449313929.html#
$2400. They have a couple ready to go. I pull my core and swap. Fast and done in a weekend.

Yeah I want a Cummins crate engine...I eventually might go that route...but I don't have $10k for the engine and adapters.

3 would be have my engine rebuilt...but every place I talk to is six to eight months out and I'm guessing that slips to a year.

And 4 is of course it does have low oil pressure at idle and just run the beans out of it until it really dies...but I want to drive it from Oregon to Montana this summer on dirt roads and while I think it would be a grand adventure swapping an engine on a trail someplace my wife would kill me.

-Mac

Ps I bought the Jeep last spring...PO said it was a rebuilt engine...I spent six months chasing down misfire codes...220k on the odometer.

IMG_20220321_134457896.webp
 
  • Sad
Reactions: Wildman
Since you mentioned plastigauge, did you happen to check the main bearing clearance when you pulled the cap? That would be a good indicator of the need for a rebuild on the crank. But yeah, the picture you posted of the bearing does make it look like thats the problem - and it fits your oil pressure symptoms.

Easiest course of action sounds like a new crank, or getting this one machined, and swapping the bearings appropriately. But, there could also be other wear issues elsewhere in the mill.

Are you burning any oil?
 
Since you mentioned plastigauge, did you happen to check the main bearing clearance when you pulled the cap? That would be a good indicator of the need for a rebuild on the crank. But yeah, the picture you posted of the bearing does make it look like thats the problem - and it fits your oil pressure symptoms.

Easiest course of action sounds like a new crank, or getting this one machined, and swapping the bearings appropriately. But, there could also be other wear issues elsewhere in the mill.

Are you burning any oil?

A little yes...so that's also rings...which yeah reinforces the just swap the engine and be done with it...

No I'm kicking myself for not Plasti gauging that bearing...it was pouring rain and I was in a gravel driveway under a canopy...my back was soaked. (And then the next day was sunny and 73 degrees and I had to work...)

-Mac
 
I look at these situations as time=money.

How much time have you wasted on your current engine up to this point? How much more time are you willing to waste on it? How do you value your time in terms of a monetary number per hour basis?

Assuming the $2400+core swap is everything it says it is, I’d wager it’s starting to seem like a pretty good deal.
 
Since you're looking and pricing things have you looked to see what the cost difference is for a stroker engine? I mean if you already have to replace it then it might be worth it to at least price one out.
 
Just keep in mind that your $2400 price tag will be closer to $3K. Reason being, it would be silly to re-install the new engine with some of the existing parts. For example, a new radiator, water pump, fan clutch, pulleys, hoses (radiator and heater), fan belt, fluids and more will be needed. It may also be the time to install a new clutch and other related parts.

That said, getting a re-manufactured engine is a good idea. You'll save time and have a warranty. Just do your homework on who to buy from, but you already know that part!
 
  • Like
Reactions: Wildman
I would vote for the reman. Like you said it's ready to go with a quick install and a warranty. A stroker would be nice but I bet it would a pretty long wait and more than double the cost.
 
Last edited:
I would vote for the reman. Like you said it's ready to go with a quick install and a warranty. A stoker would be nice but I bet it would a pretty long wait and more than double the cost.

No arguement that a stroker will cost more and it might be a while longer to get one. But I'd kick myself in the butt if I didn't at least research it and find out what the cost difference was and what the wait period would be.

BTW: mac there were a couple low mileage 4.0's on marketplace last week.
 
Another thought on this subject, Mac. If you decide that based on everything you know the best course of action is to do a reman engine, do not let the turnaround time deter you. Right now, you have a running jeep that does not seem to be about to die on you, and as such you are not in a crisis situation. Supposed the thing does die on you in six months - all the sudden you are in a crisis situation with very limited options.

My advice: Order the reman now, make it a stroker if that suits you, and baby the jeep until it comes in. At that point, swapping in the new mill will require the least amount of down time compared to fixing you current motor even in the best of circumstances.
 
My understanding about the stroker is it's about $6 or 7k for a Golan...and it gets worse gas mileage than my existing engine.

I called the shop in Portland...two hour drive north...and they don't have any on the shelf... they're willing to rebuild mine with a 4 to 6 week turnaround/downtime time.

Clutch was done 6 months ago. Headers were swapped a couple of months ago. Water pump makes sense. I flushed the radiator/engine and it was full of crap.

Haven't checked marketplace...might find a cheap 4.0 core I can bring in for a rebuild rather than being down for a month...I have a truck and motorcycle so it's not that big of a deal. I can pull the tranny and transfer case and put sound deadening material on the firewall and underside of the tub.

Thanks folks!

-Mac
 
Amazon YSTools gauge arrived...drove the Jeep around the lake...never dropped below 20 PSI... here's it idling in the driveway after...gaff taped the gauge to the windshield...new sensor...#3 arriving middle of next week... wiring diagrams printed out should I need to chase that down...looks like shared ground splice is on the right side of the transmission and that will be the first thing I check if sensor #3 doesn't fix it. No word from Napa on ATK availability... curious! Thanks!

ezgif-5-3d2cdf37f6.gif
 
Bearings look bad...no oil pressure at warm idle...here are my options as I see it...let me know your thoughts and opinions!



View attachment 317676
I have seen bearings in much worse condition than that. Unless you have an outright bottom end noise, the first thing you need to do to properly diagnosing a low oil pressure concern is........ Get a mechanical gauge on it and verify low oil pressure before you drop the oil pan and start tearing things down.
 
I have seen bearings in much worse condition than that. Unless you have an outright bottom end noise, the first thing you need to do to properly diagnosing a low oil pressure concern is........ Get a mechanical gauge on it and verify low oil pressure before you drop the oil pan and start tearing things down.
Yup! Exactly what I did! Dash is wrong...chasing down sensor issues!
 
Amazon YSTools gauge arrived...drove the Jeep around the lake...never dropped below 20 PSI... here's it idling in the driveway after...gaff taped the gauge to the windshield...new sensor...#3 arriving middle of next week... wiring diagrams printed out should I need to chase that down...looks like shared ground splice is on the right side of the transmission and that will be the first thing I check if sensor #3 doesn't fix it. No word from Napa on ATK availability... curious! Thanks!

View attachment 317997
Mac, I don't think 25 lbs at a hot idle is anything to be concerned with !
But if your heart is set on a change, the reman is a quick and cost effective way forward IF the builder actually does the build correctly.
 
Mac, I don't think 25 lbs at a hot idle is anything to be concerned with !
But if your heart is set on a change, the reman is a quick and cost effective way forward IF the builder actually does the build correctly.
Completely agree...just need to replace the sensor... hopefully the one arriving next week fixes the issue! If not I've printed out wiring diagrams and laid out a plan of attack starting with the splice block on the right side of the transmission. If that fails to resolve the issue then it's the PCM.

I'll sort it out!

Thanks!
Mac
 
  • Like
Reactions: Wildman