Mitsubishi 3000GT & Dodge Stealth Forum banner
1 - 17 of 17 Posts

·
Registered
Joined
·
15 Posts
Discussion Starter · #1 · (Edited)
What's everyone's thoughts on JDM engines?

Long story short, head gasket blew and compression numbers came back not so great. Replaced headgasket, compression numbers are still in the dumps. Kinda figured though since mine is a highly neglected, original, 180k motor. Found a JDM engine, harness, ecu, transfer case, and trans for sub 4 grand. Physically looks fine, obviously not something to go off of though.

Does anyone have experience with JDM motors? Any do's and don'ts?

Or is it wiser to have the old one rebuilt? It'd have to be done by a shop, 400-ish miles away from me since I don't have the space to do a rebuild and HOA is not very kind when it comes to a car sitting for more than 5 days. Honestly don't know what it'd cost for a rebuild but I can imagine it isn't cheap.
 

·
Registered
91 VR4 wish scissors BBK wheels and tint
Joined
·
227 Posts
A rebuild cost depends on the area you are in.

For me the cost is about the same, while the JDM is a "known good" the history isn't known.

A rebuild is a good chance to build it to your taste and while you know the history it's a good chance to replace other parts as well.

For instance a light bore new pistons rings bearings. Also a gig time to do head studs and lock tite them so it didn't blow again.



Sent from my LM-G850 using Tapatalk
 

·
Senior **i.e. OLD** Member
Joined
·
15,404 Posts
Vince,
I'm not sure suggesting LOCKTITE for the head studs is the best idea.
There are documented procedures for installing head studs/bolts....

Bob.
 
  • Like
Reactions: Boxxy

·
Registered
91 VR4 wish scissors BBK wheels and tint
Joined
·
227 Posts
Vince,
I'm not sure suggesting LOCKTITE for the head studs is the best idea.
There are documented procedures for installing head studs/bolts....

Bob.
If it's a stock build follow the manual, but if he's rebuilding for power I think it's fair to consider...

If I rebuild mine I'll be replacing the head bolts with an ARP head stud kit... And using ARP thread locker or Locktite blue

It would seem that these engines have issues with head TQ so I'm going to go above and beyond on it.

Sent from my LM-G850 using Tapatalk
 

·
Registered
Joined
·
15 Posts
Discussion Starter · #5 ·
If it's a stock build follow the manual, but if he's rebuilding for power I think it's fair to consider...

If I rebuild mine I'll be replacing the head bolts with an ARP head stud kit... And using ARP thread locker or Locktite blue

It would seem that these engines have issues with head TQ so I'm going to go above and beyond on it.

Sent from my LM-G850 using Tapatalk
I'm mostly looking to make stock power, since I'm not really sure if I can trust my engine would be able to handle anything aside from being rebuilt.

My biggest issue is I have a bunch of misc. Connectors and wiring issues that the JDM engine would fix, obviously because it's complete. I'm just a little hesitant to rebuild this one since it's been one thing after another since I bought it. I haven't even gotten to drive it more than a mile since I bought it excluding the day the headgasket killed itself lol
 

·
Registered
91 VR4 wish scissors BBK wheels and tint
Joined
·
227 Posts
I'm mostly looking to make stock power, since I'm not really sure if I can trust my engine would be able to handle anything aside from being rebuilt.

My biggest issue is I have a bunch of misc. Connectors and wiring issues that the JDM engine would fix, obviously because it's complete. I'm just a little hesitant to rebuild this one since it's been one thing after another since I bought it. I haven't even gotten to drive it more than a mile since I bought it excluding the day the headgasket killed itself lol
If you want stock consider a jdm engine.

But remember that a 30 year old car will as always need tlc.

Plastic gets brittle, gaskets fail, rubber hoses dry out etc.

Sent from my LM-G850 using Tapatalk
 

·
Chief Exec.
Joined
·
858 Posts
Hey Vince I was in the same boat a while back. I took the leap and bought my JDM engine and it has perfect compression in all cylinders as stated by the seller. Came with Tranny and everything. Car has no leaks and is running strong. I would buy from a seller who provides a warranty on the engine itself even if it's a small 90 day warranty. That gives you more then enough time to install and run multiple tests/health checks on the engine itself. Goodluck.
 

·
Registered
Joined
·
15 Posts
Discussion Starter · #8 ·
Hey Vince I was in the same boat a while back. I took the leap and bought my JDM engine and it has perfect compression in all cylinders as stated by the seller. Came with Tranny and everything. Car has no leaks and is running strong. I would buy from a seller who provides a warranty on the engine itself even if it's a small 90 day warranty. That gives you more then enough time to install and run multiple tests/health checks on the engine itself. Goodluck.
Thank you! I'm probably going to go with the JDM motor at this point after getting quoted for a rebuild. Even if it isn't in amazing health, I do get a warranty on it and an entire setup that I can either keep as parts or spares, or can at least resell to make some of my lost money back or rebuild yo have a backup.

As far as Vince, I appreciate the input and I weighed it pretty heavily that regardless of what I do, I will probably run into issues. I was planning to at the least reseal the JDM engine along with the 60k maintenance to have peace of mind.

I really do appreciate all of your help, it's nice knowing the community wants to see these cars survive.
 

·
Chief Exec.
Joined
·
858 Posts
Thank you! I'm probably going to go with the JDM motor at this point after getting quoted for a rebuild. Even if it isn't in amazing health, I do get a warranty on it and an entire setup that I can either keep as parts or spares, or can at least resell to make some of my lost money back or rebuild yo have a backup.

As far as Vince, I appreciate the input and I weighed it pretty heavily that regardless of what I do, I will probably run into issues. I was planning to at the least reseal the JDM engine along with the 60k maintenance to have peace of mind.

I really do appreciate all of your help, it's nice knowing the community wants to see these cars survive.
My apologies I thought Vince was the original Post person. My response was made for you Boxxy. :)
 

·
Chief Exec.
Joined
·
858 Posts
While my JDM engine was out i did full timing belt job along with front and rear main seal and both front and rear exhaust manifold gaskets. When that engine is in trust me that fire wall leaves little room to get to the rear of the engine. If your upgrading turbos or gutting your rear cat do it now as well while easy to get to. Cheers.
 

·
Chief Exec.
Joined
·
858 Posts
Also vince has a point replacing vacuum lines along with those t plastic adapters that the lines plug into might not be a bad idea. There a pain to disconnect and connect when the engine is in when they go bad or leak unless your doing a vacuum delete on the car.
 

·
SDSU Alumnus
Joined
·
3,877 Posts
This thread is all over the place...

The old, general "rule of thumb" was to take the advertised mileage of an imported "JDM" engine and double it. I am not going to explain why here... y'all can search

Treat it like any other used engine with no history and apply what is known about these. Minimum test should be leak-down. Recommended maintenance should be a full 60/120k, main seals, and cam seals; going the extra mile would include valve stem seals and removing the oil pan for bearing/journal assessment. If you see original, composite HG's, then you should make a decision about those (not sure on year of engine mentioned). Forgoing anything would just make it even more of a dice roll.

Personally, I would just rebuild and overhaul what you have for the price rather than risk having two pos. That would be time and energy wasted. Based on your post, you should find another person or shop. The teardown will reveal what actually needs done, and the actual cost may be less.

-sent from my Galaxy Note 9
 

·
BC3S
'95 RT/TT
Joined
·
767 Posts
considering you will be having a shop that's far away doing the work regardless, maybe price everything out first then make a decision.

JDM engines have always been a dice roll, might get lucky with a mint engine, might get screwed with a POS.
 

·
Chief Exec.
Joined
·
858 Posts
Love the 3000gt love for fellow members. Boxxy from my local club here I asked and they have used JDMPOWER, ICHIBANJDM and JDMenginesdirect. They all 3 have 100% rating from ebay and anywhere from 300 to 800 engines sold online. Cheers M8
 

·
Registered
Joined
·
15 Posts
Discussion Starter · #16 ·
So I did end up making the purchase for the full JDM drop-in. I hear what everyone's saying, and it'll be overhauled regardless but I wanna clear a couple of people's concerns!

The engine swap, I'm capable of doing and having it out and back in within 2-3 days on a really good weekend. So I'd be saving on the labor. If the engine was rebuilt, there'd be no way for me to do that in a timely manner or with being conscious about space. Plus some of the parts I may not need will be resold so I highly doubt I'll be coming up on a losing end even if the motor is high mileage as long as it's got semi decent compression. Worst case scenario here is the block is bad but it is covered under a 90 day warranty. That warranty aspect is really important to me since ideally no one wants to waste money, right?

No one in my area will touch these cars with a 100ft pole, I've made many calls around the bay area to no success except TedSpec. But I've spoken to him as well, and he was booked up for a few months and we're moving in that time frame. So unfortunately time is a very big factor in that decision of buying over rebuilding it.

A lot of people made great points, I'd like to point out cost wise to rebuild would have been around 4-5 grand since labor rates in this area are double to 2.5x more expensive than most. Even with my old boss, it'd run me the same amount as the JDM engine because labor is intensive.

The JDM engine should be here in a week or so and I'll keep everyone posted just so I can add to the "Are they good or are they just piles of junk?" lol my only big concern is how hard this motor was ran or maintained. So I guess we'll find out. But judging from the condition of the parts and how it's 100% OEM and unmolested, I have high hopes.
 

·
Chief Exec.
Joined
·
858 Posts
Awesome m8 keep us posted look forward to some pics and questions when she finally starts coming to life. 👍👍
 
1 - 17 of 17 Posts
Top