Hey guys! I am fairly new to the forum and Lexus/ Toyota's in general,
but I have been perusing for a month or so and finally decided to make an account.
I purchased a 1996 Lexus Sc300 5 speed (W58 right?) from a friend of mine after the motor threw a rod and melted 2 bearings.


It boggles my mind that It went in the fashion that it did.
The stock engine hit 115k and maintenance is all caught up 200 mi ago...
you know the usual 120k kit, and other misc items such as synthetic oil change, filter, air filter, cap, plugs, wires,rotor etc.
Seems to be running phenomenally, and at this point, I couldn't be happier!
Second drive out, I go to pick up my girl friend, and we go out cruising.
Total amount of drive time 2-3 hours and no fuss, sputter, or hesitation in sight.
I drop her off at her place and head back.
I get on the freeway and at this point its about 10pm, there are only a few cars every couple miles, so I decide to open it up a bit. 80.. 95.. 110.. 120...fuel cut.
I ease off and let it coast down, dropping a few mph a second....Then it went.
















From the pictures you can gather that it either didn't have enough oil coating the bearings (#6 & #4) and in turn, got sloppy, the counter weight hit the piston skirt, and then the rod busted
OR the bearings froze up due to lack of lubrication, and the connecting rod bolt snapped and threw the rod threw the side.
Third opinion? Being unfamiliar with this motor, I do have some questions.

Such as-
Where is the oil pluming on the 2JZ? I don't see any oil squirter's?!?!

Would it matter that it was running RP HPS 20W50 at the time with a Prestolite filter?
Could it possibly be too thick for bearing clearances to adequately coat the bearing journals?
If so why was i able to drive it for 200+ miles without any problems then all the sudden it grenaded?

What about a rumored.. "Deceleration sensor"? Is this "only" equipped on Supras?
What is its function, if is indeed also equipped on the Lexus?
Could this have contributed to the problem?

No warning lights, oil temp, pressure, level...NOTHING. Timing belt didnt snap either (not that it would matter since its not an interference motor as I recall...just FYI) and head-gasket is still fully sealed (watery substance you see in the oil pan is fuel, when i pulled the motor, it ran down the side into the oil pan). Agian, it boggles my mind!
Is there not members that have 300-400HP+ on NA-T conversions? and have more miles than 115K??
Correct me if I'm wrong but isnt this suppose to be like the God of motors if there ever was one? LOL

No matter what caused this horrid event, I purchased a JDM motor from a trusted and backed engine import company, and have begun the conversion. I look forward to learning more about this motor and car through the wealth of information on this forum!
Thanks for your time,
---Joe

 

Damn bro that's messed up good luck with the swap

 

Sounds like you know a thing or two about motors, but if i had to take an educated guess. its probably due to your 20w50 oil. You should be using 5w30 or 10w30

 

Now that is a catastrophic failure! You are so lucky. Look how close the block/rod came from puncturing your fuel line. There could have been a serious fire to go with the blown engine. So did you order a JDM GE or a GTE?

 

Thanks for the insight! I will definitely run 10W30 in the JDM motor. I had my doubts about going that thick to be honest. But coming from Nissan VG series motors, you can get away with running a higher weight oil (due to how the oil pluming is set up) . Infact Greg Dupree @ Specialty Z (a world renown Nissan Z series tuner and parts supplier) says there is no better oil for the VG30DETT ( I know, I know those are fighting words on a Lexus forum). So naturally I figured It wouldn't be a problem. But it looks as though the oil lubricates the bearing from within the journal. Very interesting design to say the least... So bearing tolerances are super tight, and oil weight is crucial in order to squeeze through the TINY oil port hole, unlike a motor that has built in oil squirter's.

Just found this thread on Supra forums. Worth checking out if you haven't seen it. Heads up... read the first post...everything else is a bunch of crap.
http://www.supraforums.com/forum/sho...ers-Yay-or-Nay

I'm wishing I bought the GTE block now....sigh. I cant believe they didn't include this crucial feature in all 2JZ's.

How right you are my friend! God was watching over me no doubt about it. It could have been allot worse! I am thankful! To answer your question, although this isn't what is most exciting...I ordered a replacement GE motor. But from what I'm seeing online, a TT or single T isn't out of the realm of possibility in terms of transformation parts, time and over all difficulty. Switching from a N/a to TT on a Nissan is HELL! Everyone will tell you to buy a TT instead of converting due to the cost involved, but its seeming to not be the case for the 2JZ series motor.

 

Well, a replacement GE is not a bad start either. You should look into putting a TT head gasket and arp studs on it before you drop it in. Then you can throw a NA-T turbo kit on it and have a solid platform ready to make big power