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Heres a good post w/that info. Note no. 5 (recommend reviewing the full thread)
Originally Posted by Live4Redline
Well, just so you know I am the only person who has used a G4JS block and lived to tell about it so you had beter hope I don't disappear.
As for destroking this block, throw your crank in it and go with your standard 4G64 destroke kit. You wont have any issues there. Balance shaft kit and all that works fine.
Now to the block its self and making it work for you. First of all the major thing you need to know is that the front case between these two blocla is diffrent and becouse of it there may be some head aches if your trying to do this from a bare block.
Step 1: While you have the block sitting there you should test to see if a 63/64 front case cover will bolt and line up with the G4JS block. I did not test it and theres a 50/50 chance it might. If it does then you can simply swap in the EVO motor mount, the front case cover and everything attached, evo cam gears and call it a day. But if it does not then your off to step 2.
Step 2: Your gonna need to get a hold of a few things, JS front case cover and everything attached to include gears, modded EVO 8 motor mount, JS cam gears, JS timing belts, JS assec belt, JS alternator and bracket, Js power steering pump with a modded bracket, and a oil pan option.
Step 3: EVO 8 motor mount for an EVO shell or 4G64 motor mount for an eclipse, lancer, mirage, galant and ect. The mount will need to be ground down in a few places. It's a simple task and I have.pictures that i can post up later.
Step 4: Modding the JS power steering bracket to clear the Mitsubishi motor mount that blocks some of the holes on the JS front face cover. It's a little odd and ill have to post some pics. So just know that it doesnt bolt right up and will need some cut and grinding done.
Step 5: Finding an oil pan... If you were able to use a mitsubishi front case cover then you can use a stock evo 8 oil pan and a modified pick up tube and an evo splash shield. Cut the bracket off the pick up tube and bent it slightly downward and your set. Just don't bend it while installed, remove it from the block first or yoh will break your front case cover like i did. Then with the splash shield you will need to cut a small slot in it with some metal sheers and your set. If your using the JS front case then you need all of the previous stuff plus you will need to mod the oil pan slightly. Flaten one side, weld up a hole and drill a new hole slighty off where the old one was. I have pics of this also. You can how ever just use a two piece JS oil pan, dump, and splash shield if you weld your oil return fitting into it. (i have all of the JS stuff from my motor and will sell it if you pm me.)
Added notes... The dip stick will clear so don't worry, and you can use 63 balance.shaft delete kit. Also be sure to use evo knock sensor and temp sensors. Can also use evo 8 head gasket and head studs. The crank sensor and crank sensor reluctor plate can be used off the 63/64 or JS motors.
Stock alternator & pump.. stock G4JS or 4G63?
also were you still able to you the a/c compressor?
Ive got an Evo 4 but want to upgrade power but goin by all forums, the Evo 4 block is the worst designed block due to rear trust bearing for the crank so I’ve bought a ‘01 Sonata as a donor..
can I use a slightly shorter crank & a taller piston to change the stroke ratio?
thanks in advance for any advice..
Extreme bump and first post. Thought i would chime in here as there is not a lot of info on this topic out there.
I have an Evo 5 currently running a complete G4JS going on 5000kms now, about 3 years total
The head has stock evo 5 valve train (cams, springs, retainers, valves, gears)
The block has Manley forged H-beam rods and 10:1 CR Manley pistons, stock 100mm crank and was bored out to 87mm
All ARP bolts/studs were used and ACL race bearings
The tricky part was the timing setup, as mentioned the stock hyundai cams and belt have a different tooth pitch so that was all chucked out.
I was able to use Tomei adjustable cam gears (Evo) along with the Evo crank gear and tensioner. The issue with this is that the oil pump gear is in a different location than a 63/64 so the Evo belt would not work. I did a lot of measuring and had a subaru idler pulley lying around so that was used in place of the larger evo idler pulley (needed some spacing but works).
The kicker is that now i had to use a SRT-4 timing belt (same pitch as Evo), as the length of everything wouldn't allow the 4g63 belt to be used. Still running the stock power steering bracket and pump. stock alternator with massaged alternator bracket but it all works and runs on a single belt, as the evo would normally.
Just confirming, on the G4JS you used Evo Alternator/ Pwr steering Pump & mount and a/c compressor.. which fitted SRT-4 timing belt with the help of a smaller idler pulley from WRX….? So using all Evo parts works fine if you can find a belt that fits?
Did you ever get this questions answered? I would like to also know which subaru pulley was used.
unfortunately no..
im guessing it’s off an EJ, they use the same idler pulley on all EJ motors.. I’ve ordered one, I’ll see how it goes and let you know but it won’t be till next year…
I’ve also order an SRT4 belt… so hopefully using G4JS head & block with my OEM evo 4 power steering, AC compressor will work with that pulley!! Only
reason is so I can use a Fluid dampener & Evo cam gears! Otherwise I’ll have to use 4g93 cam gears with all Hyundai accessories with Hyundai belt & no dampener .. 🤞🏻
Ok sounds good! thanks for the reply! Let's keep this info alive! I plan to do a full guide on using this engine when I'm done with mine. I just picked up a junkyard long block yesterday so we'll see how it goes!
Alright so after trial and error here are some my findings on how to get this long block timed with evo parts.
**The goal of this is to be able to use adjustable cam gears and fluidampr, as well as a better timing belt.**
Ignore these cam gears, they are dsm gears i had laying around.
I'm also doing a balance shaft delete, so I didn't mess with any of that, but it looks like you could use the all evo stuff here as well.
Everything with teeth needs swapped out with evo ones. oil pump,crank, and cams.
Use the JS tensioner and tensioner arm, but evo tensioner pulley.
For the belt, use a Neon SRT-4 belt. I plan to use the gates racing version with the kevlar reinforcement.
Use the idler pulley from an EJ subaru. part number in picture. (the EJ idler uses and m8 bolt vs the JS m10. The trick here is to install a thread adapter in the block m10x1.25 to m8x1.25. Use red locktite)
The timing marks on the valve cover won't line up with evo cam gears. but my plan is to degree the cams anyway. if i find a good way to make new timing marks, i'll update the thread. it will be a while until i fully build this engine, just wanted to give my findings on the timing components.
G4JS 2.4 engine
