Has anyone used the JDM engineering 1200hp rebuild kit for the iron blocks?

Fingers crossed I can purchase this kit before anything major happens ie. A blown motor. Then just add the parts in a year or so to my existing engine. I’m just looking for anyone that has had experience using this kit? Additionally I will be installing the following.

-Oil pump with billet gear upgrade
-billet oil pump gears
-billet crankshaft gear sprocket

Comments ? Input. Thanks.
@lexustech48 @RBB @biminiLX @JimIII@jdm

I didn’t use the rebuild kit, had them build me a fresh one, but the components are solid. You don’t have to worry about the plasma spray liners so you should be all set.

Are you picking up some JDM cams as well? If so, I’d upgrade the secondary chains in addition to the OPGs and lower crank sprocket.

Funny thing, I’ve been doing TONS of research for cams, from NSR to SR. Everything from down low tq loss to hp gains after a certain rpm. My car is not a daily so I’m not worried to much about drivability. My first thought was since the engine is open do cams. Just need to figure out which are the best ones.

Just learning there is more to it then just putting a cam in an ls like I did for my GTO.

ram150 said:

Funny thing, I’ve been doing TONS of research for cams, from NSR to SR. Everything from down low tq loss to hp gains after a certain rpm. My car is not a daily so I’m not worried to much about drivability. My first thought was since the engine is open do cams. Just need to figure out which are the best ones.

Just learning there is more to it then just putting a cam in an ls like I did for my GTO.

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Yeah, the JDM cams are fine if it’s not a daily. I’d consider something milder for DD’ing in city traffic, though.

I agree, might as well do cams while the engine is out. Knock it all out at once.

First you can’t go wrong with JDM but need two things:
1) what are your goals? Be specific from fuel to existing mods to what you want and what you’re willing to compromise.
2) when do you plan on building it? It seems like you’re saying next year so does that mean keeping it as is this next driving season and building next winter?
With those two answers we can help more and will determine if the iron block is the right choice.
Glad to help.
-J

Might need to start another thread for fuel alone. But to keep it short 93 for now since that’s the only thing available

Next : not really any specific horsepower goal. I know what the Gen 2R is capable of thanks to @biminiLX . I’m more so just looking to beef my engine up, like preventative maintenance I guess you could call it. It’s not a DD only able to drive it every weekend.

Build would be around next winter. I’m about to purchase full exhaust headers back for Black Friday.

I used jdm rebuilt kit for my 2011, just made 1100rwhp on e85. Check out my thread “3.6kb dyno”

Awesome numbers! So stock motor other than what comes in the rebuild kit?

Is anyone making a rebuild kit for 5.8? I’m in the process of trying to build my 13 over the winter,and seems like I’m having to piece it together.


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hostile500 said:

Is anyone making a rebuild kit for 5.8? I’m in the process of trying to build my 13 over the winter,and seems like I’m having to piece it together.


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I’ve never seen a rebuild kit for the 5.8. JDM had Manley make them some H beams that could be used with the stock pistons at one point. Not sure if they’re still available, or what your goals are.

ram150 said:

Fingers crossed I can purchase this kit before anything major happens ie. A blown motor. Then just add the parts in a year or so to my existing engine. I’m just looking for anyone that has had experience using this kit? Additionally I will be installing the following.

-Oil pump with billet gear upgrade
-billet oil pump gears
-billet crankshaft gear sprocket

Comments ? Input. Thanks.
@lexustech48 @RBB @biminiLX @JimIII@jdm

Click to expand...

If youre planning on using a 2 step, consider upgrading the chain guides and using the Accufab cam sprocket spacers. The MMR secondary XHD chain kit AND the chain tensioners should be considered. The passenger secondary tensioner is on the wrong side from the factory. The MMR stuff is good kit.

The JDM kit is the bee's knees. Not having to worry about spray liners has got to be VERY nice lol

RBB said:

I’ve never seen a rebuild kit for the 5.8. JDM had Manley make them some H beams that could be used with the stock pistons at one point. Not sure if they’re still available, or what your goals are.

Click to expand...

I saw the H beams on their website but hearing they are telling people to go with the I beam rods for supercharged applications. My goal is 800+ street car/ strip car. I just bought the new gen3 TVS and would like to just re enforce the lower end with something better than stock internals. Stick with stock heads, stock cams.


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hostile500 said:

I saw the H beams on their website but hearing they are telling people to go with the I beam rods for supercharged applications. My goal is 800+ street car/ strip car. I just bought the new gen3 TVS and would like to just re enforce the lower end with something better than stock internals. Stick with stock heads, stock cams.


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Click to expand...

JDM uses H beams in all their builds up to about 1200HP. How many miles are on your car? As long as your plasma spray liners look good and can handle a light hone you'd be fine just upgrading to those JDM H beams and re-using the stock pistons on an 800HP build.

RBB said:

JDM uses H beams in all their builds up to about 1200HP. How many miles are on your car? As long as your plasma spray liners look good and can handle a light hone you'd be fine just upgrading to those JDM H beams and re-using the stock pistons on an 800HP build.

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The car has 19k on it. I was planning on changing to the Manley platinum pistons at the same time. Along with the king bearings, ARP studs.


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hostile500 said:

The car has 19k on it. I was planning on changing to the Manley platinum pistons at the same time. Along with the king bearings, ARP studs.


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You could go with whatever rods you want then. You'll have to piece it together most likely, but I bet your liners will be good enough to hone and it won't require sleeving. I'd give some of the builders a call and see what they recommend for a 5.8 rebuild - JDM, L&M, MPR.

RBB said:

You could go with whatever rods you want then. You'll have to piece it together most likely, but I bet your liners will be good enough to hone and it won't require sleeving. I'd give some of the builders a call and see what they recommend for a 5.8 rebuild - JDM, L&M, MPR.

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Sounds good I’ll give them a shout. See what I can find. Running stock cams would you consider running the original timing stuff? I’ll obviously change out the oil pump gear along with the crank gear


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hostile500 said:

Sounds good I’ll give them a shout. See what I can find. Running stock cams would you consider running the original timing stuff? I’ll obviously change out the oil pump gear along with the crank gear


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Are you racing and running a 2 step? If so I'd upgrade secondary gears, chains and tensioners in addition to what you mentioned above. If you're not running a 2 step I'd probably still do the passenger side tensioner since the OEM one is on the wrong side.

hostile500 said:

Sounds good I’ll give them a shout. See what I can find. Running stock cams would you consider running the original timing stuff? I’ll obviously change out the oil pump gear along with the crank gear


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Forgot to mention, upgrade to the larger guide pins as well....do that regardless of your intended use.

If I purchase this kit and upgrade the cams since I only wanna do this once is it even possible to upgrade cams if I’m only running 93?

If any set of cams exceeds the HP limit of 93 I guess my tuner can DEtune it???
Either way I’m doing the kit just didn’t know if the cams would be worth it.
Thanks