Are All Forged Rebuild Kits The Same?

[stÖrmy]

Currently have an Rb25 and at the moment its tuned to 400rwhp, Eventually im going to want to get more, probably 500-600 but i want to rebuild it first and was wondering if pretty much all the rebuild kits are the same?

for example....Spool Vs CP Vs ROSS Vs Supertech ?

Spool + CP kits come out around 2.1K and supertech is around 3k.... will ANY forged kit be good enough ?

[STATUS]

many of the rods are so close its not such a worry but pistons vary alot. go the best pistons you can afford, quieter and better oil control.

[sleptema]

I am also curious about this. What about in the way of crankshafts and bearings?

[Joshbigt62r]

I am also curious about this. What about in the way of crankshafts and bearings?

You can use your old crankshaft in most cases. Just leave it with the machine shop to have balanced, crank collar installed, grub screwed ect. As for bearings I personally use king bearings. But ACL, Genuine NISSAN and king are all good bearings. Pistons I'd go with JE or NITTO or CP pistons. As for rods take your pick all the brands are pretty much the same if not are the same in a lot of cases.

Cheers Josh

[GTScotT]

I used CP and Manley in my build. My bores and rings I did close to CP recommended specs (I opened the 2nd ring a little more than they recommended) and the motor is amazingly tight/quiet. I cannot fault the build to which I attribute both quality parts and quality work (machine and assembly).

From the research I did the Manley rods are actually the same base product as the Eagle rods. The difference is the QA standards. The Manleys are very obviously finished better (visually) and they come as a weighted set with the individual end weights written on the packaging for each rod. The Eagles are less perfect in presentation do not come weighted. I would buy the Manleys again, for sure.

I like this combo, its serving me well.

[Sinista32]

Interesting discussion.

Did not know difference between Manley and Eagle rods. Cool ta

will check back for more knowledge

[stÖrmy]

Hmmm interesting, so if i buy new rods / pistons i gotta take my crank and pistons / rods to a shop first to get balanced before installing ?

[C4a0s]

i would like to think that most are the same but each brand has its own manufacturing process, metallurgy secrets and design philosophy that there will be differences in terms of weight, durability and heat dissipation etc but for your purpose, it shd be fine. I'd stay away from eagle conrods though as I have heard horror stories of the rods being porous and made in china... so durability/QC is a concern for me..

[GTScotT]

Hmmm interesting, so if i buy new rods / pistons i gotta take my crank and pistons / rods to a shop first to get balanced before installing ?

Generally not. It depends what you want to do with the motor....

For me, 500whp is what the motor can reasonably achieve in standard form. Two things to consider at that level are: Risk and Longevity.

Risk wise the stock motor at 500whp will not need much encouragement to let go. Encounter some knock due to bad fuel or have a fuel pump go lazy and you are sure to nuke it. Longevity wise the motor was never built to spin up 500whp so it will not last the usual 300,000km we are used to seeing the motors live to (under the right/factory conditions).

When you build the motor to a reasonable level IE: harder bearings, stronger rods and pistons, you will essentially be reducing the risk factors and extending the longevity of the motor. The integrity of the pistons can handle the heat/pressure, the rods will handle the torque and the bearings will last longer when spun that hard (remember that more HP is more thrust on the rotating assembly of the motor).

If you want to exceed those levels that is when you start considering additional balancing and so on (IMHO). The additional pressure the motor will see at say 700whp will warrant better balancing to again counter the above mentioned risk/longevity factors.

Another thing to consider with up-rated bearings is their sensitivity to foreign particles. There is no stopping foreign body getting into the motor somehow, and good filtration is a must. Soft stock bearings generally can absorb a small amount of foreign matter before taking a bite out of the crank, while race spec bearings will chew out much easier (harder to take more pressure but more brittle as a result). Good filtration on a built motor is a MUST. Buy a filter relocator to suit a much larger filter, such as a Z9 or similar, and run synthetic rated filters. Look at Holden or Ford relocators or similar that take those giant filters.. As long as they use a standard dash fitting for the hoses you can then buy an RB or whatever specific spin on with the same dash fitting size and plumb it up easy.

A good compromise here is to run standard main bearings and race rod bearings. Because the crank is fixed by multiple bearing shells it gets less load per bearing and therefore needs less pressure resilience. As the oil flows from the block, through the mains to the crank and then to the rods, running stock or softer mains can help increase longevity in a road use motor whilst still getting the benefit of the up-rated rod bearings.

[stÖrmy]

wow ! some very informative posts in here!

Ok i should have said what the engine is intended for! its going into a dedicated s13 drift car, ive gone from Rb20 to Rb25. I bassically bought the entire setup of a previous drifter, it made 400rwhp with a greddy plenum, highmounted garret 3076, 550cc injectors, z32 afm and tuned with powerfc.

ill be running a TD06-25G for the moment as i dont want to buy a china 3076 and hopefully the kinugawa td06 survives long enough while i save for the 3076

anyway the engine will be dedicated drift car, How ever i want it to be reliable, i was able to push the rb20 @ 7500RPM for hours on end non stop on private prac days, when i say non stop i really mean hours on end NON STOP lol, and it loved it, but at the same time i didnt really care if it blew cause its a cheap engine, I want to be able to hammer the rb25 lap after lap without worrying about it exploding on me, so ide be willing to spend the extra cash on a rebuild kit if it genuinly means its a better product.

Risk wise the stock motor at 500whp will not need much encouragement to let go. Encounter some knock due to bad fuel or have a fuel pump go lazy and you are sure to nuke it.

Currently i have a bosch 040 intank pump, would i need to go twin pumps to guarantee a good fuel supply, or would i be better of with bigger injectors and a good pressure regulator, and of course a good tune!

Buy a filter relocator to suit a much larger filter, such as a Z9 or similar, and run synthetic rated filters. Look at Holden or Ford relocators or similar that take those giant filters..

Will deffinatley look into doing this!

[Manuel Kasko]

Interesting discussion.

Did not know difference between Manley and Eagle rods. Cool ta

will check back for more knowledge

Same here

Loving all this info