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Discussion Starter · #1 ·
so, one of my boys is building a nissan RB motor for his datson and says that the 7M is one of the crappiest motors ever made. i know the 7M has its faults like any other motor but i also know that the 7M isnt the crappiest motor and is verry capable for good numbers and performance. my friend and i are now arguing about the 7M and why i think its a good motor and how he thinks its a crappy motor. i wonder if i can compair the 7M with nissan's RB? our debate is getting kinda rough so i need enough ammo to end this crap and make him know that the 7M isnt a bad motor. can you guys help me out? is this a doable debate?
 

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does he have any valid claim for why the 7M is crappy? There is nothing wrong with the engien itself. Just needs a MHG, and maybe some head studs, and you are good to go. I know some of the other guys here like Jeff would be more inclined to help your argument with actual facts though.

Alex
 

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Who says that the 7M Sucks. Obviously he or she doesnt know the Potential of the Motor.

Im inclined to pull a Vid out of my hat from last week when I finally got to race a 96 TT Supra. Lets just say that Weight does make a Difference. :)

Robert
 

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Discussion Starter · #4 ·
he doesnt realy got anything on the 7M. he says his research says that its a crappy engine. i'm about to hit with that next, though. see why he thinks its a crappy motor. our debate only just started earlier today. its game on for me though.
 

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Research Reserch Reserch..... Unless he actually had debt with the motor and seen what It can and cant do then He doesnt need to Talk. I think everyone Knows that 7Ms main Problem is that the MHG arent the Best. If someone would consider making a Steel Head Gasket like some if not all the MKIVs have, then there Probably wouldnt be a issue. Tell Him to come on it and talk. Research only tells you what you want to know, Not what the Truth might be

Robert
 

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hmmm....

man...I hate to say it...it almost hurts...but IMO compared to the RB26 the 7m is a crappy motor... :bowdown: Never seen an rb26 need a headgasket with 15lbs through it....never seen a puddle of oil under one either....I don't have much experience with the rb25, but I'd suspect that one id probably just as robust....the 7mgte is a good motor don't get me wrong, but I think it may be out classed by the rb26dett....(i don't have a pleathora of experience with them, but I have done quite a bit of work in Japan and played around with a handful of skylines....that rb motor is serious business...)
 

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I wouldnt say the engine itself is crappy because of the headgasket it comes with. That is a simple fix from what i have seen. I have seen people running 700 some HP from the stock block. Not stock internals i dont think. Now I wont say the 7M is better than the RB, but it sure as hell isnt crap compared to anything IMO.

Alex
 

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i'd agree with that.....but taking a 7m to an rb is like bringing a knife to a gunfight imo...
damn alex get some sleep...I work nights whats your excuse...;)
 

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Discussion Starter · #9 ·
thanks for the replies... my friend is building an RB25 and theres lots of differences between the 25 and the 26 of the RB's. i'm not trying to tell him that the 7M is better than the RB i'm just trying to stand up for the 7M since he says its so crappy. we're not compairing the 7M and the RB at all. our debate is just on the 7M and how i think its not a crappy motor at all. i know that the 7M's factory MHG sucks but once a better one replaces it then thats about it, theres hardly any other fault. its a strong mototr, right? forgive me, i'm still learning and you guys are the best.
 

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I would say Its a Pretty dam Strong motor. I have a Friend here that is running a T70 turbo on his 7M. Ofcourse he has Forged Pistons and all that but its not Bored out, The Headgasket is a 1.4mm and he is Pushing 28 psi.

Im not saying either that the 7M will compare to most motors but Its not a slug either. Like any motor you have, If you do the right things to it, It will treat you right. Do the Wrong things and you will be Pulling it, Rebuilding it or just Replacing it.

Robert
 

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Discussion Starter · #11 ·
SupraGuy31 said:
Like any motor you have, If you do the right things to it, It will treat you right. Do the Wrong things and you will be Pulling it, Rebuilding it or just Replacing it.

Robert

thats what i'm sayin... i'm looking to rip my homie apart with our debate. its fun we do this all the time.
 

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Why bother ripping him apart with a debate? Give me a budget and we'll build a 7M that will make his asshole feel like it just got a visit from a chainsaw, unless he's putting that RB26 in a gutted 510 he's going to have a race on his hands - even in our heavy & piggish MK3s.

Honestly, for a street car and outright power production the only advantage I see to the RB26 is the aftermarket support. The oiling system is superior but the 7M's limitations there are hardly insurmountable. The longer stroke and additional displacement of the 7M is a huge advantage particularly in midrange power if both engines had the same turbo. Yeah, you won't often see a 7M crest 10k but it has been done and done reliably.

Your car already *has* a 7M then drop $3k into it and you've got a forged bottom end and shimless buckets with good valvesprings, cam gears, beefed up oil system etc - the works, essentially a longblock that would do 700+ & 7000rpm all day long and would only really be limited by the shitty stock cams.
A single turbo manifold, 720cc injectors, VPC/AFC, 67-71mm turbo, decent wastegate, frontface intake with a Q45 TB, twin Walbros, Ebay FMIC & hardpipes, some lines, and a decent clutch of your choice and you're another $3k-$6k into it depending on your tastes in FFI's, clutches and turbo manifolds, and your entire setup is totally ready for 650-700whp on boost alone - everything costing a total of around $6-8000-ish.

Meanwhile homeboy has to drop $4500+ just to have the RB26 to start with, that still needs an RB25 or VG30 5-spd trans, clutch & flywheel, a custom driveshaft, a rear end that holds the power - so he's at least $6k into the game to just start at the same point a 7M-GTE/R154 MK3 is at with an exhaust and boost controller.

Then he's gotta build the engine to be happy above 550-600whp with a set of pistons & rods, since the stock headgasket and pistons don't like much over 550-600 and the stock rods aren't happy for much beyond 650.
The same basics are still needed like an EMS of some sort plus injectors, fuel rail, pumps, turbo setup, (could be simple or exotic, RB kits go from $2000-ish used Greddy T78 kits or GT25-based bolt ons to exotic $9000 twins) then if he wants to go above 550whp safely he needs to do pistons and a metal headgasket and headstuds just like a 7M.. then cams, cam gears, etc etc ad nauseam... Building a 7M isn't cheap but building an RB sure as hell isn't any cheaper. The only advantage with the RB is that instead of needing to make custom shit for the 'insane' levels the RB has aftermarket.

Long story short, going with an RB is spending at least $5K-$7K more for the same power, but with more RPM, higher redline and a beautiful exhaust note.

Brian, I respect your opinion in this because unlike so many people you've seen all of this stuff in action from your time in Japan.
But you have to understand that 95% of the 7M's issues can be directly traced to age and neglect - take a 130k mile RB26 that hasn't seen an oil change in 3 years and double the stock boost level and see what happens.
Most 7M owners that are blowing them up are dumbass kids like I used to be who put a huge exhaust and a boost controller on a 15 year old worn out motor and then whine about how shitty the engine is when things go bad.
 

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Discussion Starter · #13 ·
wow, right on bro. my boy is actually putting the RB25 into a datson 240. that was some good info. i like how you compaired it to the RB. good stuff. being in the military and having familly in japan, i have also been there many times. Oki and Main Land. a friend of mine that lives in Oki has an R33 stock and its not as hot as i thought it was before i rode in it. they're heavy cars, too.
 

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RB25's are far, far weaker in stock form compared to the RB26.. same shitty intake manifold path as the 7M, and the bottom ends rarely survive for long above 450whp.. RB25's are much cheaper to be had ($3000-3500 for a motor & trans set) and you don't need to go tracking down a RB25 trans seperately, but you'll need a good intake manifold to replace the stocker just like a 7M, and the RB25 isn't nearly as happy at high RPM as the RB26 because the cranks aren't balanced nearly as well, nor is the oiling system somewhat prepared for it like the RB26's. This can be partially offset with a RB26 crank swap and upgraded oil pumps, etc, but you're still at a huge displacement disadvantage compared to a 7M and you don't have that amazing RB26 cylinder head to breathe at high RPM either.

However, 240Z's are light mofos compared to a MK3 - but it doesn't take a lot to make some good power on a 7M - hell all I have is a VPC, 550's+TT pump, exhaust, and a 62-1 CT-26 upgrade and I'm at just under 400whp on 91 octane pump gas - and there's well over 160k on my bottom end at this point!
 

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Discussion Starter · #15 ·
yah, thats pretty much why he went 25 instead of the 26. i hope someday, when my MK3 is good to go, i can go back to california and show him whats up. and, hopefully by then his RB Datson will be ready.
 

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[ but it doesn't take a lot to make some good power on a 7M - hell all I have is a VPC, 550's+TT pump, exhaust, and a 62-1 CT-26 upgrade and I'm at just under 400whp on 91 octane pump gas - and there's well over 160k on my bottom end at this point![/QUOTE]


Very good point there Jeff. I have most of the same stuff you do, but with a little bigger snail, and a rebuilt to stock motor. 500+ all day long on boost. Who says that 7M's can't make power? There are plenty of high HP 7m's all over. Some built, most like yours and mine. Not sure if it is still up, but check out 7MPower.com.
 

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Wreckless said:
...But you have to understand that 95% of the 7M's issues can be directly traced to age and neglect - take a 130k mile RB26 that hasn't seen an oil change in 3 years and double the stock boost level and see what happens.
Most 7M owners that are blowing them up are dumbass kids like I used to be who put a huge exhaust and a boost controller on a 15 year old worn out motor and then whine about how shitty the engine is when things go bad.
:sad: aint that the truth....It is ashamed to see what has happened to many of the mkIII's/MKiv's....it is sad when somebody gets ahold of one of these cars and has $20 to mod it so they hit home depot to make a boost controller....Good point on the rb though, they will make power, but it's not cheap. They in stock trim have all the issues we've grown to love even the ceramic turbos...

saw a nice clean mkIII in ventanna ranch today with CT tags...light blue color...
maybe a new member to the familly....
 

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Morefaster said:
man...I hate to say it...it almost hurts...but IMO compared to the RB26 the 7m is a crappy motor... :bowdown: Never seen an rb26 need a headgasket with 15lbs through it...
I have never ever seen or heard of an RB25DET or RB26 blowing a HG. I have heard of a RB25DE+T blowing one but then again he was pushing 420+ whp on a 10:1 motor on pump gas. A ring land will always go before the hg. In Australia some people just o-ring the block and use the stock hg since it's pretty good.
The most whp I've seen out of RB25 (r33) is 586whp- totally stock long block. quickest 240sx rb25 is posted here http://supraforums.com/forum/showthread.php?t=355714
9.79 @ 149 on a stock bottom end.

a 240z is a good 200lbs lighter than a s13 240sx.
 

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rb25s14 said:
I have never ever seen or heard of an RB25DET or RB26 blowing a HG. I have heard of a RB25DE+T blowing one but then again he was pushing 420+ whp on a 10:1 motor on pump gas. A ring land will always go before the hg. In Australia some people just o-ring the block and use the stock hg since it's pretty good.
The most whp I've seen out of RB25 (r33) is 586whp- totally stock long block. quickest 240sx rb25 is posted here http://supraforums.com/forum/showthread.php?t=355714
9.79 @ 149 on a stock bottom end.

a 240z is a good 200lbs lighter than a s13 240sx.
are you agreeing or disagreeing with him? cause that what he just said, but not in so many words. lol

Alex ;)
 

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Alx2785 said:
are you agreeing or disagreeing with him? cause that what he just said, but not in so many words. lol

Alex ;)
I'm agreeing with him. I'm just saying the rb25 hg's hold up very well and I've *heard* the 7m's don't last too long when pushed. That maybe the reason the original poster's friend is bashing the 7m.
 
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