Rb25det Neo Engine Rebuild

[10MinuteCar]

Hello. im on the verge of doing a engine rebuild for my gtt r34 just to do some repairs here and there. just need some advice of what other performance mods i could do just so i don't waste money on pulling the head apart just for repairs but make use of this procedure by doing other mods as well. might have a budget of $2000 left after repairs on the engine

Edited April 6, 2008 by 10MinuteCar

[VB-]

2k wont get you far. maybe some cams/light head work. what are the specs of your motor? what turbo/fuel system etc. what are you doing before you have the 2k left over? full bottom end rebuild?

[10MinuteCar]

well a long while back the compression test i had showed that all cylinders were at 150 spot on except the 3rd one which was on 100, however with a bit of oil squirt it'd rise up to 170 so im assuming its the rings or the cylinder so i just wanted to repair that. and now im on the verge of repairing this now, and my cars real stock running stock turbo, stock ecu, and stock intercooler. i know its not a good idea upgrading anything on the engine without any base mods but ill be willing to put the ecu and fmic on at the same time as i take the head apart.

actually i ain't even sure how much the repair will cost, im assuming max $3000. any suggestions please?

[10MinuteCar]

PLEASE HELP! i need estimates of the repair cost and also what other cost effective mods i could do while im at it

[10MinuteCar]

will i be better off just forging the pistons?

[Grunta]

Well its really up to you. How much do you want out of your engine?

Having the engine down to the block is a really good oportunity to do some internals.

You could do a stroker kit, but they start around $6000 just for the kit and without doing any more work than that, it will feel more sluggish after its done than before.

My suggestion is that you replace the stock conrods and pistons with forged ones, you could nearly garantee your engine would last a life time with forged internals. This guy on ebay selling spool rods and CP pistons + rings, both good brands, for $1890. http://cgi.ebay.com.au/SPOOL-Nissan-SKYLIN...1QQcmdZViewItem

I would proberly get the 20thou over sized and get your block cleaned out, make it a nice smooth cylinder.

Thats all you really need to do for the bottom end, run high revs and the engine will ask for more. forged internals are good for around 10000rpm. a little over the skylines redline. plus you can more safley increase the boost.

With the bottom done, you will want to look at the head, a good port and polish will proberly set you back around 800-900 on average. a quick search on ebay turned up this http://cgi.ebay.com.au/ws/eBayISAPI.dll?Vi...bayphotohosting and if you could get it for 1000, thats a good buy. Sell your old head, might get $300 for a good quality one or so.

by the time you add in the labor in removing, cleaning, adjusting on your current head, it would come back to more than 1000,

plus you would be looking at gaskets, oil, filters etc, the usual stuff assoicated with a rebuild, but you would have those either way.

Forged internals and a port and polish is a really good start to any performance increase. you will get a slight gain from the internals, but not very much, the port and polish will give you a decent power gain. but your biggest gain will be from you able to increase the boost pressure much higher than on stock internals.

Might be a little more than what you want to spend, but it would be well worth it in the end.

PM me if you got any questions.

[10MinuteCar]

Grunta: Thanks, I really appreciate your help. well first of all im assuming it'll be 3 gran just to take the head apart and to replace the cylinder rings. then i'd only have around $2000 left so i was thinking of upgrading it to forged pistons however i dun think i can afford the port and polish. which one should i go for forged pistons or port and polish? and please bear in mind im running a stock turbo so would it even be effective to do these upgrades as i can't increase the boost pressure anyway cuz of stock turbo?

Or should i just put in a turbo and replace the rings?

[Grunta]

If you are limited, then I would definatley say the forged conrods and pistons, you are going to have the engine out and in pieces, its the best time to do it. Plus it is a really good base mod which you can build up from. a port and polish is simpily removing the head, pretty easy to do. Having the engine out and in pieces doesnt happen very often, I wouldnt pass up the opportunity.

apart from replacing the rings (which if you upgraded to forged pistons, they usually come with the rings you need)

What other engine repairs are required?

And when you say $3000 for repairs, is that just a estimate or is that a quote from someone?

[skylinekid]

i just dont see y ppl do half a job with certain things..... y not just wait for a lil bit then do a couple of things to bring it upto a decent motor instead of doing a half arsed job.....

and as for 10000rpm being a little over the rev limit HAHAHAHAH are u insane. (SCHLAPPP)

[Grunta]

I dont see why people make stupid comments and then dont give any explanation on why they make half assed remarks.

What would you suggest then?

"and as for 10000rpm being a little over the rev limit HAHAHAHAH are u insane." in english please. think before you type.

[skylinekid]

I dont see why people make stupid comments and then dont give any explanation on why they make half assed remarks.

What would you suggest then?

"and as for 10000rpm being a little over the rev limit HAHAHAHAH are u insane." in english please. think before you type.

ok then.... while u will have ur head off doing forged pistons and maby rods since u would be doing a full gasket kit including head gasket u wouldnt think u would do ur bottom end properly while its all apart... and u could put forgies in but with nuthin supporting the forged pistons all uve done is made ur standard engine a lil stronger on specific parts whic yes could provide you with the ability to go for an aggressive tune and so forth.... if u dont undastand wat i mean all im trying to say is while its apart take ur time dont waste ur money and do it right....

and as for the 10000rpm bit yeh sure rev it to 10... id give u a week if that...... standard internals on a 25 will not handle 10k rpm hell ive got a tomei stroker bottom end in the 26 im building and ive been advised if i want a reliable street car dont go past 9.... unless i get all supporting components which iam neways but i still want sumthin reliable.....

clear enough!!

[10MinuteCar]

anywayz, so forging the pistons is a useless mod is it now? then what do you actually suggest then skylinekid?

i mean i dun even know yet how much this could cost, cuz the actual definite cost will be given when the heads apart but im assuming around $3000 to pull out the head and to replace the piston rings, etc. Now just to do that its a waste of money IMO, so what other things should i do to make sure the engine is back to its original strength as if it were a new engine.

[skylinekid]

anywayz, so forging the pistons is a useless mod is it now? then what do you actually suggest then skylinekid?

i mean i dun even know yet how much this could cost, cuz the actual definite cost will be given when the heads apart but im assuming around $3000 to pull out the head and to replace the piston rings, etc. Now just to do that its a waste of money IMO, so what other things should i do to make sure the engine is back to its original strength as if it were a new engine.

no its not a useless mod its a gr8 idea but if ur gonna do it u may aswell just save a lil bit and do stuff to support it and make sum more power.

btw to change rings etc u would have to take sump off aka take motor of car... makes it a f**k load easier

[Adriano]

There is no way i would recommend forged rods and pistons, there are plenty of rb25's out there making more than double the power of yours, without internals. With your $2000, i would get an full turbo back exhaust, and a remap at 12 psi, should make over 200rwkw safely,dont forget to have a look at the clutch whilst the engine is out. Then when you want to spend more, get the turbo highflowed, fit a set of injectors, and a front mount(up to you) run 16 psi and make 250rwkw

[skylinekid]

There is no way i would recommend forged rods and pistons, there are plenty of rb25's out there making more than double the power of yours, without internals. With your $2000, i would get an full turbo back exhaust, and a remap at 12 psi, should make over 200rwkw safely,dont forget to have a look at the clutch whilst the engine is out. Then when you want to spend more, get the turbo highflowed, fit a set of injectors, and a front mount(up to you) run 16 psi and make 250rwkw

yes im very aware of this buddy.... my previous setup was a bog stock r33gtst motor with a turbonetics hp61 xaust greddy intake 19p and it was making 265rwkw quite safely.

if he doesnt wanna make bulk power then dont bother with the pistons and rods watever not my car.....

and yes base mods are the good starting point

[Grunta]

ok then.... while u will have ur head off doing forged pistons and maby rods since u would be doing a full gasket kit including head gasket u wouldnt think u would do ur bottom end properly while its all apart... and u could put forgies in but with nuthin supporting the forged pistons all uve done is made ur standard engine a lil stronger on specific parts whic yes could provide you with the ability to go for an aggressive tune and so forth.... if u dont undastand wat i mean all im trying to say is while its apart take ur time dont waste ur money and do it right....

and as for the 10000rpm bit yeh sure rev it to 10... id give u a week if that...... standard internals on a 25 will not handle 10k rpm hell ive got a tomei stroker bottom end in the 26 im building and ive been advised if i want a reliable street car dont go past 9.... unless i get all supporting components which iam neways but i still want sumthin reliable.....

clear enough!!

hmm, if you read my post thourghly, i said "plus you would be looking at gaskets, oil, filters etc, the usual stuff assoicated with a rebuild, but you would have those either way." so either way if you dont replace the rods and pistons or you do, your still going to need those parts. and if a mech says they gaskets are ok, just use the old ones, he should be slapped around. When ever you pull engine componets apart that havnt been apart for a long time, replace the gaskets.

I ony said to do the forged pistons and rods as he said he is limited on the cash and imo replacing these parts while its down to the block would be the best long term improvment and a good building ground for future upgrades.

I never said the skyline egine will handle 10000rpm with just the forged intenals, I said the forged pistons are rated to running up to 10000rpm (just in not so many words), didnt say you should do it.

[10MinuteCar]

Okay well i only asked so i could do something useful as im going to have my engine head apart anyway like forge the pistons BUT as im never going to aim for such big power i guess it'll just be a waste of money to go forgies and cams.

I guess il just replace the rings, or maybe the whole pistons, change oil, gaskets, filters etc and just save the remaining money to do the usual stuff like ECU as i already have full exhaust, boost controller and etc. I was just ASKING cuz i thought i'd never pull the engine apart so its better off and more cost efficient to do some useful upgrades whilst pulling the head apart. but i guess what you guys are saying is that its NEEDLESS to do if i ain't going to aim at such a big power gain such as 250kwrw YES? I mean im shit with cars ok? if theres stuff i could replace even tho its replacing it with stock parts and not aftermarket, i wouldn't mind as long as its going to help my engine be healthly after all.

Edited April 6, 2008 by 10MinuteCar

[discopotato03]

Well up to you but aside from the usual freshen up like bearings and rings there is a few things you can do with it in bits .

GREAT opportunity to port the cylinder head and if oversize exhaust valves are available (that can still use original modified valve seats) do that too . Forged rods and pistons do SFA for you most of the time and if you can keep the tune and temps right surprising power can be had with many OEM Nissan pistons .

Thinks like cams/turbos/injectors you can throw at it any time but you can only make internal mods when the engine is stripped down . You might also look at things like the oil restrictors in the block , lighten the flywheel , maybe do a bit of die grinding either side of the bucket bores in the head if you intent to run high lift camshafts later .

I guess you could also look into better rod bolts and nuts ie from ARP or whoever .

Cheers A .

[NYTSKY]

First of all you need to ask yourself what are your plans for the car?

What will it be used for?

What power do you want to make?

And what is your budget?

Once you have answered these questions the rest is easy. Just order the parts and get them installed.

[10MinuteCar]

hhmm okay guys i really appreciate your help, though all i want is to freshen up my engine again with stock internals. Thus, i would only want to replace pistons and rings (with stock ones), replace gaskets, replace bearings and what else would there be to do to freshen up the engine like stock new again? my budget is $5000 so i need to fit it in under 5k.

So could you guys please suggest what other things that normally wears out can i replace? i only ask cuz i don't know too much about engines and all not so i can mod internals. thank you and plz along with the parts u reckon i should replace can i get a rough estimate of how much i could find it for please?

BTW how much would new standard pistons and rings cost? and also gaskets and bearings?