RB26 Engine rebuild advice

[haw001]

I'm about to tackle my first engine rebuild and I am out for advice on what I should be doing while it's apart.

I know that an RB 26 is probably a big job for a first timer, but I'm planning to take my time and do it right.

Right now I'm looking for advice on what I should be putting in and doing while it's apart. My goal is not big horsepower for drags, but more in reliability and torque. It will be a track car and so I am only aiming for around 275 rwkw, but it needs to be able to run for extended periods and be able to put up with the to and fro of high g turns.

Any advice on where to buy parts would also be greatly appreciated.

Specific questions:

I'm on a budget, but I feel that forged or semi-forget pistons would be a good idea. Can anyone tell me what and where I should get?

I don't think that I want to lower the compression, but I have heard different ideas on head gaskets. Any ideas/comments?

Oil restrictors. I understand that there are lower and upper restrictors and that they should be made smaller. Can someone tell me what size hole I should get and where I get the restrictors?

I don't think that I want to change the cams, but if weakness is an issue i'll consider it.

Honing, porting and balancing. Lots of different opinions out there. Any weak points I should focus on?

Any general weak points in the engine I should address?

Thanks in advance!

[Sydneykid]

Hi Mark, my suggestions follow;

- Standard camshafts are OK for your puposes or you could go to the HKS 256 degree low lift (around 8.7 mm)

- if you can get a HKS camshaft kit (of the above spec) with valve springs cheap take it, if not Iskanderian valve springs are the go

-adjustable pulleys on both camshafts, we use Jun or Toda

- new camshaft belt, check the tensioner and idler pulley bearings.

- the standard RB26 crank (as with all RB turbo cranks is very strong) leave it alone, other than a micro balance

- the RB26 standard conrods are pretty strong and will handle way more than your power needs. We use ARP rod bolts for extra strength.

- O'ring the block, standard Nissan head gasket, compression ratio needs to be around 9.0 to 1, not much less or you will loose driveability and increase lag

- We prefer JE Pistons, stick with 87 mm or 87.5 mm depending on price.

- Total Seal piston rings, with gapless second ring.

- Balance all of the up and down and round and round bits

- GTR water pump and oil pump are OK.

- The RB26 sump is way too small, increase its capacity, around 7 litres is good, with gates and wings to prevent surge.

- use an oil cooler, a few laps increase the oil temp markedly

- Standard Nissan main bearings and Nismo big ends

- match port the cylinder head and the manifolds (both inlet and exhaust)

- Twin plate clutch, at least, we use OS Giken

- Standard injectors will be OK

- Standard fuel pump will be OK

- At least 3" dump from turbine and exhaust 3" or more

- You should realy consider having steel turbine wheels put into your turbos while they are out, or hi flowed if you want more power.

Hope that helps.

[Merli]

For 275kw @ all 4 wheels, you can leave your engine completely stock, and just go for bolt-on parts.

My mate's GTR is making in excess of 400kw @ all 4 wheels on it's stock internals, but this is definitely pushing the internals. For your goals, there is absolutely no need to touch the internals.

[haw001]

Thanks for the info, this was just the type of advice I was looking for. If anyone else has any comments please post them.

I have already upgraded the fuel pump and injectors to 550cc.

the turbos are also modified Garret t28 from a 33 GTR, cored out with 360 degree steel cores.

I have also done the down and dump pipes, but I do need to have the option of running standard pipes as I intend to run Targa tas at a later date.

What about the oil pump. Should this be changed?

Thanks!

[haw001]

I know that stock internals will work and give me up to 300rwkw, but I really want to work on the reliability.

I've got 290rwkw right now on the stock internals, but even with 550cc injectors, a new fuel pump and a malpassi, I managed to max out the injectors and do some minor damage. Uppling the fuel pressure should fix this problem, but I'm still a little concerned with durability. I don't want to be taking the engine out after every race to fix something.

Having said that, if everyone feels that the pistons and con rods will survive then I'm more than happy to leave them and spend my relatively minor budget elsewhere.

keep in mind that my engine is set up for max torque and even at 290rwkw, I am putting as much stress on the engine as an engine set up for well over 300rwkw when set up for max power.

Thanks again

[meggala]

the nismo N! oil pump would be worth looking into also a larger radiator. the sump issue sydney kid refered to is a big one a nubmer of people have had this problem with oil starvation. and increase in fuel pressure should see fuelling increased. for pistons nismo make n1 pistons which are the ones you refer to you can get them from nissan here I believe

make sure when the motor is apart all the oil squirters are cleaned out properly some people put a restrictor in the oil gallerier but this might be only for big hp pplications not sure.

check out http://www.reimax.com/product1.htm they have alot of bits for group a racing I would also talk to the guys from Just jap they have built an r32 for targa and they might point you in the right direction.

cheers

meggala

[Sydneykid]

Hi haw001, you said that the 550 cc injectors ran out at 290rwkw. We get nearly that out of standard injectors (440 cc's). Something doesn't add up, you should be getting to around 330 rwkw before the 550's run out of flow, at standard pressure. Have you had the injectors flow checked? What fuel pressure are you running currently?

Just a tip we run the highest flowing injector in no. 6, the next highest in no. 5 etc. Number 6 always runs a little bit leaner due to the plenum design, plus being at the back of the engine it runs a bit hotter as well, a little extra fuel helps both.

Hope that helps

[fatz]

maybe you would be better off getting a bran new n1 engine

they r arn't that exspensive when you compare a rebuid to it and its new!

pete

[haw001]

I have had the injectors cleaned and flowed, but I'll do it again before re-installing. Number 6 was the one that ran out, and only just. Damage was minimal. I think the pressure was 45psi, but that may be completely wrong. What pressure can I safely run with the standard fuel lines? The pump can handle it.

I've had a quick look at an N1 engine, but they are just too expensive. Not over the top, but still more than a rebuild, and even then, I would be looking at changing some parts, particularly in the Oil resevoir and pump.

You missed a good track day on Saturday Fatz. It rained and no one showed up. Only three cars in the sub 1:15 category.

[Guest Peewee]

Mate the things i would do different is not much but i would DEFINATLY put the oil restrictor in the oil gallery in block (it actually blocks it completely) you can buy this from micks metalcraft in sydney.

The gtrs get oil pooling in the head from to much oil going up there and they block it to limit it and when the oil pools and you corner hard the oil runs dry down the bottom and spins a bearing it's very common for gtrs

Also i wouldn't match port the head i'd get it done by a pro as you can easly **** it and you wont see what you have done to **** it.

There is a place in sydney i think it's called Rams and they are exeptional at what they do.

Hope this helps let me know if you need more info!