RB20DET Rebuild

[TokyoTaxi]

Hi all,

As you've probably guessed by the title, my car had a heart attack ( oil surge = main bearings go knock, knock ).

Anyway, I have a couple of questions for you all that I hope you can help me with. PLEASE keep the answers kinda serious because I need good info quickly.

1. Has anyone used "Pro Flow" located out west of Sydney to build their engine, head work etc ?? Opinions please because I'm considering using their services.

2. Forged Pistons. Looking at "Arias" pistons. Opinions please ?

3. Sump Baffles/Anti-Surge trap doors etc. Best option, who, where, how much etc please ?

4. Anything you think might be relevant while engine is out ?

Thanx

[Fast31]

mates have dealt with pro flo with excellent results

arias are great pistons

[Skyrine-Dave]

can i ask what the cause of the oil surge was?

If it was launching hard what sort of power are you putting out?

i am concerned because my car squats like a hoe and i dont want that to casue any oil starvation problems with increased power.

[TokyoTaxi]

Fast31,

Thanks for the feedback. So far so good with my current direction.

Skyrine-Dave,

Track work ! Did it at Eastern Creek either through turn 1 at over 200kph or under brakes leading into turn 2. Not sure which and I guess it doesn't matter. I'm only putting out around 200rwkw.

[Cubes]

I'd keep the CR standard 8.5:1 and do as much head work as you can afford. Maybe at the same time slap in a set of NA cam's or even better a decent set of aftermarket cams but that may blow the budget out.

Stroke it out to 2.3ltrs, Look in to using the RB25 conrods/crank, not sure exactly what has to be done.

Baffle the sump.

Not sure if you really need or want the motor to be blueprinted.

O-Ringed block and standard head gasket. From memory O-ring is a roughly $33 per cyclinder.

[Doctor]

Isnt stock CR ratio for a R32 8.1? and R33 8.5?

[Fast31]

no

[T0nyGTSt]

From memory the rb20/25 is 9.5:1

rb26 is 8.5:1

If the rb20 was 8.1:1 it would be a doughy ****.

T.

[Cubes]

The RB20DET has a 8.5:1cr.

RB25DE has a 10:1cr, not sure about the RB20DE.

RB25DET has a 9:1cr.

[TokyoTaxi]

Ah Joel,

If only I had the money.......

I'm just going to fix up the bottom end, put a set of forgies in, get the sump baffled, get the head serviced and some mild porting including match porting the manifolds to the head.

Can't afford to go the stroker and play with cams ect

So is the CR 8.5:1 for sure ?? Will help to know this when I go for a head gasket. Not sure if I want to raise the CR slightly and use less boost or continue with 18psi and keep the CR lower or standard.

[Cubes]

18psi will be the maximum I would wont to run with a 9:1 cr and a good tune.

Are you going to clean up the head a little?

VRS kits are around $270 which include valve stem seals.

If anything port match the manifold and inlet ports. (Its easy)

and remove the bumps from the exhaust ports.

Depends if you are willing to do bits your self.

Stroker would be nice if you came across a cheap stuffed RB25, bring boost on earlier and make more torque when you are on boost

[Doctor]

Yeah sorry, I get confused alot. Thats why I asked the question.

Its one of those things I keep forgetting. Only strarted when my girlfriend started to hit me

[TokyoTaxi]

Joel,

Yes I'm going to get the head fully serviced, match ported and some minor port polishing. If I do bring the CR up to around 9.1:1 I'll only be running around 16psi boost. I should still get 200rwkw and that's all I need. ( I must be getting old to say sh!t like that ).

Excuse my ignorance but VRS Kit ?? Where does one get one of these to suit an RB20DET ? ( assuming that I'm going to need one ).

If I knew exactly what was invloved in building it into a stroker I probably would but all my engine building knowledge and experience is back in the days when I used to play with my BDA Cosworth Escort. God, I am old!

[Roy]

This sounds familiar, but i still havent had the courage to take my car to a mechanic to find out if the slight cold start knock is my bottom end.

Still has good oil pressure, drives A1 and 20sec after start no noise so i am still living in hope.

Looking at the power you have, and the power you will be happy having, i would consider buying a low kms import engine. With some DIY work you can have the new engine in for les then the cost of forged pistons.

If it turns out the knock is someting terminal in my engine, my heart tells me rebuild with some good internals, but commonsense tells me at the power i will have the expense isnt justified.

[Fast31]

mate getting 200rwkw is piss easy, why spend all that money if thats all the power you are chasing

[TokyoTaxi]

Fast31. The simple answer is......so it will last !

Roy, I hear what you're saying and I've had that argument with myself a hundred times but considering what I use this car for ( primarily track days ) I don't want to go through this down time again and at least I'll know what my engine is likely to do whereas a 2nd hand engine is only as good as the last person who neglected or thrashed the arse out of it. I guess the methodology is that a better than stock engine will give the same power with less stress than a stocker.

[Fast31]

on 16 psi and with that headwork you are going to make more then 200rwkw, and do it easily,

good luck with it, let us know how you go.

Pm me what you are paying for the arias pistons too if you dont mind

[Cubes]

The more headwork the better. You get more airflow for any given psi. Remember PSI is the actual restriction to air flow.

So reduce that restriction and you get x amount of air in to the pots on less boost. So basically it will make the same power on less boost which gives you more head room and allows you at the end of the day to make more power.

I wouldn't bother with pistons. Keep the stockers.

The RB20 isn't going to make power where it needs them. i.e over 250rwkw.

Spend the money on some major head work.

It will also spool the turbo up quicker.

The VRS kit is a Valve Regrind Kit. It comes with a Headgasket, Cam oil seals, valve stem seals (required for head rebuild), rocker cover gaskets, inlet manifold gasket, exhaust manifold gasket, plenum gaskets. Thats about it I think.. Its a must and its the cheapest way to get out of buying the gaskets individually.

They are around $275. The Genuine Nissan head gasket on its own is around $75. If you buy the valve stem seals on their own they are around $300. So you would have to be stupid to buy the parts seperately.

O-Ring the block with the standard head gasket is the best way to go about things if you want to run high boost. Unless you want to buy a big $$ HKS head gasket that has the O-ring built in.

But If you are only going to be running up to 1.1-1.2bar then I wouldn't worry about O-ringing or HKS head gaskets. Stick with the OEM head gasket as they are very good.

Also when running high boosts, if you havn't got a good seal from not O-ringing the combustion chamber gases can some times seep in to your coolant galleries in turn boiling the coolant easier which will apear as the car starts to overheat for no reason. Not 100% sure on that last one but thats the way i understand it.

[5 litre eater]

"This sounds familiar, but i still havent had the courage to take my car to a mechanic to find out if the slight cold start knock is my bottom end.

Still has good oil pressure, drives A1 and 20sec after start no noise so i am still living in hope. "

Now i'm worried about my car (R32 GTS-t)... I did an ECU fault test the other week, and saw that the Knock Sensor was coming up. When the car is cold, it is very hard to start (have to pump accelerator repeatedly) and the oil pressure sits under 4 on the dash nearly at all times... Does this mean i've done a main bearing, blown the bottom end or am i just paranoid?

I'm not exactly a wizz at this whole mechanical side of life, so can anyone please explain to me what is wrong, if anything?

Thanks. Matt.

[Cubes]

I'd be hanging on to that Silvia in your sig that is for sale a little longer.