S2 Stagea RB25DET NEO stockish rebuild thread

[Ben C34]

Are you doing a stock piston with forged rods build? That's an odd combo that doesn't make much sense.

You would do pistons over rods everytime normally.

[QLDR31]

I had a scare the other day looked at the big end bearing box after I fitted them and it says RB30. Hopefully they are all the same. I better check that also.

Tonight i'm going to go through the manual check i'm not missing anything.

On 12/30/2021 at 6:08 PM, Duncan said:

It is important you check the ring end gaps before installing. Push each carefully into the bore and check the gap with a feeler gauge. The rings should have the required end gap in the included doco

I visually checked the piston rings. Pushed them into the bore with the piston.

Hopefully tomorrow i'll get the correct rings and check them with a feeler gauge.

On 12/30/2021 at 6:54 PM, Ben C34 said:

Are you doing a stock piston with forged rods build? That's an odd combo that doesn't make much sense.

You would do pistons over rods everytime normally.

Yeah it's still got stock pistons. I'm not chasing big power. I might just put an exhaust on it. I didn't want to throw too much money at it. As there is a chance it might all blow up, being my first engine build. I might learn not to do this  

[QLDR31]

Seems most of the RB engines have the same main bearings except the RB26. One thing I noticed though is main bearings are ACL race series 7M2394HX-STD. The X signifies 0.025mm extra clearance. Not sure if I needed this. I did have the engineers check the crank and it met standard specs.

My rod bearings are standard ACL race series 6B2960H-STD.

[QLDR31]

Using a plastic gauge on all seven main journals. And tightening the main ARP studs down to 60fp in 3 equal steps (ARP recommendation). I only cleaned the assembly lube off the top of the crank journals not both sides not sure if that would affect the result.

I got a reading of around 0.076mm. Nissan spec is around 0.02mm to 0.047mm depending on crank grades. So 7M2394HX-STD bearings I currently have gives me 0.025mm extra clearance (Even though I ordered the standard ones). I will be checking part numbers before I put them in, in the future.

So I think I need 0.025mm oversized bearings. Hopefully giving me around 0.026mm oil clearance in the mains.

[QLDR31]

Experimentation with the main bearings:

The 0.025mm oversized bearings were a bit too tight with plastic gauge. So I got a standard sized bearings. Tried half 0.025mm oversized and the other half standard bearings. Thought that was still a bit tight in some areas. So eventually went for all standard size main bearings. So if my eBay supplier gave me the right bearings to start with. I wouldn't of ended up with three sets of main bearings. The second two sets were bought from a performance wholesaler at a better price with parts available off the shelf.

Working out head gasket requirements:

Can anyone guide me with top of piston clearance to top of block? Whats the minimum clearance? I can't see this in the R33 engine service manual I have. I was planing on using a Nissan head gasket. Just because I got one in my engine gasket kit. If I don't have enough clearance I may need a Cometic or similar gasket. Or maybe I should just get one anyway?

Cleaning up some spots?? in the bores:

The bores have been honed by the engine shop. After cleaning I noticed some spots in the bores. I thought maybe give them a rub with scotchbrite?

Missing head dowel pins so ordered a pair of them and a set of Gates belts (already got a Gates Racing timing belt).

[QLDR31]

So I will go OEM head gasket as using standard pistons and turbo.

I was having problems fitting rings. I Visited my engine builder. He said the bead blaster cleaning has put an edge on the ring grooves. So I have been running old rings around the groove. I should be able to get the rings in now.

Fixing the ring groove I found one of the pistons is damaged. Probably from when I was putting on the gudgeon pins.

Anyone got a spare Rb25DET NEO piston?

 

 

[SLIXK]

Jeeze, rebuilding an engine looks hard lol. I mean if it’s your trade to build engines, it may be easy but to the average Joe it is overwhelming. I’m definitely paying someone to do mine in future. 
 

Good luck with your build!

[RBW49N]

On 22/1/2022 at 1:26 PM, QLDR31 said:

So I will go OEM head gasket as using standard pistons and turbo.

I was having problems fitting rings. I Visited my engine builder. He said the bead blaster cleaning has put an edge on the ring grooves. So I have been running old rings around the groove. I should be able to get the rings in now.

Fixing the ring groove I found one of the pistons is damaged. Probably from when I was putting on the gudgeon pins.

Anyone got a spare Rb25DET NEO piston?

 

 

How did you end up? Did you get another piston? Or did you just get a complete new set of forged ones?

[QLDR31]

On 6/6/2022 at 11:43 PM, RBW49N said:

How did you end up? Did you get another piston? Or did you just get a complete new set of forged ones?

Sorry for the late response. I ended up getting another stock piston through Kudos Motorsport. Took 6-7 weeks. Then I slightly damaged it trying to get the gudgeon pin in (scored it a little). So I took all pistons and rods to my engineer. The engineer said the piston looks savable. Five pistons have rods attached. My engineer is putting the rings on as well as i'm not sure how free the rings are ment to be. They got me to check the ring gaps. From a Japanese manual I found ring gaps for RB25DET NEO  should be RING1: 0.24-0.43mm, RING2 0.42-0.66mm, OIL RING: 0.2-0.69mm. My ring 1 were 0.45 to 0.5mm, and ring 2: 0.65mm. I didn't check the oil rings. My feeler guage went up in increments of 0.05mm. So some rings would be slightly over spec. I measured all ring gaps in cylinder 1.

On 5/19/2022 at 9:34 PM, SLIXK said:

Jeeze, rebuilding an engine looks hard lol. I mean if it’s your trade to build engines, it may be easy but to the average Joe it is overwhelming. I’m definitely paying someone to do mine in future. 
 

Good luck with your build!

Thanks I need some luck. I wouldn't recommend first time engine building for someone who doesn't have someone to guide them. Youtube might have some ok videos but they don't cover everything.

[QLDR31]

Ring gaps from R34 manual (I hope):

 

[QLDR31]

I finally got my pistons in today.The engine shop put the rings on. Because I wasn't sure how loose/tight they are meant to be. The pistons got bead blasted and that made the ring grooves a bit tighter. I did run around the grooves with old rings but still I wasn't sure. I moved the ring gaps to the Nissan spec. I tightened the ARP rod cap bolts to 50fp. Piston 6 is the new piston I got from Japan.

So then I ran into my next hurtle: When putting on the oil pump it looked like the inner part of the seal was poking out. Took it back then the metal part inside the seal came out. I can't get it back in. I think i'll need to get a new seal.

[Duncan]

Yep, you need a new seal

[QLDR31]

Yep I got a new seal (ordered it on Sunday, got it today). The one that just got damaged was new also.

So the seal was flush with the outside of the oil pump. There was a couple mm gap behind the seal. I probably damaged the seal putting it onto the pump.

Whats a good way to put on the seal? Vasoline?

I also bought a new main pulley bolt, they were only $9.

 

[Dose Pipe Sutututu]

Just my 2 cents, put on a Nitto or Tomei headgasket along with ARP head studs since the motor is apart.

[QLDR31]

On 7/7/2022 at 9:44 AM, Dose Pipe Sutututu said:

Just my 2 cents, put on a Nitto or Tomei headgasket along with ARP head studs since the motor is apart.

Yeah got ARP head studs. But gong OEM head gasket just because I already have it.

I was thinking of getting new bolts with spring washers etc for oil pump, water pump, rear crank seal. Maybe something for sump as well. The old spring washers don't look too springy.

Edited July 11, 2022 by QLDR31

[QLDR31]

Oil pump is on with new seal. The seal went on easy with a little Vaseline.

Rear seal is on.

I made a rookie error fitting the baffles under the block. I read the rb26dett torque settings they are 16-21Nm. But they must have M8 bolts. I think I over torqued my M6 bolts to less then 16. but replaced them anyway.

Next up is water pump and sump. then head.

One of the mechanics at work said to crank it without the cam covers to check the cam oil squirters are all working. What you guys think?

[QLDR31]

Finally got the head bolted on. I've had a few health setbacks slowing me down.

I came into a few issues.

On one end the head alignment dowel pin was holding the head up. i put a little bit of assembly lube on both sides. Then it went together.

I checked the torque settings on the camshaft bolts. One of the baffle nuts was spinning and wouldn't come off so had to cover the engine up and grind it off. Now I need to find a stud to replace it.

Ground my 1/2" deep socket so I could use it to torque the ARP head bolts without taking the camshafts out. Torqued up to 80fp.

Cam covers are on temporarily at the moment with old seals. I also put the spark plugs in to stop things falling in. I do keep it covered when i'm not working on it.

 

[QLDR31]

Anyone pulled the inlet cam gear assembly apart?

I just wanted to check I got all the parts. I can see a spring. The o-ring and hex head plug. Think I might be missing a washer.

The diagram looks different. I think my diagram might be for an R33.

Just bolt her on?

I was a bit unsure putting on the camshaft front seals. I think if there is a next time i'll buy a seal install and remove kit.

Camshafts are both torqued down now.

Anyone made up an OEM style engine stand? I'm currently using a generic engine stand bolted to the gearbox threads.

 

 

Edited February 26, 2023 by QLDR31

[QLDR31]

Apparently the NEO has no washer in the inlet cam.

On the weekend I got the timing belt on. Did another rookie error had my torque wrench set to fp instead of nm. Over torqued the tensioner. So I tossed my new stud and nut and reused my old ones.

I bought a stud install/remove kit. The remove part is too long to remove the tensioner studs but the install part works well. I loctited the smaller stud.

My engine didn't have original the cam cover bolts so I have ordered them (another 3-4 week wait). Apparently the NEO bolts are different to everything else. But I have plenty to go on with.

[Duncan]

good choice to throw the overtorqued fasteners....but I'd still buy another new set if you have time, it would be a shame to do all this then have the old one break and lunch your engine