dave1200

If it's a neo head you'll know if you've bent valves or not by just putting some feelers between cam and lifter. Standard gaps are something in the 0.010" range, if you've bent a valve you'll find a lot more than that gap. PS - I don't like your chances..... Dave

I was bored yesterday so uploaded the time lapse videos I took while building my motor - Reasonably boring stuff but for anybody who's interested have a look. Dave

I'm a DIY kind of guy. You get incredible functionality for a good price. For less than $1000 I'll get an ECU that's entirely configurable with all the I/O of a high end ECU. As I said earlier they generate more head scratching but I've got a few mates who have had good success with megasquirt as well as know a tuner who is familiar with them.

Thanks but Not sure this helps me. The problem is that the Neo NA ecu and loom are different to the turbo therefore any of the plug and play ecus won't work because nobody supports the NA motor. If I have to wire one from scratch it will be a megasquirt but I'm mostly looking at the pros and cons of replacing loom with a turbo then getting a plug and play ecu/piggyback nistune style. I think I can get a megasquirt running the complete NA motor then would just need to change injectors and go to map sensor to run a big turbo but this would have much more head scratching than the other option.

I slapped a radiator and short exhaust on it this week. Sounds absolutely awesome. Very crisp and revvy. All I need now is a car to whack it in. Does anybody have any good ideas about converting it to a Programmable ecu? I'm am idiot and didn't look into this and now have the issue of doing one if these things. 1. Buy a complete turbo loom and ecu and injectors then going nisstune. 2. As above but plugging in a pfc 3. Start from scratch with a aftermarket loom and ecu. I would be thinking megasquirt if going down this path. Any advice would be welcome. Dave T

Cheers for that. I've ended up going with the two tensioners. A little update, I got it running tonight. I nearly fell off my seat it was so loud running straight off the headers right next to me. I set up an oil pressure gauge in my little switch box and it's making plenty. I only ran it for a few seconds since there's no water in it yet.

Can you elaborate on this? I don't understand how the tensioner hole position has any influence on the timing marks. The drive side of the timing belt is phasing the belt teeth based on the length of the path the belt follows. I reckon using an idler pulley doesn't get the crank to cam sync quite right. The other thing is that the timing marks on the head backing plate are probably only as accurate as they needed to be assuming you were putting a timing belt back on an RB25 block (ie you aren't wrong by a hole tooth). I am probably thinking about it too much and if I truly want to get it right I would need to dial the crank to the cams properly. Thanks for the help!

Hey guys a bit of an update. I lost a battle with the committee and had to sell my R31. I did however decide to keep building this motor. I found a healthy R31 Rb30 and as of tonight just got the Rb25 head torqued down. I set up all the timing gear and turned up some oil restrictors before cleaning the block and giving it a coat of paint. Here's a couple of pics for anyone who's interested. I've actually set up my gopro to take time lapse photos of the build for shits and giggles which I'll whack up one day if anybody would be interested. A keen eye will spot I have used a block without the machine face where the idler pulley sits. I've made up a 5mm plate to bridge it and machine that amount off the idler to suit. Not ideal but hey we're building a budget setup. Has anybody else noticed when you use the concentric idler in the drive side of the timing gear that you timing marks don't line up perfectly? I have trialed a second tensioner in that place and can dial in the timing marks HOWEVER this makes me nervous in the case that it slips and throws the cam timing out. Thoughts?

sounds like coil packs or plug gapping issue. What gap are you running?

Yeah I knocked one up a couple of weeks ago. I'm going to run this hose to the 3/4" BSP fitting in the block since I'm going N/A. Then Vent this tube also up to the catch can (in the bottom also acting like a drain for catch can). I'll plumb the 2 rocker covers to the catch can also then run the catch can breather to the inlet to keep it legal.

So after reading this I thought bugger it ill just Weld it up. Decided while I had the tig out I'd just Weld up the oil feed as well since there is zero chance of it ever going back on an rb25 block. I attached some average pics for anyone who may be interested. The old water gallery is a typically contaminated surface so be sure to run plenty of AC balance.

I can't understand why I don't here more discussion on this forum about twin scroll setups. If you're going the GTX3076R get it with the 1.04 Twin Scroll rear housing and get a PROPER split pulse manifold with duel wastegates etc. I did this on my FJ20 and it runs a GT3071R with the 0.78 rear split pulse and manifold. Makes 21psi at 3500rpm and peak torque just after that yet pulls hard to make around 270rwkw. The engine is a midrange animal. I can only imagine on the twin cam RB30 with a relatively small turbo (GTX3076R with 1.04 split pulse) You'd probably have full boost before 3000rpm and still make 320rwkw. That to me sounds like the ideal street motor. The added benefit of the proper split pulse manifolds is the improved volumetric efficiency which may negate the need for aftermarket cams at that power level all together.

nah not worried about overheating. just didn't like the look of the thin landing that's holding the water system. But that's all the encouragement I need. Cheeres

Hey just a quicky - Did you bother adding material to either the head or block to get a better seal on the headgasket around water galleries? I was overlaying the 2 and there is clearly a mismatch but still some landing that would probably make a seal. I was thinking about just using a little RTV around that area since the rubbery rings in the headgasket in that area won't engage on the head. I can fairly easily add material to the head and dress it back but if you've got first hand experience of not doing it I could be talked out of the work. Dave

Yep good call. Thanks for all your help by they way!

When you say machined, they are just a blind hole in the block on a small spot face right? If so can't I just drill and tap to the correct depth? If I had to I could probably throw it up on the mill but would have thought as long as you can get your pilot drill started you should be able to step up the hole carefully to the tap pilot size. I'm guessing they are a 1/8 or 1/4" BSP parrallel so should be right? Can you see any benefit in reusing 1 of the knock sensors in the centre location in the RB30 block and then running the resistor on the other? Yeah I've got all the other sensors/connectors sorted via resurrecting the ECM/COIL relay as well as the couple of items on the IGN relay.

Awesome thanks for the quick reply. I do plan to add the knock sensor loom into my chopped down engine loom but just forgot so it's good to have an option. Is there any other items in that loom that may be crucial to getting the ecu running as per normal? Oil pressure sender? any of the alternator wiring?

Can anybody help me out with a wiring/ecu question? What will the Neo ecu do with no knock sensors connected? Will it think there's no knock and run as normal or will it spit the dummy and go into limp mode? The reason I ask is because the knock sensor loom is not in the engine loom and I had planned to leave all r31 loom on the lower half of the motor. I've already stripped and rewired the engine loom and I spotted this afterward.... Derr

I've given this a bit of thought and it really should run OK on the standard ecu. I'm not going to go near the afm resolution limit, the 270 cc injectors will flow plenty. The only issue I can see is that it will be accessing load points in the map that the rb25 was not supposed to see. Knowing Nissan tuning it will result in a rich top end. You're probably right that if I added a nistune I could pull fuel out of the top end and free up a few more killer wasps.

yeah will do. I'd be happy if it made a good torquey 125rwkw. I imagine it'd be a bit of fun like that.

Cool thanks for the advice. At this stage I'm hoping the bottom end of the donor car will be healthy enough. I figure that since it's an N/A build it should be ok since it won't see the stress of a boosted version. I've finished rebuilding the head and making all the oil supply and drain mods. Next job is to start hacking up the wiring loom to remove extra wiring plus integrating with the R31. Should be some head scratching going on! I should be clear, I'm not building on a budget. I am challenging the idea of how cheaply can you build one of these motors? At this stage it's looking like I should be able to get the R31 running on a neo head with R34 n/a ecu for about $1100 all up.

I've been thinking a little more about this; how would you know that it wasn't working? Your ecu could be actuating the solenoid but if your oil pressure is insufficient to actuate the cam then I don't know how you'd know? Unless you had previous seat of the pants experience with the motor or another car with similar specs to compare against? It's not like a light comes on in the dash when camshaft is advanced?

Actually I take that back.. Had a closer look. Derr..

Care to elaborate? I've got a Neo head in bits sitting on my bench At the moment and there's no way the oil comes through the Cam then to the solenoid.....

Pretty sure this is wrong. The oil supply quite clearly comes up through the head from the block, passed the solenoid (depending on its state) then to the cam.