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I'm pretty confident on the compression, calculated while we were building. Is there anything I could get done to the head to fix the issue? Really don't want to have to pull the motor back out to replace Pistons and get it all balanced again. I think if I have to go that far I'll put a 26 head on it while it's out.

Cam's can only go one way due to the VCT gear on inlet. Yeah you are seeing correctly, they are dished. 9cc. (Dished because neo chamber is alot smaller than the normal 25-26 head They are a wiseco piston, here is a close up. Did not do anything with the pistons... It's seeming more likely these are the issue with the knock.

I guess that is possible, but I doubt it is the case.. Here is the pistons I am running and a pic of combustion chamber. Thinking about putting some pon-cams in it to try help it breath a bit better

They did play with the dwell and it didn't make any difference apparently. Here's what we ended up with after dialing the cams in. terrible. N/A cams? Ive got no idea...

Will do. I think it's set to 4-4.5 at the moment though

I had timing scatter issue with my sohc and went to a crank trigger. But it used to almost sound like it was breaking down when that happened where this thing seems to rev out smooth. 6x ls2 coils

Ok not sure where to go next with this thing. Got the cams set at In 121. Ex113 Gets to about 5000rpm and starts detonating even with only 13 degrees timing on only 17-18psi, still making no power or torque. Afr are good Compression is 170-165 across all 6. It has around 2.5 psi exhaust back pressure And 2.5psi pressure drop from hot side to manifold Head was decked down to 46cc to get the comp up a bit. To much compression? Is it possible the vct gear is stuffed and causing the cam timing to move around?

Would we be able to buy just the cam part of the kit?

A pic of the Rpm log Maybe timing scatter/ interference?

Well yeah I was looking for at least an extra 30-50 hp. Going from a single cam head to a twin cam head.. The single cam head only had a baby cam. I expected the boost and power to be on earlier and make more torque and power in general. Yeah we double checked ignition timing. Pretty confident on the comp, its a tad higher then 9:1 i have it here somewhere. Fresh fuel. And Ive done over 1000ks on the motor with a soft tune. Not sure on the vct one but I thought if off its just normal and energized it will advance? Even being advanced you would think the power would be on alot sooner

Hey guys. Went for the tune of my 25/30. We cant get it to make hardly any power. And compared to my old slap together SOHC setup, it makes less power less torque and it all happens later, Also its starting to knock up high at anything over 19psi (98ron). We suspected cam timing so degreed the cams in again, (found the exhaust cam 15 degrees retarded). intake cam is 4deg retarded but cant adjust that with out pulling the gear off. Set the exhaust back to 115 deg *standard cams. It made it better but not a whole lot better. Motor specs Rb25/30 Neo 9:1 comp (old motor was in the 7s) forged pistons, rods CPC plenum steam pipe manifold gt35 3inch exhaust 1 muffler no cat 660cc injectors vipec v88 Standard head with upgraded springs and retainers still has vct but didnt turn it on yet. Exhaust, turbo and intercooler plumbing is exactly as it was on old motor. Here's a pic of the run in comparison to the old sohc. Any ideas?

What temp thermostat does everyone run/ recommend? Currently has a 89 in it, just wondering if I should go a bit colder before the final tune?

Open to offers. Need it gone as I need the VL balancer

That seems too cheap to me =\ Just get your local hose shop to make some up (enzed, hydralink etc).

Performance valve springs. Do a spring and ti retainer set for the Neo. Don't know how good they are but I'm running a set and I know that's what john from nextup with the 700+hp Neo had in his with big cams and he had no issues

Keen to seperate the 34 disc?

Yeah I agree, I'm not going to drive it till it gets a tune. Hopefully Saturday. Had a leaking front crank seal, fixed that today so hopefully good to go.

Yeah I suspect it'll be a fair way out, surely the dohc will be flowing a lot more at all revs as well as the extra comp. and ecu has no way of knowing

Got it going, excuse the crappy red breather lines. Cruises and idles very nicely. Limiter set at 4500 for now and will not drive it now till it goes for a run-in tune in few days. Would the tune be out by a fair bit? Difference being New motor with higher comp and the twin cam head vs old motor low comp and sohc. Everything else is basically the same.

Have a RB26 metal jacket balancer for sale. Used. $300 posted

Progress

Sorry mate, ended up using them.

Cheers. That's what I thought. So it gets me thinking why the rb25neo fuel rail has the plazmaman emblem upside down =\ Rail fits fine but that just seems a bit odd (2nd pic in first post)

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Can anyone tell me if these are normal rb25 or rb25 Neo runners