I haven’t seen much in the way of reviews for the RB platform on the components that CNC innovations sells. I have seen their products floating around online through Instagram and Facebook for a little while now, and decided I would take a bit of a gamble and purchased multiple products from them for my new engine build. Hopefully this might sway someone to decide not to go ahead with purchasing from them, or maybe even entice someone who is happy to do a little bit of extra work themselves to save some money.
I purchased for my RB25DET Neo engine an upper timing cover, lower timing cover, cam covers, intake manifold and came with billet fuel rails. I got these all in a raw aluminium finish, as I wanted to powder coat them to match other components that I have powder coated. My issues started before the products were even shipped, luckily sending me a photo before packing them. My upper timing cover was to have “RB28” on it in raised machined lettering. The cover in the photo they sent me didnt have this, despite it being written in my order as a drop down menu option that it was to be there. Their solution was to just laser engrave it, which I’m not sure how that would’ve worked with raw material as their laser etching basically removes the anodised finish and gives you a raw aluminium finish where the text is, but i wanted to powdercoat the letters and numbers red and the cover itself black, so would have been useless to laser engrave these. They had to make me a new one which added a week to the order being shipped out. It was about 3 weeks in total from my order being placed to them shipping it out plus another week for shipping to Australia from Malaysia
My next issue was some of the quality of the machining. You can see in the photos there is a visible 0.47mm step in the machining on the manifold, which also happened to go straight through where a fitting was to be installed. There was also a similar issue with a smaller step in the machining all around my upper timing cover but luckily i could linish and sand that back before powder coating. If my parts were anodised i would have been furious as I wouldn’t have been able to fix that and probably would’ve visually stood out with the anodised finish. The first three linked photos show this step in the parts, all the way across, so must’ve been a issue with the machine, as the line is perfectly straight where it steps up along the parts on the same plane. This is on the underside of my intake manifold so I left it as is
Next came the fitment of the timing covers. I went to the shop that was assembling my newly build engine, and luckily I did, because i discovered that if i bolt on the lower timing cover, the upper timing cover doesnt fit. And if i bolt on the upper timing cover, the lower one doesnt fit. You can see in the 4th and 5th photos that the bolt hole doesnt line up by about 5mm. This is because they havent designed these properly to work together. Luckily the stock lower cover does fit with the billet upper cover so I can use that. Another issue with their lower timing cover was the fact it doesnt actually seal up to engine components like the factory one does, leaving large spaces that would allow dirt and road debris to get into the timing belt area. Theres a reason Nissan made the covers seal around all components, as the timing belt needs to be kept as clean as possible to prevent premature wear and failure. I’ve shown this in the sixth photo where you can see the red-highlighted gaps between the cover and the engine block and components, which goes straight to where the timing belt is, allowing stuff to get in there. Again, luckily i can use the stock cover that seals around those components to protect the belt
I also test fit the fuel rails and tried putting in a stock factory RB25DET Neo injector, and discovered that the billet brackets were too long for the stock injectors, so the injectors did not sit properly inside. They provide other brackets from laser cut and folded stainless with multiple height options to try resolve this issue, but they were too short and the injector doesnt fit inside. From my research the nice billet ones that i want to use would work with RB26 injectors from a GTR but not RB25 injectors as the RB 26 injectors are about 10 mm longer. This isn’t a major issue, but it is something to note as it was advertised to work for RB25 engines
Final issue was the intake manifold. First off they have no allowances for the factory sensors, which are both M12 threads, one for the coolant gauge and one for the ECU. All they provided was a 1/4 NPT thread which doesnt work with these sensors. So you basically would end up having to purchase a aftermarket sensor that works with the ECU, and then you cannot have your coolant gauge on the dash work. Which would really annoy me on my R34 Skyline. Next issue with the manifold was that they provided this “water merger” as you can see in the 7th photo, with absolutely no instruction on how it is meant to be used or positioned, nor do they have a diagram or photos on how the hoses (which arent supplied) are meant to route from the coolant passages in the manifold to the radiator inlet. Theres have been weeks now of back and forth emails trying to just get a diagram of how the hoses run, and they send me a low quality diagram from some other engine that isnt an RB25 engine saying that the coolant passages “arent that simple” on this engine. My response was a photo of the factory stock manifold from Nissan that came off my engine which clearly shows all the water passages on the manifold going to one place, the radiator inlet. Because there have been so many back and forth emails with absolutely no solutions, and i needed my engine to be completed so it can go back into the car, i have had to make do with what i had, purchase a coolant merger kit with hoses and the right sensors threads machined into it from another brand of manifold for $90, weld on a barb fitting to the CNC Innovations manifold, and purchase additional fittings to make this work. I ask for photos from others who have installed this kit and all they can send me are views of it from the top of the engine bay, with absolutely no indication on how the coolant hoses are routed
The only component that worked with no issues was the cam covers.
To sum everything up, i do like the end result, mainly due to the extra work i had to put in and parts i had to buy to make it all work properly, but it has been an absolute headache and so much time has been wasted. I’ve included some final photos of the parts. before being installed on the engine after powder coating. So much extra parts and work was needed to make these products work, and my lower timing cover is absolutely useless so its a very expensive paper weight for now. There are still ongoing back and forth emails with CNC Innovations but it is such a slow process to resolve any of these problems, and I am hoping they make it right in the end but I am not pleased at all
