Nissan RB26 Cylinder Head Build
When it comes to your RB26 cylinder head build various components come into the discussion. Common upgrades include valve springs, camshafts, valve guides, larger valves, etc. Depending on what components you go with for your build and your desired power goals or build requirements, different machine work will be performed including valve job, cutting valve seats for a larger valved motor, port and polish to enlarge intake and exhaust ports. You may find that the direction that you take with the cylinder head build will play a role in supporting mods as well included oil pump, cam gears, pistons, head studs and gaskets. Raw Brokerage is here to guide you through what might be seemingly huge task to get you the correct parts for the build you want!
Step 1: Verify your cam angle sensor.Check to see which cam angle sensor (CAS) you have on your engine to narrow down compatible camshafts. The main difference is the camshaft drive design as seen in the illustrated comparison. Raw Brokerage classifies these into two types:
Type-1 sensors are full aluminum in construction. The cam drive has a female spline drive with a male half moon.
Type-2 sensors are a combination of both aluminum body and a plastic cover. The cam drive is round with an offset slot though the middle.
Drop In Cams
The factory lift is 8.58mm on the intake camshaft and 8.28mm on the exhaust camshaft.The maximum lift you're able to run on a factory cylinder head casting is 9.35mm before your camshaft lobe makes contact with the cylinder head.Any camshaft less than 9.35mm of lift while retaining a factory size base circle can be considered a drop in camshaft.
Camshafts that Require machining to cylinder head
More aggressive camshafts: If you're desiring additional duration and lift in your valvetrain additional machine work and cylinder head components are required to properly install more aggressive camshafts.Camshafts exceeding the above mentioned 9.3mm of lift requires the casting around the camshaft lobes to be machined to provide extra clearance (see picture). The factory base circle on the camshafts are 32mm. As long as the camshafts maintain the factory base circle diameter you'll be able to use your factory (of factory replacement) lifter buckets.
Camshafts that Require machining to cylinder head and Lifters
When considering camshafts with even higher duration and lift the base circle of the camshaft is reduced (see picture). To compensate for the difference in lash tolerance a taller lifter bucket is required.
RB26 LIFTER BUCKETS
Step 2: Depending on your cam selection you might require lifter buckets for your cylinder head. Or perhaps you need to compensate for a larger than factory spec lash shim, where a taller lifter bucket will come into consideration.
RB26 VALVE SPRINGS
Step 3: Valve springs are one of the most commonly upgraded items when it comes to the RB26 cylinder head. The factory springs allow for much room for improvement when it comes to keeping the valvetrain in check. Your horsepower goals and targeted RPM range will determine how high of a spring rate you'll be looking for in your valve spring selection. The coil bind height of the spring will determine if it will be able to accommodate the cam lift spec during your camshaft selection process.
The main difference in the spring kit selection is choosing between a single or dual spring configuration. Typically the dual spring kits are able to achieve higher seat pressure with the addition of the second spring.
Single Valve Springs
DUAL Valve Springs
Step 4: A suggested component in any cylinder head overhaul is replacing the valves. Usually expected in a RB cylinder head rebuild are 20+ year old factory valves that have seen their share of heat cycles, excess boost pressure and some rev limiting fun. Replacing and upgrading to aftermarket valves will not only provide you with new more reliable valves but provide stronger and better material to make a higher horsepower and torque capable motor. Typical materials used in aftermarket valves include inconel, stainless steel and other exotic metals.
An opportunity to make additional power is to increase the size of the valve. For the RB26 usually you'll find oversized valves at +1mm head diameter. This requires a machinist to cut the valve seat to match the larger valve. Larger valves allow for greater airflow in and out of the combustion chamber with the intention of rendering greater power output throughout the powerband.
Standard Size VALVES
RB26 VALVE Guides & Keepers
Step 5: Valve guides are perhaps one of the most upgraded component in the RB cylinder head. The stock guides are usually show signs of wear and tear by the time you are rebuilding your engine. This doesn't help that the factory guides are not the great to begin with. Most manufacturers follow suit of each other by offering bronze (and sometimes mixed with other alloys) for replacement guides. Although upgrading guides requires some additional machine work of removing the old ones, fitting the new ones and honing them to spec, it's money well spent insuring your valvetrain stays in place.
WHY BUILD YOUR CYLINDER HEAD THOUGH RAW BROKERAGE?
Raw Brokerage has over a decade of specialized experience in offering Nissan Skyline owners and RB engine owners alike with performance parts, professional engine building services and consultation. We have been involved in maintaining RB26 engines long before the Nissan Skyline GTR was available for importing into the USA. We've built engine from a factory refresh and overhaul to 1,500 HP+ drag racing setups. From drift cars to street cars we've broken, replaced, analyzed and ran the components on the market. Through this knowledge we're able to provide you with the best recommendations for your project without breaking the bank. Saving you both time and frustration while getting the best value of your hard earned dollar.
It goes without saying that modifying your car gets expensive. Just like you we are car enthusiast looking to go fast and our money to go far doing just that. Here at Raw Brokerage we strive to achieve that for you our customers. Finding the right parts that will do the best job at a low price. All without sacrificing quality and safety of your build. But the saving don't stop at the price tag of the parts you're looking for. By offering you everything you need to get the job done right the first time, we can offer you the convenience of knowing that you'll be able to get everything you need to complete you sought out goal. So don't delay your build at your machine shop by shopping for parts else where only to find out that you're missing something from the beginning. Save time, save money, go faster!
As a customer of Raw Brokerage we make it a priority to make sure your shopping experience with us is outstanding. Keeping you constantly in the know of the latest products updates, pricing, and order status. Using a suite of sophisticated software, we're able to manage the process to stock the parts you need, where you need them, to get them to you when you need them, accurately! We know you have plenty of 'choices' to shop from online. However, we differentiate from those online retailers that list product only to flip at a profit, as we have the knowledge to back what we sell. Likewise, unlike larger performance shops by delivering that personalized attention to YOUR build.