My 1995 GTR project thread.

[cortexx]

Correct , when you look at the lobe , the thickest part of it's profile will be facing away from the bucket (up in the air) leaving the thinnest part of the profile closest to the bucket . This is when you have the gap you measure for . When blueprinting the head the final check to make sure you have everything shimmed properly is to rotate the cam in turn to each position where it fully compresses the valve spring. You measure the face of the valve with a dial gauge to make sure you have the right lift (in this case 9.15 mm). I'll demonstrate this when i get to this stage and throw up some pictures.

Check out this pic - when I do it the lift point of the lobe is totally vertical (12 o'clock) unlike this picture where the lift part lobe is about 60 degrees before 12 o'clock. But at least you can see the principle of how to measure the clearance.




Time permitting each stage of the entire engine assembly will be posted here with pictures and explanations etc .

[NismoS-tune]

Nice write up and pictures sir! Appears you know what you're doing. I sometimes wonder if I should have taken the challenge of building my own engine but didn't know where to learn the tricks and information I needed. Definitely book marked for my next build (#3).

I have a green horn question though, I'm trying to picture this. when you measure between the cam lobe and bucket, that's when the lobe is downward? So the bucket is sitting down there with no spring (since the bucket isn't touching it?). Sorry haha

[cortexx]

As you can see I need a fair few shims , alot of think ones.

Another word on cam installation , these cams are hollow to save weight as are alot of cams in high performance engines these days . It's good to lose alot of mass on moving parts in a high revving engine but they are alot easier to damage.

You'll notice when you look at the cams closely that the caps are located in between each pair of lobes for each cylinder. This spreads load very evenly across the length of the cam but you have to be very careful on install not to bend them.

No matter what position the cam is in , it never has more than 2 pairs of valves open at any one time. This means that to seat the cam easily and safely you can place it in position and gradually torque it down using just the caps that sit in between the lobes that are going to compress their valve springs. Once the cap is just about touching the head you can pop the other caps on , spin down the nuts by hand and then torqe everything down properly . This saves a monumental amount of time on installation and you dont bend anything in the process

more updates soon ..

[cortexx]

When working on anything like this it is a great advantage to keep accurate records of what clearances were and what has been assembled with what torques etc. . This is the scribble sheet I used to record the exhaust and intake clearances. It's not pretty but it will be kept in a binder with all my other notes and records in case I need to refer to it..




At this point of the evening it was time to wash up and grab a tea so i went into the house only to realise it was almost 3am ....

Next morning after taking a few advil to get rid of a hideous migraine probably caused by sniffing copious clouds of brake cleaner and staring transfixed at the faded markings on my feeler gauges - i decided to set-up a simple spread sheet to calculate the shims i need and also record movement of shims to their appropriate locations. This makes it so much easier to keep track of what goes where once i disassemble and complete the final assembly of the valvegear/cams.

This took about 1/2 hour, 4 advil and 2 cups of coffee




Ill explain what it means as it probably means nothing to anyone except me.

Top group is the intake section , bottom is the exhaust section. Nissan states that the clearances can be as per the grey box at the top. You'll notice that the 2 cells contain median measurements allowing for +/- 3mm smaller or larger to stay in spec. This makes utilization of the shims i already have a bit easier.

Current shim is the thickness of each shim currently installed into the head.

Measured gap is the current gap between the bucket and the cam lobe

Required shim is the thickness the shim needs to be so that the clearance is in spec.

Populate from existing valve means that there is an ideal shim elsewhere in the assembly that can be utilized ( moved to this valve), this cell will either have the valve location where one can be taken from OR NEED meaning one needs to be supplied.

Taken/Open is a reference to show which valves have been earmarked (taken) to be installed in another valve location.

If anyone thinks they can make use of this spread sheet they are welcome to it , you can delete my shim sizes and gaps , insert yours and it will automatically calculate the shims you'll need. Its done in open office specifically so that you don't need to have excel to use it.

[cortexx]

I am using a head restrictor , got a Tomei one with my gasket BUT the block i have already has one installed

And yes i'll continue to use the RIPS catch can , in fact when i go single turbo the catch can will drain back in to the front turbo oil return as the single turbo will use the rear drain.

So last night work began on further assembling the head . This is what i started the evening with :-



All parts being reused were blasted with brake cleaner and wiped down with lint free shop towels , basically they are surgically clean after this . Cleanliness is paramount . The wooden bench you see was wiped down with a couple of Tac cloths after being rinsed off with a damp sponge earlier on . The helps reduce the chance of debris contamination . Not exactly an engine building room but it's pretty clean here

Parts that are being reused :-



All of the followers were checked with my trusty digital calliper and found to be all the exact size and exactly middle of the road according to the tolerances started in the Nissan bible . A few had some very slight marks that i could feel with my finger nail when removed from the head so these were removed at the machine shop .

The Head is being upgraded with a set of Tomei Cam Cap studs. The head comes from the factory using bolts to keep the caps on , but using more aggressive cams in combination with raising the Rev limit of the engine puts a tremendous strain on the original design , so we replace with a set of precision studs that use 100% of the thread in the head to increase the overall strength of the cam cap fitting and ensure they stay in place.



After a bit of research online it was apparent that the small end of the stud was designed to bottom out in the head . When installed and torqued to the right spec (7nm) the thread in the head is in perfect contact with the thread on the stud. 2 Nuts are used to achieve this ...



It's also recommended to use a good thread lock. I used blue lock by Loctite which is not permanent simply because I might want to remove these studs at some time. The head has been decked , valve seats cut to +1mm valves, so certain mods have made the head not particularly rebuildable in the unfortunate chance that it needs to be. I can just extract these and transfer them to another head if i have to.

Once the locktite has been applied you have about 10 minutes before it semi-cures , during that time the corresponding nut needs to be torqued down with exactly the same pressure as the stud was set into the block with (7nm) .





You have to wipe the excess thread lock from the base of the stud so that nothing stops the cam caps seating perfectly.

Eventually we have the studs all in place and ready for the cams to be installed ....



It's also worth noting here that prior to installing these into the head , the threads on the head were chased with a tap and die set then thoroughly blown out with compressed air to remove any debris or swarf that might have been lodged inside . Any time machining has been done this really should be done as a safeguard. Foreign objects in the stud hole can at best stop the stud seating all the way down , at worst chew up the aluminium thread when torquing them in.

May seam anal - but i have all winter to get this done so time is not an issue and being meticulous is definitely a virtue .

Cams in next then the install and torquing of the cap nuts . I'm using Tomei Poncam b's here known for their excellent idle ability and the extra 10 deg of duration on the exhaust side will really help turbo spool by increase gas pressure. This build is about a balanced compromise between response , usable power, durability and reliability for the street .

The cam lobes and journals have been lubed with a coat of Tomei assembly paste - this will prevent scuffing the surfaces while rotating cams to measure the clearances. The shims and buckets have been carefully installed dry so that the lube does not prevent an accurate reading of the shims. It will be disassembled and lubed , re shimmed again shortly once i have the correct shims to install..





The seat and open pressures from the Brian Crower springs make it incredibly hard to spin the cams by hand compared to other engines i've have worked on . Next came the laborious task of measuring the clearances to calculate what shims if any I need. The head came to me in pieces and the shims in a bag so I just picked them at random when installing . It is inevitable that adjustments will need to be made here.

[PurpleStreak]

Any reason for not using the Tomei head restrictor? Will you still be using the RIPS catch can?

Sent from my MB860 using Tapatalk 2

[cortexx]

oil system will be a tomei oil pan baffle kit , tomei pump and an Accusump 3 quart pressurized resevoir.

Not this Winter but maybe another winter will see the tranny get an OS gilken gear set .

[NismoS-tune]

Nice! Now you just need some badass support mods, a dry sump and hopefully a hollinger. Then you'll surely be the best built gtr in canada IMO.

[cortexx]

Pretty much a list of whats on my invoice :-


Block degreasing and acid etched
Inspect block for cracks - defects
magnaflux block
Bore block (87mm)
Install ARP main stud kit
Alignhone block
lighten , polish and zero balance crank
resize rods at op temp
balance piston,rod, pin assemblies
assemble reciprocating mass
coat block ext - epoxy GMG
install new frost plugs
check oilpump drive clearance
check ATI HB friction fit

Strip head to casting
degrease and check for cracks defects
Mach valve seats for +1 oversize valves
install guides
CC chambers and adjust
install valves , springs , retainers
measure valve stem heights and disassemble for shimming springs
install shims and reassemble valvetrain - check
diassemble for decking

Dummy build block head assembly for 88mm 1.2mm headgasket thickness
machine deck of head to spec 8.5:1 comp
actual compression 8.379:1 comp
reassemble head.

Cost of work $3018 + HST .

[gtrjon]

If you dont mind me asking how much did machining/labor run you? Not including parts just strict machining/labor im guessing 3500ish?

[ColinR33]

Oh man, that is beautiful. Makes me want to start saving up for that.

[cortexx]

Ok this is the calm before the storm , I have a ton of stuff to install but everything has been waiting for the block and head to return from Active engines.

So with much anticipation I went to pick both units up this week and finally managed to remove the block from the back of my truck tonight. I bolted the engine stand brace to it then bear hugged it off the truck bed and mounted it on the stand in one motion with my nervous wife stopping the stand move around the shop on its wheels as i struggled with it.

A RB26 block with crank , rod and piston installed weighs allot , i'm going to be sore tomorrow morning.

So once mounted i pulled off the plastic and this is what i have. The block is coated with a gunmetal Rustoleum epoxy coating which looks pretty nice . I don't like black , makes it hard to see oil leaks etc and I didn't want red either. Maybe for a 57 chev with a BB but not an RB26 :-



It consists of a lightened R34 crank , Carillo H-beam Pro Rods , CARR rod bolts , Wiseco 87mm forged pistons and a custom set of ARP studs for the mains . All riding on ACL Pro race bearings. The whole assembly has been blueprinted and Zero balanced , bearing journals resized after being measured at intended operating temps.

Active engines are sending me the complete blueprint sheet which ill post up here with their permission.

Next is the head that was tanked , x-rayed for flaws and machined to take oversized valves . Again wayne at Active engines replaced the guides with supertech manganese bronze units , supertech inconel x750 exhaust valves (+1mm) , and supertech black nitrided stainles intake valves (+1mm) . These are followed by titanium retainers and single coil springs from brian crower all shimmed to have exactly 90lbs seat pressure and open pressure of 195lbs - this allows me to up to 30+ lbs boost if I absolutely want to without valve float. The valve stem lengths were all equalized to be exactly the same length as each other to make shimming the cams a breeze.











The workmanship by the machine shop is impeccable , going to start other sub-assemblies tomorrow and updates should be coming on a regular basis in the near future . I plan to do a step by step on how i assemble this thing .

There is a change of plan for the induction side of things - going to experiment with a single turbo instead of twins which is pretty exciting . The under hood view will look a bit different at next years skymeet if everything is back together and running in time. There will be less shiny stuff that needs to be polished for sure. Im going for simple , functional and a little intimidating .

[cortexx]

The number pad thingy is a pin entry for the ignition system - No pin , no start car

[MattRose]

Looks great man! Also, what's that number pad thing for?

[Kunzz]

Looks great...let me know if you have any issues with the new knob heating up if the car is out in the sun for a while. I know with your old Nismo knob which I have it's a bit of a problem. Thanks