My 1995 GTR project thread.

[GTRADDICT]

Good call on the align hone. Might as well do it right.

[cortexx]

So after agonizing about the cam cap all day I came home and ripped off all the cams and valve gear ( curses to who decided to make the RB a 24 valve engine ) . With the sheer size of the financial investment in this engine build i can't have anything be questionable when i turn the key.

I reinstalled the cams with no valve train to see how well they turned when the caps were torqued. I installed the end caps and the center one first and span it to make sure nothing was binding all was good . Installed the remainder of the caps and tested one by one and the second cap from the cam wheel on both cams caused a significant amoutn of drag . This included the cap i had drilled out and the same cap on the intake side .

So the head is all packed up ready to go back to active engines , the caps will all be align honed and the m8 bolt hole will be re-machined for a helicoil and proper stud.

Plastigauging the cap caps actually showed the 2 caps in question had next to no oil clearance , and 4 other caps had way too much (one of them more than 3 times the specified amount).

Holding off on the head progress and having this taken care of i'm pretty sure will contribute to the integrity of the build. Thanks to the guys who second guessed it and made me paranoid all day

Tonight after the head was packed up I installed the tomei oil pump on the block , 2 new woodruff keys on the crank , the cam sproket plate and a new cam sprocket ( holy crap almost $180 from nissan for that ) , New cam belt idler pullys and associated fasteners and the water pump. I also installed the ARP head studs into the block and checked stud heights to make sure each stud was at the correct depth and nothing was binding .

I'll post some pics up tommorrow , cam batteries were dead tonight and currently being charged ..

6Boost twinscroll manifold came today - it's very purdy and weighs a ton lol

[NismoS-tune]

Oh man, your story about the Tomei cam cap stud... been there done that haha.

I broke one last year (I was the other guy that broke one) but I had used a crappy Princess auto torque wrench (though I had a canadian tire one and a napa one too... oops).

Anyway, same story here but I didn't use any lock tite. I ended up drilling out the broken stud, tapping a slightly larger hole and using a helicoil (the tomei stud was weaker than the stock bolts which I tested in fact, 17 pounds before bust), I believe the tomei studs could handle more stress but over torquing was their fail point maybe. I think the fact that I used lube when torquing is why mine broke. I never did brake another but I did replace one that had streched funny, even at 7nm...

Best part was that I coudln't just get 1 tomei stud, I had to buy a whole new set at $200 some so I now have spares lol. I know your pain bro.

You know, I could probably send you the helicoil kit and a stud haha. I don't know if I'll ever need it if you've followed my build thread...

[PurpleStreak]

I second revisiting the torque spec on the different stud. torque will change with thread spec and more so with larger stud size (increased root area). You can back calculate the required tensile load for the stud and get the appropriate torque value for the new stud.

Sent from my MB860 using Tapatalk 2

[cortexx]

actually if you bolt the cam caps on the head without a cam and do them just less than finger tight you'll see there is a slight movement of the cap - this helps the cap seat over the cam jounal perfectly when it's being tightened down , with the tomei studs the caps were incredibly tight and without the cam in place you can feel a lip where the cap and head but together .

I asked the machine shop about this and they suggested slightly opening up the holes in the caps to allow a certain amount of movement again so that that caps can sit without binding on the cam. They told me the ideal way would be to start fresh with a new head casting , fit the studs and alignhone the caps to make it all perfect . I asked about the movement of the caps and they told me that this wont happen when running - if it was going to happen nissan would have pinned the caps like they did on the cam angle sensor bracket or the oil pump .

I'm either going to replace the studs with another kit if tomei step up , machine the head to take m8 bolts all around , or going back to the factory bolts ( which incidentally i put one in vice with a double nut on the thread and torqued it till it snapped which took over 20 lbs/ft to do - go figure lol ).

[cortexx]

Here are the seals that everyone is paranoid about damaging , they are alot tougher than you realise ...



before and after cleaning of the throttle springs and spring stop plates ...



those were soaked in wd40 after to protect the metal from corrosion as per the throttle bodies..

STarting to get the subassemblies ready to install to the block - here is the tomei oil pump being preoiled before installed - the pump comes pretty much dry so this helps with the initial startup of the engine ..

[cortexx]

Thanks Frankie , thats what happened when i try to do build updates while sat at my desk at work on the phone :P , i corrected my inaccuracy !

So last night was up to 3am working on making things look like new again and had a new Ally to help with the work , a 9 litre pail of Kleenflo Carb and metal stripper/cleaner.

I grabbed a few other nasty looking castings to strip and threw them in the can of foul smelling liquid - this stuff is nasty - need to wear eye protection and a good pair of chemical proof rubber gloves for this .



and this


that was very nasty ..... and this



the shaft is rusty and badley pitted , not sure how to tackle this - will consult the oracle (google)

Now the throttle bodies came out of the wash tank looking pretty sorry still so i stripped them and dropped them in the tank of toxic waste , only gave them 30 minutes because i didnt want to destroy the seals on the throttle shafts and they came out nice and clean , I then removed the buttterfly plates and removed all the junk and stains with salvol polish. They are made of brass which is relatively soft so I didnt go too crazy as i didnt want to remove any metal .

Did one at a time so that they didn't get mixed up or put back in back to front.

This looks alot better



I used red locktite on the butetrfly screws - these are screws you definately DON'T want to come lose while the engine is running ..




Before these were cleaned you could shine a light behind and no light came through , now they are clean , there is a thin rim of light around the butterflies that will be eliminated with a coat of throttle coat from Tomei ..

The throttle bodies already had this coat on them but whomever applied it used it on the worng side of the butteryflys so it wasn't 100% effective ...

The throttle bodies were then masked up with frog tape and the corrosion and stains sand blasted off the outside with baking soda ...



after blasting , cleaned with brake cleaner ( i swear to god this stuff is the most used chemical in my work shop , i buy it by the case load ) , and then sprayed with fluidfilm.

When the aluminium casting has been blasted the metal is exposed and porous - this is a good time to seal it to protect the surface from corrosion . WD40 or fluid film is great for this , i soaks into the metal pores and does the job....

A quick blast of throttle body cleaner and its all ready for the assembly of the linkages and throttle coat ( tonights project ).

[xcye]

I'd say you should have helicoiled it and used the original cap bolt. The fit between cap and cap bolt is very tight and probably less than 0.001inch so the cap centers correctly and does not move during operation. Furthermore, the torque spec will not be the same when you change the thread spec. I'd strongly suggest to have a good machine shop to take a look at it.

Well anyway , problem has been fixed , the stud would not come out , tried 3 different stud extraction divices and no joy - so going back to basics i grabbed the head , put it on my drill press and bored it out creating a fresh clean hole in the process - cut a new thread for an M8 bolt, re-washed and assembled everything and ended up with a fresh start ...



of course this meant i had to machine out the cam cap to take a larger part but that didnt take too long ...



This fitting torqued down no problems to 8nm/ft and all seems ok.

[Windstheory_bnr32]

More now!!!!!!!!!!!!!!! Great read in lovin' it!

[frankiman]

This fitting torqued down no problems to 8nm/ft and all seems ok.

what??

my spidey sens is tingling
newton-meters/feet ?

[cortexx]

mooooar



The more i took this all apart the more obvious it was becoming how terrible the crap buildup inside it all was , going to need to purchase some chemicals to help with the restoration .. This is the AAC valve that you're not supposed ot take apart and clean , it was full of tar ...



Barbacue cleaner spray and some denatured alcohol does a good job of cleaning up carbon deposits if you let it all cook for a while

[cortexx]

Well anyway , problem has been fixed , the stud would not come out , tried 3 different stud extraction divices and no joy - so going back to basics i grabbed the head , put it on my drill press and bored it out creating a fresh clean hole in the process - cut a new thread for an M8 bolt, re-washed and assembled everything and ended up with a fresh start ...



of course this meant i had to machine out the cam cap to take a larger part but that didnt take too long ...



This fitting torqued down no problems to 8nm torque and all seems ok.

Still no response from Tomei , i'd like another set of studs from a new batch number to carry on using these parts , but we'll see what they say - I honesty don't trust any of the other studs now . I wish ARP made a set. If tomei don't take care of this i'll have a custom set made up i think .

All back in 1 piece ....



Next part of the project is the intake side of things, here is what it all looks like in the nude ...



As you can see the intake manifold , throttle bodies , balance tube etc are suffering from a severe case of corrosion and dirt .



moar



moar still ....

[GTRADDICT]

Why is there so much horror stories with jdm parts. Crazy. The joys of mechanics I guess!

[cortexx]

My client looked at the shims made by mississauga engine and tested the material only to inform me that they had been probably made from a non annealed 302 stainless material and was no where near durable enough to be used for the intended purpose. So in essence my screw up brought to light a potential problem in the near future as the shims would have flattened out over time and would have binded on the keepers possibly causing them to let go of the valve stem and drop a valve.

3 hours later i had a complete set made from 440b steel took along time to grind these down to the right thickness's. Charged me $60 for 14 shims and I was all set



SO feeling uch more confident this time I started the laborious task of reinstalling the cams , here are all the parts layed out ..



Test fitting the cap caps to the head bought about 2 observations .

1: the caps were a much tighter and more precise fit on the tomei studs instead of the bolts .

2: This sucks because when you torque everything down uisnt he original bolts - the cap settles over the cam journal and seats accurately on the head . Using the studs made it painfully obvious that the lack of lateral movement made it impossible for the cam caps to centralize over the top of the cams so that the cam journals did not seat perfectly round . This meant i had to painstakingly increase the cap's stud holes by about 5 thou longitudinally so that they had enough movement on assembly to correctly align with the journal part in the head . Without doing this a cap cap torqued down without the cam installed meant you could run your finger nail around the inside of the journal and feel an edge/lip where the 2 castings butted together .

So 2 hours of frigging around with a Dremmel taking tiny amounts of metal out of the stud holes in the caps I had everything lining up perfectly. (WTF does drop in cams and stud kit mean Tomei ? , this isn't exactly drop-in ). Another observation was how close the cam lobes come to the casting of the head . I measured this gap and it was 22thou - scary stuff when its all spinning lol . It states in tomei's installation guide that poncams do not need any machining of the head . If i had known this earlier I would probably have machined it a bit for piece of mind .

Anyway , after fingering all the interference parts with Tomei assembly paste we installed the shims ( for the third time) ..



then the corresponding buckets with moar green Tomei goop --



Everything seems to be going slowly so in with the exhaust cam , tighten the nuts all down with the torque wrench in sequence and HOLY F&^K .... i swear to F&^K!$$ god - the last cam cap nut on cap #1 let go at about 7Nm of torque ( rest were all torqued to 7Nm ) ... FFS

I put a couple of nuts on the stud to carefully extract it thinking the threads in the head had let go but NO , the cap stud had snapped in the head , the head itself is fine . this is the result :-



the busted stud ...



I emailed Tomei yesterday and have not got a reply yet . I drilled a small hole in the broken off stud and ill extract it tomorrow , glad i didn't use red thread-lock .

Tomei says these studs are made of chrome molly and are harder and stronger than Nissan studs (even though Nissan used bolts). I'm not sure if i trust these studs from Tomei now but i'll wait to see what they say. I seem to remember someone else breaking one of these studs on these forums a while back .

Somewhat dejected at this event i continued on with the intake cam which thankfully all installed ok - i checked the clearances on the cams on all lobes except the ones around the cap that had the busted stud and this time all numbers looked great - everything is in spec at last.

Going to extract the stud tomorrow when it's not 1am in the morning .

[cortexx]

stardate 14th sept 2012

Continuing with head work and getting the cams shimmed in properly this week , have been slow to upload the updates because of some stupidity on my behalf and also a mini disaster while assembling

So i get my shims made up based on the previous measurements taken that i put into the spreadhseet BUT unfortunately - getting the shims back the next day and installing them proved to make it painfully obvious when i rechecked the clearances that something had gone wrong. I had valve clearances ranging from .12 mm all the way up to 1.10 mm .

I pulled everything to pieces and checked everything from valve stem heights to bucket deck thickness and nothing seemed to point to an error of judgement until -- i took a look at the spreadsheet used to calculate the gaps. Seems that while formatting the moving things around in the spread sheet the calculation cells had been grabbing data from the wrong cells so had made errors of calculation.

After fixing the spreadsheet calcs i recorded all the new retarded clearences and recalculated the new shim vales .

Here is the CORRECT sheet ...




Somewhat angry with myself I didn't want to go all the way back to mississauga engines that made the shims for me so I called one of my local clients that has a machine shop and he agree'd to help me out. I took some of the shims that mississauga engines had cut for me so that he could grind them down to the right thickness and took them to his shop.