Broken cam bolt, very upset.. Help please!

[Godzilla32]

I was very carefully tightening down the exh cam shaft in many stages when one of the bolts snapped! Im really upset now cuz i've never fixed this kind of problem before... Please can sumone guide me thru wat i need to do. I roughly know how but im scared of doing more damage. Also paranoid about metal shavings etc.... What should i do???

Thanks again,

Deren

[GTRgeoff]

Been here before mate. Use some strong magnets and a 3m drill bit in a cordless. Centre punch the broken bolt heavily to ensure the dril centres well. Locate the magnets to pick up swarf and use some rags to cover the rest of the head. Drill it out slowly and use an ezyout to remove the bolt.

Replace all the bolts as they are prone to this. Use torque of 9-12Nm.

[Godzilla32]

Thanks heaps for that info mate! I've got a friend coming to help me out 2morow. He said to use the same technique that you just said... Where should i get the new bolts from?

Thanks again Geoff

Deren

[GTRgeoff]

I just extended the thread on the Autobarn grade 8 bolts in a handy pack. Try Nissan or Repco or a specialist bolt place if you want them pre done.

[Godzilla32]

Hey Geoff, i did exactly as you said and managed to get the broken bolt out without a hitch! Thanks very much for all your help lately

Cheers,

Deren

[GTRgeoff]

Glad to hear it

[Godzilla32]

My next dilemma! I got it all torqued back down and now i cant budge the camshaft. I oiled it up upon installation. I did however fail to mark all the cam brackets before removal, so now they are all probably mixed up apart from 2. The front one and the 2nd one which i had marked for lining up the cam. Am i in trouble again? I dont want to reinstall everything incase i go to start the engine and the cam jams and everything hits everything else!!

Please help

[GTRgeoff]

Cam caps are marked E1-E7 exhaust and I1-I7 inlet. Check my PM.

[Godzilla32]

Thanks i'll get them in order but im still confused about the rest of your PM...I replied there. Thanks mate

[Godzilla32]

I just looked then i cant see any markings at all on any of the caps... I dont think it would have been possible for me to bend a valve as each time i installed the cam i made sure it was the same way as when it was first taken out... Im just puzzled as to why it wont rotate?

[SteveL]

It seems that RB26 cam caps do not have markings for alignment - I recently did the valve shims on my GTR and found that was the case. I find this a bit strange as the the RB20/25 heads I've worked on certainly had markings as suggested. It might suggest alignment is unimportant for RB26 engines, but I consider that unlikely given that the cam journals are line bored.

I would strongly suggest (very) carefully removing the cam again and closely checking the caps you haven't marked for any fine scratches that might be used to indicate their correct postion (eg compare the contact face of each of the caps with mating face on the head, or look for fine markings on the cam journals that might mate with similar marks on the bore of the cap).

At the very least you should back-off the cam cap bolts to see if you can get the cam to move, BUT:

- do not force the camshaft - if it doesn't move somethings wrong

- do not rotate the camshaft once free (I think you know not to do this)

- cam cap bolts MUST be undone and done up in a specific sequence, which is in the workshop manual

- it is very easy to have the cam 'bind' at the thrust face - take it slowly and (again) use the cam cap sequence in the WS manual.

Good Luck

[wrxhoon]

Rb 26's have the cam caps numbered just like other rbs , have a better look and you will find they are marked as gtrgeoff said .

You are having your fair share of problems there Deren .

The 6 mm bolts on the cam caps get tight in the caps from alloy corrosion ( white stuff ) , when i have them out i always clean them .

[SteveL]

Rb 26's have the cam caps numbered just like other rbs , have a better look and you will find they are marked as gtrgeoff said .

How does a microscope sound ?? that's right, I've looked that closely....I could put them in our scanning microscope if you like, wouldn't make any difference. I have more experience at this than you can possibly imagine.

[wrxhoon]

How does a microscope sound ?? that's right, I've looked that closely....I could put them in our scanning microscope if you like, wouldn't make any difference.   I have more experience at this than you can possibly imagine.

All the 26's that i had pulled appart have numbers on them , anyway if they didn't i would make sure that i mark them !

[GTRgeoff]

This is an 89 GTR so it may have been a later mod to punch the cap number on. Deren is taking it slowly and I think has swapped some of the caps to get a good fit and clearance to allow movement.

Nice to see someone learning and taking it easy while DIY all the basic stuff.

[Godzilla32]

Thanks guys but i spoke to Geoff and we worked out a good way for me to get some more movement. It worked very well and i now have a much freer smoother rotating cam. There was deffinetly no marks on mine whatsoever. I have had a few tough spots on this mild rebuild of mine but im getting there now. I put in the rear turbo tonight and got the second ready. I've cleaned up the whole block, head all ancilliarys. Also ever part i am putting back on is getting a through cleaning and polishing! It'll look great when its all finished. Im pretty fussy when it comes to perfection!! Once again thanks for all your help, especially Geoff!

Deren