Making some more progress with my VVC K series engine but maybe a set back.

I set up the VVC timing yesterday evening including installing the new gaskets to the VVC mechs and fitting the new oil seals and had a bit of time left so the next job is to put the head back onto the block.

I positioned the new gasket, carefully lined it up and placed the head onto the dowels. I checked the length of the new stretch bolt against the ones I'd taken out and they seem to be identical (might come in handy later!)

All ten new bolts went in gently and hand tightened to just start to pinch then out came the trusty old torque wrench. They are supposed to be tightened to a torque of 20Nm and then turned a further 360 degrees (no final torque figure given)

I set the wrench to ten to start with and then followed the sequence giving each bolt a quarter turn at a time.

After (I think but might have lost count) 6nr quarter turns on each bolt I felt that the bolts were starting to give a reasonable resistance to turning and then it struck me that the wrench should have been clicking by then as it was only set to 10Nm. I tried the wrench on one of the engine stand bolts and tightened it hard and still no click. I tried putting the 1/2" square in the vice and still couldn't get it to click whatever torque I set it to. It seems the wrench is not functioning!!

So, I don't know how much torque I've put on the bolts and whether I've maybe overtightened them.

I'm hoping that the distance I've turned them should mean that I haven't as if I have only done 6x 1/4 turn then even if it was up to the 20Nm when I started I've only gone 1/2 a turn beyond the extra 360 degres after 20Nm. I'm guessing that at least 1/2 turn from 1st pinch would probably be needed to get to the 20Nm.

The bolts must be around 400mm long and have a very fine thread so each turn can't be more than 1mm - if so then even a whole turn too much would only stretch them by 0.25%.

I'm after some reassurance and advice - should I back the bolts off to loose again and start again with a good torque wrench? If I do this I'm concerned that the MLS gasket might not like being relaxed again?

Should I just loosen them a little, say until it takes 20Nm to turn them back again, and then do a full turn?

Should I take just one bolt out fully leaving the others as they are and measure the bolt for stretch (against one of the old bolts) my worry with this is that it would leave uneven compression and maybe induce a warp.

Or take all the bolts out, buy new bolts and another new gasket :'(

Anyone got any experience in how tight they become during the final 360 degrees of tightening? I'd guess that from experience my human torque gauge was giving it around 30Nm at the point I felt it was way more than 10?

Oh dear!

Don't re torque as they will snap (well you have a good chance that they will).

Did you feel any sense of 'yield' as you tightened? I would hope you did. The whole point of the stretch bolts is that you use them within their elastic limit to keep the clamping force but allow for expansion.

They don't 'tighten up' in the classic sense of clamping solid items using high tensile regular bolts.

You have to remember that the length of the torque wrench means you can generate quite a bit of torque with small effort.

MLS gaskets can generally cope with reuse but I have seen the bolts break (admittedly used ones).

I'd personally leave it as is now they are tightened equally & the additional angular tightening isn't excessive.

Note to self - buy a decent torque wrench & always store it with the torque set low. Always check that it clicks off before tightening in anger!

Stew.

Okay, all sorted and happy again ;D

I Borrowed a torque wrench form a fellow Bristol Kit Car Club member and K series guru Dave Bence - you have to admire a home mechanic who has an up to date calibration certificate for his torque wrench!

Anyway, I checked what I'd torqued the bolts to previously and they were clicking at 35Nm so my human torque calibration is 5 out as I'd guessed 30. Dave had bought a tuned head from Dave Andrews of DVA Power who had advised to go 20Nm, 40Nm, back off, back to 20Nm and then to the 180, 180 angular torquing. So, based on the Dave Andrews method (and as far as I'm concerned anything that is good enough for Mr DVA is good enough for me) I still needed to tighten them up a bit more, back them off, up to 20 again and then do the 180 then 180. So, that is what I did. I checked what the torque was for the last few degrees and it was 58Nm so I'm confident that I hadn't got anywhere near to the yield point of the bolts previously. I have to say that I expected it to be a bit tighter at the end of the 360 degrees though and I didn't get any feeling of the bolts starting to yield. I'd say that they are still in the elastic phase so now I'm wondering if they need to go further. I'm guessing the original method of 20Nm, 180, 180 was for the original type gasket, not the MLS that ford introduced after they bought Landrover but all the advice I can find still says to use the 20Nm, 180, 180 so that's how I'll leave it. (I chose to go MLS because the one that was in there was MLS and there was no sign of it having leaked)

I've also fixed my torque wrench too. It was actually my late father in law's. I dismantled it and found the problem was that the part that the spring pushes to hold the bearing against an angle on the drive end was rusted solid to the inside of the tube. A bit of release oil and a long narrow drift pushed it out. Everything cleaned up and greased and back together I checked it's calibration against Dave's by holding the shaft of mine in the vice. A 15mm 3/8 drive socket on Dave's fitted perfectly over the 1/2 square on mine. It was then a matter of trying various settings and checking whether they clicked in harmony. It turns out mine is within 2Nm of Dave's at every 10Nm from 10 to 60 so that's good enough for me. There doesn't seem to be any way of adjusting the calibration on mine (could maybe add shims between the screw and the spring) but mine was low at the low end and high at the high and spot on in the middle so I'll leave it alone.

its nice to see you have it all sorted