Evening all.

I have a slight dilemma. I'm currently porting the heads on my KLDE V6 so I can fit ITBs and generally clean them up a bit. This obviously then means re-fitting the heads. And the KL uses stretch bolts.

The problem I have though is that the new ones I have are no where the quality of the original ones, with the bolt heads and threads not being as well formed Mazda say that as long as they are below 135mm long they're ok to re-use. Mine are all roughly 128mm, so well under. So do I re-use them or risk the newer but less good ones?

You suggestions, and reasonings, please folks!

I would double check the lengths again as you have a massive difference 8mm normally stretch bolts only have a couple of mm tolerance.

I have just checked all the bolts again, and they're 132mm. Must've rear the wrong dimension off my whiteboard. The 135mm is right though!

So is 3mm enough to use the originals?

Main thing is make sure the threads are 100% clean and screw freely into the block by hand for the full length of the thread as the first torquing stage before tightening is the most critical.

I have just done a Rover engine and after a soak in white spirit used a pressure washer on the bolts and found it very good for cleaning the debris and gunge out the threads.