Rear oil strainer - 6 bolts - wierd feeling?!

[Apolan]

Hey,

me and my friend started putting together my new engine today. We've done almost the entire bottom end and there were no problems.

But when i wanted to put on the rear oil strainer plate with those six bolts the feeling was just wierd. The manual says tighten them 9.3 Nm, but when i started to screw in the bolts, the feeling was very "buttery" like they were going to snap off any minute and one screw did! And thats even before i've reached the "pitifull" 9.3 Nm. Theese size 10 bolts have two line marks on them (- -). which, according to manual are 5T grade and should be able to withstand 32 Nm. I really dont want to break all of them..

Anybody else had symilar problems? Advice, what should i do?

[ZDoman]

I had the same problem when I tighten them with torque wrench.
I'd advise you to buy new bolts with 8.8 mark on them!
I had an engine where these OE screws fell out.
Doesn't worth playing with these craps...

[Apolan]

That is indeed what i was planning to do. Still, the 9.3 Nm seems very little?

[Ivan141]

I had a few bolts snap on me too while working on the lower end of my current block. Replacing the bolts is not a big investment, and worth the piece of mind. Another thing I would advise you to do is to run a tap through ALL threads on your engine, because dirty bolt holes will cause more bolts to snap.

[Apolan]

yes clean engine is a happy engine, but i have already put my hart and soul into scrubbing off all of the carbon deposits with diesel.. i smell like i was working on an oil rig for half a year.

buying new, stronger bolts. Not sure what to do with a snapped of bolt? its stuck inside.. not sure i can drill it, im afraid i will daamge the threads?

[Ivan141]

often, they are not too difficult to get out once there is no tension on them anymore. If it is seized in place, heating it up might be your only chance, but this means you still need something to grab the rest of the thread by.
Of it snapped off exactly level with the surface around it.. then you might have to drill and hope it comes out..otherwise retap the hole one size bigger once your done.

[Apolan]

yes it broke level with the surface. i might try drilling a really small hole in it and using a counter-thread tap and than "counter"-way bolt to unscrew. Just unnecessary work