Stripped threads.

[LennyK]

Hi all.
Got some good weather in Taz that lines up with a couple days off at last, so decided to clean out the oil from a blown turbo and do a compression test on Lenny my Td5, to check for any bent rods. I think the compression readings are ok with number 1@425psi, 2@415, 3@420 and 4@405. I'm a definite newcomer to diesels so any comments would be greatly appreciated 😁 One nasty I did discover when I removed the inlet manifold to clean out the oil were 3 stripped studs. Does anyone know if these can be drilled out safely and oversised studs fitted. If so are oversised replacements available anywhere?

[trout1105]

You can try using helicoils which would be the easiest option here.

[dero]

Helicoils are generally shunned by engineering types , but they are relatively cheap & I have had good sucess with them on manifold studs .

[LennyK]

You can try using helicoils which would be the easiest option here.

Thanks for the advice trout but I'm more concerned with drilling the head and damaging it. Was unshure of how close the stud holes are to any internal structures.

[LennyK]

Helicoils are generally shunned by engineering types , but they are relatively cheap & I have had good sucess with them on manifold studs .

Thanks for the post dero. Cant say I have had any experience with them but would rather use oversized studs if possible. Just concerned about drilling out the original holes and damaging something in the head.

[DeanoH]

How badly stripped are the threads ? Might sound a funny question but I've had success using Unbrako's (also called socket capscrews), those Allen key headed bolts in partially damaged threaded holes.

I think it's got something to do with the Unbrako's being rated 12.9 so they have a 100% thread machined as opposed to an 80% thread for other bolts. Haven't really done any research into this and am assuming this from 'machine shop theory' learnt some 50 years ago ha ha. But Unbrako's definitely have more meat on them and will hold in a damaged hole if not over torqued, Locktite can be your friend here.

Deano

[trout1105]

Maybe a slightly longer bolt would do the trick as there is usually an extra length of thread in the hole to stop the bolt bottoming out.
I have never had to try this but if you can measure the depth of the hole and match it with a longer bolt so that it still doesn't bottom out you could utilise the unused thread at the bottom of the hole.
Just kicking ideas around here