timing tensioner diagnosed fatal.

[316injection]

So I took my E30 316i M40 for an annual TLC session. Was running fine, floating like a butterfly, as it always has for the many years I've had it.

Mechanic hears a rattle, inspects, and shows me a bolt hanging loose inside the timing belt casing at front of engine. I agree to belt and tensioner change and a few other things.

Next day mechanic calls and says the thread for the bolt is so worn down, a new bolt cant be fitted, meaning timing belt system is unrepairable. I'm told the options are rebuild engine or buy new engine = muchos cash.

So I'm pretty gutted right now - and confused. The diagnosis makes sense, and I was aware of the on off rattle. However, the mechanic's hint at a 200 quid scrap price after diagnosis has planted "am I being conned...?" thoughts.

So I'm reaching out to you comrades on the forum for opinions and suggestions for workarounds.

Cheers!

[kam-325i]

is it the thread on the bolt or the thread for the bolt in the block....

[316injection]

in the block

[kam-325i]

Helicoil repair.........

[316injection]

helicoil, for the block? any testimonials from users as to effectiveness in block, timing chain environment?

[Grrrmachine]

Don't use helicoil, use a threaded insert like a TimeSert. Much stronger than a Helicoil.

[kam-325i]

Don't use helicoil, use a threaded insert like a TimeSert. Much stronger than a Helicoil.

Err......yeah, i would second that actually......

[maggspower]

Both Time-Serts and Helicoils will work fine for the job as long as they are fitted correctly.

I would however suggest looking for another mechanic. Fitterz should not be looking after older motors, and offering you scrap value

Rescue you car and take it to someone who knows what they are doing.

[Speedtouch]

Or try a tap and die set to clean out the thread.

Failing that, it could probably be drilled out to a larger size and then tap & die'd to give it a thread.

Another possibility is to weld a nut of the right size over the hole in the block, assuming there's room...

[Speedtouch]

I suppose a temporary 'get you home' fix would be to use JB Weld, Araldite or Chemical Metal to bond the bolt in - that would at least get it mobile again, so you could take it for a proper repair.

[scjimbo]

Depending on what size the bolt is thats come out, (i.e M6) The od of the thread across the tops of the threads is 6mm. If the bolt is actually slopping around in the hole it is probably worn to about 6.2-6.5 mm. The tapping drill size of a 8mm thread is 6.8mm. If you get a nice clean GOOD QUALITY tap from your local engineering suppliers and go very steady, It will probably cut the excess out of the way without re-drilling the hole anyway. However if you are new to the metal cutting game it may be worth popping to a local friendly engineer who will know how to handle a tap correctly. The last thing you want to do is snap the tap off in the hole. A tap is much much harder than a drill.

[316injection]

The mechanic has fantastic reputation on this forum hence I took it to him
Is there a point at which Time Sert HeliCoil would not be effective eg could the thread be too far gone?

[scjimbo]

A helicoil requires a new much bigger thread to be cut. What size is the thread that's stripped mate?

[gooner1]

The mechanic has fantastic reputation on this forum hence I took it to him

Who be that then?

[316injection]

The mechanic has fantastic reputation on this forum hence I took it to him

Who be that then?

ill see how this plays out, and if im left unsatisfied i'll consider blowing the whistle.


re size of thread - i dont know. whatever size the tensioner bolt is in an M40 timing belt set up... any one know?

[wellard]

Which bolt is 'hanging out?'
Iirc the tensioner is on a 10mm stud secured by a 15mm nut and the two guide pullies are on 8mm bolts.

[scjimbo]

Ok well depending on which one it is. A 10mm stud would need a 14mm ish od helicoil in it. That means about an 11.8 tapping drill. (Helicoils use their own odd thread sizings for their inserts). If its one of the 8mm studs I believe it goes out to about 12mm which is a 10.2mm tapping drill.

The good news for you, is you can fairly easily take a 10mm worn hole out to 12mm with some care. The tapping drill size for m12 is 10.2mm.

Not being au fait with your engine though, you will have to take some advice from someone on here more learned than me, as to whether the tensioner can be modified to take a 12mm stud and nut.

My advice though, is if you are going to do this yourself, I would take the radiator out so you can get yourself square to the hole you are tapping.

Hth

[gooner1]

http://www.realoem.com/bmw/showparts.do ... g=11&fg=10

Not having a pop at your mechanic, he may well have good
reasons for suggesting another lump, or a rebuild.

Can you get him/her to point out which bolt, from the above
link, is causing problems due to the block thread being knackered?

[316injection]

http://www.realoem.com/bmw/showparts.do ... g=11&fg=10

Not having a pop at your mechanic, he may well have good
reasons for suggesting another lump, or a rebuild.

Can you get him/her to point out which bolt, from the above
link, is causing problems due to the block thread being knackered?

Thanks Gooner, from my memory it looks like part no2 the shaft seal was loose in the casing. When I got the call next day mechanic said the thread was worn for the tensioner bolt. I spoke to them again a few days ago and now Ive been told the bolt has snapped off in the block. I have also been told "the part" they need to fix it is not available. Its a different story every time I call.

And this is one of most reputable mechanics on this website

[Speedtouch]

Well, that doesn't make sense; if the thread was worn, why would the bolt then snap off in the block, when surely it would either waggle about or pull out?

[DanThe]

Sounds like they are trying to cover a f***up

[TPS]

Sounds like they are trying to cover a f***up

+1

[gooner1]

And this is one of most reputable mechanics on this website

There is no such Animal here.

[316injection]

Sounds like they are trying to cover a f***up

now that could be a possibility. why would I be given a diff explanation each time:

explanation 1. worn tensioner thread in block, get new engine
explanation 2. cant get the part, get new engine
explanation 3. bolt snapped off, get new engine

thats 3 totally different explanations. doesnt add up does it....?

[Speedtouch]

How many miles has the engine covered, and did it use oil or smoke at all?

If the rest of the engine is in good condition, then it's worth having a go at repairing it - probably alot easier and cheaper than fitting a replacement engine.

[maxfield]

Sounds like they are trying to cover a f***up

+1

+ 2

I can't see there being an issue with the threads, unless they've fucked the threads up themselves. It's a bolt that only gets undone and tightened back up 2-3 times in its life and it isn't open to the elements.

[bmw9818]

unless timing was set wrong resulting in new donkey

[316injection]

basically they are whatever the fault - worn thread / snapped bolt/ part not available - they say the ONLY solution is new engine.

[Speedtouch]

Sounds like b*ll*cks to me...

[316injection]

Sounds like b*ll*cks to me...

yeah, and they wont let the car out of the garage, saying they will only allopw it to leave on a trailer or when its roadworthy. like i said, one of the most highly regarded mechanics on this site!

[bodger]

Sounds like b*ll*cks to me...

yeah, and they wont let the car out of the garage, saying they will only allopw it to leave on a trailer or when its roadworthy. like i said, one of the most highly regarded mechanics on this site!

tell them its your f*cking car you will do what you like with it, name and shame i say

[maggspower]

[gooner1]

316injection,

have you told the reputable mechanic that you have posted all this
on here?
Would be interesting to see his/hers/their response.

If the engine is fooked, how else would it leave the garage other than
" on a trailer" ?

[scallyally]

Let's hear this "mystery mechanics" response, you may have a valid reason for suggesting a replacement engine.

Come on, what's your side of the story? We've got a fellow zoner's car laid up ( held to ransome)? Man up! Or be named and shamed.