Cam tower leak

[Sparky]

Mike's ( @MPx ) lovely TE is in for a C service and investigation of a big exhaust tower leak.  The lower rear bolt won't achieve torque.  Mike told me it had had some insert work previously.  So, before any service work, belt removed and towers off.

First item of note is the replacement tower bolts (apologies for crap pic).

Inlet tower threads seemed good (some with inserts) and all passed the torque test.  Unfortunately another exhaust tower insert let go on testing - so it's both lower rear ones.  There's evidence of attempts to stem the tide of oil with shedloads of sealant and even what looks like epoxy, but it was never going to work.  The inserts came out with very little effort.

It's better than I thought - I was prepared to pull the head, but maybe there's enough meat for oversize inserts to be fitted insitu.  Fingers crossed...

[MPx]

Blimey that's a first - starting an investigation with some potentially good news.  I'm sure it wont be long before the inevitable sucking of teeth...

Nice that they used such a good colour match of sealant...there looks to be quite a few potential worms to lose into the oilways. 

Exciting times...to celebrate your start, I bought a new set of boots for it today 

[Sparky]

I was never much good at managing expectations.

[910Esprit]

That's seriously nasty... I wondered what all that 'casting flash' was, but assume its just some JB weld type stuff.

These are some of the only fasteners I dont 'oficially' torque down on an Esprit, I just take the slack out of them and nip up by feel with a very short T bar.   It makes me wince when people recommend tightening them to stop leaks - They are only ever 1/4 turn from disaster....

[Sparky]

Yes, JB Weld or equivalent, yuk.  I will torque these to spec (which is low) but very carefully.  Most of the time I find them heavily overtightened.

[Barrykearley]

I stuck some helicoils into the manifold ones on the S4 - by god you could tighten them up nice. Actually felt far far better to tighten than the non helicoiled studs

[Sparky]

I've decided I really don't like Time-serts.  The holes left are huge, and I feel there's a risk of fracture if I drill/tap much larger.  So, a chat with Mike and we decided to bite the bullet.  Head off today, I'll strip it tomorrow and get it off to someone to build it up.  Will also get some surfaces checked on head and towers.  This head has already been skimmed but unsure how much was taken off, so will wait to see how straight it is!

Apart from those two threads, everything is in lovely condition.

 

 

[MPx]

....I knew it wouldn't be long before the teeth sucking started!    

Nice to see it coming along and none too shabby in there.  

[Sparky]

Not a good day.  I've had 2 engineers tell me Big-serts might work, but it should be welded.  2 welders have told me I should install inserts as the welding will make a mess of the head, and one other told me to source a new head.  At least that made me smile.  The quest continues...

[fjmuurling]

How about using a Twinsert Helicoil ?

https://media.boellhoff.com/files/pdf12/helicoil-kits-repair-solutions-en-0180.pdf page 38

[andydclements]

The way the ali thread is pulling out reminds me of a head that's been over-heated and the metal is then fatigued. Hopefully that's not the case.

 

What about imperial sizes, that may give an option to increase the hole by less than the next size metric would require.

[Barrykearley]

4 hours ago, Sparky said:

Not a good day.  I've had 2 engineers tell me Big-serts might work, but it should be welded.  2 welders have told me I should install inserts as the welding will make a mess of the head, and one other told me to source a new head.  At least that made me smile.  The quest continues...

A decent and skilled welder would be able to fully fill that hole. You’d need it skimmed for flatness after - but you were looking at that anyway.

think you need to find the correct person to ask the question of.

[Sparky]

Damn right mate.  They seem to be few and far between in my manor nowadays.  I used to have a few I could call on. <sniff>

I've done a lot of investigation into inserts, but those holes are HUGE compared to a helicoil, and I think drilling/tapping runs the risk of breaking out. By the time I've run a tap in, I'll be looking at 12mm diameter.

Anyways, just had a lovely chat with Wayne, and Gosnays is definitely an option.  Top bloke, and plumber.

[Barrykearley]

Good bloke ? Plumber ? 

Thats an oxymoron if ever I’ve heard it

[MPx]

Like the sound of what Gosneys do according to their website...although you obviously don't need to be a very good engineer to write a good story!

They don't specifically mention the type of head repair we need, but I guess you've already covered that!  Thanks for all your efforts as always Gary.

[pete]

23 hours ago, Barrykearley said:

Good bloke ? Plumber ? 

Thats an oxymoron if ever I’ve heard it

Poor electrician even more so

[JerryS]

Hi Gary, the Timeserts may have already opened up the hole too large for a normal helicoil but what did you think about the Twinset Helicoil suggestion? If you could cut the thread for the outer helicoil without compromising the surrounding metal the superior anchoring helicoils provide should do the job. Maybe worth a try on one before going the welding up route.

I appreciate the hole depth limits things in this case but I’ve always thought it would be good to find an appropriate taper tap to use before the single tap provided in helicoil kits.

 

 

[Sparky]

Hi Jeremy

I think it might take those, but I remain nervous about cleaning and tapping those holes.  Gosnays have suggested a couple of possibilities, and I hope to get the head to them today.  If all else fails, the fallback will be something like Twinsert.

[JerryS]

Yes Gosnays sure to sort it, I was impressed with Wayne’s repair.

[Sparky]

It's in Gosnay's hands now.  Hope it'll be ready by Wednesday, as I might be across the pond for a few days after that.

What a great bunch of chaps!  Plenty of banter and Lotus abuse, but I was able to help them with some V8 engine specs, so with luck they'll be nice to me now.

[Chillidoggy]

Those V8 engine specs, are they the rose-tinted ones?

[Sparky]

Is there any other type?

[Barrykearley]

8 hours ago, Chillidoggy said:

Those V8 engine specs, are they the rose-tinted ones?

Just be careful - or the petals will fall off

[top-plumber]

On 15/03/2018 at 19:42, Sparky said:

It's in Gosnay's hands now.  Hope it'll be ready by Wednesday, as I might be across the pond for a few days after that.

What a great bunch of chaps!  Plenty of banter and Lotus abuse, but I was able to help them with some V8 engine specs, so with luck they'll be nice to me now.

Great news that they can help. ✌️

[DaveyT]

Hope things are progressing well here, Sparky.

'scuse my ignorance, but what are the syptoms of cam tower leaks, and under what conditions would they normally be spotted? Just in case I ever get my bloody car going again, like....

 Tia, Dave