We had the first heavy frost this week, and the next day muggins here goes out to fire up the Jag, only to find it wouldn't start.

Well a "few" hours later I discovered that the "On Coil Spark Cover" was actually rather loose - resulting in the damp getting into the coils etc at a guess. A previous owner had sheared off all of the bolts along the top of the cover - takes some doing but there you go.

A squirt or two of WD40 into the coil area resulted in the car starting up nicely, however the problem remains unsolved...

How do you get out the sheared off bolts so that the cover can go on properly?!

Right now, WD40 and Holts Autoplast have been implemented to do as good a job as poss.

 

A set of good used cam covers from a salvage yard would be my first guess.

The plastic covers have brass inserts so if you drill them they MUST be dead-on center or you will drift into the brass.

The rear holes will be difficult to access and you will likely need to remove the covers anyway.

If the brass inserts strip from the plastic cover (heat or torque) you will be on the search for replacements.

bob gauff

 

Bob,

Many thanks for the reply.
I assume the brass inserts will be from a scrap dealer too?
If not, do you know of a specific "ebay-able" name for them at all?

I had better practice my drilling abilities to sort this one out eh?!
If I can get two out of three, I'd be happy though.

Chris

 

The threaded insert is what I'm talking about. They are formed in the cam cover but can become loose with heat from drilling or torque from removing the broken bolt.

You might try to epoxy them back in but I just replace them when they fail.

bob gauff

 

I'm with Bob on this one, takes some doing to snap the bolts off without the insert spinning!

I bought a couple recently on eBay around £40 each

 

To be honest, I hadn't thought about the housing ie cam cover... so I'll probably delay changing those covers if the drilling doesn't work... or at least until I get up enough nerve!
Will have a hunt for tips on that next.

Thanks chaps!

 

You COULD simply "glue" the cover in place with RTV silicone. Simple & effective.
Barring used valve covers try drilling using left handed drills, if they catch they could back out the remainder of the screws and the day is saved. If you manage to drill them without loosening the inserts and do get into the brass just tap them a slightly larger size, an SAE fastener is sometimes the closest oversize.

 

+1 on a pair or scrap cam covers....cheap as chips on eBay like 'racer says £40.

While you're in there you can check the state of your secondary chain tensioners, if plastic replace them before they cause engine damage.

 

Well, I did my best with the left handed screw driver (drill bit ) but as you'd probably guess, neither bolt budged an inch. It was practically impossible to get the drill dead centre either. I think that technique is best for larger diameters and especially ones that aren't rusted in. In future situations, I would possibly try a standard drill to literally take the whole bolt out as per Ross1's suggestion.

I also tried using an easyout but it was far too thin to be of any great help and sheared off itself. Thankfully I could remove the shards without too much bother.

So after my attempts, I agree with Bob and the others as they are definitely right about the simplest cure being to replace the covers, but for now I have chosen to seal the gap as per Ross1's sealant idea. I will attempt to change the covers myself once I have found sufficient information on it.

I had the tensioners changed this summer, so it's a shame the mechanic didn't mention the sheared bolts etc at the time, all things considered.

 

Unless he was the one that sheared the bolts.

 

removing the valve covers is not that much of a headache, but having done so a few times a few points :

- use a drill socket adaptor - it will save so much time removing and refitting all the bolts (coil cover, valve cover and coil packs). A usually inadequate 9V cordless drill is ideal here.
- do not overtighten the valve cover bolts when refitting - a little over hand tight is enough (8NM is specified but I dont think a standard torque wrench can be that accurate at this setting - do it by hand with a 1/4" ratchet till the bolts just start to pinch). If you do overtighten they will leak oil. If you've had the tensioners done I assume new gaskets have been fitted, if so they should be ok. Watch for any spark plug seals that may fall out as you remove the covers.
There is a torquing sequence for the valve covers which you can look up - in a nutshell do the middle 3 first, then the outer ones starting from the middle in a up-down zig-zag pattern.
- the (UK) passenger side cover (B-bank) requires removal of the dipstick tube. Some people cut a groove in the plate where it attaches to the bolt so it can slide out. I just removed the nut and gently pulled/twisted the tube upwards out of the sump enough to clear the bolt.
- the (UK) drivers side requires removal of the air intake ducting - easiest way is to detach the two bolts from the throttle body, gently disconnect the full load breather hose from the intake duct, disconnect the maf sensor, unlock the air filter box clips and lift the whole assembly away.
- careful with the coil pack connectors, I use a small thin screwdriver to lift the locking tabs, then a thicker flat screwdriver with masking tape wrapped around the end to ease the connectors away from the coils - I dont like the idea of pulling on the connectors to loosen them as the wires can be brittle !
- with the covers off give them a good clean inside - I use white spirit, the only thing that will effectively remove sludgy oil. The drivers side cover will have a guaze(?) filter inside for the breather tube - removing any c**p from this will do your car no harm at all.

Regarding your stuck bolts - it may pay you to drill them out as suggested, then use a thread repair kit on the inserts. I dont know what guage bolts are used, I would guess 6mm but check that with a good one. With the covers off it should be pain free. Use cobalt drill bits - they are quite brittle but very very hard and will cut through steel very effectively. Its up to you of course to weigh up the costs / hassle factor.



Good luck!
AndyP

 

5mm FWIW

Or you can do what I do and replace them with something shiny