Hole in the engine - help! :(

[jp4mance]

Hi all,

I'm new to the forum and new to french engines, so any help appreciated on this one.

On the way home from a track day at Brands Hatch we found a hole in the engine which was coughing up oil over the manifold. I thought at first it'll be a simple case of whipping off the rocker cover to assess the internal damage (if any), but i've since read the rocker cover forms part of the camshaft carrier :S

Would i be right in saying that the pulleys have to come off to remove this part shown here in the pic? I'd like to have a go at stripping it down my self, but if it involves timing gear i'll probably leave it alone.

 

[ian-speedy]

Yes the rocker cover holds the cams in place , and you have to remove the pulleys to take it off , how is there a hole in it ? It the engine making any funny noises ?

If all seems ok , you may get away with filling over the hole carefully with liquid metal which you can buy from somewhere like B&Q , it would stop it leaking oil out and may fix the problem .

Other than that , it needs taking apart and welding up

 

[jp4mance]

Yes the rocker cover holds the cams in place , and you have to remove the pulleys to take it off , how is there a hole in it ? It the engine making any funny noises ?

If all seems ok , you may get away with filling over the hole carefully with liquid metal which you can buy from somewhere like B&Q , it would stop it leaking oil out and may fix the problem .

Other than that , it needs taking apart and welding up

The engine sounds and runs fine. It's the not knowing what caused the hole that's worrying. It has been suggested that a stone chip may have caused it, but I put that down to wishful thinking...

I suppose we could drain the oil, change filter, use some engine flush and check for contaminants. If all seems ok then just plug the hole and see how we get on.

 

[bmh.01]

The other trouble you will run into is as the cover has the top half of the cam bearings cast into it the head and cover are machined as one, you cannot swap covers over between heads. You'd have to get a good head+cover set complete and swap the lot.

 

[Dan519]

The other trouble you will run into is as the cover has the top half of the cam bearings cast into it the head and cover are machined as one, you cannot swap covers over between heads. You'd have to get a good head+cover set complete and swap the lot.

you can get another rocker cover and have the 2 parts align-honed, I've had it done before. Head still has to come off, but it means the head isn't scrap due to a damaged cover

 

[jp4mance]

you can get another rocker cover and have the 2 parts align-honed, I've had it done before. Head still has to come off, but it means the head isn't scrap due to a damaged cover

I've managed to source a new cover, so this could be an option for us, thanks.

 

[jp4mance]

Update - as suggested above we used some putty type weld mix which sets rock hard. It held for quite a long time and even managed 3 hours of abuse around Brands Hatch before it came apart. Given the way the engine performed i'm fairly sure that it's ok internally so i want to avoid taking it apart, but i need something stonger to patch the hole.

Is the cover made from cast aluminum? If so, welding would be no good i guess due to the high temps? How about aluminium brazing rods and a blow torch? I've read a little about this and from what i gather the rods have a low melting point of about 370 degree's which make it ideal for welding aluminum....

 

[Fred@BTM]

i would want to know what's caused it, i bet you've broken a rocker arm

 

[jp4mance]

i would want to know what's caused it, i bet you've broken a rocker arm

Is it possible for the rocker arm to break without any loss in performance?

 

[Chip-mk1]

Is it possble for the rocker arm to break without any loss in performance?

You'd notice it a bit at high rpm as you would be effectively halving your exhaust valve area on that one cylinder.

 

[jp4mance]

There are no signs of loss in performance. It rev's to the red line and still does 115mph across the back straight of Brands Hatch, just as it did before the hole appeared in the cam cover. We've also had an internal camera look inside and nothing appears broken.

 

[Chip-mk1]

Maybe you dropped a heavy tool on it while working on it?

 

[Andyrg@ ClioTurbo]

im sure you could get that welded up

 

[jp4mance]

I'm thinking it was something like that, Chip-Mk1. Something may have fractured/weakened it externally without us knowing and then after a few spirited drives it's just let go and spat oil out over the manifold, lot's of smoke, bad times.

Anyway.... back on topic Aluminum welding... i've heard it can be a tricky one on cast metal. Anyone know a thing or two about it?

 

[Fred@BTM]

fine to weld, but i'd still be doing a compression check etc just to confirm

 

[Chip-mk1]

Not a skill I have personally, but based on what people I have spoken to who can say, the key is to get it hot before welding.

someone like Pro-alloy for example could do that for you no problem, but they arent particuarly cheap.

 

[Fred@BTM]

cleaning it, using the right rod material (probably 5%mag would do it) heat as chip says - bingo

 

[jp4mance]

Thanks, guys. I'll get a compression test done and play it by here. All being well, i'll phone around a few metal fabricating companies.

 

[Chip-mk1]

Contact details here for Pro-alloy, you dont have a location so no idea if you are near them or not (suffolk)

http://www.proalloy.co.uk/pages/contact-us-48.htm

 

[Fred@BTM]

you can tell you're a ford fanboy Chip lol, the ford boys bum Pro Alloy!

 

[jp4mance]

Contact details here for Pro-alloy, you dont have a location so no idea if you are near them or not (suffolk)

http://www.proalloy.co.uk/pages/contact-us-48.htm

Thanks, we're based in Kent. I have a compression test booked for Wednesday and i know a few garages who owe JP4mance (plug) a favour

 

[Laine_16v]

Surely a compression test would NOT highlight any issues with an exhaust valve that wouldnt open? (providing its not bent). What im saying is, it wouldnt prove if you were running 15 valves instead of 16.

 

[Chip-mk1]

Surely a compression test would NOT highlight any issues with an exhaust valve that wouldnt open? (providing its not bent). What im saying is, it wouldnt prove if you were running 15 valves instead of 16.

Indeed, it wont. Neither will a leak down.

 

[Fred@BTM]

^correct, it may or may not show it but its worth a crack, a dyno should show it up though

 

[Chip-mk1]

^correct, it may or may not show it but its worth a crack, a dyno should show it up though

Only thing it would show is if a snapped off bit of rocker was somehow jammed stopping the valve shutting I guess, but that seems unlikely.

But for 2 mins to check, its worth a try, and its a good thing to do regularly anyway.

 

[Fred@BTM]

i had a phs1 172 years ago that was a 15v from factory, only showed up on the dyno, it just stopped reving at around 6K

 

[jack_davey]

odd one this!

I struggle to see how you could have something make this hole and still have a running engine!

I would suggest pulling the manifold off to see if the nearest valve is opening as a compression test wouldn't really highlight a non opening valve, however this would involve dropping the subframe and is probably more effort than taking the head off.

 

[jp4mance]

odd one this!

I struggle to see how you could have something make this hole and still have a running engine!

Tell me about it! If we knew something was wrong internally we wouldn't mind having the engine taken apart, but it runs perfectly (aside from the obvious). It's just a budget track day toy so we don't want to shell out big bucks on labour costs unless we really have to.

 

[Dan519]

Rocker cover needs removing to weld it anyway so you should see anything obvious then. Aside from that, having a look down the bore with a camera/scope would be helpful.

 

[jack_davey]

If you remove the cat first (a bit harder on a 172 than a 182) you may well be able to get the manifold off the studs far enough to get an inspection mirror in place and see if all the valves are opening, I've managed to do this on a 182 when replacing a manifold gasket, although that's all I was doing, I wasn't looking at the valves. Alternatively, a well equipped workshop may be able to get a boroscope (or similar) down the plug holes to see if there's any valve damage

 

[Jaff.]

If you were closer I would offer the Boroscope we have in work for a look. Bit far just for a look tho