Is This Head No Good

[Obey_R 23]

 

After removing it to sort out my headgasket problems I noticed there is a crack, as per the photo, underneath the camshaft seal. The hole looks to go down the back of the block where I can see what I imagine is the oil pump chain? The seal that was in the wasn't chewed up or anything, however there has been a fairly constant oil leak that I put down to the rocket cover gasket.

 

Any ideas?

[Ryan 99]

That hole is there as standard, I think it's an oil drain for the seal.

 

Hard to believe given how crap and rough looking it is.

[welshpug 1,666]

its just an oil drain

[Obey_R 23]

Brilliant Yeah I thought because it is so rough looking that isn't not meant to be there. Thanks Now just to get it pressure tested, I couldn't see any obvious signs on the gasket of where the water/oil was getting in, but this was the result...

 

 

Is that more likely to be a cracked head/block than just a gasket failure?

[M@tt 77]

looks like it's possibly been going between the rings on the left hand side of the pic comparing it to them on the right handside although the pic is a bit fuzzy.

 

To check whether the liner is cracked wind the crank pulley round a bit so that the piston goes to the bottom and check for any cracks, to put it back make sure you un wind in the opposite direction so you are back where you started rather than keep windingit other wise you'll be 180 degrees out.

 

####Make sure you clamp the liners down first before rotating the crank so as not to disturb the liner seals####

 

More than likely just the HG though although check the head for and cracks which will usually start from one of the valve seats

 

you're doing great on the job well done, keep up the good work!!

[Obey_R 23]

What do you mean 'between the rings's? I'll try and get some decent sized piping to clamp the liners down and check them for cracks, I take it any cracks would be obvious, not so small I couldn't see them?

 

The underside of the gasket looks just as 'clean' wit no obvious blows, is it normally much more expensive to get the head pressure checked whilst it's being skimmed?

[DamirGTI 344]

 

 

Is that more likely to be a cracked head/block than just a gasket failure?

 

 

It's a head gasket ... gas blow by in between the two cylinders (No.3 and No.2) and coolant outlet as well (hence washed out appearance on piston No.2) .. you can see it by discoloration on the gasket fire rings in between the cylinders , and the gasket base going towards the head bolt hole (bolt No.1)..

 

Reasons ? well id say overheating issue sometime in the past , insufficient bolt clamping force (reusing old bolts more than once , wrong tightening method/torque , dirty bolt threads etc.) , warped/twisted head base (get the head skimmed before assembly - it's a must !! do the skimming always for alu. heads .. this one will most certainly be sinked/twisted from the corners inside , so kinda like oval shape base which will not seal up again properly if not skimmed ..) , dirty block gasket mating surface , sunked liners ..

 

So check/correct :

- cooling system (fan , thermo-switch , thermostat , hoses , expansion bottle for cracks , expansion bottle cap for pressure leak ..)

- check the ignition timing (for over advanced or over retarded .. but over advanced will do major damage to the gasket rather than retarded ..)

- as said , skim the head

- clean up the block mating surface

- check liner protrusion (difference in height in between them and in between the block surface)

- use new head bolts (clean the bolt threads inside the block before assembly and oil the bolt threads and area beneath the bolt heads prior to tightening , use good torque wrench and correct tightening method/sequence)

- new timing belt/tensioner/water pump

.. and that's about it ... if done correctly you'll be fine

 

Damir

[Obey_R 23]

That's great Damir, thanks for the breakdown.

 

It did have overheating problems when I first got it, to the point where the MOT tester said it boiled over on idle. I've since changed the thermoswitch and made sure there is 12v to the fan (was only 6 before!) so the fans work fine on both speeds now.

 

I need to get the timing set-up properly, will be doing this soon after getting it running again. Is it something I can do accurately myself or best taking it to a garage?

 

I've already got all the parts, the plan was to do the waterpump, cambelt, tensioner, head set inc. gasket and new bolts etc whilst it's all apart so that will be done. As was I planning on getting the head skimmed, I'll be taking the valves out over the next few days to re-lap them and send the head off to be skimmed - is it worth doing a pressure test, how much extra is it?

 

Will be cleaning the block up with some very fine wet and dry, is this okay?

[smithy 1]

Ignition timing needs to be set with timing light so unless you have access to one it will need doing at a garage.

Always worth pressure testing while they have head for skimming from memory about £40 was the cost.

 

I cleaned my block with some coarse paper initially then worked down to fine,otherwise the fine alone will not remove the crap.

Just make sure the liners are securely clamped,if you have slightest suspicion a liner has moved best to have them out and change seals before head goes back on.

[Tom Fenton 1,548]

I have never had much luck trying to accurately set the timing on a 205 with a timing light, mainly due to crap/no access to the marks. The way I've almost always done it is by gradual increasing advance until it just starts to pink under max load low revs say up a hill, on whatever fuel you are planning to use, then back it off a touch.

[Obey_R 23]

Keep the liners clamped down whilst cleaning the block? I wouldn't be able to clean the whole surface if that was the case? Is it as easy to taking the liners out, putting new seals in and refitting new ones or is it more complicated than that?

[Anthony 1,003]

Can o' worms.

 

Pretty much, if you're taking the liners out it's a complete engine stripdown job, as you'll need to undo the big-ends anyway and you're bound to cover the crank and everything else in sediment when you remove the liners and clean up the liner seats - assuming the later isn't excessively corroded, which many are.

 

Trust me, if you're just doing a headgasket swap, don't touch them if the liner protrusions are correct (which they usually are)

 

A bit of emery is normally sufficient to clean up the top of the liner without disturbing the liner seals.

[Obey_R 23]

Thanks Anthony, I'll just be extra careful when cleaning near them! Just need to strip the head down of valves, get it skimmed and start putting everything back together!

 

Anthony, any chance you can move this topic into my Novice head gasket thread now my question has been answered?

 

Thanks

[lagonda 42]

Still worth checking your head isn't cracked. As already stated by someone else, check from the exhaust valve seats. Mine was cracked in the middle two combustion chambers...in both cases the cracks ran from the exhaust valve seats to the spark plug holes.