[engine_work] I Forgot How Much I Missed It!

[petert 586]

Seriously though, I don't think you'll ever know with this what came first, chicken or the egg. A common mistake after a blow up is to remove spark plugs. If there is damage like in yours, the plug destroys the thread on the way out, then you'll need a helicoil as well. The head is salvageable. Take you time to get it fixed properly as it looks like a good one. In the meantime, enjoy the GTi6!

[allye 530 3 Cars]

Nothing constructive to add other than that's a bloody good job you've done there!

[DrSarty 90 1 Cars]

Thanks. The head was the one on my 2.2 Mi16, built by QEP several years ago.

 

It had the triple-cut valve seats and also had the valves unshrouded because it was previously fitted to an 87mm over-bored XU10J4 iron block. Could the latter have been an issue?

 

But I agree, it's time to live with the failure and move on.

[petert 586]

No, none of the unshrouding work would cause mechanical failure, unless the shrouding leaked out past the 83mm gasket line, possibly leaking gases into the coolant. The 2mm difference would still be covered by the fire ring I'd imagine. Double check it however.

Edited November 11, 2013 by petert

[DrSarty 90 1 Cars]

Just out of interest, what can cause a liner to crack?

 

I assume over-heating, although this engine since I had it never over-heated. I can't imagine it being built with a cracked liner, or could it be that the liner had a minor fault which worsened over time?

[wicked 103 3 Cars]

If you haven't removed the liners yet, I would measure the protrusion and the difference between the liners (more important with metal HG). If the liner is not straight up, it could see some more pressure from the head than the other liners and maybe trigger a weak point in the liner. But just a powerfull engine can also make a weak liner crack....

 

The cracked liner could explain the pressure in the bottom end, as the pressure in cylinder can bypass the piston rings via the crack.

 

Edit: did you match the liner size with the pistons??

Mi16 pistons/liner come in 3 tollerance sizes (A,B and C). If you put a larger piston in a smaller liner and heat the piston......

Edited November 11, 2013 by wicked

[DrSarty 90 1 Cars]

The engine wasn't built by me.

 

I bought it ready-made with receipts from an engine builder or made it for a long-time forum member who decided to stay 8v.

[wicked 103 3 Cars]

The sizes (d=piston, e = liner):

 

​

 

 

The size of the liner is stamped on, but not always readable on older liners:

​

Edited November 11, 2013 by wicked

[welshpug 1,657]

Enjoy the gti6 engine Rich, I think you'll like it.

[kyepan 291]

(Perhaps specifically aimed at Kyepan (Justin)):

STOP! You kind of have a habit of not reading things and asking about things which have been stated already, and then making huge comments or statements after reading far too much into what you have decided to read.

 

 

It's not that rich, your posts are at times a little hard to follow and the simple facts are not exactly clear.

 

 

 

 

Although not clear and conclusive - and I have stated that it's not a definite yet that the HG was fitted 180deg out rotationally (which would mean blocked oil feed and drain holes) - faint witness marks on the deck appear to indicate that the HG WAS fitted the correct way (???):

 

 

So it's possibly not on correct, but there are marks that suggest it's on correct.

 

 

3) So I then rotated the HG so the teardops looked right, as shown above, i.e. correctly positioned over the corresponding block holes, as well as the dowels locating into the HG holes.

Therefore this is why I was confident the HG had been fitted correctly.

 

on correct.

 

 

My mate Guy since this has happened, said he checked the HG too but without me knowing, I suspect to ensure it'd been done right. He said he didn't turn or flip it, so currently I believe it was lifted up, checked and replaced as I had placed it. Perhaps the devil lies in this HG fitment somewhere?

 

Again on correct and verified by a second person.

 

 

 

 

This final picture (again of other Mi16 parts I have) is the correlation of block>head oil feed holes, which MAY have become blocked by the potentially incorrect HG fitment.

​

 

 

Potentially not correct and or blockage.

 

 

So it's currently still a slight mystery, although I've dealt with the frustration and have concluded it was the HG fitment.

Not correct...

that's just from one post...

A simple question Richard, when you took the head off after the blow up, what way round was the gasket?

J

[DrSarty 90 1 Cars]

Justin:

Let's not come off the rails here; my posts are clear saying for example that the engine's in the car, and then you ask if the engine's in the car.

 

Ref the above attempt from you at an example concerning the HG, I've made it clear that the fitment of the HG was in doubt. I've said I lifted the head up enough to slip the HG out but regretfully didn't note the orientation. I even mentioned I was a bit frustrated that I didn't note its orientation but stated that it's hardly important as the damage is done anyway. The whole history here has some contradictory elements which may never be explained.

 

What is clear and has been noted by others, is that you don't either read posts properly or somehow don't understand parts of them, but still comment as if you do. Again, this has been noted by others, and personally I've found some of your posts almost worded as if to provoke a reaction, clearly indicating that you simply haven't read what's been written. You will find posts hard to follow if you don't digest all the info and read it all in context.

 

If this causes friction in this topic or in the forum I regret that; if you wish to complain directly to me or to the mods then feel free to do so. I'm not everyone's cup of tea, but I'm 100% honest, I mean what I write and I'm careful to try and make it clear. I read what people write back, and if I ever misunderstand or misread I apologise.

 

So here's the situation in summary:

> We'll probably never know if the new MLS HG was ever fitted correctly, as I didn't/couldn't check its orientation based on how I removed it

> There are signs and a history 90-10 in favour of the HG being fitted correctly but we'll probably never know, although the symptoms prior to failure and lack of oil in the head lend themselves to it being the HG fitting, despite no clear evidence

> One valve smashed a piston, but that was probably AFTER some other event which caused a temporary lock in rotation which stretched the cambelt

> Everything was fundamentally new/freshly rebuilt

> We can now see a cracked liner on cyl 3, but we don't know if that happened before or after the main failure

> The head is out of the car and I'm preparing to lift out the alloy block, clean the bay and drop in a GTI6 lump on my bodies once the cambelt's been done

 

I will keep investigating the XU9J4 slow-time and focus on enjoying the '6.

Edited November 11, 2013 by DrSarty

[Anthony 1,003]

Surely the HG is a red herring Rich, and the noise you thought was the lifters not being filled was actually a bent valve tapping away to itself until it eventually broke off with the expected (and expensive) results?

 

GTi-6's with bodged belt changes are notorious for tapping, but Mi16/S16's can do the same - Kyepan's did for example when he fitted the new cam out of alignment and dinked the valves turning it over by hand, where it ended up needing something like 8 valves from memory. It still ran, if a bit down on power, but sounded horrendously rattly apparently and would no doubt have failed eventually had he driven it rather than pulling the head off.

 

Sound familiar?

 

The valves on that head looked fine to the eye at a glance and all but one cylinder had excellent compression (the other was about 25% down from memory), but there turned out to be loads of them bent!

[DrSarty 90 1 Cars]

I wholeheartedly agree with your logic Anthony, and trust me, Guy and I have poured over this whole subject including the same suggestion as yours for hours.

 

There could be some merit in some or all of it, but unfortunately when taken into account with all other factors we end up back in a huge grey area again.

 

Here's what I mean:

We could've made a mess of the cambelt re-fitting; it's never easy in-situ. But the cam pulleys were swapped over from OE to the 2 vernier pulleys with 100% care, triple-checking etc to ensure that they were pinned to the head (and even zip tied together) to 100% match the OE pulley positions when locked to the head via the holes. On that basis, surely the valves were all correctly positioned relative to each other, meaning they couldn't touch?

 

The head was off on the bench, cam caps off, old lifters out, new lifters in, OE pulleys removed, inlet pulley swapped first then the exhaust to ensure cams weren't swapped by accident, then refitted (cam caps bolted down in order), then cams rotated to the correct orientation to be locked as per OE pulleys ready for head fitment back to engine. The crank pulley had been locked the whole time.

 

Even though the above seems bullet proof, I still question myself if there's any way in which the valves could've touched, perhaps just the once whilst rotating the cams in the head on the bench the short distance needed to lock them up. But would that ever be enough to bend valves?

 

Once in the car and re-fitting the cambelt, the tensioners were done evenly whilst everything was still locked and tension set for a 45deg twist between finger and thumb on the longest run. Now (question), if that tension was wrong or slightly biased, could that affect cam timing once the pins were removed and everything rotated sufficiently for valves to touch, thus noise etc etc?

 

So if it was bent valves, as you say, that explains noise and would link to power being down. BUT, we then run into a wall again when we have the block pressuring and subsequently find that the head has very little oil in it when the cam cover's removed during inspection.

 

Everytime we follow one cause, something contradicts the conclusion. I'm now starting to think it's basically a 'comedy of errors', i.e. multiple things. I know that might seem confusing, but that's because it is, and it's very frustrating.

 

Today on further inspection of the head, the cam bearing caps don't appear scored or having been subjected to seizing (that's only a layman's inspection though), and 7 of the lifters were very difficult to remove, almost seized in the follower holes. I'll post pics tomorrow.

 

And then we get to the cambelt, i.e. why did it stretch, what caused the rotational stoppage? If the valves had clipped during assembly and bent one or more, would the valve to piston clash have caused the cambelt to stretch?

 

Further again, why did only one of the inlet valves on one of the cylinders (cyl 3) hit the piston?; why not both?

 

And finally was there a cracked cylinder liner for some time which was the root cause of this, as it explains block pressure, but then what about the noisy head, or was that valves?

 

It's like a bloody merry-go-round!

 

 

So the head'll be stripped and valves checked for true/straightness, and slowly but surely we'll fill in some of the background to perhaps get to a conclusion, although I'm almost not bothered any more. I only wish I'd blobbed some paint or attached a small zip tie to the MLS HG rivet tab at right front so I would've known the HG's fitting orientation.

Edited November 11, 2013 by DrSarty

[kyepan 291]

Handbags aside, What i've been trying to say, is... it's not the head gasket that caused the failure, it's got to be valve damage, working out where it happened so it doesn't happen again is the important lesson to be learned here. Now it sounds like you fitted the cams with standard pulleys, then swapped for verniers that matched the woodruff position and the teeth position.. so far so good, that seems safe and sensible.

 

The head was off on the bench, cam caps off, old lifters out, new lifters in, OE pulleys removed, inlet pulley swapped first then the exhaust to ensure cams weren't swapped by accident, then refitted (cam caps bolted down in order), then cams rotated to the correct orientation to be locked as per OE pulleys ready for head fitment back to engine. The crank pulley had been locked the whole time.

 

Perhaps this is where the valves got bent then, if the cam carriers were bolted back down whilst on the bench, then rotated and pinned, the head would have been resting on open valves, unless you fitted the cams with the block on it's side. I believe the ones that are rocking are number 2. Usually i fit the cams in situ, with the head bolted to the engine, the pistons at half mast.

 

On the HG, there's just no way you got it on the wrong way round, however MLS gaskets are notorious for not sealing under anything other than very exact tolerances, if any of the protuderances were even the slightest bit out under OEM spec, ie more than 0.02mm out across all liners in all directions and the corresponding points on the block, you've got issues anyway.

 

These will only be made worse by an MLS gasket because it has virtually no squish to take into account any variance in deck height, or wave. Bearing in mind the MLS gasket specs are much more stringent than our fiber OEM, fitting one on an engine that's not just been freshly machined and flattened to the correct spec is always going to be a risk. So much so, it's exactly why i didn't fit one, and fitted a standard gasket instead.

[petert 586]

I always like to assemble the engine with the standard pulleys, locked in position first. Then when happy all rotates properly, lock again and carefully replace with vernier pulleys. I hold the cam with a spanner so it can't rotate by accident, tension belt, then adjust the cam timing.

[pronta 1]

Right.

This is an oil issue . Period.

Even if the valves clipped......why is there no oil in the head ?

 

Even if oil was bubbling out of the dipstick tube ..... why was there no oil in the head ?

 

So what if the liner got cracked.......why was there no god DAMN oil in the head ?

 

It's first and only answer is because there is an oil flow issue.

Either...

1. Incorrect gasket fitment. ...unconfirmed.

2. Foriegn object falling in oil supply to the head....also unconfirmed but where my money is.

 

If the pump was shagged then why was it bubbling out of the dipstick ?

Answer because the pressure was so high as it had nowhere to go and the reciprocating parts inside the block lift the pressure higher and it finds the path of least resistance.

The vernier was mistimed. ..but why no oil.

The belt jumped...The pulley moved. ..The belt stretched. ..The. .The. ..The. . Why no oil in the head...

 

Its a given the liner was cracked by being smacked with a broken off valve that had momentarily seized in the stuck out position.....why had it seized ?

Because there was no oil in the head that's why..

 

Now before you all jump up and down, yes valves do rely on lubrication if only a little bit and yes I know the phosphor bronze that they are generally made from has very slippery properties but they still need lube.

 

Richie didn't bend a valve putting the head on the bench as with the inlet plenum on and the cam plate it would be utterly impossible.

He didn't clash valves on fitting the cam as even the most ham fisted loon can tell the difference between compliant resistance from a cam and solid resistance from clattered valves.

Had they just glanced each other he would of heard/witnessed it at close hand.

 

Before making any helping comments that will progress Richie forward the answer to "why is there no oil in the head" must be answered.

All other arguments/notions and incidents are all invalid until that answer is found.

 

If you find me rude, then so be it, I won't lose any sleep over it but that's my 2p.

 

Find the blockage Richie and you'll find your smoking gun.

 

 

 

life is full of questions and idiots are full of answers...you just have to wade through the idiots to get the facts

Edited November 12, 2013 by pronta

[allye 530 3 Cars]

That's a breath of fresh air!

[kyepan 291]

Why are the cam journals in good condition if there is no oil in the head. A Mazda I took apart that ran low on oil spun a cam journal nearest the pulleys and made a right mess. The oil bubbling out of the dip stick can't be explained by a restriction in the head, the pressure relief valve on the pump would simply open, and dump the oil back into the sump which is what it will do above 4k rpm when cold. If the pressure release valve was struggling to cope you would see sky high oil pressure. and on engines with solid lifters they run a restrictor between the head and the block anyway.

 

Also my dipstick was not sealing correctly and getting lifted out, until I changed it for a new one. The rubber o ring was slightly perished and not sealing. It would lift under load and then spray oil on the underside of the bonnet. There are some videos of oil in the sump on aap running engine and its essentially a foamy froth.

 

Lastly, what was your breather system doing at this point, was it verified as clear, was it catching deposits more than usual? Did you unplug it gtom yhe catch tank and let it vent to atmosphere to check if that resolved the dip stick lift? Because if a good dipstick is being lifted, there has to be an enormous volume of blow by gas escaping to atmosphere that is not being coped with by the breather circuit. Again I suffered with more blow by when moving to bodies, and had to modify the basic breather setup to go for a larger diameter more agricultural setup... I was under the impression it was pressurising the crank case and lifting the dipstick, when it was a combination of change of breather config for the bodies and dipstick being old and s*it... Essentially exactly the same symptoms as you. You might state that this breather setup is the same as on your 2.2 but every engine breathes differently depending on the ring gaps and bore clearances, the volume differences are in litres per second.

[DrSarty 90 1 Cars]

That's the whole point of the discussion; it's quite a puzzle. As said before, every time one route is pursued and looks good, it leaves another question unanswered.

 

You may have a good point concerning dipstick lifting/block pressure and breather systems, but again we have:

> it was working fine before we changed the HG

> it then appeared once the CR lifted to 11:1 and the ITBs were fitted....BUT, I've never seen it before, even on my 2.2 running ITBs, 11.6:1 and the same breather system

> the breather system as stated in a recent post (!) was clear (all pipes, breathers and the catch tank itself)

 

The cam journals looking fine is confusing when evidence indicates (hence Guy's conviction above) that there was restricted oil flow to and perhaps from the head. I don't believe Guy means as stated 'no' oil to the head, as damage would've been worse spread and sooner, but there is no denying that there was hardly any oil in the head.

 

For example, when we changed the HG, the head was full of oil and spilt all over the bench and the floor, perhaps 0.5-1.0 litre. When I disassembled the engine for inspection here, without draining any oil and upon lifting the cam cover, there was only a film of oil on everything. It's undeniable that there looks like a restriction of oil supply to the head.

 

And whilst I appreciate MLS HGs are apparently less forgiving, please do not forget (as stated several times) that the engine was effectively newly built, with proper liner protrusion, deck properly true and surfaced and head face suitably machined/faced. I do not believe the HG blew as such; I'm sure now the coolant loss was caused when the liner cracked as a result of the valve to piston clash. The engine was never lumpy, compression was good, idle was smooth and there was zero coolant loss until the big bang. So I agree with Anthony and also Guy (Pronta) that the HG is basically a red herring.

 

Pete:

Thanks. That was one of the two ways you've described I considered for swapping the OE cams for verniers. I went the other/my way for 2 reasons:

> I wasn't confident of accuracy holding the camshaft still with a spanner whilst swapping pulleys

> {As I'll double-check and hopefully show in pics later today} It was really easy to make the verniers act the same as the OE pulleys and be easy to lock as if they were OE with a suitable locking hole

 

Finally, if I can get a valve spring compressor today, I will try and confirm how many if any valves are bent (less the one which has broken completely of course).

 

It will be good to rule out some factors to see what we're left with. Once the valves are out, the head's oil feeds will be checked thoroughly.

Edited November 12, 2013 by DrSarty

[pronta 1]

I dont recall if I've read in the thread if Richie had mentioned that the head filter insert when removed was damaged.

I witnessed it as in good condition.

If there was a partial blockage of the oil way then it may have been providing a small amount to the spray bars which kept it alive.

Many years ago when I was playing with straight six 2600 rover engines they suffered terribly with poorly drilled galleries and some would tap, some would wear the cam and some showed nothing until they let go and stuck valves out and smashed them to bits. What I'm saying is each engine's different and there was no definitive explanation as to why they died differently.

But I've seen stuck out valves from lack of lube before and it not damage the cams.

 

The oil breather was fine, it had been emptied of condensation prior to restart.

It had previously been run on the 2.2mi with zero issues.

It pretty much can be discounted.

 

So the new question is what caused the filter to get damaged ?

My thinking is that a Foriegn object pushed through it into the head causing a partial blockage.

Direction of the damage can help determine if it's heat and its melted or if it's FOD assisted by oil pressure.

6bar is the best part of 90psi and that'll fire an object a bloody long way at high velocity.

This needs looking at as it may answer the lack of (as opposed to no) oil in the head question.

It may be a bit of swarf or gasket has dropped in the blocks oil supply. I lost a washer once that pinged off from the other side of my workshop and of all places for it to land was straight down the number 3 plug hole of the 8v golf I had in for work. Confused the living snot out of me as to how it could do such a thing.

 

Conversely I've seen a three cylinder polo that spun it's cams and screwed the head that was bathed in plenty of oil.

 

Noisy lifters, lack of power on the rollers (felt like it was being held back) (friction?) A 20hp drop in power from the last mapping session when swapping from gti6 inlet to itbs, these are all clues mot just symptoms

[wicked 103 3 Cars]

The oil enters the head on the cam journals; so those are the first ones to get oil.

So on a partial blockage those just got enough to avoid damage (don't need much), but the valve lifters and valves didn't get enough, making the valves go up slower and make the valve in the 3th cylinder meet the piston first.

[welshpug 1,657]

There is only one oil feed, and you can see a few pages back that it was not blocked by the gasket at all.

 

If the gasket had been fitted incorrectly you would have had a lot of water in the sump straight away, I read a member on the 306oc made exactly this error a few days ago and the coolant just filled the sump up, they managed this due to running head studs and forgetting the dowel, and forgetting to confirm the gasket was on correctly.

 

So I highly doubt as Guy has said that the gasket was on incorrectly.

 

When fitting a belt on an Mi16 you don't need to disturb the crank pulley which clamps the oil pump drive (though it is keyed anyway)

 

So I can't really imagine any causes to the lack of oil up top, other than the contaminated oil was piss thin and has all drained back down during the week or so between the valve dropping incident and actually stripping down, or there's a physical blockage that has bypassed not only the oil filter but also the gauze in the head oil feed.

 

 

 

 

Regardless, forget about it for now, get that gti6 in, and enjoy the simplicity of an engine that will produce as much power and more torque than your 1.9 would have done without changing any parts.

 

 

It will be interesting to see the actual difference between an MI16 lifter and the aftermarket followers, I know you have said a number of times you cannot believe a manufacturer would produce a part listed as being compatible with a number of engines, when it turns out it is not.

 

Simple case is that manufacturers DO make stupid mistakes like these, ask Sandy about TU5J4 Wossner pistons!

 

Jenvey XU16v inlet manifolds, they point the trumpets straight over a 205 slam panel and you can't fit a decent length tract to make good rounded power!

Edited November 12, 2013 by welshpug

[DrSarty 90 1 Cars]

Thanks for the recent posts. The investigation continues, and I'm particularly pleased and in agreement with Wicked's recent post, because - like a Columbo film - even if the assumption or deduction appears pretty radical, if it's the only solution that fits fully it must be right, or at least very nearly right.

 

Here's what I've done/found today, with pictures to follow later:

> All valves removed - NONE BENT (except for two in cyl 3 where there was piston contact plus the smashed one - also from cyl 3, one other is fine, 1 is bent noticeably & the other only marginally bent)

> The head at some point had machining to allow lumpier cams - wasn't me (or even needed really), and cam rotational tests once all valves and springs taken out showed plenty of clearance even without the machining (this is understandable as my cams are only regrinds of OEs)

> The head oil feed is clear* - as Wicked said, the front left oil supply hole in the block (nearest alternator) feeds an oddly shaped hole to the centre of the left-most cam bearing cap (cap#5)

> Whilst the cam bearings show no scoring, the cams do, even with discolouration indicating friction

> The cam pulleys have been marked with white pen to indicate the woodruff key position for comparison of my verniers with the OE pulleys regarding locking holes (however with no bent valves, I suspect all will be fine)

 

*This is my concern now and where I will focus, and this indicates that the noisy head WAS the lifters, starved of oil, as no valves are bent.

 

As oil flow has quite obviously been restricted to the head, we have to find where. Options are:

~ HG fitment, now looking extremely unlikely if we consider all evidence plus Welshpug's last post

~ Something in the block restricted flow even before reaching the HG>head crossover

~ As I now know the head oil feed gallery is clear, perhaps the exit hole crossover into cap#5 somehow failed - I'm going to inspect all cam bearing caps, fitment in photos and especially cap#5 and the spray bars

 

Ref the cam bearing caps, I was momentarily considering they'd been bolted on 5>1 right to left, i.e. cap#5 nearest cyl 1 and the flywheel, which is the wrong way round; it should be 1>5 right to left, as cap#5 (situated nearest the cam belt) has the odd oil feed hole in the centre which mates via a small rebate to the angled hole in the head.

 

They do fit the wrong way round, BUT, the end caps (#1 & #5) house different sized camshaft oil seals and simply won't accept the cams with the seals fitted.

 

What I am going to look at is if the hole in the cam bearing cap#5 somehow was blocked, OR the oil spraybars are somehow blocked. A recent blow through didn't indicate that. My money's now on that simple, single hole in cam bearing cap #5 become blocked or trying to feed into a blocked oil spray bar. This would deliver all of the results we have seen.

Edited November 12, 2013 by DrSarty

[kyepan 291]

We ran my engine with no spray bars fitted for about fifteen minutes after timing up the stage one inlet, Paul spotted them on the bench as we drove out for a shakedown got on the phone and said get the f*** back here, blocked or missing, I doubt spray bars are to blame. Especially as they Dowse the lobes not the journals. The pressure even looked normal for a cold engine, head was quiet too. If you remove the oil way core plugs you'll be able to find any debris trapped within the head, that or shake it and see if it rattles once its just the casting.

 

Also, you do have bent valves, perhaps only the cylinder 3 valves were bent. We needed to put mine in a drill and spin them to see most that were bent, it was not visible to the naked eeye. except on one I think. you could make out a feint dink on theback lip of a few others though, so inspect for signs of contact.

[welshpug 1,657]

Indeed, the XU7 and XU10J4R don't have spraybars at all for example, they just reply on the oil bath to lubricate the cam lobes.