Engine Died

[AustHaflinger]

Today I had been driving around near home - all offroad and the Haffie ran great. Then had to drive across town and Haffie was going great then when doing about 65kph the engine started loosing power and would no longer hold 5th gear - dropping back to 4th it would hold 40kph but would drop back off when changing up to 5th would die.

I pulled over and engine would not keep running. There was some oil coming out the crankcase breather but there was still oil pressure on the pressure gauge.

I recovered the haffie back home and tried starting and while it would fire a bit it would not start - clearly is now right down on compression.

Tomorrow I will do a compression test then pull the engine out. I will start with the tappets and valves, then the heads and head gaskets, then rings etc. Oil coming out the crankcase breather indicates pressurisation which can be rings or problems with valves letting gasses into the rocker covers and pressurising the crankcase.

Oh well these things happen - I had to pull the engine out before too long as the bearings in the clutch were a bit noisey.

I have heard that the tappets are a weak point, so any other areas I should specifically be looking at?

Cheers

Garry

[heinkeljb]

Bad luck Gary!

After all your efforts tuning it. I hope this failure isn't a result of your tuning efforts As you say, start with compression test, then rocker covers off, then cylinder heads off.

Next thing if you don't see scoring in the bores is to drain the oil and look for metal flakes which might indicate main bearings / big ends / little ends failure.

Let's hope it isn't any of those and is some thing as simple as ignition timing having moved!

John

[AustHaflinger]

I took it off the trailer this morning and tried starting - it wanted to go and ran by itself for a few revolutions - I suspect low compression caused by - we will see.

Oil looks OK - oil pressure is 40psi on cranking and was at 70psi when the engine was failing so all normal there.

[heinkeljb]

Compression test first then.....

We wait with baited breath for the next installment of: Who was the culprit!

John

[AustHaflinger]

Went to check the timing first off this afternoon - connected up the remote starter and timing light and the engine actually burst into life. Took it for a run around the block and while down on power did run but on the second lap it died - my track is such that if it dies I can coast back home.

Back home it started first go and ran but sounded like one 1 1/2 cylinders - idle was at 750rpm but timing seemed to be set at TDC - I noticed my mechanic who did the work previous has marked the fan with a 5mm punch dot, a 7mm stroke and a 9mm dot. I adjusted the timing to the 7mm stroke and idle was a bit smoother. The engine now starts first go. I was intending to do the compression test and remove the rocker covers but I have had a few phone calls so is not going to happen - now 10pm.

I am now thinking tappets have closed up again or something up there has broken. Can anyone tell me what the weakness is in the standard tappet/valve system.

Cheers

Garry

Edit - curiosity got the cat so it is now 11pm and I have done the compression test. No 2 cylinder is showing 110psi so that is close enough to being OK but No1 cylinder shows 10psi compression, so basically zero. This is the cylinder that has always been the weakest of the two with lower compression and has always had an oily plug. I would love to think it is just a blown head gasket but I guess I will not be that unlucky - as planned I will pull that rocker cover tomorrow and see if there is anything obvious there.

Can I assume that to take the head off the engine needs to come out? Also can I assume that when the head is removed the barrel is then loose?

Thanks

[heinkeljb]

Gary,

As far as I can tell from the parts book, the barrel is just "sandwiched" between cylinder head and crank case. There are only nasty things I can think of that go wrong.. things that have snapped for example. I hope that's not the case!!

John

[Julian B]

The cylinder barrels are indeed just "squashed" between the crankcase and the cylinder heads.

Not sure if you have to remove the engine to remove a cylinder, but to be honest it is so quick and easy to remove an engine that I would have thought that it would be worth doing, if only for general access and elbow room.

[AustHaflinger]

I agree about removing the engine - it is just past midday day here, I am still in my jarmies and trying to work up the motivation to go an pull it out. I need to replace the spigot bearing and the clutch withdrawal bearing anyway so is a good excuse to pull it.

I might go down to Maccas for a Cuppacino, chocolate donut and a read of the paper to get my energy back before starting the task.

As I have VW barrels I should be able to gaskets locally.

Garry

[AustHaflinger]

Engine is out - took a bit longer than I would have expected from the comments by others on here.

Tappets are working and I have shoved a scope down the spark plug hole - doesn't appear to be any holes in the piston and I can see the honing cross hatching on the bore but I can also see vertical lines that could be gouges bit equally good be oil. I could not see the valves. On removing the exhaust there was a lot of unburnt sump oil in the pipe that bolts to the exhaust port - has to come from somewhere.

Tomorrow I will put the engine on an engine stand and pull the head.

I put the the scope down No2 cylinder and all looked fine with only the honing cross hatching visible but I will pull its head once I have sorted No1 cylinder.

Garry

Garry

[AustHaflinger]

After a bit of mucking around I managed to get the piston out.

There seems to be a few things going on .

1. There is light erosion on the exhaust side of the piston top most likely the result of pre-ignition at some time.

2. It looks as if the valves have impacted the top of the piston bit seems not to have damaged the valves but there are some intents on the top of the piston. No evidence on the exhaust valve but there is a bright impact spot inlet valve - indents obvious on the piston. This may have actually occurred previous with the tappets turned up tight that were not allowing the valves to close. Unfortunately I don't know what piston was like at the start - looks like a flat dome with indents for both valves.



Inlet side


Exhaust side


The valves - see the bright spot on the inlet valve that batches the damage on the top of the piston. Nothing on the exhaust valve (covered up by carbon is my guess) which makes me think this is from when the tappets were too tight.


3. The cause of my current issue - is looks like the extended piston skirt on the inlet side has somehow impacted with the conrod near the bigend and broken and cracked the lower half of the piston.


Where it probably impacted the conrod - you can just see a mark on the conrod in the centre of the pic.


The bore is undamaged though right at the top there is some erosion similar to the the top of the piston most likely cause by pre ignition. Is perfectly serviceable.

What does have me confused is why there is no compression on this cylinder even with the damage to the piston the top of the piston is basically intact and even if the rings are damaged (which they do not appear to be) there should be at least some compression.

The oil is all good, no metal at all, the broken chunky bits from the piston have been recovered and did not go through anything and there are no small bits in the engine. I will wash out the bottom end with some like oil to ensure anything that might still be there is removed. I have not pulled the second piston - while there is nothing wrong with its operation and it has full compression I guess I need to pull it to check whether the valves have kissed the piston and do whatever is required to ensure what happened to No1 piston does not happen to it.

My guess is that whoever built this engine has made some tolerances too close. Valves to piston and piston skirt to conrod. The big end of the conrod looks as if it has been ground down (the shiny bit in the pic above) to give clearance to the piston skirt. I cannot work out what pistons are actually in it - all 87mm VW pistons I have searched have all been flattops so tomorrow I will go to a VW specialist to discuss. I will also take the barrel to my engine guy for a rehone but if it needs more that will mean the other barrel will also have to go in. I will also discuss if I am able to take a bit off the piston skirts to give a bit more clearance.

So there it is.

Garry

[heinkeljb]

My next guess is bent valve(s)!

If there are any sort of marks on either valve or piston that appear to be impact then the most likely outcome is a bent valve stem. Definitely take them all out and get them checked for damage / straightness - even a slight bend will mean worn valve guides. burning oil etc.

It's sounding like an expensive engine rebuild is on the way..... Hard luck Gary.

John

[AustHaflinger]

I agree - they have to be checked and if that is the case then the other head will also have to be checked.

Cheers

Garry

[AustHaflinger]

As I am mid way rebuilding a Rover 4.6 V8 I have an on going dealings with a local engine builder. He said that the engine has been running for a time with advanced timing - new that fixed previously and that while there may have been inlet valve impact this time around it looks like it has been happening for a little while - the exhaust has previously impacted but with its current carbon build up it hasn't happened recently - this would tie in with previous tight tappets and it now being OK.

He said the the cylinder has been over heated as it shows it in the bore and on the sides of the piston. There is evidence of seizing on the piston and bore when the piston was at TDC. He suspects the piston seized in one area and the piston at the bottom slammed into the side of the bore either breaking it then or causing a crack which subsequently broke the bottom of the piston.

He also spotted that the head is also cracked where it fits over the barrel and is warped. The barrel and piston is Mahle but no one has ever seen a piston like mine as most are flat tops. So if you recognise this 87mm Mahle piston please let me know.



I have two spare old heads so I will get these refurbished though getting sodium filled valves will be an issue here.

PS - I have just pulled the head and barrel on No2 cylinder and it is as new - no issues - nothing at all. Where force had to be used to do No 1 cylinder, No 2 just came straight off no issues. So this would also point to earlier issues with No1 that all came to together the other day resulting in failure if this was not the case No2 cylinder should also have had some problems.

Cheers

Garry

[AustHaflinger]

CAUTION - VERY LONG POST

I have been spending a bit of time with my engine builder and doing some "forensic" analysis of the damage and why it has happened. The undamaged No2 cylinder shows that the mods done to the engine were sound. These were, the installation of a 87mm big bore VW kit for the aircraft version of the VW beetle engine (standard Haffy is 80mm bore). The evidence now shows the piston top was turned down to provide the raised section in the centre of the piston and the insets for the valve were milled in. This provides increased compression ratio and raised the capacity of the engine to 762cc. The exhaust valve is standard but the inlet valve is increased to 40mm. The only down side of the modification is that the inside rim of the head has been taken out to fit the top of the 87mm barrel and this takes a bit too much metal out where the pushrod tubes are as that is where the head is thinnest.

In my engine's case No2 cylinder has worked well but not so with No1. Firstly it seems that when machining the barrel to fit the piston stroke they took a thousandth of an inch too much off and the top of the piston has been touching the bottom of the head - in the pics of the head and top of the piston you can see the erosion around the edge of the piston and head next to the exhaust. Also it would seem the head did not go on straight as it was only this side that was touching. It would also seem at this very early time after the build, and because of the tight tolerance the valves have also touched the piston. As you can see in the pic above there are dents in the piston but the valves are not bent (checked today). This indicates the valve and the piston were going in the same direction (ie valve closing and piston going up) and the valve just got a hurry up from the piston and from then on the extra dents in the piston top have provided the clearance needed for the valves.

Since I have owned the Haffie compression on this cylinder has always been a bit down and this was subsequently shown to be because the tappets were tight and inspection today showed that while the exhaust valve is OK the seat was a bit burnt not allowing the valve to close correctly. This is most because of the highly advanced ignition found six weeks ago - not sure why No2 exhaust didn't suffer the same. So it would seem that No1 cylinder did not have the tolerances required but while the engine was under performing it held together.

6 weeks ago the tuning of the engine is set up, the ignition set right to develop max power and the tappets set correctly - power is now much greater and what is was designed for - No2 cylinder responded but it was built with the right tolerances. No1 cylinder was now also developing more power with its associated heat. However it does not spare capacity and as the piston is still touching the head and other bits are not working to full capacity the cylinder overheats at the very top and the piston seizes on the the exhaust side at TDC where is also touches the head. There is a slight turning moment in the piston as it is momentarily stuck to the bore next to the exhaust and this cracks off the piston skirt extension on the opposite side of the piston and causes the piston to crack - the piston is 86.5mm in diameter and the bore is 87mm so there is .5mm gap which is huge at the speeds the piston goes - there is a graze mark on the bore.

Without actually being inside the engine when this happened it is difficult to know what exactly happened but the above does seem to fit with the damage.

WHERE TO FROM HERE

The bottom end is all OK. No 2 Cylinder is all OK.

No2 Piston


Any work done on No1 cylinder will have to be done on No2 so that equilibrium exists in the engine.

We are getting a new 87mm big bore kit and the pistons will be turned down to replicate the current pistons. To get around the issues of taking too much metal out of the heads to fit the barrels, the tops of the barrels will be turned down - they are strong enough but fit inside the head any way so are reinforced by the head. The barrels will be made 1/1000 inch longer than is needed to ensure the pistons do not touch the heads. New heads are needed as my old ones where skimmed to take the barrels and I have these from an old engine carcass in my spares. The older haffie heads are a slightly different casting that the later ones. The new valve seats for the 40mm valve have already been cut. As the piston/barrel kits only come in 4 piston lots I will get the the spare two pistons and barrels also modified so I have spares in the future.

The lot will be dry fitted and blued to ensure clearances are there but we should put the engine together properly and all blued and run it to operating temp and then pull it down but that will be difficult. As long as we build to current No2 specs and add 1/1000th inch to the length of the barrels all should be OK.

So there it is - not as expensive as it sounds, though I don't have the bill yet - the extra cost is in having to buy four piston/barrel sets rather than just two.

Garry

[heinkeljb]

Gary,

What work has to be done on the crank case to take the new barrels? Does any work have to be done to the con rods / little ends? Could you get the second pair of barrels and pistons done and sell them to help offset the cost of your set? Would mean having to pass on the required information of the work need on the cylinder heads, but that should be to much of a problem.

Maybe you could sell the spare barrels and pistons to the VW crowd? Possibly some one might need only two barrels and piston for their build / repair - there are people like that out there!

John

[Westernair]

For VW barrels to fit you have to open up the case with a fly cutter.
If you get early 40Hp VW parts, the Steyr connecting rods will fit them with out haveing to open up and replace the the piston connecting pins.

[AustHaflinger]

I am not sure what was done to the crankcase to fit the barrels - they are supposed to be slip in so in theory nothing should have had to be done but I don't know. Remembering these barrels are designed to go into a 1300cc VW engine that has a similar bore to the Haflinger.

No changes to the conrods were made at the little end but on the big end, the sharp corners on the reinforcing ribs were rounded.

The main changes were made at the head end where the heads were taken out to fit over the top of the barrels. In my engine builder view this was the wrong thing to do as there is not a lot of metal in the heads around the pushrod tube - as you can see a crack has developed in this spot on the damaged cylinder - there is no crack in the other head but you can see where it is a bit thin. The tops of the new barrels will be turned down to fit inside the new heads.

[Westernair]

The base of a 87mm vw barrel is larger than a huffy barrel and has to be opened up to fit.
Just like the heads.

[AustHaflinger]

Just an update but not much happening.

The engine builder had to buy four barrels and pistons as they are only sold in sets of four. The pistons are being machined to match the old ones and all four pistons and barrels will be done so I will have two new spares, the old barrels and the old good piston. Plus the old heads.

I dropped the crankcase around 6 weeks ago so that the barrels and pistons could be fitted and clearances checked. I went around to check a couple of weeks ago to check but nothing has progressed - the crankcase is still where I left it .

I made the mistake of telling the builder the car was a hobby car so not urgent and along comes some Merc V6 with a blown engine so that engine has taken priority. I will go around and chase them up this week.

The reason for the failure goes back to when the engine was first built a couple of years back - the left barrel was machined a little too tight on tolerances and as a result the piston had been "kissing' the cylinder head and over time this took its toll on the piston which cracked. The valves hitting the piston early in its life did not help matters. With the right hand piston - tolerances were right and there were no issues of any problems at all - showing the basic idea of the mods were sound.

Now my engine is capable of exceeding redline in top gear so any mods need to account for this. This highlights the folly of changing Haffie engines for VWs and Subarus etc as these engines do not rev any higher - if you want more power you need to either put an engine in that will rev much higher and maintain those revs for extended periods or change the gearing in the haffie - I guess changing 4th and 5th gears is not really an option (though I would like to get an old gearbox and see) so the only options are higher speed hub gears and larger wheels and tyres - I run 185R14 wheels and tyres which are fine on the road but make the C of G offroad a bit high and the track is a bit narrow for the lift created by the larger diameter tyres. For offroad I am looking at putting on ATV tyres on my standard 12" rims.

Anyway - I am looking forward to getting my engine back and on the road.

Oh - my engine has a No2 camshaft which is out of a very early engine not the later engine I have - any ideas why? and what are the characteristics of the different cam numbers.

Cheers

Garry

[AustHaflinger]

Got the engine back today - if I had a first born I would have to sell him/her into slavery . Certainly high speed hub gears, Mud tyres for my Range Rover, ATV tyres and 14" muddies for the Haffie are now off the list. Maybe I should sell a kidney.

On reassembling the engine the builders also found that the bush in the little end of No1 piston conrod was chewed out so the piston would have been flopping around like an untrained seal. All aspects of No2 cylinder was perfect so all issues just related to No1 cylinder.

So over the next few days the engine will go back in and then running in.

The builder who has a lot of experience with VWs said he often sees similar damage to my engine when the head nuts have loosened - and certainly the bottom two head nuts on my No1 cylinder were barely more than finger tight and the barrel was not quite aligned. He suggested that when the tappets are routinely adjusted (and these must be done regularly) that the head nuts are retorqued.

I will let you know how things go.

Garry