THE PORTAL HUB - Pinzgauers, Haflingers, Volvo 303s and more!

Today I was driving along at about 65kph in the Haffie and 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.

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

Cheers

Garry

I would start, as you said, with the winkelhebel, rods, rockers and valves.
Sucks as you just got it running well

Thanks - while I was running below redline when this incident happened I know the engine since I got it sorted will run to about 5500rpm in 5th gear though I try not to go above 4500rpm and tend to stay around 4000rpm on the highway. I suspect the previous owner in putting a big bore kit has not taken the opportunity to improve other aspects of the engine to cope with the rev increases. The valve train as I understand it is marginal even with the standard engine. So if this current issue does prove to be major (as in engine pull down) I will research ways to improve all aspects of the engine to cope with higher revs. However at this stage I suspect valve train.

If I can find a set of good priced hi speed hub gears I will put them in as it will slow engine speed.

Oh - it wanted to start this morning with plenty of weak fires but only enough for a couple of revs under its own power - a sign of low compression.

Cheers

While not cheap Leo here in the states builds amazing heads for these little motors and can also do a much needed oiling system upgrade to the motor to run the higher revs
An email to him and he may share some of his wisdom on this. He mainly builds pinch 500 race motors that can turn 10k to 12k rpms on the track.
Pm me if you need his info.

Thanks Shawn - I might contact him if the answer is not obvious.

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 .

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 adjusted the timing to the 7mm before TDC and idle was a bit smoother. The engine now starts first go.

I will do the compression test and remove the rocker covers. 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.

EDIT: 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

Cheers

Garry

No you can take them off in the truck but like a VW it is easer to pull the motor.
Remember to pull the push rods before you try to separate the head from the cylinder. In the truck it could be over looked. At the angle they sit you could damage something if you try.

You can take them off in the truck a bit harder but doable. On top of removing the cooling tin from the head and cylinder, make sure you pull the pushrods as unlike a VW they are angled and will keep the head from being able to separate.

Thanks Shawn - going to pull the engine - I also need to change whatever is the equivalent of the spigot bush and clutch withdrawal bearing as these rattle a bit and I have been waiting for an excuse to pull the engine to do these.

Cheers

Garry

Engine is out - took a bit longer than I would have expected.

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.

Do you have stock ignition? It sounds like a condenser failure to me.

pinzinator wrote:Do you have stock ignition? It sounds like a condenser failure to me.

Yes I have standard ignition. Other than being too advanced and causing pre-ignition which it wasn't on both counts, I am not sure I follow with respect to condenser failure - when I removed them yesterday the spark plugs had plenty of spark.

Cheers

Garry

You will get a spark under test conditions, like low RPM. It's when things crank up that the internal leak in the condenser starts to short out badly. I have had this happen on my Haffy, I worked for hours troubleshooting everything except an $8 part, which was basically new. I have Pertronix now, so that issue won't come up again. That's my opinion from the other side of the planet.

pinzinator wrote:Do you have stock ignition? It sounds like a condenser failure to me.

With 10 psi on 1 cylinder and 110 psi on the second cylinder I suspect I'd be leaning towards the mechanical failure theory. Mind you whilst reassembling everything checking the ignition system for health wouldn't hurt.

Hope all goes well.

I don't know how I missed that part but it makes sense that the issue is mechanical.

I suspect the rings have seized in cylinder No 1. You might be able to free them with out breaking them if you are very careful about cleaning the edges of the slots with a sharp Stanley knife type blade before you try moving them.

I have made a few motorcycle two stroke engine run again after rings seizing and releasing them. Then rubbing down any aluminium high spots on both piston and bore with very fine emery cloth.

The "money's no object" approach would be to replace the pistons / rings and have the bores honed if there is no scoring, or a rebore if the bores are scratched.

John