I give up! - advice on who can help - oil everywhere post rebuild

Full set as the others may also be damaged and you can't buy single AA pistons anyway.
But...where did the burnt piston debris go? What is the point? Just to get it running albeit possibly contaminated with debris that could have already scored and embedded into the bearings?
What it needs...is starting the build again, cleaning everything first, with new barrels and pistons + care to get the CR right, set the timing right and not jet the carbs lean.

 

Exactly, you don't burn a piston with overfueling. You'd really want the piston out and in your hand before you can diagnose the failure mechanism, but the odds are in favour of overheating through a lean mixture or air leak giving a lean mixture in that cylinder.

 

Are Southwest Splitz going to give a refund for the breather box that wasn’t required?

Unfortunately, there seems to be several specialists giving you poor advice. You don’t need a maxi oil pump, or so-called high-pressure oil pressure relief valve springs and you don’t really need an oil cooler either. But that’s not the cause of the problem.

40 IDF carbs are too big for the engine capacity and the smallest available venturies should be fitted, but that’s not the cause of the problem either. Carbs don’t pressurise a crankcase, the engine sucks through the carbs. The carbs need to be checked before use and the float height adjusted. And the fuel pressure must not be too high.

AA pistons are usually okay but not always, AA pistons rings don’t have a great reputation and many engine builders won’t us them. Pistons and rings need to be carefully checked before use and the ring gaps should be measured – were they?

Trying to fix basic problems with unnecessary aftermarket parts will just keep costing money.

Fuel doesn’t sit in the barrels and burn but liquid doesn’t compress and if the engine is started when the barrel is half of fuel the pressure has to go somewhere – through the piston for instance. The con rods and crankshaft can be bent too.

Changing just one piston is bad advice, the engine needs to be properly cleaned and rebuilt with all the parts checked and clearances measured.

 

Overfuelling would have resulted more in cool running - this is overheating from lack of oil more recently - a few minutes running without oil circulation when the filter blew off for instance.

You cant burn more fuel than you have air flow for, so all you do with the extra petrol is cool down the burn with evaporating the petrol.

Burnt out holes are oxygen rich fuel lean , so the whole overfuelling story is one of several problems, like it was tuned lean or had an air leak or vacuum hose fall off, then the fuel pressure or just leaving it with a full tank got the fuel into the oil.
Lean running could be the inability to control the mixture with over-large carburettor venturis, without a decent vacuum signal from revving the nuts off it, your mixture is very vulnerable to changing massively with a slight change in the fuel level in the float chamber.

Petrol in the oil would have most likely led to siezing bearings, not a melted hole in the piston. Hydraulic locking usually either bends con-rods or more likely just stops it dead cranking.

However the good part of the story will be that if the engine filled with metal with a full flow filtration system, all you need to do is clean out the case, oil pump and the filter head, and replace the hose feeding the filter head. Fragments will not have reached into the oil galleries, just inside the case and up to the filter.

And I dont consider the full flow filtration system with a cooler and the maxi3 pump excessive - its only the same size as a stock pump.. I had to do it because my previous engines would run hot. Once I got a Preservation Parts engine from JK, it ran cooler - has EMPI cylinder heads that are better made than late VW ones, and AA pistons and cylinders on an Autolinea case. So now I barely need the cooler but before it was a fight to stay below 122C oil temperature.

After my home built engine broke big-time (after 18000 miles), there were also metal pieces of the piston that had bounced around into the other cylinder same side, and some dust even in the opposite cylinders.

I am still running an oil pump which has little dents in the body but not the gears, where the shrapnel went through it. And I threw away the pipe to the oil filter. But I simply swapped over the oil pump with the CB Maxi 3 feeding my full flow system as soon as my Preservation Parts engine had done its 500 mile run -in.

At around this point, either learn your lessons and rebuild the engine yourself using your greater experience, or shell out on a new-parts engine and just get it on the road.

And maybe even fit a 34PICT-3 carburettor as that will actually match the engine to start with, then grow away from it by changing things a bit at a time
Or start with Weber 32s .

 

Chicken or egg? I believe this hole has been there undiagnosed a while, so for every gallon of fuel he went through, a fair bit went through the hole as evidenced by the case pressure.

 

Winner, winner, chicken dinner!

 

I guess we dont know for sure whether the piston melted, was duff from the start or damaged somehow when i put it together. I was pretty careful and no way was one dropped but i guess its possible something found its way in there but unlikely.

More wil be clear when the engines out but maybe you guys know what to look for and can say whether the pic i uploaded looks like a melt.

I always thought you had to be lean to run hot and wondered what the overfuelling would do but never thought melting a piston was it as mike said, but its hard to argue when i'm new to this level of problem.

I think the carbs were overjetted as the guy who was the supposed tuning expert said they were on the large size which helped cooling.

I also cant think it was running lean with a leak as i was careful to make sure the carbs were on properly out of the van as its a mare to get at the nuts in place.

I now tend to think ftom what you all say that the piston has just broken or something was in there to do the damage - is that what the damage to it looks like?

Anyhow im between the devil and the deep blue as the vans stuck in exeter and i have no means of getting it back so my easiest route is maybe to take the gamble on the garage to get it going and see how it pans out.

 

Chicken din dins indeed to devon123

 

And wise words from mike and all i think.

Thanks all.

 

And does anyone live near Dartington in Devon who fancies lending me a shoulder to cry on and maybe some looking over and help on the engine if i eventually get it back.?!

 

.

 

Don't do that. If matey had done a compression test a week ago, at least you'd have known what the problem was and wouldn't have had all that bling put on your engine. Better to hire a transporter (not that expensive), get it home and do it yourself.You've put an engine together yourself, and it worked - sort of. You can do it again

Wipe the breather box and stuff off, and ask for a refund. You weren't paying for guesswork.

Been having a mull (I do like a good mull). Why is it just one cylinder? The burning fuel thing just doesn't make sense. Pure uncompressed fuel doesn't burn hot. I reckon you've had a "hydraulic lock". The engine's stopped with one inlet valve open, and an overflowing carb filled one combustion chamber with fuel. First time you cranked the engine, the piston hit the incompressible liquid and smashed itself. Would explain the neat split/chunk. It's the reason they turn radial aircraft engines over on the prop before cranking, or there'd be conrods coming through the case.

As above, you won't know until you've got the piston in your hand. If it is just big broken bits, should be able to fish them out of the case. They won't have gone anywhere - the oil strainer would've caught them. @77 Westy will scold us, but I can't see why you couldn't just replace one piston . Worth checking the conrod on that cylinder as well.

Good luck!

 

Going on previous experience a hydaulic lock will do exactly that - lock the engine when you try to start it .
I doubt that caused the damage but i`m with all the others - get it back and DIY . You won`t be able to diagnose the issue until you have the piston(?) in your sweaty mitt . It`ll be cheaper in the long run to pay for a lowloader back to yours rather than pay someone to remove , strip and refit the engine .

 

Nope !

 

I see your reasoning on the lock and to my limited experience eye the piston looks like something hit it or it cracked as you say rather than a melt.

It does make lots of sense.

My problem is also that i borrowed lots of gear from a mate to do the build and he is miles away. For me to buy the neccesaries, spare the time, and do it single handed is a prob at the moment. I also like the guy at s w splitz and would lkke to give him the benefit of the doubt. I will have a frank chat with him and seek some assurances on the way he will do things before i make a final decision.

 

You may be right - just a thought! Does look like the piston’s smashed, rather than burned.

 

Reading this thread I get the impression that you don’t want to get that involved in sorting it and that you just want to get using it.

I wonder if you might be better of just getting a recon exchange engine and fitting it or get them to along with some better suited carbs.

Apart the holed piston if you’re have been running it with fuel in the oil the main bearings could be shot, they might get it running by changing the piston but for how long ?

 

I think you found me out there Matty!
Its a case of weighing up the options. It wasnt driven with fuel in the oil more than a mile and in all its done no more than 10 miles or so since the build and has had three lots of oil in it over that time. I am hoping and weighing up the risks, costs and time which i dont have. Its a tough conundrum.

I guess if i get it back and she goes pop its lesson learnt the hard way. Could be they wont want to do the work on it too as i have already said i dont think i should be paying for the breather stuff ...