GRiSO (Red Devil from Germany) with PVM Wheels

Stock size

You said it was a big bore motor?

Sorry, I thought he meant the PVM.

1380 ccm

So 1400 barrels and pistons or over-bored early 1200 barrels with something else. How'd I'd they tackle the crankcase pressurisation issues? Any idea?

yes, it is the 1380 ccm stock set from the 1400 MG.

How did it solve it for you?

Well I hope they modified the barrels and/or heads because the cooling circuit an are completely different between the 1200 and 1400. If they just put the stock 1200 heads on the 1400 barrels there's nowhere for the cooling oil to go and it will simply be being dumped back into the timing chest through the oil pressure relief valve and the loading on the pump gear will be frighteningly high! No cooling for the valves either!

As for the pressurisation problems? Mark has a larger separator/condensor system.

Our 1400's needed higher flow injectors too. It was either that or raise the pressure in the rail. Bigger injectors were easier.

Of course the oil circuit was modified. Radicalguzzi has certainly provided more than 50 engines with the BB.
There hasn't been a problem in the German forums yet.

Well good. I was just interested. There are a lot of pretty strange modifications out there, many of which are less than well thought out or executed.

Hey RedDevil, would you please post a pic of the rear of your sump, where the oil return line is?

Please ask Radicalguzzi.

Pete,
of course it's even better to do a mass balance to compensate for the increased piston weight. However, this costs at least 100%-200% Euros more. The engine then has to be completely removed, opened and everything put back. And the modification with the oil return works perfectly. There were no problems that I knew of, even with forced driving and long, fast stretches of motorway!
For my next project, I equalized the weight difference per piston to 13 grams. You don't notice anything anymore.

I can only praise RG's work (very good price/performance ratio) but it was at least unfortunate for Radicalguzzi to state that the horsepower was far too high (they have now revised it). In fact, it's around +/- 15 RWP over the stock roller engine and a very promising torque curve.

Quote :

Please ask Radicalguzzi.

No, I won't. It's not rocket science. Take a photo. Something like this:


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... sieht so ähnlich aus.

Thing is I'm not concerned about how the oil gets back to the sump, it's how it gets to, or doesn't get to the cooling circuit around the valve seats.

The thing is on the 1200 heads the oil flows through a number of drillings around the exhaust seats and then flows out through two drillings in the mating surface of the head at the front of the combustion chamber. These flow through slots in the gasket and galleries in the front of the barrel to a drain hole in the front and centre of the barrel that returns the cooling oil to the crankcase.

The 1400's system is completely different. The head casting has great voids in it very similar to the water galleries in a liquid cooled car cylinder head. They hold a lot more oil than the simple drillings used in the 1200 and the return path is completely different.

If you put a 1200 head on a 1400 barrel using a 1400 head gasket the two oil returns are completely blocked! That means that there is no flow of oil around the exhaust valves and no cooling! It also means that the oil that should be flowing through the cooler, the circuit and returning to the sump carrying heat can't! So it will just get dumped back into the timing chest through the cooling circuit oil pressure relief valve!

It may well be that Radicalguzzi has addressed this? There doesn't seem to be any mention of it though to customers who I would have thought would need to understand how the system works!

As it is I'm simply casually interested. I've built 1400's, I know how it can be done and I know what has to be done if you want the cooling system to work. It's not secret or magical. It's just plumbing! But you CAN'T just slap a pair of 1400 barrels onto a crankcase and stick 1200 single spark, big port heads on it and have the cooling system function and the knock on from that is if it isn't working it will produce a host of other problems down the line.

(Edit.) Just going back through some pics I got the exact return path wrong. There is a central drilling in the 1200 heads for oil return that is missing on the 1400 heads. It still leaves the fact that if you bolt 1200 heads onto 1400 barrels there is still no path for the cooling circuit to return.