Wrong way pistons

[keelcooler]

Hi Don,
Had to pull the engine in order to repair broken scupper drain fittings and hoses. My 1963 A4 ran well however cabin fumes were a big problem. With the motor in my car port I cleaned out the cooling system (raw water) and removed rust from block surfaces. Green head gaskets and small head leak aft prompted me to pull the head to install Victor gaskets.Compression was excellent ,120 PSI across the board and I only anticipated clean up.
I found piston top arrows pointing forward towards flywheel not aft.This may explain my blow by problem.I just completed interior refinishing,had new cushions made and no longer want the cabin to smell like Jiffy Lube! I poured some MMO in the combustion chambers and within an hour it all leaked down past the rings.I had not noticed an oil consumption problem, however I do oil changes twice a year and may not have observed a decline.I so do want to make this worthy little engine "right"and prevent overnight cabin crew mutinies.I have purchased the Indigo PVC device, however am afraid the unit may not fully be able to overcome this extent of blow by.
Any advice you could render will be greatly appreciated.

Thanks,
John

[Don Moyer]

John,

I can identify with your daunting decision to reinstall the engine and hope for the best regarding the Indigo kit (which is a very effective kit by the way) versus disassembling the engine for some level of rebuilding.

I don't see the arrow on top of the pistons as a significant factor in your decision. The orientation of the arrow on top of the piston is to ensure that the expansion slot on each piston is away from the "loaded" side of the piston; i.e., so that the unslotted side will absorb the load. The loaded side of the piston is the side against which it is pushed as the expansion of combustion is forcing the piston down through the bore on each power stroke.

While the general rule to keep the solid side of the piston facing the load is certainly understandable in higher powered engines, we've seen many cases where the pistons were reversed during a previous overhaul, and to our knowledge, we've seen no evidence that pistons suffer dramatically in our application when reversed, I suppose due to the low compression ratio in the Atomic 4 and the fact that we usually use them at no more than half of their rated HP output.

With your great compression values and otherwise good performance (no oil consumption, good oil pressure, etc.), I'd be inclined to rely on the Indigo kit to clear up your blowby. In addition, there are other things you can do to minimize blow by which I'll attach for your consideration.

As a final thought on cabin fumes, there are quite a few cases where an exhaust leak behind the engine can create high levels of fumes. Blowby would usually be seen as coming out of the oil fill tube over the flywheel housing.

Don

[keelcooler]

Don,

Thanks for your help.Your vote of confidence is reassuring and a big relief. Major surgery to the motor and my wallet would have been a ball buster. I have enjoyed fixing up this old Triton we picked for a grand.A working A4 with good compression sealed the deal. Many hours of quality family time has been spent aboard.Thanks to Moyer Marine I have been able to keep the engine reliable.It has not yet failed us,except when I ran out of gas (operator error).













You are correct in that most of the blow by appears to be emitting from the fly wheel area. Last year I installed a hose from the valve cover to the blower hose thinking this may help. It did not. Lets hope Tom's smart PVC device cleans up this old smoker. I will keep you posted.

Thanks,

John






















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