SOLVED: Low compression. Car coming out of storage

Just bought a low mileage 1979 GT4 which had spent most of the last 2.5 years in storage. Started weekly, but no significant mileage put on it. PPI (as we all know, but some still ignore) was an absolute must.

Initial compression test showed 6 of 8 cylinders at 140 - 145, with two at 130. Leakdown on one of the cylinders was only -5% not indicating a problem. The Ferrari expert (Tim Stanford in Ft Lauderdale....great guy by the way) was cautiously concerned about the low compression, but thought it might shake out after driving a bit. He kept my "Ferrari fever" at bay, and we asked the owner to take the following actions over the next week:

> MARVEL Mystery Oil (very old product, now in the Turtle Wax product line) added to both the gas, and the crankcase oil.
> Drive the car at least 300 - 400 miles

The car was driven 500 miles in about 3 trips, then we retested the compression and voila ! 175 across the board, and no leakdown concerns at all. PPI passed with flying colors so it looks like the mystery is solved with Marvel Mystery Oil. (it at least did the trick in this instance).

THANKS to Tim at Tim Stanford Foreign Cars....if it had not been for his persistence in working with me, I would have passed up one of the nicest GT4's I've seen.

John Feeney
Boulder, CO

 

thanks for sharing

it's good to know that low compression might not always indicate a serious problem

 

I've heard about the Marvel Mystery Oil stuff before...here on FChat, actually. I'd be curious to hear in what "doses" did you (or Tim, I suppose) add the MMO to the gas and crankcase?

 

Would you still add the oil to the gas with fuel injection?

 

The previous owner added the recommended mixture from the manufacturer, I believe (but not 100% certain). Probably worked out to be about a container per tank of gas, and a single (quart) container to the crankcase.

However, I am not certain.

As for fuel injection, again, not sure. This is all very new to me. Perhaps others on the chat will respond with their more technical advise. I am just happy that it worked.
John

 

I'm wandering if you are giving too much credit to the Mystery Oil...I'd bet running it the 500 miles did more to bring the compression back to normal. However I'm glad it was rescued.

 

I have had good results with the Marvel as well. JJ

 

I dont know whats in it, and I dont know anyone else who knows, but to me it smells like the kind of oil you use on a trumpet, or any type of musical horn instrument. Although thats maybe just some smell I remember.

MMO is very well known in the piston engine aircraft community. The old timers had been using it for decades, actually breaking the law, while the FAA inspectors generally turned a blind eye. A couple years ago the FAA finally approved it, though its possible it was only a sleight of hand to the old timers so they wouldnt ever get in trouble. At any rate, its the ONLY oil additive ever sanctioned by the FAA. There isnt anything else you could legally add to your oil.

I spent some time working with Bob Leader, the only aircraft engine rebuilder in my state. He has been overhauling aircraft engines since the 1940's and he swore by the stuff. He always said not to use it in new engines, or the rings wont seat. From what I know its very highly detergent, protects against corrosion, and is very lubricating. There were guys who had many thousands of hours on aircraft engines from the 1960's that had never been apart, and they really liked that stuff.

What benefit it may have played in this situation is unknown, but many people I have come accross in the last 30 odd years have recommended it to free sticky rings in engines that had lost compression. My first 308 was actually the first engine I had taken apart after having about a quart and a half of MMO in it. Although I couldnt have known what it was like before hand, all the internal parts were extremely slippery and very clean. It does not wash off very readily in mineral spirits either. YMMV.