Packard Forum Index » Post-War (1946-54)

Glad that it was nothing obvious with the valve train. I agree the next step should be a compression test. Does your car have an oil pressure gauge that is reliable and if so, do you recall what it showed, hot idle and running at road speed? If the compression test shows everything normal, you might want to drop the oil pan and check the rod bearing clearances.

Compression test is needed...
I'm with OD .Whats the oil pressure ? Might be the video quality,but I don't see alot of oil at the lifters.
RT

If your car has more than 80,00 miles or so and has never had new piston rings I would vote for the broken-piston-ring-through-the-top-of-the piston theory. Sadly, I have seen it very many times on this engine. A piece of the ring
is now holding your exhaust valve slightly open, thus the .030 ventil spiel. It could be a piece of carbon, but normally that would pound out after some miles. Es tut mir schrecklich leid.

For a photo, check out my old post searching: ring-job

G'day all, I would be more inclined to believe that you have a sticky valve or valves. I have encountered these on some of my Packards over the years and they can be quite common on the 282 motors. I would discount broken rings/ piston problems unless you are suddenly blowing lots of smoke or have developed blow by symptoms in the sump. I would recommend using a strong light and inspecting the exhaust valve stems of cyls 5 to 8, with the valves closed, for evidence of galling on the stem or carbon. A compression test would be handy but probably inconclusive if the engine hasn't had a valve grind in the previous few thousand miles. Good luck .. Peter

OK, oil gauge and compression tester are on the way. I was able to determine cylinders 7 and 8 are bad. #7 spark plug was black and seemed a little oil fouled, and #8 was clean, but not combusting. I was able to pull plug wires 7 and 8 at idle and noticed no change in idle, so they're the bad ones.
The oil dummy light goes off right after starting the car, so I imagine the oil pressure is OK, but also noticed my oil filter is plumbed in 'full flow' and not bypass mode which has me thinking the oil filter could have gotten plugged and starved oil flow? Is the return into the block after the filter/gauge only feeding the valve train, or rods and mains also?
I will test compression and oil pressure when I get the tools, and plan to remove the rear valve cover and inspect the valve stems next before I remove the cyl head.
The engine doesn't blow smoke, but the engine was replaced about 15 years ago from a well running doner car. I don't know how many miles are on it.

Are the valve spring compressor tools available someplace? I have a contact coming over from the US in 2 weeks, so will ask him to put some tools and parts in his luggage
Thanks for the ideas guys. Mike

edit:
When I shut the car off, the oil filler vent smokes a little bit. Is this bad blowby, or normal since there is no PCV?

A few wisps of oil fumes coming from the filler tube whenthe car is not in motion is perfectly normal; profuse fuming would indicate blow-by. The (lower) crankcase vent tube is cut on a bias and creates a mild suction from the air passing by it as the car moves, this draws the fumes from the crankcase and as soon as the car is stationary, there is no longer any draft on the tube.

I don't know if L-head engine valve spring compressors are still in manufacture, but they are certainly plentiful. Find an old-time mechanic and I'd bet he has at least two in his tool box. Every flea market I go to I seem to see a dozen for $2 or $3 buck each. YOu might be able to use an OHV compressor but I suspect it would require removal of the manifold, at the least, and be awkward to use. If you absolutely can't find one locally, PM me and we can make some arrangement for you to borrow mine.

If it weren't for that one valve that had 0.030 inch tappet clearance, I'd think you might just have a blown headgasket, but that valve clearance would seem to indicate, as Ross suggested, something has come loose and become lodged under the valve head. Perhaps you have 2 issues?

A local "oldtimer" garage or car owner should have the valve spring compressor. I am sure many flathead engines were used in Germany in trucks until the fifties or sixties. I believe Mercedes made a flathead 170 model car until the early fifties.

Well, Oil pressure is 35 psi at idle and 40 psi at 1000 rpm, so that looks good.
I ran a compression test with a 'somewhat warmed up' motor, all spark plugs removed and throttle blocked open... Here's the Good, Bad and ugly...
Cyl: Psi
1: 120
2: 100
3: 100
4: 100
5: 120
6: 120
7: 120
8: 0 Nichts, n?ll Toten Hose! (Dead pants)
I guess we can rule out the blown headgasket between cyls 7-8.
I can try putting oil in the three cyls that read 100psi and see if the rings on those cyls are just hanging on, which would suggest a ring job is needed, and that a ring in cyl 8 is broke.
I'll also double check the compression on cyl 8. I can't believe that 0 anymore... Strange that cyl 7 is not running if it has compression. Spark is there at the wire end...Champion J11C are the plugs that only have about 400 miles on them... suspecting perhaps a bad plug now with cyl 7, but 8 must be some mechanical problem....Ach mensch.

Don't tear into it too deep yet. I agree with Peter Packard. The probelm is most likely the sticky #8 exh. valve hanging open causing the .030 clearence.

Try removeing the spark plug and snake oil the valve stem when valve is fully open. JUDICOUSLY use a small brass drift to see if u can LIGHTLY tap the valve closed when crank is correctly positioned. Usualy, on MOST Flat head engines the exh valve head is very near and under the sparking plug hole. I don't know if that is the case for Packard or not but it's a most common design.

Bottom line, i'd attempt to free up/UNstick the valve before any major disassembly.

The sticking exh. valve problem is becomming rather wide spreead among a variety of engines over the last 2 years.

I didn't look real close but i believe i saw one of the flat head spring compressors NEW IN PACKAGE by Lisle today over at the auto parts store. It caught my eye from some 5 or 6 feet away cause i was suprised to see it.