My son's 85' 240 started rapping on his way home for X-mas break. We towed it home and proceeded with our DYI diagnosis. The engine started effortlessly. Running very roughing, missing and a chatter on the upper end.

The oil was not contaminated: we borrowed a compression tester and found 180 psi in 3 cylinders and a "0 psi" in the last. Our next step is to remove valve cover to look further. What might we expect to find and could father and son make repairs or is that beyond our backyard skills.

Broken valve spring? If so, expect to yank the head and replace the valve. Of course, if you're extremely lucky, the valve did not contact the piston, so may not be bent. Then you might be able to install a new spring without pulling the head (a real Christmas present!).

But if you determine that the valve is bent, it might be better to look for a good used head, have it resurfaced, and toss it on. You won't need to screw around with valve adjustments.

If the gods are really against you, the piston might be holed — then you should look for a motor or car. (But I'd guess this is not the case.)

If the '85 is a turbo, then it's a B21FT motor. Finding a good used head will be more difficult (though I know a few hanging around). If it's the N/A engine, then it's the B230F engine.

Don Foster (near Cape Cod, MA)

Merry Christmas....defrosted the hands after removing valve cover. really impressed with the basic brick engine. 250K + miles and the cam looks like it just came out of the box. wasn't aware that these babies had OHC.

Oil was thick enough (17') to start her up and observe. First lifter to fire wall chattering somewhat. not sure how to remove cam and check spring.. will locate schematic Tues. and go from there.. any advise? Thanking you ahead of time.

(ART-on Buzzards Bay)

Art --

"...on Buzzards Bay..."

Be more specific, please? Near New Bedford?

"...lifter...chattering somewhat..."

This might be good news. If the spring is partially broken, it will remain open, hence no compression or combustion from that cylinder. But if the spring's not too broken, the valve might be fully intact, unbent, and never in contact with the piston.

I believe you can do everything with the cam removed (easy to do when compared to yanking the head).

Don Foster (near Cape Cod, MA)