84 b2000 knocking??

[acekicker]

Just started today, valves are tight, but the first cylinder doesn't seem to be working. yank the plug wire and nothing changes. Doesn't knock when idling, only when there is a load on the motor ( in gear and moving) Is a piston bad or cracked,

The cylinder is firing and has compression.

Any help would be greatly appreciated.

[BadDog2000]

You didn't mention how many miles are on the engine but I have an idea what to check.
(1) Since you say it has compression (considering it is close to the other cylinders) Piston slap might be ruled out.
(2) Could be a wrist pin wearing on the piston or rod.
(3) Check the Oil pressure. Has it remained the same during all of this or has it lost some pressure?

I think that you may have a rod bearing going out on you. At idle, there is not as much load on the rod,crank,piston, etc. But under load, The piston is trying to keep up the rotation of the crank rpm's and torque. At the same time it is also trying to rotate the crank. I would talk to a mechanic and get His/Her opinion. I could be completely off base but it might give you an idea of where to start. Hope this helps. I am no mechanic but I did stay at a Holiday Inn Express last night!
It definately sounds like it needs some attention!



Good Luck, Keith

[mazda13]

The first time my 83 started this it had cracked the head at the back of #1 the next time (on second engine) my 3 year old had sprayed water in the intake and when I drove around the block it started knocking. I got lucky this time and it just blew out the head gasket. replaced gasket and but 10000 miles on it scince with no problems