Engine knocking, cluncking

[Techno Duck]

BTW, i should add the problem is compounded when running low on oil, basically what happens is the pickup becomes completley uncovered and sucks up air. The other issue is with heavy braking, all the oil moves to the front of the pan, also giving you the same issue. I think this is only a problem for cars running massive front tires (more traction before lockup).

That does not mean its okay to overfill the oil either. Running to much oil causes foaming (the crankshaft will be constantly agitating the oil in the sump). This will cause the same effect as sucking up air into the pickup.

There are a few things that can be done to prevent bearing failure, but nothing is a complete fix other than going with a dry sump system.

-baffled pan
-better windage tray design
-better / larger oil cooler
-choosing the correct weight oil for your application
-balancing flow through crank by cross drilling
-Accusump might buy you a few seconds to save your engine, but you need to be paying attention to your gauges!

Mind you most of this applies to cars that see the track, most typical daily driven cars dont need much more than normal oil changes. And as you start adding more grip to the car (IE suspension and tires), its time to really start looking at the oiling issues.

[nomadclimbing]

So, I replaced the lifters all eight and the compression is much better. Also replace the wires, cap and rotor and a couple of the injectors. Once I got it started she idle good but the knocking is still there. She idles pretty good and has no problems with acceleration. Oil pressure is still bouncing around so I have decided not to run it any more. Other than the loud knocking it actually runs pretty well now. I think I will replace the rod bearing in the near future to see if thats the problem. Thanks to all for you input.

[John_AZ]

Originally Posted by nomadclimbing

Hello All,
I just bought this 1984 944. I took it to a general mechanic, not a Porsche mechanic, and he said it was the push rods. Thanks Mark
http://www.nomadclimbing.com/ebayporsche/index.html

Quote Mark," How trivial is the timming belt tool if I just remove the cam housing? Thanks"
Quote Mark, "So, I replaced the lifters all eight and the compression is much better. Also replace the wires, cap and rotor and a couple of the injectors. Once I got it started she idle good but the knocking is still there. She idles pretty good and has no problems with acceleration. Oil pressure is still bouncing around so I have decided not to run it any more. Other than the loud knocking it actually runs pretty well now. I think I will replace the rod bearing in the near future to see if thats the problem. Thanks to all for you input."

This post started at 10:08 am yesterday and Mark picked up the parts and finished all the above work by 3:20 pm today. This is one speedy wrench with a just purchased 1984 944.

John_AZ

[bigyagi]

easy test for the "big end" aka rod bearings. pull your handbrake on real tightly, bring rpm's up to around 1500/2000rpm, hold steady, and with car in first gear, slowly let the clutch pedal out, and load up the engine. you will feel it strain, as it wants to move, but if the rod bearings are bad, you cannot miss the heavy knocking! not only will it be loud, but you will feel it too !
good luck !

[manbarepig]

that sounds almost exactly like my car did, the problem was a spun rod bearing, as a result, the piston was slapping the bottom of the cylinder head, good luck with whatever it is