an oil pressure test ia a bmw will highlight this
2006-12-16 03:54:44 · 12 answers · asked by Anonymous in Cars & Transportation ➔ Maintenance & Repairs
A "mechanical" knock means a knocking sound related to an actual internal problem with the engine...bad rod, bearing, etc. and is usually the sign of an abused engine that's ready to self-destruct. A "spark knock", however, is related to the fuel delivery system and/or the engine timing...it's a "pinging" sound caused by bad or low octane gas, sometimes combined with improper engine timing...this is easily corrected by using higher octane gas, and/or making some minor changes to the timing and fuel delivery system. Hope this info helped.
2006-12-16 04:02:32 · answer #1 · answered by answerman63 5 · 3⤊ 0⤋
Usually either Tappits, Cam-imbalance, Big ends or Small ends. Tappits don't really matter they just make a noise, Cam-imbalance will require a new cam-shaft and tappits, slightly pricey but can be lived with. The big/small ends mean a new engine. BMW's don't tend to suffer from cam or tappit problems, but do have ring and big end problems, so on a BMW I'd go for Big ends.
to test for this, take it down a hill at approx 35MPH, put into second gear, let clutch out and don't touch accelerator. If you get a machine-gunning sound the engines had it. If it's fairly smooth it's probably tappits that normally only show themselves on tick-over properly. Cam-shaft is harder to determine but sounds a bit softer than big-ends on tick-over, and won't really notice on the over-run. Small ends only really let you know they are faulty by blowing up!! But can provide a mechanical knocking sound first if your VERY lucky.
2006-12-16 10:46:13 · answer #2 · answered by Bealzebub 4 · 0⤊ 0⤋
It means that the piston's in the engine are running up and down in a worn bore ( wear and tear ) you could try a re-bore so that over-sized pistons can be fitted also the main bearing's at the bottom of the connecting rod could be worn as well, you could have a reconditioned engine fitted, the second choice would be the best option. so long as the body of the car is in good condition, then it might be worth doing it, other wise say good bye to the car and look around for a replacement.
2006-12-16 04:13:55 · answer #3 · answered by ? 6 · 0⤊ 1⤋
A mechanical knock usually refers to either oil pump rod ,spindle bearings or lifters all these will make a knock .
I would guess that they were talking about the oil pump rod if they were testing the oil pressure . I can tell you a really easy redneck way to locate the noise on your motor if you want :)
2006-12-16 04:01:49 · answer #4 · answered by chris78corvette 2 · 0⤊ 0⤋
It usually means bad news your engine could be on it's way out. Get professional advice before getting rid of it before it costs you a fortune, unless you can find a good mechanic who does jobs on the side.
2006-12-16 06:06:32 · answer #5 · answered by alex winefly 4 · 1⤊ 0⤋
Its really called octane knock. The gas that is sold now is not leaded and is lower octane than when your car was made. You may be able to help it by lowering the timing mark on the distributor.
2016-05-22 23:24:19 · answer #6 · answered by ? 4 · 0⤊ 0⤋
Without seeing your car, a heavy knocking sound from any carfs engine especially if it is low down is usually big end failure. but as I dont se your car it could be anything.
2006-12-16 04:48:53 · answer #7 · answered by DIAMOND_GEEZER_56 4 · 1⤊ 0⤋
big ends are on the way out
time for the scrappy
2006-12-16 04:39:04 · answer #8 · answered by Anonymous · 1⤊ 0⤋
BIG ENDS going, new engine soon, do not go for a long drive, it will let you down.
2006-12-16 04:03:27 · answer #9 · answered by Anonymous · 2⤊ 1⤋
Get your wallet out
2006-12-16 05:08:17 · answer #10 · answered by Anonymous · 1⤊ 0⤋