After much work my 69 bug passed its blue slip today. thank god.
However the mechanic told me there was a lot of 'knocking at high revs' in the engine. When I told him I won't be hitting the highways a lot he
said that was OK, but....
Can someone explain the problem to me (ie what is knocking, etc?), what it means, and how does that reflect the leftover life in the engine? I know
to fix it would be pulling the engine, but is it a major repair? Thanks,.....
Knock or pinging is early detonation of the fuel in the cylinder ie the fuel explodes before the spark fires instead of burning. Knocking will
severely reduce the life expectancy of the engine.
It does not necessarily require any disassembly of the engine. Knocking can be caused by several factors:
1)Using fuel with too low an octane rating for the compression ratio of the engine. Search the forum for posts on fuel for all the info on what
people use, there are lots of them.
2)The timing is too advanced. Check that the timing is set correctly.
3)Overheating. If the engine is running hot pinging is more likely to occur. Check that all the tinware is in place and properly sealed up, even
little things like the rubber boots over the spark plugs can make a difference. Make sure the fan is running properly.
4)Sticking valves. This is the only one which requires any disassembly of the engine and obviously requires removal of the heads. This is the last
resort if the first three all check out OK.
So it is not necessarily a major repair. If you want the engine to last longer, I would get it fixed. Remember, you don't only hit high revs on the
freeway but also driving around town so you will probably notice the knocking as you drive. Get your mechanic to do full tune up and service if they
haven't already.
you want to get this before it does too much damage to the pistons and causes a blow by. cause this what i had happen to me with my 1700:duh
TRy using shell Optimax... and dont flog the guts out of the engine on hills.
bp ultimate works as well ether of these two is what i run my dub on
knocking could also mean something like a knwocking noise, ant may be due to bearings going etc