1964 220SE pinging/running issues - Page 4 - PeachParts Mercedes-Benz Forum

kdlemon · #46 10-14-2008, 10:58 PM

hi guys

another update.

this morning i removed each HT lead one by one and put the car under load to test for pinging. i figured that in this way, if there were a problem in a specific cylinder, the pinging wouldn't be present. it was present with either cylinder disabled.

i've been setting the car to 3 degrees BTDC with a timing light. today i attempted to set the timing statically, using the 3 degrees as a baseline (with the slotted adjuster centered). when i loosen the adjuster and rotate it, the whole distributor shaft rotates with it. the advance weights dont seem to have much of a positive detent, and i find i can rotate the shaft back and forth by about 25-30 degrees. when i move it back and forth, there is a sort of clunking from the drive sprocket area. when i rotate it, it seems the shaft lifts and falls slightly. because it is so hard to find the rotor's "natural" position, it is impossible to set the timing statically.

with the distributor out of the car, the advance weight detents are very obvious as you'd expect.

any comments?

kdlemon · #47 10-14-2008, 11:37 PM

some more information.

these have vacuum RETARD rather than advance, don't they?

there is no vacuum at the port at idle, and very little when slowly accelerating.

this may well be the problem, but could this be a function of the cam timing being off 7 degrees?

kdlemon · #48 10-21-2008, 01:19 AM

hi guys, some new information to consider.

recently i had the rocker cover off and was just mindlessly turning the engine over by hand when in noticed a strange noise, like running fingernails over a radiator core (but more hollow and pronounced), would occur just as number one and six exhaust valves open. i pulled the relevant spark plugs out and the noise remained. it doesn't make the noise when any other exhaust valves open.

i am now fairly sure this is the noise i am hearing, but i still have no idea what it is.

mercmad6.3 · #49 10-21-2008, 03:06 AM

Can you post a picture of the cam?.

mercmad6.3 · #50 10-21-2008, 03:14 AM

Quote:

Originally Posted by mercmad6.3

4 month old fuel wouldn't do that,as for pinging when cold,well that's new to me,in fact I am wondering if it is pinging and not a broken piston. ( as it warms up the break closes quietning down) .
Pinging happens regardless of engine temp except when an engine is overheated..

Remember this? You have a sound you can hear when you turn it over with the cover off. I now stand by the above.
I have heard similar sounds coming from broken rings in engines that have been overheated ....and you have said the Previous owner had the head off for repairs. Overheating is as good a reason as any to pull a head.

kdlemon · #51 10-21-2008, 03:57 AM

why would it make the noise when number one or six exhaust valves open? would one of the pistons be at the top or bottom of its stroke? the compression is high if anything, and the only cylinder with appreciably lower compression is number three.

i'll get a pic of the cam tomorrow.

mercmad6.3 · #52 10-21-2008, 04:18 AM

Quote:

Originally Posted by kdlemon

why would it make the noise when number one or six exhaust valves open? would one of the pistons be at the top or bottom of its stroke? the compression is high if anything, and the only cylinder with appreciably lower compression is number three.

i'll get a pic of the cam tomorrow.

I think i just had a "senior" moment. Try slackening the two injector line musts on the fuel pump ( 17mm) and see if it still makes the same sound.

kdlemon · #53 10-21-2008, 09:58 PM

hi i tried turning it over stone cold and there was no noise. i started it briefly, then tried again - the noise was present. i opened the injector lines and the noise went away.

now that i think about it, the noise does come in three pulses. could this possibly be the cause of the noise whilst running or is the noise quite normal?

mercmad6.3 · #54 10-22-2008, 01:43 AM

It's not unusual to hear the injectors opening when cranking over an engine when it's cold other than that,because i haven't heard it run i cannot comment further.

kdlemon · #55 10-27-2008, 09:31 PM

another update

when i turn the engine over by hand (cold, but briefly run), when #1 and 6 exhaust valves open, there is a metallic pulsing noise, most of which goes away when the engine is turned over hot. i am now quite certain this is the source of the "pinging" as it is very loud when cold, but largely absent when hot

is it known for these injectors to rattle when cold, as diesels are occasionally known to? or is the problem more likely to be in the distribution blocks? i have generally speaking, the whole injection system is noisy, from pump to injectors, when probed with a stethoscope.

mercmad6.3 · #56 10-27-2008, 10:06 PM

yes they will,it's not common ( my 6.3 does it) but not unusual. You should run ATF in your Fuel (1 liter per 100 liters of fuel) Mercedes recomend this for the MFI.