I have not driven my yellow baby for a few weeks, been house sitting and left it at home to rest while we use our Land Rover Defender a bit more...
I went home and gave the old girl a start up, it took a fair bit to get started, had to use some Eze-Start to fire her up.
she ran fine, i was holding the throttle open a bit to keep her revs up, and then after about 15 or 20 seconds a nasty knocking noise started.
very noticeable, so i shut her down and removed the rocker cover to see if something had come loose in there, as thats where it sounded like it was.
but i see no damages in there.
all the valve timing thingies look fine, all the clearances felt tight, and the loose ones only had the tiniest amount of movement. (I had set them all to factory clearance not too long ago)
so i put the lid back on and started her up again, and the same knocking is still there.
sounds like it's coming from up the back near the fuel pump... but can't be 100% sure.
could something have gone wrong with the fuel pump? it's not too old, i think i've posted about when i put that fuel pump in new...
maybe a year old?
I think i may have put a little too much oil in it a couple months ago, and been driving it slightly over full for a couple weeks...
could this nasty sin be the reason for a knocking noise to develop suddenly?
probably caused by the eze-start
should use gas instead
i just hauled home a tercel that was started with some kind of starter fluid
and it caused it to knock
most likely a cracked piston
seems like others have warned about this on this site
Love those Tercell 4x4 wagons but they sure suffer from road noise.
You might pull the spark plugs and look in the chambers with a strong flash light, turn the engine over by hand slowly and inspect the tops of the pistons. if you see damage, or loose parts, the head has to come off.
Several things may have caused it, a burnt exhaust valve that breaks off and bangs into the head with each TDC of the piston (this would be a very hard mechanical knock). A broken piston that slops back and fourth in the cylinder, this would be a loud slapping noise (not a hard knock), likely cause a lot of blue smoke too. Bad rod bearing, usually only caused by running low or without oil.
I have not seen a failed fuel pump cause a loud knock, but I think some on the list has had that happen once.
In all cases except the fuel pump the engine has to come out. But better find the cause first, and than decided what to do.
I used the starter fluid all the time for various reason and never had any issues, but you can not put too much in, just a squirt or two.
Try carefully pulling one plug wire at a time while the engine is running. If the knock mostly goes away when one is pulled, you've located a bad piston/rod/bearing. Engine pulling time...
yeah, thanks guys. very informative.
the noise just started suddenly, it was very noticeable to me, but i'm not sure if it would be called a hard or loud knocking, i wouldn't have called it slapping.
anyway i'll try all your suggestions now.
thanks again guys, your all very helpful.
Many years ago I had developed a odd sounding knock, a slapping kind of clunk, clunk, clunk that occurred on the first Tercel4wd I owned after about two years of hard driving (I think it had about 190k miles on it). Before this there was this odd chattering kind of noise at certain rpms, that came and went as the rpms rose. I paid little notice of it, I had not owned one of these cars before so I did not know what was "normal". Than all of a sudden the slapping/clacking noise started, it still ran, but was down on power, and it smoked badly.
I pulled the head off and rotated the crank, one of the pistons (I think the number 3) would rock side to side about 20 degrees. I pulled the engine and removed the pistons, the skirt on the piston had failed. Just broke right off from below the oil ring on both sides of the pistons, allowing it to rock back and forth. The piston skirt pieces and the mangled oil ring was down in the pan. I was amazed it was still running at all.
Before the failure what I was hearing was the worn cylinders were allowing the pistons to slap in their bores, causing the chattering at certain rpms. The extra clearance eventually fatigued the skirt and it failed. Some of the unfailed pistons looked battered in the skirt area, so their failures were not far behind.
I liked the car, but the body was a bit rough, poor paint and it was a little rusty, so I was undecided whether I should rebuild the engine or not. I deiced to keep the car and just do a low budget overhaul.
I bought four new standard size pistons and rings, new bearings, and than did the rebuild by honing the cylinders. The bores were worn over sized, but I figured the new pistons would be way better than the worn ones that came out, and it ran many miles with the worn out pistons. I just honed the cylinders, I did not want the expense of over-boring. I thought I would have more clearance than spec, but it should run fine. I got it together and it ran great. I was unhappy that rebuild did not result in more power, ususally with 188k miles you are down on power because of engine wear, but not in this case. One can normally expect more power when you rebuild it, but I did not realize how underpowered these cars are even when new. I did get it all together for less than $400., cheaper than I could buy another beater. I did notice I still had the chattering sound at certain rpms, but I did not think anything about it (this was normal wasn't it?).
Less than 6 months later of daily driving, one of the new pistons failed in exactly the same way. So trying to cheap out was just a waste of money and time. I did not want to admit defeat, so I determined to rebuilt it properly and try and get more power out it. I bit the bullet and over-bored the cylinders, and went with the flat top pistons +.040" oversize, balanced the engine, lightened the flywheel, put in all new valve guides and reground the seats and valves, all new seals and gaskets, ported the head, performance regrind cam, resurfaced the head and got it all together. Piston Slap was gone, and finally had more hp, and it ran smooth and powerful. I spent about $800 on the overhaul. Than I started blowing head gaskets....
So if your piston skirt has failed, replace the engine with a low mile one, or overbore the engine and do a proper overhaul.
thanks petros,
wish i had the equipment to do that sort of work, would be fun.
will get back on how she runs after i take it for a drive.
i had a look through the plug holes and only spotted a couple minor dints in the top of number 4 piston, about the size of match-heads.
and they all look very greasy and gunked up, probably because my weber is running way too rich...
plugs also are very oily/cruddy with dark gunk...
