Ughhh Rattle From Engine

[NoStickDrift]

I searched quite a bit but I am not 100% sure what the problem is. I have a 89 240, At idle it makes a erratic "Marble in tin can" sound. I figure like most it is the timing chain or the guides, but like I said not completly sure. At idle it makes the noise, as the RPM's go up, it stops, once i let off throttle it will make it again about 1500 RPM to idle irraticly. So i figure sense its not making it as I go up its not Valve tap. Sound right? Is there anyway to find out without ripping the damn head apart? And if so how? Also I have no where to work on it, so I am gonna prolly have to take it somewhere to get fixed. Has anyone had this done some where and what are the prices ussaly. Any help would be apprecated.

[240marcuSX]

marble in a tin can and rattling are two different sounds.

marbles in a a tin can sounds like pinging, or detonation.

Rattling, like dragging a heavy chain on a wooden floor, is what the timing chain rattle sounds like, and its real quiet at first, so you cant hear it at higher revs.

valve tapping will get louder at higher revs, but you still might not hear it because of exhaust/engine noise.

first, check your oil, if your low, or leaking, it could be your valvetrain not getting the oil it needs, and its tapping, that has happened to me before.

If that doesnt help, maybe check your ignition timing, if its too advanced, it might be detonation, Or run a higher octane fuel and see if that helps.

Other than that, put your ear close to the valve cover (watch out for the fan and belts) and see if its coming from the very front of the motor, if it is, its probably the timing chain.

[benemorius]

I like to describe pinging as BB's in a tin can, and timing chain rattle as marbles in a plastic cup.

Ditto on checking your oil level, and don't drive the car until you figure this out. If it is the timing chain rattling, it could very likely be due to low oil pressure from a bad oil pump and that would just be bad.

[NoStickDrift]

The oil level is fine and the pump seems to be working well. I dont hear the sound past 2k. And its very irratic when its in Drive. When i sit somewhere in park it is more frequent. I really dont have the bloody time to do this job. I can but i dont have space or time. There is no way to access the Timing chain guides to pull them off without taking off the head? Any suggestions?

[Shinnco]

pull the valve cover and look at the t-chain. See if the top chain guide has broken(happens all the time). if so you can pull it out and still run it.

[lbrowne]

Could be a sticky lifter. My 240 had this when it had sat for over a year but one cycle to normal operating temps seems to have fixed it.

When was the last time you changed your oil? The sound I had was there for a while when the car was first started after sitting a year, then went away and came back several times until I took it for a careful drive after what appeared to be its final tappin fit.

Try some lucas oil treatment for a few Ks and then change it out. From what you're telling me and what I've experienced from a couple of vehicles I owned that had it, sounds like a sticky lifter. At idle your oil pressure won't be as high, so if the lifter is going to act up it would then. Since it goes away at a higher RPM then I would think that because of the increased oil pressure its being forced to do its job. If the tapping stayed at higher rpms and changing oils etc - you most likely have to change the lifter.

I didn't think the SOHC had a upper timing chain guide - thought that was only the 91+ DOHC.

All this said I would personally have to hear the noise because it could be so many things. It could also be, and I seriously hope for you sake its not, a main bearing knock. My old 89 240 had it but that damn KA made it literally across Canada loaded to the gills with belongings and 3 people. And it had been making that sound for a while before it embarked on that journey.

sorry for the long post, just trying to pour ideas to ya.

[BusyBadger]

+1 for Bad Timing Chain Guide