M180 Oil Pressure

[zenuff]

I have a 1967 230S. What is the proper oil pressure? the gauge is pegged at 45 psi when cold at idle or driving. After a few minutes it warms a little and drops to 30 at idle still goes to 45 when I accelerate.

After Its totally warmed up and driven a few miles I've got 10-15 at idle in gear and 25-30 psi when going down the road. It makes a clacky sound as it reaches the top of the gears right before it shifts to the next. Right after the Shift it quiets again until the rpm's come up some, although when hot it clacks all the time unless at idle and still seems noisier at idel when warm than fresh cold start.

When driving in top gear on the highway especially it will clatter if I am barely on the gas just to maintain cruising speed, usually at around 45 to 60 mph.
Im getting worried it's the oil pump or engine bearings wearing out.
I just changed to 20-50w from 10-40w and added half bottle of Lucas oil additive.

The noise mainly appears when warm and pressure drops off some.
Does anyone know of a diagram of the inside of the engine that you could link me to?

Thanks

[todds]

I have a 1967 230S. What is the proper oil pressure? the gauge is pegged at 45 psi when cold at idle or driving. After a few minutes it warms a little and drops to 30 at idle still goes to 45 when I accelerate.

This description is accurate for my 67 230S in all cases.

After Its totally warmed up and driven a few miles I've got 10-15 at idle in gear and 25-30 psi when going down the road. It makes a clacky sound

This is not. Something is up. My car's been getting wickedly hot lately, too hot and it still maintains pegged oil pressure or slightly lower at idle as you initially described. Do you have your owner's manual? I think it will back up what I've said.

[zenuff]

I don't have the owners manual unfortunantly. I felt like that was low, but I need to find the cause of it. It may just be wear and its probably got some being this old .

Can someone tell me where the oil pressure relief valve is located, and does it sound like that could be a problem?

Thanks

[wbain5280]

You have typical (really) old car wear, bearings etc. I suggest using thicker oil for the mean time and consider an overhaul. The noise is due to low oil pressure.

It could also be caused by a worn oil pump. The oil pump can be inspected by removing the lower pan and then removing the oil pump. The fuel pump must be removed first. The oil pump and the distributor are driven by the same shaft.

The oil pressure relief valve is located in the timing chain area low on the drivers side. There is a plug on the front of the engine that must be removed and the valve unbolted. This is not your problem, excessive bearing clearance is.

Look here:

220S M180 Engine Work

[GGR]

I think the lowest oil pressure allowed is 15 psi at idle with warm engine. Pressure should immediately go to the maximum as soon as you rev it a bit. Is the noise coming from the higher end or lower end of the engine? Camshaft wear is quite common on these engines, especially if you have a weak oil pressure at idle.

[zenuff]

It definitely sounds like rod bearing noise to me. It doesn't happen very much when the engine is cold, unless I get the RPM's up high.
There was a little bit of gold flakes in the bottom of the oil filter can. I think its rebuild time.
Also today I pulled out the relief valve and cleaned it. Strange though, it looked like it hasn't seen oil in years, it was dry and kinda light surface rust on it. It wasn't totally free in its bore so I took off the snap ring and cleaned it up really well.
Still trying to decide what to do. Im getting a 230 with a great engine in it. Should I swap it into the 230S? Or just get the 230 on the road. Either way its going to be some serious work.
Is the 230S a rare or sought after car? More so than the standard 230?

Oh yeh, their is a cover plate above the pressure relief plug, square cover with 4 bolts on it. What is this for, can the oil pump be checked from there?

[wbain5280]

The sprocket for the distributor and oil pump drive are behind the square plate.

If your pressure relief valve was dry, then the timing chain is not getting as much oil as it needs.

[GGR]

The way you describe it indeed looks like one or several journals are worn, but it doesn't seem to be that bad yet. Usually when a bearing starts going bad you hear it well for a few seconds when you start the engine, before oil pressure builds up. When cold, try to start the engine with a bit of pressure on the gas pedal so that when it fires the engine goes immediately to around 3000 rpm. If you hear a loud klaklaklaklak just when the engine fires and disappears when you release (immediately in that case) the gas pedal, then this is it.

You say that when hot, the oil pressure remains at 25 30 psi while driving. This is not enough; it should be to the maximum, especially with the 20W-50 oil you are using.

Worn journals will cause the oil pressure to drop below tolerance, even with an oil pump still within tolerance. But a weak oil pump may have been the cause of the damage in the first place, so it's a bit of a catch 22.

If I were you I would take the oil pan out and look for some play where the rods connect with the crankshaft. If you find some, then you may have to replace the journals after having checked/sanded the crankshaft. As you're at it, take the oil pump out and check if it is still within tolerance. This may be a reasonably cheap and quick fix to enable you drive the car again for a while. But it only makes sense if the rest of the engine is worth it. To determine this you should measure the compressions. First make sure your valve adjustment is correct (check/adjust the clearance while the engine is cold). Then, engine warm, all spark plugs out, crank the engine with the starter motor for 8 to 10 revolutions with the gas pedal floored. If your measures are uneven and/or well below tolerances, then it's time for complete rebuilt or engine swap.

Don't wait too long as the problem may worsen to the point that you may damage the crankshaft and ovalize (not sure of the term in English) the con rods. Then you are into additional work and expenses.

[todds]

How many miles on this car? This is a pretty unusual problem to have on an m180.

[zenuff]

I think its 270,000, But I may be off by a hundred thousand.
I don't have records for the car so I may never know for sure.
I know these models rev high on the highway but, this car seems to wind up so high I often thought it may damage the engine. It seems that this started after a lot of highway driving.
I did go slower than the speed limit but it was still wound way up at 55-60 MPH.
I believe the oil pump has gotten weak and led to worn bearings.

Can I just replace the bearings at this point, along with a new oil pump?
Or am I into some serious machine shop work on the crank and rods?

[strelnik]

Originally Posted by zenuff

I think its 270,000, But I may be off by a hundred thousand.
I don't have records for the car so I may never know for sure.
I know these models rev high on the highway but, this car seems to wind up so high I often thought it may damage the engine. It seems that this started after a lot of highway driving.
I did go slower than the speed limit but it was still wound way up at 55-60 MPH.
I believe the oil pump has gotten weak and led to worn bearings.

Can I just replace the bearings at this point, along with a new oil pump?
Or am I into some serious machine shop work on the crank and rods?

I had a 67 230 s that was a dream car, with a manual. ran great. I sold it and within 2 years it was dead. The guy never changed the oil, just kept adding cheap oil as he drove, and even though I had sold the car with just under 200k on it, it never made 250k. It threw a rod bearing.

I think your car is saveable with minimum effort or expense but you will have to spend something. Marvel mystery oil will not save you.

My advice:
1. Adjust the valves, carefully examine the cam lobes for scuffing and THEN do a compression test by the book, as described, no short cuts.
2. Pull your oil filter and with a magnet, test the residue. If there's bearing material in it, you know the answer.
3. Good job on cleaning the relief valve. BTW, did you put any oil or anti-seize on it before re-installing?
4. Pull the pan and check the oil pump and the con rod bearings, mains if you can. Pull the main farthest from the oil flow listed in the factory service manual oil flow and see what it looks like.

I think you need bearings. With any luck that's all and you can live happily ever after for maybe 100k miles more

[todds]

this car seems to wind up so high I often thought it may damage the engine. It seems that this started after a lot of highway driving.

I did go slower than the speed limit but it was still wound way up at 55-60 MPH.

They do wind high, even for a 60's car. General consensus is that they can take it due to the mileages people get out of the engines. Some things that make them FEEL like they are worse off than they really are can make it seem like the engine is strained even though it isn't. Stuff like driveshaft donuts and bearings causing vibrations above 30mph, noisy valvegear, leaks at the manifold flanges. All that kind of thing makes a high revving engine even more obvious and less refined.

It is most likely that your lack of oil pressure is causing the undue clatter which makes the engine seem like it's overrevving and causing the wear. It's all a vicious cycle. I doubt it was so much highway driving specifically as just plain mileage that wore out the engine, or mileage in a marginalized state.

I wish I could answer your questions, but they have pretty serious outcomes monetarily if I am wrong. I'd rather defer to the experts here. A possible mileage of 370k is still a lot for any engine really, it might just be worn out.

[ja17]

Hello,

I like the idea of closely looking at the bottom of the oil filter canister. You also can tear apart the old oil filter to examine it for metal. Small cooper metal flakes as mentioned is normally a sign of badly damaged bearings. Damaged bearings will also make the engine run hotter (friction) and damaged main bearings may cause the engine to become "tight" and hard to turn over when starting hot. On a 230 engine each main bearing services two rod bearings ea. with oil. A worn main bearing will starve a couple of rods of oil supply. Eventually these rod bearings fail and begin to make noise. The noise becomes worse when the engine oil is hot and when the engine is under load.

If you really want to find out what is going on, remove the steel sub-oil pan (5mm allen bolts). After is is off you can inspect what is in the bottom of the pan, inspect or remove the oil pump and its screen. You can also remove some engine main beaing caps and rod bearing caps to view the condition of these bearings.

Allowing the engine bearings to completely fail will cause a lot more damage and expense. If you think this may be the case, you should look into it soon.

[zenuff]

I know this seems backwards but the 10-40w oil I had in there previous to the 20-50w seemed like the engine ran smoother and had more oil pressure with that.
Could it be that the oil is too thick or heavy and causing trouble?
Im still investigating all suggestions. Thanks for all the replies. I will get the oil pan off there soon and I'll let you all know how it looks.