Go to post #42 to see where I'm at Long story short I have issues with my 230ci Plymouth flathead. The car sat since 1974 until may 2010 when I got it running, its been running fine til now. The symptoms: the low oil pressure light kicks on(Plymouth advertises that this happens at 10 psi and i believe its working correctly), it looses power and starts to run rough(happens before low oil pressure light comes on). The low oil pressure light only comes on when it warms up and goes away when its Rpms are fairly high, most of the time this works(I have not made a practice of this, only once or twice to diagnose). I'm running 5w-30 oil in it. it is not overheating, I can spit on the head and it doesn't boil off. It had a couple stuck valves before I got it running and I got them unstuck by just working them up and down. So what am I overlooking? and since pictures are always fun here's one:
The manual says that under 10lbs at idle is acceptable as long as it comes up at speed. Rule of thumb 10 lbs per 10mph. 40 to 50 max. If its been sitting for a while your probably sucking crud from the tank. Tke the lione off the tank side of the fuel pump and shoot some low pressure compressed air back through the line. there is an intank filter, and the air will blow the crud out of it. There is another thread today about a 50 chrysler ot starting when hot, read through that for some more usggestions.
5W-30 Seems kinda on the light side for an engine of that era. I would use a straight 30 weight, or 10W-40. Multi weight oil didn't exist until the 60's. Good Luck!
I would recommend that you consider dropping the pan and cleaning the crud out of it. Most of these old engines I have taken down have a thick layer of lead paste in the bottom of the pan and often are blocking, at least partially, the pickup screen. I agree the 5w-30 seems a bit light, at least until the ambient temps stay below 30* this winter..........shouldn't be long now in MN. Ray
Koolkat now that you bring that up I think I have heard of not using multi weight oil because it just doesn't work the same. ply 46, the tank is clean no crud in it at all. It had a few rust holes in it, so i cleaned it out jb welded the holes then used a gas tank coating product called red coat to seal the inside of it. I will check out that other thread it probably does have something that covers my problem in it. Even when I had it going at some speed the oil light was coming on, the first time it did it I was on the freeway, and it had plenty of oil. Another bit of information, the valve seals are bad. The thing smokes a ton from the breather on the fill, and the pipe that goes down the back edge of the block. but basically nothing out of the exhaust unless I'm on the throttle.
And when I drove it to Back to the 50's this year in June it wasn't acting up at all, so I don't think the weight of the oil is the entire problem
i never trusted idiot lights,, might want to put a gauge on it an see what the oil pressure really is..
I agree on using straight 30wt, on these old engines. Now from what you have stated..it had been sitting a long time, had stuck valves, has low oil pressure, and blow by, it sounds like this engine is in need for an overhaul. A compression test will reveal a lot also. Sometimes there simply are not any shortcuts to take. Good luck.
I think you should follow most of the recommendations to date but I fear that you've erred in using a coating in your gas tank. I hear of more failures than successes in that regard. The sealant tends to flake off and clog your fuel supply system (filters and carbs). That smoke from the crankcase breather and the road draft tube is an indication of blowby which is caused by worn rings. You may be in for an overhaul. Note: I didn't say rebuild-as in remove and turn over to a machine shop. I mean an old fashioned ridge ream, rering, rebearing (if the crank checks OK), and a valve grind.
The blow by at the oil fill and out the road draft tube is a symptom of blow by. Compression pressure bypassing worn rings and pressurizing the crankcase. Worn guides/seals will usually show blue smoke out the exhaust during start up and high vacuum situations, and sometimes after hard left turns. There are several pipe plugs on the oil galley. You can easilly plumb in a mechanical oil pressure gauge to verify your actual pressure. The galley is a raised casting running horizontally along the bottom of the of the engine block on the drivers side just above the oil pan, the oil filter is fed by one an the oil pressure is screwed into aother one but I believe there ar one or two more tapped openings. I run 15w 40 oil in my rebuilt 56 engine. these engines have a floating pickup that is suspended near the top of the oil sump. they have a screen on the bottom that can get get partially clogged, as the oil level changes as you accelerate and corner the pickup may ad my Dyson says loose suction as it floats up ad down depending on which area is exposed tot he oil. You might want to drop the pan and see whats up. There is also a oil pressure relieve valve that has a sprint in it if the spring gets weakened or even broken, it will have an effect on the plunger that moves back and forth to regulate the pressure. Also there is a removeable cover on the oil pump on the pass side of the engine, you might want to remove the cover and check the condition of the oil pump gears.
as already mentioned, sounds like you're due for a freshen up. 1) The oil pressure part sounds like loose main clearances 2) blowby IS rings, and these engines are known for having broken ones upon teardown here's what I'd do before surrendering to a teardown: heavy, modern detergent oil changed FREQUENTLY (20w50 Valvoline Racing @500 mile or less increments) and clean the junk out of the pan. After that, Lucas or BG MOA with 10w40, every 1000 miles. Likely it's too late, but, this might get you another summer of cruising while you save the bucks for a rebuild.
Have you had the head off recently just to see the overall condition of the top end?... I"m wondering how the rings look. Speaking of the pan drop. my rebuilt 218 has quite a bit of the junk listed earlier in it that you literally have to scrape out. the engine itself is clean as a whistle but that pan collects a lot of build up over the years so right now i'm making sure i get all that out- Keep us posted on how it's commin along
I agree with all of those that have stated that 5W-30 is too thin for that motor. Suggest 15w-40 with a cant of STP. You can rebuild that motor in the car. Pull the head and drop the pan. New bearings and rings. Scrape the ridge out, pull the pistons and rods, hone lightly and knurl the skirts if needed. Regrind the valves and you are done. I would strongly recommend that you retrofit a PCV system. The stock road draft crankcase vent systems do a great job of inhaling grit, where it kills your rod bearings. It is easy to install a PCV system on this motor.
Sorry about disappearing last night and was a little preoccupied. The motor only has 385-- miles on it. I took the head off this spring and everything looked fine, I didn't notice any rust ridges in the cylinders from sitting. It was fairly free spinning when I got to it, but I'm worried about when my boss and his friend(neither are mechanics) in '99 tried getting running, what did they do. I'm also wondering could I be having a problem with the oil bypass just letting the oil drain straight back into the pan? I'll probably pull the pan sometime today if I can scrounge up a pair of jack stands, all of mine are 150 miles away. I did have a working gauge on the oil line but I don't think it was meant for use with oil and now it doesn't work. I did check this first thing when I got the car running to see if the idiot light was working right and it was. I'm just trying to get this running well enough that I can get it to my bosses shop for the winter, about 150 miles away. And cause pictures are always fun, here is the car at Back To The 50's:
Probably best to drop the pan now, check for sludge and check the bottom end clearances with plastigage. Check the relief valve too for dirt or a bad spring. If your running an oil filter. it returns thru a passage in the relief valve the that keeps oil in the filter when the engine isn't running (no pressure). I run 15W40 Rotella with no problems. Check it NOW. The engine below had the same problem and failed in a few hours.
I was going to remove the oil pan today, but I don't see how it can be removed without removing the engine. There is only about an inch or 2" of clearance between the pan and front cross member. I put a new oil pressure gauge on it and found that the low oil pressure light comes on when it is at about 10 psi. I have cleaned out the oil bypass but I'm not sure if it is really seating all that well, I might take it apart again and check the spring tension and compare to what my service manual says. I'm also worried to run it right now, cause it started making some noises and my ear is not well trained at identifying noises.
The rough running and low oil pressure are most likely not related. Low oil pressure is usually caused by worn bearings. I would put a gauge on it and see what the pressure actually is....
The fuel tank lining was highly recommended by a friend that has used it for quite some time. And I had someone come over that actually knew what they were listening too, and they heard something in the valves then when it got warmed up we revved it up a little bit and there was a knock...
As was mentioned, the oil pressure relief valve should be on side of engine. I would check this out to see if crud got in there. Also check the spring to see if it did not break. To get the oil pressure up a little can be done by putting a small spacer (a slug from an old metal electrical box might work) between the spring and the valve cap. As also was suggested, look over the oil pump gasket real carefully. These things do go bad on old cars like these.
Am I mistaken, or does he not have a bypass oil filter? There is not relief valve with this as the oil pump pumps directly to the main bearings and only a little bypass oil gets to the filter. I agree that the rough running has nothing to do with the suspected low oil pressure. I hink you should consider stopping obsessing over it, get rid of the 5W-30 oil, refill with 15W-40, add a can or two of STP and stop worrying already. These motors always had low oil pressure when hot and they were never intended to run thin oil unless you are in Siberia.
Seems to me that increasing relief valve spring pressure would only raise the high end pressure when the valve "relieves" the excessive pressure from cold start up etc. If I understand the relief valve concept correctly, it only is functioning when oil pressure is excessive, not too low. Ray
I believe all engines regardless of by pass, full flow, or no filter, have a pressure control valve. Its a spring and plunger affair on the drivers side of the block just behind the gennerator. If the spring is broken it can yeild strage pressure readings, if the plunger gets stuck you can see very high pressure, 85 lbs at anyspeed over idle.
Yep it has a bypass valve on the side of the block. I changed the oil to straight 30 weight just like Plymouth says it should have been running. I got a new gauge plumbed into the oil system, and the pressure is right where it should be. I cleaned the bypass valve out, and it looked good. However it has a very apparent knock now(no squealing yet). So now I have a winter project of pulling it apart and finding how bad it looks and deciding if I refresh or if I find a 318. Slightly off topic, but a friend is going to haul it to the shop I work out of in Iowa and I'm going to borrow a engine puller and an engine stand from a friend. I look forward to trying to take on my first engine overhaul, especially since my boss(that I bought the car from) is going to be helping pay for some of it.
Sounds like a rod knock. Weird why it knocks now that you put a higher viscocity oil in. Put a long screwdriver near the bottom of block while running and put the handle up to your ear and listen. This will tell if your problem is bearings or elsewhere. If you hear the knock, the problem is lower end related, aka crankshaft and bearings. If not, check at head to see if the piston might be striking head or head gasket.
I had someone come over with a mechanics stethoscope and we put it right behind the oil fill at the base of the block and that's where it was loudest. Since I've been so rude so far in not saying thank you. Thank you all for your help. I'll keep you updated as to what sort of fun things I find.
another test is to pull the spark plug wire of the suspected cylinder and then run the engine, If its a rod bearing, the know should be less apparent or gone without the plug firing. Changing a rod bearing with the engine in the car is pretty simple if the crank isn't beat up.
If your intank filter is the pourous sintered bronze filter and you used the tank seal you could very well have clogged the majority of the filter unless you blew air through the fuel outlet of the tank. Not sure what years Chryco used these filters but there is one on my 48.
I figured I'd update as to what I've been up to. I got the car back to the shop and finally borrowed the engine hoist and stand and pulled the engine and opened up the bottom end to find: -A pretty beat up rod bearing and crank on the #3 cylinder. -Some crazy ridges on the #1 cylinder where it must have sat before I got it. That's as far as I got into it since I needed to get on the road. So where do I go from here? I'm assuming I'd need to get it bored to get rid of the ridges and get the crank done to fix the messed up bearing. Putting in a V8 is out of the question, I really like getting 20mpgs. The fuel filter wasn't in the tank when I coated it.
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