Should be bringing her home this weekend, there is a wierd ticking noise in the video that the current owner attributes it to "the valve guide wiper seal" needing to be fixed, but it will still run and just smokes a lot because of it. Anyone have any ideas on where to start from the video? Hoping its not too big of a deal to do... Thanks in advance for any help http://www.youtube.com/watch?v=mhuwx0EYUjA
I would first start with a compression test and compare all 8 cyls. This could tell you a lot about the condition of the engine. Pull the valey pan and you will see the lifters, cam and pushrods, also pull all the spark plugs. With it in neutral, turn it over slowly (clockwise) using the crank bolt on a long cheater pipe as you check for the loose pushrod/rockers. Try to identify which it is, and address from there. There are ways to free a stuck lifter, but I wouldn't rule out that it could also be a wiped out cam. That should give you a start...
I think Erik pretty much covered it all. One thing that kinda concearns me - that sounds a lot like my 401 when it broke a rod about 10 years back.
Ok, so what exactly should i be looking for? Im also assuming ill need a new gasket for the valley pan. Grr...I hope not, I heard the bottom end is the best thing about these engines
You'll be looking for which cylinders are down on compression. That will narrow down the area where the problem is. As far as looking in the valley, check for anything obvious. Bent pushrods, etc. They're pretty bullet proof, however, if memory serves me correctly, often times excessive reving w/o a load (reving in park or neutral) can eventually lead to a failed rod. Usually on one of the rear driver side cylinders I think. It's been a while since it's been talked about on here, but I remember it being discussed at some point.
You got it! I guess Ill have to get someone who has the tool to test compression, then itll be on to the valley pan, I hope itll be something simple and then I can just do the basic tune up stuff to get her running top notch! :3gears:
naahhh... Too high pitched for a rod. A compression test will tell you how well each of your jugs are sealing to make power. You are looking for a varience (bad) between them or a realy low one. That could indicate piston/ring issues or a valve. There is another handy way to tell the difference if you get that far, but we'll save that for later. If you find a loose pushrod (excessive valve lash that is making the ticking noise), it could indicate a couple things: worn cam, bent/worn pushrod or rocker, a stuck lifter (they are hydraulic), and is most likely the case, but lets verify that first before we get ahead of ourselves... I failed to mention to do this with the valve covers off so you can see. The gaskets will likely be hard and brittle, and yes, you will need to change them once you break them. If not and you are careful, you can get away with re-using them. You can also get away with just RTV on the valley pan as there is no pressure or oil up to there... Napa usually carries them. BTW- that 401 never came with valve seals untill 1966 and only on the intake, so you shouln't see any on the top of the guides though the springs anyway. Erik
Rocker arm noise,,,,, caused by slack in the valve train,,, caused by either , bent pushrod, collapsed lifter,,,, wiped out cam /destroyed lifter,,, busted rocker arm ect.... if a valve sticks in the closed position, when the cam lobe comes up , there is so much pressure that something has to give,,, most times the pushrod bends,because that is the weakest link,,,,occasionally the rocker arm will break,,,, if the valve is in the open position, there is a ton of slack in the system and you get noise like that,,, compression test on the engine will confirm.... use this as a bargaining chip ,,,, cars with engine problems aint worth as much.... make a low ball offer pointing out the engine noise ,,,, but it aint bottom end noise imho..... pull the rocker cover on the side that the noise is on and ck all the rockers and push rods....if they are all ok,,, then there is a high probability that the lifter is collapsed,,,, pull the lifter out and ck it,,, if the bottom end,,, called the ''foot'' is scuffed and worn then the cam is also gone,,,,, if so,, then the bottom end bearings and the oil pump will be damaged too.....
Not to disagree with Doc - he is most likely correct in all that he has said here - but do not assume that the cam is gone if the bottom of the lifter is worn or spalled. Check the lobe carefully. Over the years, I have replaced at least a dozen nailhead lifters that were badly worn and yet the cam (which is steel) was fine. In my 425, we had to replace the cam because the distributor/oil pump drive gear was badly worn. The lobes were fine.
Supposed to be bringing this car home soon, having trouble getting a trailer for her even though shes drivable. The owner said I technically could drive her but she only gets 5 MPG!? is it really that bad? Is it even a good idea to be driving it anywhere with this potential problem?
If that car is only getting 5 mpg there is something obvious wrong. A fuel leak, a totally screwed-up carburetor, timing way off, stuck in first or second gear, a busticated overrunning clutch in the stator of the torque converter, etc. Doc is right. "Shipshape," that car should do 16-18 mpg driven sensibly on the highway. BTW, that ticking is definately at valve speed (1/2 crankshaft speed).
just got her today and wanted to double check before starting to tear her down. Would this potential bent pushrod/lifter problem be causing the engine to smoke a lot when running?
You got it. Tomorrow I remove valve covers intake mani and valley pan in search for clues. I dont want to start it anymore while this problem persists. I will also be restoring all the parts I take off
