One thing I have noticed about my 250 Inline 6 is when I get up to around 55-65 MPH the engine gets a good knock going on. I know its not the head, its coming from the block. Does anyone have any ideas what could be causing this noise? It doesn't seem to effect the cars performance. Driving around town there is no knock. The only time the knock shows it self in town is if I stomp on the gas and make it downshift. I would like to know what the deal with this thing is because worse case senario is I go down to my local junk yard and pickup a good running 250 for around $225-230 out of a 64 Falcon. It just would save me time if I could figure this one out. Any ideas? Thanks in advance and sorry for the long post.:confused:
Ill check on that and see what happens. It sounds like rods, something of that nature, but Ill definately check the timing on it. After all it is an old car, you never know. Thanks.
I have a tendancy to go with Frank, just going on what you told us. I'd back the timing down by a couple of degrees or so - try it, back some more, test, then move it up until the knock starts again, then back down 1 or 2 degrees. This is assuming that the knock is actually a detonation. Might try running some high-octane in it to see if that helps. - or it could be wrist pin going out Good luck and keep us posted. Rick edit: was writing post when you posted last.
Thats an idea, what and where are the wrist pins? Do you know about how much they would cost? I have heard of them just not really sure what they are and on what part of the engine they are located. Also, what would I have to do to replace them? (Afraid to ask) I know she has a lot of power for only runing a inline 6. I would rather get her fixed and running like a ox as soon as possible since it is my daily driven car (or soon will be). I know the motor has plenty of power since I have had her up to around 95MPh without any trouble at all and it knocked the entire time my foot was on the gas. It only does it at higher RPMs. Around 55 you can just barely hear it. When you get closer to 60 then it becomes very noticeable. When you reach 70 (flange leak) you can barely hear it but I believe if the flange was fixed I would probabily hear it at that speed. Hope this information will help a little. I know its hard to diagnose a problem without actually hearing it. Thanks in advance.
Hey my71comet Wrist pins are what hold your pistons to the rods. The knock comes from slop in the cyclinders and will eventually "blow-up" I would look at a rebuild or a motor swap. If you want to keep the 6 you can find a motor pretty cheap from some one on the board. Later Tim
I would check the timing and try a higher octane fuel. It really sounds like that is the problem and it is easy to fix. Wrist pins are not!!
Yeah I checked out the auto parts stores and a lot of the machanics I talked to said that it sounded more like a timing or a vaccum problem. I am going to check it out because I was thinking that worse case scnario I could either buy a good 250 or just go with either a 289 or 302. I mean the car has a nice solid C6 automatic and I know that it would bolt up to a V8, just am not sure what all I would have to change other than the mounts. Thanks guys.
my71comet, first I wish to assure you that you don't have a C-6 behind your 250 six. the six cylinder engines, 289's and 302's came with C-4 automatics. The knock sounds like it is either a main bearing knock, twisted rod, wrist pin or timing knock. There is a minor chance that it might be a timing chain slapping against the cover or a sticky exhaust valve. Changing to a V-8 will require different mounts and supports. The throttle pressure / kick-down rod to the tranny will have to be replaced and the throttle linkage modified or replaced. The front springs will have to be replaced to take the added weight and the radiator changed out for the V-8 cooler. If you get an engine out of the wrecking yard you might be able to have them include the starter and other accesories but if not then you will have to get them too. The tranny will bolt up but the internal parts (clutch packs) should be up-graded to the thinner pressure plates and the number of clutches increased to take the extra load. The parts to do this are available without much additional expense when purchased in a kit. PaulS
Well I hope it is only timing. If it is something more major I will just save up a little cash and go down to the local junk yard and take one out of a 64 falcon which was transplanted with this engine. I was told by the previous owner that he swapped out the original C4 with a C6 because the old one went out. I was in disbelief too, so I crawled under the car to check the numbers. Sure enough it is a C6 from what I could tell. I was told you can tell by the first two digits on the transmission label on the side. It either starts with C3, C4, or C6. Mine started with C6. Besides the transmission is quite large to be a C4. I could be reading it wrong because I am not fimiliar with Fords that well (kinda learning as I go). Not too conserned if it is a C4 because it shifts like it should, its just the freakin engine that bugs the heck out of me.
If you are talking about the part designation C3 = 1963 C4 = 1964 and so on. D1 = 1971 E2 = 1982 If you give me the entire prefix (four numbers) I can tell you more and the number following the prefix provides the part group (all distributorsare the same number) and the sufix provides you with the month and day. PaulS
oh okay. I wasnt sure, Ill check because I am kinda curious. Make since. I think the knock is timing because it will make the same noise when at idle if I bring the RPMs up, and if I rev it a little higher it goes away. Ill check that and if doesnt fix the problem then I will start looking at other alternatives. It doesnt comprimise power at all, the car has quite a bit of get up and go for a inline 6. If I have to replace the engine I will probabily stay with the 6 cylinder. One question though, what conversions would I have to make if I was to put in a 200 Cu In Inline 6. The engine came out of a 1980 Ford Mustang, so I was wondering what the difference was. I know the engine only has 1,200 miles on it after a rebuild. Was wondering what will enerchange and what I will have to change. Thanks in advance.
The bellhousing and the converter will have to be changed on the tranny because the 250 uses the same bellhousing and converter as the V-8's. The 144 - 170-200 all use the same smaller bellhousing and converter. The linkage for the throttle will have to be changed out. Everything else will work with the swap. PaulS
That's not too hard from the sounds of it. Thank you for the info. I might just drop that one in because it would be cheaper than going out and buying a new engine when I already have one that I have personally heard run. Thanks again.
Noise at idle and then going away sure sounds like a rod or even a main bearing. Try a couple of things to isolate it. Remove one plug wire at a time and see if it still knocks, usually a bad rod bearing will stop when the pressure of the firing cyl is taken away. If it still does it, shut the engine off and get under the front or maybe can do it from the top, and with a good prybar, try to move the crankshaft foward and then backwards. Should move only .008 to .010. This is hard to tell without a dial indicator but if it is a worn main thrust bearing, it will sometimes clunk and have a distinct amount of movement to the eye. Have you done a compression check and even a oil pressure check, with mechanical gauge, yet? Will give you an idea of the overall condition of the engine.
