Cylinder #3 & #4 have 25 & 30 psi. Another has 110, and all others are in the 120's. So, currently have MMO poured into the two bad cylinders to see if that might free something up. Should have done another test with oil in those two, but I didn't. If nothing changes when I check again, I'll attempt to tap on the valves and see if that frees something up. Assuming the rings are bad, which I'll find out sooner than later, what do you all think about pulling the one cylinder head, pulling the pan, and replacing the rings on just those two cylinders? I've nver done rings, but it seems fairly straightforward. Let me know if I'm UNDER-thinking this. The engine itself has not many miles on a rebuild, though the rebuild may have been 15 years ago; the truck sat for a long time in a barn before I got my hands on it. I've had the pan off recently and the cross-hatching is still visible in the cylinder bores, which tells me it's somewhat fresh. I ultimately plan on replacing the flathead with a SBF, you can see my other post about that. But since I've been running this thing on only 6 cylinders, and smoking out the neighborhood in doing so, I'm very curious to see how this pig drives on all 8 cylinders. Thanks!
Two adjacent cylinders could be a head gasket problem. The two cylinders are blowing their compression into each other.
If it smokes that bad, it must be stuck rings, because you said rebuilt not too many miles ago, but then sat forever. But, that might not be the case, if you soaked the heck out of the cylinders and got a lot of oils in the muffler, it can take an hour to burn it out. Did you do that with oil? and if so, how long have you driven it? tapping on the valves is only done on a barn find when you know the valves are stuck or not closing all the way. On those engines when they finally get running, the valves will free up completely due to heating/cooling and rapid movement. BTW, seeing cross hatching from below, does not mean anything really. You look after the piston is out, at the upper part of the bore where compression/firing happens.
Take a compression test. Then pour some oil into the bad cylinders and run another test. If it comes up substantially, bad rings. If not, suspect head gasket or valves.
This is a good point. I'd like to rule it out, however, because I just replaced both head gaskets. Had water in the oil, found a gasket problem at cylinder #2. Had the aluminum heads machined; the machine shop said they were definitely warped. Engine has run for about one hour since then, and I've re-torqued the heads three times.
I poured in some MMO, but didn't retest; I ran out of time. I'll let it sit for a day or two, maybe re-check compression then go from there. Good to know on the valves, I've certainly driven the truck a bit, maybe a couple hundred miles since I've owned it. And good to know about the cross-hatching, I'll have to really check that If I end up pulling the head again.
I think if the compression is substantially better when I re-test, then I'm gonna pull the head and see what i see. Probably I won't be able to tell anything from the top end, at which point I'll want to pull the intake, where I'll be able to see if there's a bent valve or something, right?
You might try a "quick-n-dirty" cylinder leak down test. With a bit of air pressure pumped into the weak cylinders you should be able to hear or feel where the air is leaking from those cylinders. Remove all the spark plugs, prop the throttle open and remove the radiator cap. Listen for air escaping at the carb and tailpipe. Block off the crankcase vent tube and see if you can feel air coming out of the oil fill tube. And look for bubbles in the radiator tank. Actually, you might want to keep the radiator cap on, but loose.
just be sure to have all plugs out when doing the compression test. This will tell you if it may be a head gasket or not. The two adjoining cylinders will share the compression making it low, if the plugs are out, the compression will escape through the blown head gasket and out the other plug hole. Hope that makes sense, just pull the plugs on both cylinders and if you still have some compression, probably not the gasket.
I just may try that quick n dirty leak down method. Yes, all the plugs are out. If I'm hearing you correctly, you're saying that it's likely NOT the head gasket, since I'm getting some compression. 25 & 30 pounds isn't much, but it's there. If the head gasket were bad, I likely would get zero compression because the air would leak out into the next cylinder. Will definitely keep posting my findings.
The following is from experience. I may use a phrase or two to make a point but it's not meant to be condescending. Also I may use you or we, but may not be referring to you personally...it's more in the general, not the personal. I'm trying to help by sharing the lessons I have learned. Here goes.... The definition of insanity is trying the same thing over and over again hoping for a different result. Sometimes we do this. I'm guilty of it. The reason is we really know there's major work or money involved in fixing a problem so we try to avoid the root problem. In the end, it has to be fixed right. We wind up having to do it anyway. You have either a head or block that's untrue....maybe both, or a cracked cylinder or valve seat. The block and head being untrue....you can fix that at home. A cracked block or cylinder.....you cant fix at home. Rings...Valves....That's secondary right now. First you must confirm that the basics....the foundation of all of this. Make sure that it is good. You tried the head gasket fix. Now it's time to go further. Now is the time to confirm your heads and block are good. Heads.... Easy Peasy...You had them trued but....you need to verify this. It takes some time but it's pretty easy for a dirty check. 1. Check the head surface with a straight edge. 2. Check and true the surface with a good flat file and a sharpie marker. Untitled by Travis Brown, on Flickr Untitled by Travis Brown, on Flickr Untitled by Travis Brown, on Flickr Untitled by Travis Brown, on Flickr The photos above are of a flintlock rifle barrel but the concept is the same. I did the same thing to my 8RT...(truck version 8BA) and a set of Mercury EAB heads I literally dug out of the dirt. A gave my Edelbrock Heads away and used those Mercuries. Check the head on that side and make sure it's true...paying close attention to 3-4. The block...... How can you really work on and check that block in the truck around all that sheet metal? In my opinion you cant. You can do one of two things.... 1. Pull engine and work on it on the bench or on a stand. 2. Remove the front sheetmetal from the cab forward. This way you can see up close and work. Sucks...I know but 2 may be the best option. You know....Option 2 may even be better for option 1. Even with removing an engine to go on the bench...getting the sheet metal out of the way means you do not have to lift as high and if there was an unexpected problem in the lift, Valuable and frankly irreplaceable sheet metal is not damaged.. On the bench or with the front removed you can actually see down in the cylinder. You can check that block with a straight edge. You can file to do some rough truing. It's impossible to do this and do it well trying to contort around those fenders and in that tight engine compartment. You can get a rough idea of the block deck with a straight edge. The file will tell you a little more IMHO. To file the block deck....You'll have to remove the valves. If you are going to run a flathead now is the time to learn this stuff and get the tools required. Plus with the valves removed....check out those seats with reading glasses or a magnifying glass. Look for dumb stuff! Oops now I see I left a piece of old gasket between 3 and 4....whoops. In a situation like this I would love to find something like that. A old gasket piece, a chunk of greasy dirt stuff like that. That discovery would be wonderful. Inspecting those cylinders.... Which one is bad...really bad.? #8 Untitled by Travis Brown, on Flickr # 5 Untitled by Travis Brown, on Flickr #8 is cracked at the bottom. It needs a sleeve. You can see that the crack rings around the bottom. When it was clean and running 23 years ago.....that crack on #8 would catch your fingernail. This engine would idle all day long cool as a cucumber. Drive it and 5 minutes late all the coolant was blown out. Even revving it would blow the coolant out the radiator overflow. No water in the oil or oil in the water. The water did smell of gasoline and exhaust instead of that sweet smell of coolant. Notice that I talk about all the senses...sight..smell .....and feel! Since it's down this far....You may want to go ahead and pop out number 3 and 4 piston and rod assembly to check the rings. If the ridge will not catch your fingernail, I personally would try to pop it out. If there is a ridge....you'll need to get a ridge reamer. Use with care. I really think you have a seal problem between 3-4. I used iron heads with fiber heads gaskets....Honestly I was not impressed with copper gaskets...heck...I was not impressed with aluminium heads..... Check it out. This is what I would do...Maybe some of this will help.
F-ONE thank you for your response and suggestions. I definitely won't be taking a file to either the heads or block, because I'll screw that up six ways to Sunday, but will be sure to check for any warpage if I do end up removing the head. If things are warped, I'm finished with this engine for now and will replace with a 351 this winter, most likely. I really only want to see if I can find a solution to this problem in order to run this truck on all 8 cylinders to see what I've been missing out on. I know the flathead makes little power, but if it's been running on only 6 of 8 cylinders, I've been missing out on at least 25hp. Maybe that's not much, but for an engine that only makes around 100hp, well then it's something.
You seem to me to be pushing toward overthinking and problems that are NOT the likeliest. Since the engine is a temporary employee, massive work in testing and repairing makes little sense...major probs would be better met with a quick punt and a trip to the junkyard for a 302. I would for a quicky approach assume that the rebuild was good and that problems are from long storage in moist air. The two MOST likely failures are rings sticking and especially in a flathead valves sticking or rusted seats. If getting the engine to turn was not a big deal with screaming, cursing, and huge crowbars it is unlikely that rings broke...if correct MMO and some run time should be good therapy. Valves run dry in storage and can rust, and of course nice fresh seats on valves and inserts can rust. Non violent properly aligned tapping will verify movement and disassembly of the 4 suspect assemblies won't take to long...an "okie valve job" will easily fix moderate rust on sound parts, replacement of 4 or fewer valves if necessary won't kill you if rust is bad. And unless you used lots of stickum in assembly/violence in disassembly I would not replace the head gaskets. Beyond this, turn the engine over to someone planning to run it and put your work into the permanent engine... don't waste time on serious work approaching overhaul. Hell, I'd even accept the pathetic hulk for therapy here!
Bruce Lancaster, you're not wrong. It absolutely isn't time well spent since this engine is a temp. But like I said before, I just really want to run it on all 8 to see what I've been missing out on! Let's be honest though, probably not gonna notice a difference between 6 & 8 cylinders. I do need to drive the truck in a few weeks - we use it in our business - and was hoping to be running on all 8 while not smoking out the entire roadway. Probably I'll just pull the plug wires on the offending cylinders and run it on 6, maybe without the smokescreen. But let's hope the MMO does the trick and life will be good!
UPDATE: Re-tested compression with some oil in the bad cylinders and no change. Still only 25-30 psi. Also tested with the spark plug installed in adjoining cylinder to test if there's a head gasket leak in between the two cylinders and I got the same 25-30 psi.
Cut the porcelain out of a spark plug and weld or braze an air chuck fitting on it. Screw it into one of the bad cylinders, and hook an air hose to it. With compressed air going into one cylinder, check with the plug out on the other bad cylinder and see if air is coming out of it. If so you have a bad head gasket. If not, listen to where the air is coming out from. Crank case, bad rings, intake, bad intake valve, exhaust, bad exhaust valve. Of coarse the piston has to be at TDC on the firing stroke so both valves are closed.
Sea donkey....... Best bet for replacement.... SBC Any overhead valve Ford is going to be a big pain in the ass, any of them. Mounts.... pain in the ass Exhausts....pain in the ass Compatibility ...adapting to present drive train..... real big pain in the at 3 to 4x the cost for adapting. Front sumps....,pain in the ass... SBC, Speedway Hursr Early Ford V8 front mounts...Speedway adapter bell and a set of ram horns..... done. Fits as good as a flathead.
Bruce & BJR - Looking to perform the poor man's leakdown when I get a chance. Betting it's a valve issue. If so, would a valve lapping possibly be enough to clean the mating surfaces up? F-One - A Chevy in a Ford?! No way! You should know by now that I'm not looking for the easy road - wish I was sometimes - but my brain refuses to work that way! It builds character...?
Valves: They commonly stick in guides when left unused for long time. Find a local flathead person who owns a valve bar, valve and guide come out together for cleanup or replacement. you probably have hard seats, but not all of these late engines do. See if seat cleans up or has deep pits...if trouble there is light, a minor abrasive cleanup can do the job without major complication, valve itself well scrubbed and put back in unless major damage. Guide gets a rifle cleaning brush through the bore unless really bad. Here I am assuming engine was well rebuilt and most parts are hence good. Due to engine construction this stuff is easier than it would be on a modern V8. Small black chevy...perfect fit, most are bigger than common sbf's, cylinders should last longer due to decent rod length, better oiling system, EVERYTHING cheaper than the toy Ford engine. I can't imagine any reason for choosing a small block Ford over one.
I have one argument for using a Ford engine in a Ford truck: because it's a Ford! I won't cross-pollinate, it's a general rule I follow, similar to helping senior citizens cross the street or stealing candy from my children - I just have to do it. Anyhow, I'm gonna run a few quarts of MMO through this thing in all the different ways and try to sneak in the leakdown test also. Will report back when I have some results.
Fix flathead! It's the smart move . Engine swaps will nickel and dime you to death. It's been in there 68 years. Fix it fix it right be done.... it's all there. There's no reinventing the wheel.
UPDATE: But not a very infomative one. Just writing to say that multiple bottles of MMO has NOT fixed my problem, unfortunately. Two cylinders still down and still smokes like a banshee. Haven't had time for a proper leakdown test. The flathead will come out soon and the 351W will go in, just trying to decide on a trans.
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