dieseldoc Posted August 5, 2009 Share Posted August 5, 2009 I do not have the rotunda gauge bar and adapters. Anybody have any ideas for a good accurate way to measure crankcase pressure. I have a 7.3 that is tired I think and need to see what kind of shape it is in. Wondering if any of you guys have built your own manometer or found a good alternative. I know I have read about this in a thread here before but couldnt find it. Thanks for tips guys. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted August 5, 2009 Share Posted August 5, 2009 Backyard test- take the oil fill cap off and power brake it/ rev the shit out of it and see how much blowby comes out. What year is this? Gen 1's and early '99s are the worst. Have you checked the turbo inlet hose for grit and turbo compressor wheel for dirt wear marks? Physical compression test? From my book: Dusted Engines or excessive crankcase blowby: caused by not having the air cleaner recall done and driving it in dusty areas with a loose air cleaner. The short test to find a dusted engine is to start the engine cold and give it full throttle. If it bogs and hesitates for a short while around 2000 RPM before it goes to full RPM, there may be excessive blowby past the rings. The fix is a longblock and turbo. The Ford tool for measuring crankcase pressure fits on the oil filler, it measures 6" long, 1" O.D., 3/4" I.D., has a .410" orifice at the upper end and the tap for the magnehelic gauge is 3 7/8" from the upper end. The crankcase breather has to be blocked and the engine run at 3300 RPM. Ford published spec of 6" for 97 and earlier or 4" for 99 and newer. Ford's spec for the older IDI trucks is 6" of water at WOT, and require the CDR valve be blocked. Another quickie method is the go WOT and pull the oil filler cap to check for crankcase blow by. Testing crankcase pressure is done with a special tool, and a Magnehelic gauge. If no gauge is handy, a substitute method is several feet of clear vinyl tube looped and colored water. The spec is 4” of water at WOT. I've tested good engines that measure about 4", and bad engines that blow all of the water out of the tube. I have the big gauge set, too, as they can be bought on Ebay cheaply. I have this picture which I think is the correct tool for a 7.3, and it's marked 7.3 PSD, but I'm thinking it should have screw threads on it for the oil cap hole. Maybe it's the IH version. Does yours have screw threads or a half turn oil cap? Quote Link to comment Share on other sites More sharing options...
dieseldoc Posted August 7, 2009 Author Share Posted August 7, 2009 It is a 96 with 160,000 miles that missed the lid update. The compressor wheel does not have real sharp edges anymore. The compression is in the low 300's. It uses about a 2 quarts of oil in 3500 miles, and about 4 quarts when it is hooked to the trailer for a month hauling hay(gets about 3000 miles). I know my injectors are about shot. I have resealed them and my IPR% is better now at 11(hot idle). Here is the wierd part the engine still starts great in the winter. I put 10-30 in it in november and even when it is -20 and sits unplugged for 8 hours while I am in work. I cycle the plugs twice and it pops right off. The diesel theory that I learned suggests that this engine should not start like that when it gets cold. I am mostly just curious what the blow-by is. I dont intend to overhaul right now, since it still runs pretty decent. The engine runs decent but is rough at idle. The compression readings suggest that #4 is the cause of the rough idle because it is at 280psi and the other 7 cylinders are at 305-320 psi. I have been watching the gauge bars on ebay but not sure what a good price is on them. Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted August 7, 2009 Share Posted August 7, 2009 It is a 96 with 160,000 miles that missed the lid update. Ugh! The compressor wheel does not have real sharp edges anymore. The compression is in the low 300's. What's your altitude? I'm sure you know that's low.... It uses about a 2 quarts of oil in 3500 miles, and about 4 quarts when it is hooked to the trailer for a month hauling hay(gets about 3000 miles). I know my injectors are about shot. I have resealed them and my IPR% is better now at 11(hot idle). Here is the weird part the engine still starts great in the winter. That's what a good set of glow plugs, some decent injectors (?) and luck will do. I put 10-30 in it in November and even when it is -20 and sits unplugged for 8 hours while I am in work. I cycle the plugs twice and it pops right off. The diesel theory that I learned suggests that this engine should not start like that when it gets cold. I am mostly just curious what the blow-by is. I don't intend to overhaul right now, since it still runs pretty decent. If it's yours and you know the history on it, you might be able to get by with a set of pistons and bearings. The block is a very high nickel alloy and they don't wear much unless it's ingested a lot of dirt. Even the severely dusted engines I've torn down still had the hone marks in the bores, though the pistons were really trashed. Sometimes they had some dirt scrapes in the walls, though. The engine runs decent but is rough at idle. The compression readings suggest that #4 is the cause of the rough idle because it is at 280psi and the other 7 cylinders are at 305-320 psi. I have been watching the gauge bars on ebay but not sure what a good price is on them. I wouldn't worry so much about a gauge bar as it's not as accurate as a tube of colored water. The pressure being measured is so low, I'd be concerned about the accuracy of the gauge if it had been dropped or handled roughly. Does your oil filler have a screw thread or half-turn? I could loan you the tool if you like. Good Luck! Quote Link to comment Share on other sites More sharing options...
dieseldoc Posted August 7, 2009 Author Share Posted August 7, 2009 I believe that we are about 900ft here but dont know for sure. I know that compression is low, it should be about 400 or better if I remember right. I have the threaded cap in the right valve cover. I found that we have a manometer here at work, we also have a blow-by indicator that we use on machine engines that we cant dyno. The only trouble may be finding a spec that is in ft3/hr. I guess I really shouldnt worry about it too much. It still runs well, pulls like an animal and gets 18mpg. Like I said I dont plan to overhaul it right now, just curious what the number is. Maybe I should just try to get a hold of the adapter. Bruce do you think if a guy took an old fill cap and drilled a hole in it and tapped it so you could thread in a pipe fitting for the gauge it would work? Or is there a specific orifice in the ford tool? Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted August 7, 2009 Share Posted August 7, 2009 Bruce do you think if a guy took an old fill cap and drilled a hole in it and tapped it so you could thread in a pipe fitting for the gauge it would work? Or is there a specific orifice in the ford tool? Yes, you could make one using the above dimensions in my earlier post. It does have to have a specific orifice, .410". I'll look and see if I have the correct adapter for your truck. Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted August 8, 2009 Share Posted August 8, 2009 This is with the Canon SD1200 Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted August 8, 2009 Share Posted August 8, 2009 Still blurry, Jim. Try shooting on a white background the next time as it makes contrast better. You ain't young, you got "the shakes"? What's the PN of the small adapter? I don't recognize that. Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted August 8, 2009 Share Posted August 8, 2009 Blurry??? Now you have me wondering who has what for a problem Actually, that is on <auto> and I read a user review that warned about blurry pics. There is a work around that I might have to get used to utilizing presets. 2002 PC/ED lists "part of Pressure Test Adapter Kit 014-00761". I'm halfway through my holiday and I already ventured into the shop to take the pic.. I am loathe to make a return trip if I can avoid it. Quote Link to comment Share on other sites More sharing options...
dieseldoc Posted August 9, 2009 Author Share Posted August 9, 2009 I greatly appreciate your commitment to us and venturing into the snake pit on your time off jim. After I saw your pics I cruised around on ebay and found one for what I think is a reasonable price. I am going to bid and see if I get it. Thanks for all the help guys. Now just to find an accurate gauge that will work with the adapter. Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted August 22, 2009 Share Posted August 22, 2009 Still blurry, Jim. Try shooting on a white background the next time as it makes contrast better. You ain't young, you got "the shakes"? What's the PN of the small adapter? I don't recognize that. Better late than never... the adapter is 014-00743 Quote Link to comment Share on other sites More sharing options...
Bruce Amacker Posted August 23, 2009 Share Posted August 23, 2009 Thanks! Quote Link to comment Share on other sites More sharing options...
ChristopherH Posted September 8, 2009 Share Posted September 8, 2009 Our gauge bar is trashed and I personally don't trust its test results. I found an inexpensive water manometer that I use for crankcase pressure tests that works well. It is a Dwyer Item# A1221-16K--just my two cents. By the way, at our altitude (5900 feet above sea level) even a good engine only measures 350psi on a good day! (I had to argue this with the hotline on a few occasions because they told me the engine had low compression when I gave them the numbers--results with three different diesel compression gauges compared to each other on the same engine and compared across several different good engines) Quote Link to comment Share on other sites More sharing options...
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