| carpguy | -- 02-22-2010 @ 4:19 PM |
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Afternoon, After a year working on my '37 ford pick-up I thought I had it licked. The engine was rebuilt a few years ago by someone else. I could not get it to fire, after checking the timeing and all everything was good but I had only about 10 pounds of preasure or there about in all cylinders. I took the head off and checked the valves and they where working right. What else would cause the low compression? 21 stud '1937 85 H.P
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| Pauls39 | -- 02-22-2010 @ 6:28 PM |
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We have seen this before when the suposed pro rebuilder did not adjust the valves. The valves had less than zero clearance on the lifter, thus holding most of the valves slightly open. The other thought that comes to mind is that the cam gear may not be timed correctly. It is possible to miss match the mark on the cam with the mark on the gear when they are assembled. Of course the cam and crank gears could be mis marked.
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| 37RAGTOPMAN | -- 02-23-2010 @ 1:54 PM |
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low compression all cylinders ? I would first check the gauge,try it on a different car, just to check, if that is ok, turn the engine so one of the pistions is about 3/4 from the bottom, use a little gas and see if stays on top of the piston, if it goes past the rings fairly quickly this might be the problem,if the engine sat to long the rings could be rusted to the pistons,this does happen, you will have to pull apart one at a time and free up the rings, use a very good rust buster,buy a gallon,soak the whole piston in a small bucket over night, I made a special pick tool,and moved the rings a little at a time,till they would spin around on the piston by hand, you should have tested the compression first time dry and the second time wet,and compared the 2 readings, if you still have one head on do a compression check on that side wet and dry, and see if compression comes up, like it was said before the timing gears could be off and will have to be checked, if someone used cheap parts, or after market foreign gears could have went kaput,does the valve go up and down when the engine revolves ? how long did the engine sit? whats a few years,? only way I know of you will have to pull the timing gear cover and turn the motor till # 1 piston is at TDC,and check the marks on the gears, and see if they line up,and the valves should be tight down on there seats,and if the intake is off you should able chek the adjustment of the gap of the valves, let hear how you made out,37RAGTOPMAN
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| Stroker | -- 02-23-2010 @ 3:30 PM |
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All: Good advice! I'd like to add one more "test" that has worked for me. Take an old spark plug and punch out all the ceramic "innards". Braze, or weld a male air fitting that matches what you use for shop air to the steel body of the plug. Remove the air cleaner. Lock the engine by putting an appropriate socket and breaker bar on the crankshaft bolt to immobilize any crankshaft rotation (you may need a helper to hold the breaker bar) . Apply 50-100 psi air to each cylinder at top dead center, (compression stroke), and "listen". Repeat following the firing order for each cylinder. If you hear air coming out of the carb, you have a leaking intake valve. If you hear air coming out of the exhaust pipe, you have a leaking exhaust valve. If you only hear air coming out of the oil-fill-breather, you have bad rings. This test will not only isolate the problem (rings,valves), but will also tell you which cylinder is at fault, or any or all cylinders at fault. Dan
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| carpguy | -- 02-25-2010 @ 5:51 AM |
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Morning All, Thank you for the replys. At this time I'm just fit to be tied. I bought this truck in good faith and new I was going to have work to do. It is a nice looking truck but needed to be finished, the one thing I was told that the motor had been rebuilt in Spokane. I got this for my first project to keep me busy. I made it through everything learning as I went and from a lot of help from this site. After all this work I found the compression issue and it just got worse from there. I started to tear stuff down and check stuff when I took the driver side head off there was water in the #7 cylinder, you could see the crack. I took the motor out and started stripping motor when I took the fly wheel off the cover plate at the end of cam wasn't even tighten down and the bolts came out with very little finger preasure If i had not took the motor apart I could of lost all oil and had a real mess on my hands. I will be talking to the guy I bought this from and try and get some of my money back. Needless to say I'm pissed off!! Gary
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| 1932BB | -- 02-25-2010 @ 6:19 AM |
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Sorry to hear of your predicament! Unfortunately our hobby is not at a loss for rip-off artists. There is no shortage of stories out there that are similar to yours, even in my small town. When I had problems with the "three steps forward and two steps back" nature of the process my wife would gently remind me that this was supposed to be FUN! Since your truck is good shape sheet metal wise, most of the struggle is behind you. There are plenty of engines out there. Go for it!
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| 37RAGTOPMAN | -- 02-25-2010 @ 6:53 AM |
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GARY real sorry to hear about your problem,where is the crack,in the head or block, either could be repaired,they have a cold stiching process with tapered cast iron plugs, you can buy the kit,I have done many FORD ENGINE, with no problems. as long as the crack is not to near or inside the valve chamber,it get a little tricky because of tight quarters, LETS HEAR HOW YOU MADE OUT !!! I for one hate to hear when someone gets ripped off, if the person said it was rebuilt, it should have been rebuilt,and he should give you that amount back, or offer to pay for the repairs to be done, where is this person,??? hope not a EFV8 MEMBER MY 2 CENTS WORTH, 37 RAGTOPMAN
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| Pauls39 | -- 02-25-2010 @ 7:33 AM |
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Sounds like a poor rebuild job, but now you have the opportunity to do it right. Blocks can be repaired with sleves and iron plugs by most competent machine shops. If the truck has a good body you have the worst problem solved already, just a little more grief to deal with. I hope the seller will help you out with the engine. Let us know how you make out.
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| supereal | -- 02-25-2010 @ 11:10 AM |
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Repairing block cracks is not an amateur job, as it requires "decking" the block to reestablish a suitable surface for the heads, which should also be trued. It is sad, but true, that half or more engines that come to our shop are bungled "rebuilds". Just because the seller tells you it was "rebuilt", spend a few bucks before you buy to have a shop check it over. With sound blocks becoming very scarce, we will see more of this problem.
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