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Discussion Topic:
39 Deluxe timing issues
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carcrazy |
07-03-2020 @ 12:50 PM
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Senior
Posts: 1674
Joined: Oct 2009
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Many of the 1939 and 1940 Flathead V-8's had steel cylinder sleeves. These sleeves are of .o40 wall thickness. They can be removed by a competent machine shop but new sleeves are no longer available in this size. What can be done is to purchase new pistons that have the O.D. of these sleeves plus .003" and hone the cylinder walls to the correct size for these new pistons. Your new bore diameter will be approximately 3 1/16" + .083". This works out to be approximately 3.1455". Be sure to verify that your block is crack-free before proceeding with your rebuild.
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TomO |
07-03-2020 @ 7:40 AM
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Senior
Posts: 7256
Joined: Oct 2009
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If you are going to rebuild the engine, make sure that the machine shop is familiar with the 1939 and 1940 blocks. Many of them were made with thin steel sleeves and all of them had floating rod bearings. If the block has the steel sleeves there is no need to bore the engine, just replace the sleeves. Just removing the sleeves and using the block requires that sonic testing of the cylinder walls be done. These blocks are old and rust may have made the walls too thin to accept an overbore. If it does not have sleeves, the max overbore is .062. Any larger bore can result in thin spots in the cylinder walls that could fail when driving the car. The floating rod bearings require that the bearing has an inside and outside specification. The rod bearing opening must be kept round or the bearing will fail. You can also install a crankshaft from a 49-53 Ford or Mercury and use the fixed insert bearing rods. Dan, you should edit your profile to allow private messages and your location. Having your location will allow someone that lives in the same area direct you to local resources, like mechanics and machine shops.
Tom
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therunwaybehind |
07-02-2020 @ 11:51 AM
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New Member
Posts: 180
Joined: May 2019
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The decision to rebore depends on the dimension of the bore and whether it has an out of round or a severe ridge above where the piston rings ran. The appearance is of carbon which can be scr*ped off. You need a ridge reamer to remove the pistons by tapping them out the top without breaking the piston ring interland areas. When putting them back in you need a ring compressor which could be a sleeve exact for the bore or a wrapped up steel spring band for whatever bore you choose. There is also water deposits where the head gasket had holes for the water jacket and lead deposits as forms on spark plugs. You will have to take the oil pan off to get the rods off the crankpins. Put short sections of fuel line hose over the rod studs to avoid nicking the crank journals. Each bore is an individual. New pistons can come in sets of four matched by selective fit to about a half thousands in bore. The rod caps are also individuals to each rod and cannot be reversed on the rod either. Don't just tear it apart and scatter the parts. Some folks use muffin tins or bread tins with labels and others prefer to put tape on each part with a label.
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Dan39Deluxe |
07-01-2020 @ 12:30 PM
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Member
Posts: 13
Joined: Jun 2020
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I think these pistons need to be replaced. I should get this re bored out right? Any suggestion on bore and piston size?
This message was edited by Dan39Deluxe on 7-1-20 @ 2:54 PM
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TomO |
06-29-2020 @ 7:52 AM
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Senior
Posts: 7256
Joined: Oct 2009
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You should fix the cause of the distributor binding before doing anything else. You may been one of the lucky ones that installed the distributor 180 out and did break the casting, but knocked the point plate loose from its position. You may have damaged the rotor in the process.
Tom
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Dan39Deluxe |
06-27-2020 @ 4:10 PM
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Member
Posts: 13
Joined: Jun 2020
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It is a 91-99. But no fuel line hooked up I've been just pouring fuel or starting fluid in. I had a strong blue spark last I checked. It's possible I fouled the plugs last time I tried starting it. I'll try again and I'll make sure I still have a good spark first.
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40 Coupe |
06-27-2020 @ 5:35 AM
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Senior
Posts: 1679
Joined: Oct 2009
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What carburetor do you have ? The Ford 91-99 is a model of the 94 carb that was used for many different years on Fords. These carbs have a power valve that can fail with backfires. A failed power valve will allow too much fuel into the engine causing flooding on restart and while running. Even with a failed PV the engine should start and run but very poor performance It looks like the engine has not run for a long time. I would not be overly concerned at this point with the low compression. Get it running and retake compression after valves are free and seat better. The MMO will help with the valves. It does take time. Keep working on it. You may want to take the carb apart and clean it then reassemble without replacing anything. This may help starting . Plus you will learn a lot about the carb. There are a lot of photos of the internals on the web The same can be said of the distributor. Take it apart and find out what is causung the binding and clean it up make sure everything is free to move and lubed. Clean the contact points and check for about .015" spacing.
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carcrazy |
06-26-2020 @ 5:27 PM
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Senior
Posts: 1674
Joined: Oct 2009
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Sounds like your spark plugs are fouled out. You don't have any spark if you can't get it to fire with starting fluid. Replace all of the spark plugs with new ones that are properly gaped and tightened down. Even with low compression, 50 to 60 PSI, the engine should start up and run if it has properly timed spark and fuel.
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cliftford |
06-26-2020 @ 4:22 PM
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Senior
Posts: 845
Joined: Jan 2014
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I agree that the compression is a way too low Should be more like 80 to 100#. I would pull the heads and check cylinder wear and valves. since they apparently are all low.
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Dan39Deluxe |
06-26-2020 @ 1:37 PM
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Member
Posts: 13
Joined: Jun 2020
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@Tom ya the starter was the first thing we fixed my dad unfroze it but worth taking a closer look. I wasn't so worried about the solenoid and cables cause I was getting a good blue spark. There's prob over 50% chance I'm wrong about the cranking speed anyway. Prob just not used to the slower 6v system. And there's prob a bigger reason why it's not firing. I read somewhere that with low compression they won't start. @carcrazy ya I tried that a bunch already with both straight fuel and starting fluid. She just won't even putter. The weirdest part is it would fire with the firing order wrong and backfire consistently. But now when I'm like 90% sure I got the firing order right, it wont fire. I'm already started now on the long grind of disassembly. It had to be done cause I need to either repair or swap frames and I want to get everything cleaned up anyway. Will try again with everyones tips when she's all put back together. appreciate ya'll
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