Bloo

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About Bloo

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  1. On a compression test its the balance that matters. The 20 percent usually means balance. In a perfect world cylinders would all be exactly the same, but with rough cast combustion chambers it just varies. Many shop manuals say 20 percent. On a new engine I would expect it to more or less meet that, but wouldn't suspect trouble if it barely missed. Random cars off the street could have 25 percent or maybe even a little more and not be broken. If your lowest was 100psi, 20 percent would be 120psi. Thats not far off from what you are seeing. Matching the absolute numbers in the book is another thing entirely. I have a pretty good compression gauge (snap-on), and have never duplicated another person's exact numbers. The balance will be the same as any other competent person gets. If there is a cylinder at 40psi (burned valve) it will still be super low when I test it. If cylinder 6 was the highest compression, it still will be. I ignore the absolute numbers entirely, unless its so far low or high that I suspect wrong valve timing. Compression testing is easy and quick, and can find stuff like burned valves (most common cause of a cylinder way lower than the others) or worn compression rings (by dry checking and then wet checking). Leakdown testing is more trouble but tells you a lot more. You have to bring each cylinder to exact TDC, then adjust a regulator on the tester. It tells you PERCENTAGE OF LEAKAGE. Again, like compression results vary with different people and different testers, but some average cars might have 20 percent. some tired but just fine ones might have even 35. A new engine, fully broken in, might have on the order of 5 if its really good. It might be 10. You want less. 2 would be nice, but if you have that, you probably spent hours in the machine shop nitpicking every last little detail of every detail of every detail. In the real world I doubt you will ever see it. Those numbers assume it is all ring leakage. While the tester is running listen for air. Figure out where the air is going. This is where the leakdown tester really shines. If an exhaust valve is burned, It will hiss out the exhaust pipe. If an intake valve is warped or burned (extremely rare) it will hiss out the intake (open the throttle and listen). A head gasket blown between cylinders would hiss out the adjacent cylinder. A head gasket blown into the water jacket blows bubbles in the radiator. It should only hiss through the crankcase (listen at oil cap), because the leakage should all be through the rings. One cylinder with a much higher leakage number might indicate a broken ring or holed piston or a scored cylinder. Have someone disconnect the air from tester for a moment while you listen to the various leak points, so you don't get fooled by the "sea shell" effect. The reason I thought of your PCV experiment was that I thought there wasn't an actual pcv port on the carb. If the port was out in a manifold runner I would expect the oil to go to one cylinder. Maybe 2. On a carbureted car, a tiny air leak at a vacuum connection on a manifold runner can cause a miss on one cylinder by making it too lean. I would expect oil vapor to follow the same path, and foul one plug.
  2. You cant really tell much about static compression ratio with a compression gauge. Everyones gauge behaves a little differently, cranking speed affects the readings (condition of the battery, gear ratio of the starter drive, etc). The cam grind affects it too. Some people hold the throttle wide open while taking the reading, some do not. Readings can be dry (lower) or wet (with a drop or two of oil, higher). The main thing with a compression gauge is that the readings are fairly close to the same. yours are. I wouldn't have been upset at all about those readings on a 9:1 Mopar back in the day. On the other hand one of my friends was driving around a Buick Electra with a 401 Nailhead and couldn't get good enough gas for it. The compression ratio was just too high. It's way better for the static compression ratio to be too low than a teeny bit too high. You can tell a lot more about the condition of an engine with a leakdown test, but the static compression ratio generally has to be measured with the engine apart. Your plugs look mostly ok. Light tan is perfect (other colors are possible with the gas now). Too rich would be black, Too lean would be white, often combined with signs of overheating or detonation (little balls of metal). The one plug with the buildup is most likely oil burning. If these plugs were in when you were experimenting with PCV, it could have easily come from that. The oily ones could be oil burning, but probably aren't. They look too clean. Oil can come up the spark plug threads on an oil burning engine. I doubt it though. If theres any sign the oil could have come from the outside, like a leaking valve cover gasket or oil cap, then it probably did come from the outside.
  3. Nearly all 904 (or 727) pan leaks are actually shift shaft leaks. Take the shift shaft and its concentric partner the kickdown lever off and replace the 2 seals. I drop the pan and remove the valve body usually to do this. I think its easier. Here is someone who changed them from the outside without even dropping the pan: https://www.vanning.com/threads/ubbthreads.php/topics/580264/torqflight_727_seals.html
  4. Looks good! Rebuilding the originals is the way to go. I guess you could peel the edge back, but I never thought I could do it and then get it back together looking good. I always ground them apart like you did, and then silver soldered or brazed them back together. I didn't have access to TIG. For what its worth "Chore Girl" type scouring pads work well to replace the mesh, either the stainless or the copper. It also works for the draft tube filter in some cars.
  5. The pushbutton shift wasn't electric on those cars. There should be 2 cables. One is for park, operated by a lever. The other one is for the pushbuttons, and selects reverse, neutral, drive. low. There should be a mechanical linkage, made of rods and bellcranks, going up to the carburetor. This linkage must be present for the transmission to work properly. It tells the transmission how hard and how late to shift. It also provides a kickdown to second gear. The transmission cannot survive long without it. Best of luck finding your parts, and welcome to the forum!
  6. Matt Harwood: I have been following this saga for years as well, and can understand the frustration. After reading online somewhere that the Auburns were FINALLY here, I called. They said they had them in stock (6.00:16 only) and would have sold me a set that day. They are pretty expensive, but I might have done it if I had a second set of wheels ready to go (I don't). This took place about 2 months ago. I suppose its possible they could have other sizes in stock now, thats why I suggested calling, but I see you already have. To be clear for everyone else following along, the "Diamondback Auburn" is a designed-from-scratch radial that looks like a vintage bias tire, pie crust edge and everything. AFAIK it is only a 16 inch tire, I think it was supposed to (eventually) be available in 6.50:16 and 7.00:16 in addition to the 6.00:16. DIamondback tires in smaller rim sizes 15, 14 etc., as far as I know, are modern off the shelf radial tires that have a whitewall permanently vulcanized to the side.
  7. Call them. Last I heard they had only 600:16. That was a while ago.
  8. No The crank is out 180 degrees EVERY OTHER rotation, because it turns twice as fast as the cam. It's completely normal. It IS, however, possible for the distributor to be out 180 degrees with relation to the cam, because it turns the same speed as the cam. This is NOT your problem. If it were simply 180 degrees out, it could not run at all. Its impossible. I would double check the ignition timing again, and the firing order. Could the wires be put on the distributor incorrectly? See which way the distributor turns, put on #1, then follow the firing order around the distributor in the direction the rotor turns. To be clear, when you put the #1 wire on, the engine should be on top dead center of the COMPRESSION STROKE for cylinder #1. Remember this only happens EVERY OTHER turn of the crank. Put #1 on the post the rotor is pointing at. You may need to advance the timing a little bit to get it to start. To advance, turn the distributor SLIGHTLY in the OPPOSITE direction the rotor turns. If its kicking back while trying to start use less advance. If that doesn't help go back to the basics, and do a compression test and a leakdown test. Good luck!
  9. That looks like a Delco solenoid to me. Is it? On a Chrysler? ALMOST everything on that solenoid is rebuildable. The adjustment on the front just sets the pinion depth. There should be a spec in the manual for that. The copper disc has a little spring so that it can bottom out on the copper bolts a little before the solenoid bottoms out. Copper discs if not available can often be taken off and turned upside down. Copper bolts often have half of the heads burned off. They can be replaced. If not available sometimes they can be turned around backwards to get the full height back around the side that contacts the disc. The only thing that cant be fixed is a bad winding. There are 2 windings, check continuity on each of the two windings. I would really need to see the manual to tell you more. Is there a relay inside the cover? If so, look for one winding to be from one of the relay contacts to one of the copper bolts on the solenoid. The other one should be from the same relay contact but to ground. If the windings are good, you can rebuild it. If not, its gonna be expensive. Good luck.
  10. The first thing to do is to check if the gearing is ok. Gearing is a separate issue from speedometer calibration. Take it out and drive it 10 miles, while paying close attention odometer and to the mile makers. If you gained a tenth, the speedometer is geared 1% fast. If it gains a mile, thats 10% fast, etc. Gearing is fixed with the little set of speedometer drive gears in the transmission. The steps (for different gears) are usually around 5%. A different tire size can also make a correction. If the speeedometer still reads wrong, then it needs calibration. You could drive 60mph (one mile a minute) by the speedometer for 10 miles, and have a passenger time you with a stopwatch. It should be exactly 10 minutes. You can caluclate how much change you need to make from there. I don't know about the magnet. I usually get the gearing right and let a speedometer shop calibrate the head if it needs it (it usually doesnt).
  11. For crankcase ventilation to work you need 2 things, 1) a way for air to get in and 2) a way for air to get out. The air coming in must be filtered or dirt will be sucked into your crankcase. On a draft tube system the way in is usually a breather cap and the filter is in it. The draft tube creates a suction when the car is moving, and air flows in the breather cap and out the draft tube, hopefully taking the crankcase vapors out with the air. Draft tube systems left to their own devices would suck oil out. There has to be a way to separate the oil from the air. I don't know how the nailhead accomplished this, but for example on a Chevrolet 283, there is a can shaped thing with a series of baffles that seperates the oil and drains it back into the lifter valley. On a Ford 352, there was a steel or copper mesh like the one used in the kitchen to scrub pots. It can cake up with carbon and plug. You need to get that draft tube unplugged, and the oil separator, if there is one, also unplugged. Just connecting a PCV valve isn't going to accomplish what you want. If the draft tube is unplugged, the pcv will try to suck dirt up the tube. If it's plugged, its gonna create a vacuum in the crankcase and probably interfere with ring sealing. If the engine has a lot of blowby, draft tube systems tend to smoke out the tube at stoplights. It might just be a little. On the other hand, if you have a lot of blowby it can look like the car is on fire. I had a Ford like that. Pcv can help. You still need a way for the air to get in, and a way for it to get out. The breather cap is the way for filtered air to come in, and the PCV valve is the way out. On older engines, this usually means putting the valve in the hole designed for the draft tube. More modern systems put the breather cap on one valve cover and the pcv on the other. Any leftover breather tube hole would need to be plugged. This ventilates the rocker areas better but tends to leak more oil on the outside of the valve covers. Now, about that oil scum around your breather cap. If your engine is not basically brand new, with perfectly sealing rings, its normal. Every old car I have owned with a breather cap did this. No pcv system EVER keeps up all the time. The manifold vacuum cannot support enough flow for that without making the engine run like crap. When it doesn't keep up, oil vapors will come out the breather cap. In the 80s, they plumbed the breather cap vent up to the air cleaner. That just got the oil all over the air cleaner. On systems that have the PCV valve in the opposite-side valve cover, there has to be a baffle under the hole to keep the oil from the rockers from getting sucked up the pcv valve. Some aftermarket valve covers omit the baffle. Without the baffle the oil consumption will be astonishingly high. I wouldn't get too concerned about the flow rating of the valve. If you have a smooth idling cam, Dynaflow, high rearend gears, etc. then one from any similar displacement smooth idling automatic will be fine. Probably even a Chevy 350 one will be fine. The spring isn't supposed to be strong enough to hold the valve shut. They basically rattle. They are open at idle. Its normal. Some early systems didn't have a valve at all, just an orofice to restrict flow. The downside is if the engine backfires, it can cause a crankcase explosion. The valve is supposed to slam shut and prevent the fire from getting to the crankcase vapors. Supplying vacuum to a PCV valve is the tricky part. It is a huge vacuum leak. The trick is not making the car run like it has a huge vacuum leak. First, you are limited by the engine itself in how much air you can let in (the flow rating of the valve determines how much actually gets in). Then you must mix the air in such a way that it does not screw up the fuel distribution. This is toughest at idle. Just hooking it to a power brake nipple or whatever will not work well, you will have a horribly lean cylinder or two. Almost all factory PCV systems mix the air with the fuel/air mixture coming out of the idle jets. The PCV port will split and come out right under them. Sometimes its built in to the throttle body of the carburetor, sometimes its a plate under, but in 99.9 percent of all cases, this is how its done. The other 0.1 percent don't work very well. If you cant mix the air in under the jets, you would be way better off with a draft tube. Good luck with the project!
  12. Sounds good, but what route in a prewar car like the ones Brass Is Best posted? Who has done it and which way did you go? Assuming your prewar car is not a Buick Century or a supercharged Graham or something, are there slow enough roads today?
  13. I have an excellent one that is branded "Pacific Power Batteries", but I suspect that is a regional brand. I'm in Washington State. I wouldn't convert it to 12v. Most 12v conversions I have seen are about 75%-90% working. There is always something that doesn't work right with the conversion, some gauge, or the radio, or a heater motor, etc, and then you open the hood and theres an alternator. I'm sure there are some bad designs out there, but generally speaking, the engineers designed these things to work on 6 volts and they did. They do crank slower, but this is by design. It just sounds odd today. At 6v, current is twice as high as it would be at 12v to do the same work, so clean connections a must, as is larger wire in the battery cables. Generally speaking, the ones sold at parts stores for 12v cars are not big enough. Why do you need it to crank for a few minutes? Most 12v cars cant do that.
  14. No documentation would be needed in the US. In 1975 the only common wheel diameters for cars were 13" , 14" , and 15". Anything larger in diameter would have been for a very old car or a truck. Wider 15" (and 14" and 13") tires and wheels were readily available. You just bought them and put them on. No one had to approve a different size. It is still like this, but today the common sizes are 16" and larger.