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My first time posting here.
YouTube - 1000000951.MOV My brothers and I have been working on this car since last fall. So far we've done the following: - Had the zenith carbs rebuilt and bench synchronized - Did a compression test - they were all around 112psi - Changed the oil (actually just replaced all the oil that had leaked out of it). - Changed the points - Checked static ignition timing We still have the following immeate tasks on our plate: - Adjust the valves - We think that's what is causing the wicked backfires... Any input is appreciated. - Replace a leaking oil pressure sending unit - Fix an oil leak around the oil tank (see around 13 seconds in the video) - Rebuild all 4 brake calipers We hope to have it in drivable condition by the end of the summer. Wish us luck ![]() ...Peter Last edited by pwalke; 03-21-2011 at 05:48 AM.. |
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Join Date: Apr 2005
Location: outta here
Posts: 53,349
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Try running it with the air cleaner assembly in place. When you get it running, hold it at a constant throttle opening.
JR |
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Thanks for the tip, java. We were keeping it revving because we didn't want to let it die. We did let it settle down a bit in the middle of the video to see if it would hold an idle.
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Join Date: Dec 2003
Location: Arapahoe County, Colorado, USA
Posts: 9,032
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Peter,
First, WELCOME to Pelican ![]() You will find a lot of help here. Some more plans: When you rebuild the brake calipers, replace the four rubber brake hoses with original (OEM) rubber hoses. You should also replace the brake master cylinder. If it hasn’t already failed, it will after a bit of driving. When you are at the pedal assembly, check that no brake fluid has leaked onto the pedal assembly. I suspect you will find 15+ year old tires. Replace them now. Not infrequently one will fail catastrophically not long after being used again. Now is a good time for decisions on wheels & tires. Your rear may be a bit wide if you lower the car to ‘normal’ height. Check inside the rear fender (at the top, 2-5” up from the lip) for prior contact. The oil leak at the oil tank may be the ‘oil filter console’. This aluminum casting bolts to the oil tank with an O-ring seal. Hopefully replacing the O-ring will fix the leak. While there, inspect the grove and outer perimeter at the O-ring. It is common for the aluminum to have corroded, leaving the O-ring unsupported. You said: “Changed the oil (actually just replaced all the oil that had leaked out of it).” You may find that the ‘leaked’ oil is in the crankcase. If you added oil to the dipstick level, you now have too much oil. (Your oil leak may be from overfill.) A 911 drains the oil from BOTH the sump plate on the bottom of the engine AND from the bottom of the tank. It takes 7-8 quarts to initially refill. To measure the oil level, the oil must be hot, car level and engine idling. Use the dipstick, don't rely on the gauge. Does your tach follow rpm? Is it ‘steady’ or does it occasionally bounce? While ‘idling’, check the ignition timing with a strobe. Is it stable? Does it advance and return as rpm varies? These are usual indications of the points needing resetting or cleaned from too much lube. This can be related to your idle issue. Check again. When you ‘rebuilt’ the carbs, are you sure the idle circuits (fuel & air) are clean and not restricted? Try opening the throttles a bit with the stops on the levers (links disconnected). Can you slowly adjust down from (say) 2500 rpm? As you adjust slower, maintaining L/R balance, does it suddenly transition from running to stopped? If so, that is an indication that all the idle circuits are not functioning. Almost certainly you need to drain and clean the fuel tank. Even if you just added fresh fuel, put it in another car. There is a screen filter in the fuel tank outlet fitting. At this age, it must be cleaned (or replaced if damaged). There a number of hoses at the fuel pump adjacent to the fuel tank. All of those are 41+ years old and should be new. Same with the rubber hoses from the firewall at the front of the transmission to the carburetors. Be sure to use the original-type N-S hose clamps so to not damage the rubber hoses. There should also be a good fuel filter in the engine compartment. Without that filter, you may have re-contaminated clean carburetors. After 15+ years, all the high voltage components need replacing (cap, rotor, plug wires, plug connectors and spark plugs). These have time dependent life that is reduced by the environment. Before you drive, check / change the transmission oil. Remove the fill plug first. Inspect the drain plug for unwanted debris. There are dozens of other systems (large & small) that will need attention. Address the ones that are safety and running related first. We can help with priorities. It is very worthwhile to research a subject and then post questions. Detailed, high resolution, in-focus images really help. Eventually, you will ‘touch’ everything in your nice 41-year old 911. Congratulations on your first milestone – IT RUNS. ![]() Best, Grady
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ANSWER PRICE LIST (as seen in someone's shop) Answers - - - - - - - - - - - - - - - - $0.75 Answers (requiring thought) - - - - $1.25 Answers (correct) - - - - - - - - - - $12.50 |
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Grady, thank you for the well-written reply. With regards to a few of your points:
-Starting It is very slow to turn over, and we were only using one larger battery that we had lying around the shop and just connected the two terminals together in the other battery tray. We then hooked up another good battery so and it was still slow to turn over. Neither of the batteries fit... they are both a bit large. They were just to get the engine to turn over. Even with enough amperage, it is still very slow to turn over. You can see how slow it is in this video from us doing the compression testing. YouTube - Compression testing the 911 -Oil Great insight. I forgot that the dry sump system would influence readings... I didn't think that it might drain back into the crankcase. We added 5 quarts, which we knew was less than capacity, but we could still be in an overfill scenario. We'll check again and get back to you guys. - Fuel Tank We're thinking alike here, Grady. We actually hooked up a lawnmower gas can clamped just above the fan to eliminate this as a possible source of problems. We already drained and cleaned the tank, but for the first start, we wanted to eliminate as many variables as possible, so we used the lawnmower tank ![]() - Brakes Good point about the hoses... those are probably hard a rock by now. When we got the car, the calipers were seized. We took the calipers off and tried to move the pistons with compressed air, but they didn't move under 100psi. We're thinking of reattaching the calipers back to the car and using the brake line pressure to attempt to move the pistons We'll also take a look at the master cylinder while we're in there. Tires / wheels -Tires are definitely on our "todo" list. The tires are dry-rotted and are only good for keeping the car off the ground and rolling it around the garage. We'd like to keep the car as close to stock as possible. We aren't looking for a trailer queen. I think we'll keep the original tires/wheels. Maybe some fuchs wheels are in the future, but that's probably not until next year when we plan to start tackling the cosmetics. - Idle We didn't spend much time running it because we were concerned about oil leaks. As you can see from the video, we were moving the throttles to keep it running because we had a hard time starting it. We It seemed to hold an idle ok, but the engine was still cold. We'll spend some more time running the engine once we're confident that we have good oil pressure and fix the leaks. Carb rebuild - The carbs were sent off to a reputable carb shop in the area. They disassembled them, soaked them for a while, blew out every passage and put a new rebuild kit into each one... gaskets, orings, etc. They then did a flow test on the bench. I think they're in pretty good shape. We'll see once we run it a bit more. -Wires/plugs/cap/rotor,etc. I should have mentioned that we already replaced these... just part of the normal tuneup. Keep the tips coming. This is great advice. Regards, Peter |
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Grady,
You are the Best ! Vr,
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Bavaria911 1970 911T w/ 2.4S 1971 911T Targa w/ 2.2 RG Member # 818 |
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Congrats!
I love the beer cans on the roof ![]()
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Chad Plavan 911ST Race Car/2.5L SS Race Motor #02 1972 911T- Numbers matching- Restoring to stock 2011 Porsche Spyder Wht/Blk/Carbon Fiber Buckets/6-Speed (Sold) 2016 Elan NP01 Prototype racecar- Chassis #20, #02 |
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Grady, thank you for the well-written and well-thought-out reply. With regards to a few of more points:
-Starting It is very slow to turn over, and we were only using one larger battery that we had lying around the shop and just connected the two terminals together in the other battery tray. We then hooked up another good battery so and it was still slow to turn over. Neither of the batteries fit... they are both a bit large. They were just to get the engine to turn over. Even with enough amperage, it is still very slow to turn over. You can see how slow it is in this video from us doing the compression testing. YouTube - Compression testing the 911 -Oil Great insight. I forgot that the dry sump system would influence readings... I didn't think that it might drain back into the crankcase. We added 5 quarts, which we knew was less than capacity, but we could still be in an overfill scenario. We'll check again and get back to you guys. - Fuel Tank We're thinking alike here, Grady. We actually hooked up a lawnmower gas can clamped just above the fan to eliminate this as a possible source of problems. We already drained and cleaned the tank, but for the first start, we wanted to eliminate as many variables as possible, so we used the lawnmower tank ![]() - Brakes Good point about the hoses... those are probably hard a rock by now. When we got the car, the calipers were seized. We took the calipers off and tried to move the pistons with compressed air, but they didn't move under 100psi. We're thinking of reattaching the calipers back to the car and using the brake line pressure to attempt to move the pistons We'll also take a look at the master cylinder while we're in there. Tires / wheels -Tires are definitely on our "todo" list. The tires are dry-rotted and are only good for keeping the car off the ground and rolling it around the garage. We'd like to keep the car as close to stock as possible. We aren't looking for a trailer queen. I think we'll keep the original tires/wheels. Maybe some fuchs wheels are in the future, but that's probably not until next year when we plan to start tackling the cosmetics. - Idle We didn't spend much time running it because we were concerned about oil leaks. As you can see from the video, we were moving the throttles to keep it running because we had a hard time starting it. We It seemed to hold an idle ok, but the engine was still cold. We'll spend some more time running the engine once we're confident that we have good oil pressure and fix the leaks. Carb rebuild - The carbs were sent off to a reputable carb shop in the area. They disassembled them, soaked them for a while, blew out every passage and put a new rebuild kit into each one... gaskets, orings, etc. They then did a flow test on the bench. I think they're in pretty good shape. We'll see once we run it a bit more. -Wires/plugs/cap/rotor,etc. I should have mentioned that we already replaced these... just part of the normal tuneup. Keep the tips coming. This is great advice. Regards, Peter |
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Terrific start-up list by Grady.
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Bump... it took a while for my reply to get posted.
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