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| crappy fuel milage https://www.slantsix.org/forum/viewtopic.php?t=63670 |
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| Author: | wjajr [ Wed May 29, 2019 1:17 pm ] |
| Post subject: | crappy fuel milage |
Last summer about this time of year I received the old slant back from the machine shop after a full rebuild. Some of you may recall it ran hot as a fire cracker at idle, cam was installed retarded and it hardly ran. I advanced the cam from 104 to 99*, and now have rolled on1200 miles since then. Engine runs at correct temperature, seems to have good acceleration, and last check was swilling fuel at the rate of 13 MPG. Occasionally the engine has spin back when shut off when in Park, but dies correctly when shut off in gear 90% of the time. I picked up a dial back timing light this weekend, base timing is set at 15*, mechanical is 30* all in at 2800rpm, and I discovered today the vacuum advance is not advancing but its pod holds vacuum. Have not had a chance to mess with the vacuum advance problem, probably something jamming the base preventing it rotation... The cam installed is #346 from Oregon Cam Grinders. Compression is at 9.5:1 Engine builder had to bore from 30 over to 40 over, and did not take that modification into account to keep my requested 10:1 compression request. What would be a good base timing to start with now that engine is broken in, and what mechanical advance should I be shooting for? |
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| Author: | Dart270 [ Wed May 29, 2019 3:12 pm ] |
| Post subject: | Re: crappy fuel milage |
Your 15 and 30 deg settings should be quite close. Not sure why it is spinning back. Is this on premium gas? If not, run premium. If so, might want to try a colder plug (2 heat ranges colder for a start). With properly working vac advance, you should get 10-20% better MPG. Lou |
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| Author: | wjajr [ Thu May 30, 2019 5:16 am ] |
| Post subject: | Re: crappy fuel milage |
Lou, Current plug is NGK UR5, so two steps cooler would be UR7, right? Porcelain on plug is on the white side, with light gray ground electrode. Mixture must be close to ideal. I have a stumble during throttle opening, and it's probably due to wrong power valve (maybe a 5.5 or 6.5) not opening soon enough to pick up the slack. I need to check vacuum levels at idle & while under way, and get the correct unit. I'll dig into the distributor problem this weekend. Thanks Bill |
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| Author: | wjajr [ Sun Jun 02, 2019 10:00 am ] |
| Post subject: | Re: crappy fuel milage |
A funny thing happened on the trip over to O'Rilley Auto Parts the other day. Pulled into lot, parked, shut it down, decided to relocate in space, turned the key for a re start... Nothing but a feeble click, several more key turns nothing. Well that's good I thought. Left the 67 boat anchor, went in to get Lou's recommended spark plugs... As usual O'Rilley didn't have them something I have grown used to looking for 1967 HI parts at that place, same for all the others no listing so no parts. But, that's another story. Back to the dead Dart, I was dealing with the store manager, and asked if he could perform a battery test, its five or six years old. He did, and battery was OK, loaned me a hammer to persuade the starter thinking bendex may have become lazy; that loving tap, tap yielded one more click, and that's all it had. I employed one of two tools I carry the AAA card, one hour later tow truck arrives a brand new shinny 2019 Ford flat bed and a young guy that thought my new fuel tank was some kind of skid plate LOL. Anyway he was able to shoot the car right into my garage easy peasy. There it sat for the next two days, other projects occupied my time. The third day I started to figure this heap's problem out. Hooked up remote starter button, it activated the starter. Tried to start engine with key, it would fire in start position but not in run... That's easy popped in one of two spare ballast resistors residing in glove box; same problem won't run on run circuit. Than out came ignition switch, checked it for continuity, it checked out just fine. Some head scratching, looked up my notes on the harness modifications I had made, and decided those could not cause the current problem, opened FSM electrical diagram and notice after some studieing run circuit is a blue with tracer conductor; ding, ding, ding. That's a bell ringing in my head. When removing ignition switch there was lose, not landed blue with tracer conductor which I thought was to be attached on a spade excluded from the multi connector containing four or five conductors to back of switch labeled as ground which I had before getting to this point landed that blue wire on. Then I realized that blue with trace needed to be included in the multi connector. Here's what happened, eleven years ago when overhauling the wire harness, I neglected to make sure the little brass leg that locks female connector into the plastic was crushed flat so it would not lock in, and when multi holder was pushed onto the back of the switch it made just enough contact to last for eleven years before vibrating loose braking the run circuit. Big PIA, but my inner cheep bastard was happy, happy, happy, I didn't spend anything for the tow or new parts parts like a starter counter guy wanted to sell me, and lowering brake in idle rpm a bit, the spin back problem seems to have gone away. Its taken 1200 miles for this engine to loosen up and want to run. |
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| Author: | wjajr [ Sun Jun 30, 2019 8:39 am ] |
| Post subject: | Re: crappy fuel milage |
Me quoting me: Quote: I picked up a dial back timing light this weekend, base timing is set at 15*, mechanical is 30* all in at 2800rpm, and I discovered today the vacuum advance is not advancing but its pod holds vacuum. Have not had a chance to mess with the vacuum advance problem, probably something jamming the base preventing it rotation.
Well I finally got aroung to pulling distributor to see what was not allowing vacuum pod to advance timing. Problem was the little tit at end of shaft from pod that connects to plate in distributor was not in its hole. After a little bench time, backing off of the hex key tip-in adjustment it got it installed correctly, and now it advances timing. I still need to make sure tip-in is where it should be.
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