The original wire to the coil gave the full 12v when cranking to make starting easier then dropped voltage to 9.6 when running to prevent the points from burnig.
Referring back to my last post regarding the differences in tuning recommendations between Carter and Edelbrock... I just noticed that Carter uses larger jets, which makes up for their smaller metering-rod size. Working out the math and comparing the the two carbs indicates that the "effective area" of the jet and metering-rod combination are very similar.
This is an MSD Ignition. All the original + coil wire does is turn the box on. The box is powered directly from the battery, and the box provides the voltage to the coil, which in an MSD set up, can top 450 volts.
Drew, A 1112109 distributor has between 12 and 16* of mechanical advance stock. Did Dave modify that for more? His paperwork should show you how he curved it. When you power time the engine, take the blue springs out, and replace them with the 2 yellow springs. This should bring all your mechanical advance in by 2000 RPM, but you should verify that by revving it until the balancer mark stops moving upward. I suggest you leave the vacuum advance off completely. Set the total to 32* with the yellow springs. Then put in springs that get the advance in at 2500 RPM, or as close to that as possible. Verify the RPM when it is all in. The RPM specs that are described in the Crane instructions are only a guide. In your distributor, it may take more or less RPM. Again, you must verify that the timing is in when you want it. If you have 25* total and 3-4* initial, that means there is at least 20* of mechanical advance in the distributor.
drew, i knw this is kinda off topic but ive been meaning to ask you how you mounted your kickdown cable for the 350. did you find a bracket that fit or did you make one?:beers2:
Larry, Yes, I know the advance numbers do not add up, and I can't not find the info from Dave because I had to surrender my PC when I left my last job. I was sure I printed it out, so it must be around here somewhere. The info was just a copy of his original order form that I filled-out online... Does he normally send out an ignition cure plot?... Would be nice. If so he did not send one to me. I spoke with him a week or 2 ago but I did not ask him about any details on exactly what he did to my distributor. Was just covering the basics making sure I didn't overlook anything. He did ask if I decked the block or not. He said that these SBB are prone to hot-spots when they are decked, my machinist said it was still at the factory deck height. On several occasion I did follow your power tuning guide: switching to the stiff blue springs, setting initial timing at low RPM w/ no vacuum and then checking the over-all timing with the yellow lighter springs. I'm beginning to think I have some bad gas, wrong spark-plug heat range or carb issues. I've not given up just yet. Since the rain has gone, I'll be playing with it again today. I need to drive the gas out of it so I can filler up with a better brand. Regarding the MSD, I'm not sure but I believe it's "on-off" circuitry is TTL logic, so the voltage level to turn it "on" only needs to be about 2.5V and above... So who cares if it's at 9.6v. Randy, I went with the bracket that was suggested on your post (I think it was yours?), I think it was either Mr.Gasket or Edelbrock? Yes it does work but needed modification to fit the carb I'm using, and I'm still playing with it. It seems the slot in the cable is too long and I can't set it any further back. I'm going to try to have the car over at the Hot-rod get-together in Santa Clara (Scott & El Camino) this evening from 4 to 6 or so. Drop by.
As far as the MSD goes, yes, it turns the box on, so it doesn't need to be battery voltage. Dave has a place on his form to request a specific spark advance curve. If you didn't fill that part out, I suspect he gave you 20* mechanical advance. If you look at the stock specs for the 340 engines, Buick gave them between 26 and 30* total timing not including the vacuum advance. Your engine may or not want 32* or more, it may want less. Make sure there are no vacuum leaks. The motor should pull a vacuum consistent with the cam that is installed.
if you are refering to the post about putting a th350 in a 65 being a bolt in then it was mine. i think i put one in the carb section too but anyways.... i forgot i had that post. i remember someone posted that bracket, ill have to find it... if i didnt have school so friggen late i would have stopped by. do they do it every week? maybe ill go soon i just gotta time it right. :beers2:
Randy, Not sure how to copy a link or a quote here yet, but the thread was titled "Edelbrock throttle bracket for SBB that works!" writen by ElectrJim last December. You replyed to it so it should be in your suscription list on your "user CP" page. BTW... it is a Mr. Gasket bracket.
This thread? http://www.v8buick.com/showthread.php?t=167642&highlight=Edelbrock+throttle+bracket+SBB+works
I have not read all the post here, but will add a little pasted experience. First I bought a new GS 340 in 67. It liked to ping on about anything I put in it at the time except the Sunoco 260. I had a L79 66 Nova with 11 to 1 compression and it would run well on any preminum fuel. Needless to say I was disappoointed. Also the Nova got better fuel milage. I fooled around with it , but if you stopped the pinging it was a slug sure enough. I just don't think that combustion chamber likes much compression . My 2 cents. Jim N.
thats the one. there was a different one that was mentioned in my tranny thread. ill have to check out how drew got his to work before i get it. thanks sean :beers2:
Hot-rod get-together in Santa Clara (Scott & El Camino) this evening from 4 to 6 or so. Drop by. is this wed nights? if so to early for me i don't get off work until 6:00P.M. can you also shoot me a email im in san jose also just put in a 350 in my 72 skylark.
Emoore, Yep, it's every Wednesday night and the official hours are from 4-8PM, but it starts to thin out about 6:30 or 7. Last Wednesday there were about 130 cars. I also chatted with a guy who brought his blue 70 455 Skylark with a GS hood.
I finally discovered what the problem with my 340 tuning/timing issue is... too much cylinder pressure or compression. I figured 150 miles was enough to seat-in my rings enough to get a reliable compression check, so I went back to basics and did it. My average compression is 156 PSI. I then divided that by 14.7 to get my dynamic compression, which is 10.6:1 and way too high for 91 octane. I need to get my cylinder pressure down to about 145 PSI, this will give me the compression I was looking for... about 9.8:1. I could solve all this by getting the TA double-roller set up which includes the adjustable timing crank gear, but that goes for $145 + shipping. At any rate... Would a chevy offset woodruff key fit? Would be much more economical. Anyone have a the dimensions of a SBB woodruff key so I cam compare it to a chevy or any-other? Thanks
Drew, you can't equate static compression ratio to cranking compression. The only way to calculate static compression ratio is to have accurately measured all the volumes in the combustion chamber (everything over the piston crown), as it's a volumetric ratio, not a pressure ratio. Then to calculate dynamic compression, you have to have onhand that info plus the specific intake and exhaust valve timing events. Do you have any of this info so we can do some accurate calculations for static & dynamic compression? Devon
