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| Mac Winter 76XB351GS |
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Gday,
I have the MSD 8350 Billet Ford ready to run distributor in my 351c. Ive got the engine running and its going well. I havent changed the advance curve from stock (Slowest curve 20deg above initial advance at 4000rpm). I currently have the initial advance set at 10deg and there is no sign of detonation anywhere in the rev range. I only use BP Ultimate 98. I usually drive inbetween 1500 and 2500 rpm and have a cam and intake designed to run up to 5000rpm. I dont take it down the strip, only drive on the street. Just want to know what people have experienced with this dizzy in regards to changing the curve with the weights and springs provided. Also what type of curve should I choose? What is the max advance I should run, both initial and total? Thanks
_________________ 76XBGS, 383c, custom crow cam, 4V p&p heads, Isky SS Valve+springs, extractors, 2.5"twins, MSD Ignition, Edelbrock intake, Forged bottom end, Barry Grant 750DP, thermo, discs, toploader, Holley fuel pump, SUPERCHARGED! |
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| brenx |
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What camshaft do you have and what are it's specs. What is your diff ratio too?
Generally small cams (not stock) like 34deg total on 98ron all in somewhere between 3500-4000rpm. With 2V cc heads. This all depends on the type of cyl heads too. Then you have something like this setup: 351 F246 10.5:1 2V cc cyl heads 750dp 3500-4500rpm convertor 4.11 gears This setup generally likes around 14-18 deg inital and 36-38deg total. All in by 4000rpm. If you ran alloy cyl heads? Generally no more than 30 deg total.
_________________ XB Fairmont sedan 11.07@123.02mph |
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| Mac Winter 76XB351GS |
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Ok I have the crow 21666, I would have gone bigger but I cant afford to be swapping out the gearbox and diff just yet so I chose one that works well with the C4. I set the cam to 0degrees because it kicks in fairly early anyway.
216661,2 IN.25/65 EX.74/26 270 280 204 214 .484" .510" 1600 4600 K2102 Dual pattern economy/performance cam for stock to mild engines. As far as I know it has the standard compression for a 2v, but the pistons are 20thou over. The heads are a brand new set of iron 351 that have had a port and polish but nothing done to the chambers themselves. I am not sure of the exact ratio of the diff, I expect it to be a 2.73 out of an XD as I do approx 2000rpm at 110 in 3rd. I want to change to a 9inch 3.5 or 3.7 later on, like what came standard in the car. I might try 14-16 deg initial and see how it goes. Take it up some hills at full throttle and listen for any detonation.
_________________ 76XBGS, 383c, custom crow cam, 4V p&p heads, Isky SS Valve+springs, extractors, 2.5"twins, MSD Ignition, Edelbrock intake, Forged bottom end, Barry Grant 750DP, thermo, discs, toploader, Holley fuel pump, SUPERCHARGED! |
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| brenx |
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Don't put any more than 32-34 total in it which is almost stock timing. Stock timing is 6 inital + 24 mechanical = 30 total. Somewhere around 10-14 initial will work well with your cam. Don't let it come in too fast. You can speed up the advance further when you change the diff ratio.
I currently run a locked dizzy on my alloy headed engine @ 30 deg from idle->7500rpm. Mine won't ping due to the 98 ron fuel, 4.11 gears and 5400rpm stall convertor.
_________________ XB Fairmont sedan 11.07@123.02mph |
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| Mac Winter 76XB351GS |
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Thanks, I'll give it a go tomorrow. Hopefully change the diff out soon. Staying in 1st till 100 without redlining is all well and good for freaking out subarus but more bottom end would be better.
_________________ 76XBGS, 383c, custom crow cam, 4V p&p heads, Isky SS Valve+springs, extractors, 2.5"twins, MSD Ignition, Edelbrock intake, Forged bottom end, Barry Grant 750DP, thermo, discs, toploader, Holley fuel pump, SUPERCHARGED! |
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| Mac Winter 76XB351GS |
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Ok, I finally got around to winding the timing forward today. Its a pretty hot day so I figure if its going to knock it will be now. I set it to roughly 14-15deg and no signs of detonation that I can tell. There is a knocking sound inbetween 1400 and 2000 from the left bank of the enging but im pretty sure it is just the dent in the extractors as it has been there since I bought the car. It sounds like noisy lifters but the valvetrain had been totally replaced, still there.
So currently im running 14 base, with 21 centrifugal to make 35 at 4000rpm. With a shorter diff, 3.5 to 3.7 I should leave the base and total where it is but bring the total advance in earlier? If so, how early should I be looking at, I have springs for 3750, 3150, 3000, 2200, 1800.
_________________ 76XBGS, 383c, custom crow cam, 4V p&p heads, Isky SS Valve+springs, extractors, 2.5"twins, MSD Ignition, Edelbrock intake, Forged bottom end, Barry Grant 750DP, thermo, discs, toploader, Holley fuel pump, SUPERCHARGED! |
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| 66 coupe |
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Mac,
I've got an 8850 on my 351, using one light blue spring and one light silver spring (Curve E in the manual) Also using the black bush with 16 degrees base timing. This gives a very responsive bottom end, and all advance is in by 3000 (which is well suited for clevo's) I also run BP98. Check the plugs regularly, even though you dont hear detonation, it can still be happening, which will show as tiny dots of metal / alloy on the plug insulator. With the knocking / ticking, mine does a similar thing, for me, its a combination of leaky extractors, leaking gaskets between extractors an heads, and a couple bent pushrods. I will get to it one day 
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| brenx |
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You would possibly be able to bring is down as low as all in by 3000rpm. If it does knock just a tad you have a few options? Raise the all in by rpm, reduce timing or colder plugs.
I'm not sure what you have in there now? Generally clevo's have BP5ES with irons from memory. If you go a 6? Thats one step colder. I run 6's myself. A mate of mine with really high cyl pressure 210-220psi runs 7's.
_________________ XB Fairmont sedan 11.07@123.02mph |
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| 66 coupe |
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Yeah, use BPR6FS plugs as a minimum, 7's if the motor has a lot of work done to it, and sits on high rpm's a lot.
Use the BPR plugs as opposed to BP plugs to solve interference problems. Std listed plugs were 5's but they are a bit too hot for todays s**t fuel. |
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| Mac Winter 76XB351GS |
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Im running the 5's at the moment. The 6's with the resistor sound the go for me as high revs dont really come into it and the motor isnt too hot. I mite buy a set and keep a few 5s in the glovebox as spares. Only bought the plugs a couple of weeks ago....
_________________ 76XBGS, 383c, custom crow cam, 4V p&p heads, Isky SS Valve+springs, extractors, 2.5"twins, MSD Ignition, Edelbrock intake, Forged bottom end, Barry Grant 750DP, thermo, discs, toploader, Holley fuel pump, SUPERCHARGED! |
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| 66 coupe |
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if the 5's are new, and its not pinging or running on, just leave them in...
change them at the next service. |
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