70 Iron Posted February 24, 2014 Share Posted February 24, 2014 Need some advise on this 427 Chevy Crate engine timing,It calls for 10-12 Base and 34-36 total.I have it on 12 with the vacumn off and blocked,idle at 600 .I have a vacumn gauge connected to set the carb and on the gauge it reads "Late ign Timing". Can this be because of the cam ? It has a .527 intake /.544 exhaust,Duration 224 intake/234 exhaust @ .50 "lift. Centerlne 110 LSA. Its running great but was just curious If not the cam what would be your "expert opinion" Thanks Terry Quote Link to comment Share on other sites More sharing options...
Andreas Posted February 24, 2014 Share Posted February 24, 2014 What kind of vacuum gauge is that? What is your vacuum reading at idle? I have similar timing values on my 454 BBC, but can not keep a 600 rpm idle, more like 800 rpm... Quote Link to comment Share on other sites More sharing options...
70 Iron Posted February 24, 2014 Author Share Posted February 24, 2014 Hi Andreas,Its a compound meter ,fuel pump and engine vac,nothing expensive. I set the idle back to 6-700 rpms while setting the base timing and carb I need it to be around 12-1300 in park ,in gear it drops to about 900 rpm. It has a scale at the bottom ,red says Late ign timing and green that says normal motor ,also says at the bottom hand should remain steady in green zone At Idle in park at 1100 rpm its pulling about 30 inches of vac. Terry Quote Link to comment Share on other sites More sharing options...
Andreas Posted February 25, 2014 Share Posted February 25, 2014 Holy Smoke, 30 inches is pretty good... I would be happy if my Monte gets 20 inches in idle and park... This is the first time I hear vaccum related to ignition timing, but it probably can be done somehow... Quote Link to comment Share on other sites More sharing options...
70 Iron Posted February 25, 2014 Author Share Posted February 25, 2014 It may help if I read the manual :)reguarding the reading on the bottom of "Late ign timing" The needle was on around 30 inches and this is where this red /green scale about the timing was.My old ga only read vac and a no brainer. I'll find the manual and see what it says,maybe I was sucking in too many exhaust fumes and was delusional I thought 30 was high too my other BB only reads around 22 +or - Terry Quote Link to comment Share on other sites More sharing options...
Mike 57 Posted February 25, 2014 Share Posted February 25, 2014 Cams have a lot of influence on vacuum. That seems like a lot of vacuum! Are you sure you are not on a "ported" vacuum source. Try to pull vacuum at another source. I don't understand your gauge! 36 is a good number for "all in" timing. Quote Link to comment Share on other sites More sharing options...
70 Iron Posted February 25, 2014 Author Share Posted February 25, 2014 Hi Mike,I was on the vac port that screws in the rear of the mainifold.I would have to be on the carb to get ported would'nt I ?It was reading more then 30,around 32-33 inches at 1100 rpm. Maybe its a bad gauge ??.Don't know why the Green/Red scale is at the bottom and what its for. Its an inexpensive gauge that I bought at harbor frieght.It doesn't mention anything in the manual about it. I was just curious if anyone seen this on there gauge ,it idles good around 8-900 in gear and runs very well so it can't be too bad. What do you mean "All In " Mike ? Terry Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted February 25, 2014 Share Posted February 25, 2014 I think you need a new vacuum gauge to get 30" at idle is nearly impossible with the cam you have, my guess would be 15-17 at idle, my 454 with a thumper cam (227/241, 107 lobe sep, 102 centerline) and I run 16-18 degrees and am luck to have 11-13 inches of vacuum in park, my 350 has 19 with a near stock cam Quote Link to comment Share on other sites More sharing options...
70 Iron Posted February 25, 2014 Author Share Posted February 25, 2014 It sounds like it Sam,I've had this one for awhile and never used it until today so I can't take it back.I'll use my buddys gauge at the garage and see what inches of vac it really has. My Truck engine ,350/330 hp new crate engine only has 21 inches when I checked it a while back but with another gauge. Thanks guys,I knew it was a crazy question but couldn't delete it when I came to my senses Terry Quote Link to comment Share on other sites More sharing options...
Mike 57 Posted February 25, 2014 Share Posted February 25, 2014 Sorry, All in, is a term for initial plus centrifugal advance. I run my timing at 38 degrees, There is 16 degrees of centrifugal advance in the distributor, plus 22 degrees initial at the timing mark, equals 38 degrees "all in" Quote Link to comment Share on other sites More sharing options...
Andreas Posted February 25, 2014 Share Posted February 25, 2014 Is it this one? http://t.harborfreight.com/fuel-pump-and-vacuum-tester-93547.html If yes, u might be using the wrong scale. The vacuum Is Red from 0 to about 17 and green at higher values. Also the description Says the gauge reads 28 inches vacuum max... Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted February 25, 2014 Share Posted February 25, 2014 I think Andreas is on to something here Quote Link to comment Share on other sites More sharing options...
70 Iron Posted February 25, 2014 Author Share Posted February 25, 2014 Yes it looks like the one And I was reading the outside scale Andreas, Will check it again using the right scale tomorrow,thanks guys for helping this ole man out Terry Quote Link to comment Share on other sites More sharing options...
72 LS5 Posted February 25, 2014 Share Posted February 25, 2014 I have that same cam and only get about 12-13 inches in a 502 at 800 rpms with 14 initial and 34 total. Quote Link to comment Share on other sites More sharing options...
70 Iron Posted February 25, 2014 Author Share Posted February 25, 2014 I took another reading this morning and used the correct scale this time and thats what mine is reading 12-14 . The outer # were larger and eaiser to read Thanks Terry Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted February 26, 2014 Share Posted February 26, 2014 that sounds better Quote Link to comment Share on other sites More sharing options...
70 Iron Posted February 26, 2014 Author Share Posted February 26, 2014 Is old and Sinial a good defense Sam TR Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted February 26, 2014 Share Posted February 26, 2014 did we teach you anything? if so who says you can't teach us old dogs new tricks Quote Link to comment Share on other sites More sharing options...
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