Re: TDC Question
[Re: 6PAX]
#3168555
08/17/23 02:43 PM
08/17/23 02:43 PM
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Joined: Jan 2003
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440Jim
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Looking at the top two pictures, would you say cylinder #1 or #6 is on TDC? With the balancer set on TDC, the top pic are the lifters for #1 and the bottom for #6. Top two pics, #1 is firing and #6 is on overlap. It should be even more obvious 20-30 degrees after TDC on the balancer/timing marks; the cylinder on overlap will have the intake opening.
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Re: TDC Question
[Re: 6PAX]
#3168561
08/17/23 03:00 PM
08/17/23 03:00 PM
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Joined: Oct 2007
Posts: 4,209 New York
polyspheric
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master
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Both are @ TDC: one is firing and the other is on OL. Every 360 degrees they switch
Boffin Emeritus
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Re: TDC Question
[Re: 440Jim]
#3168809
08/18/23 01:44 PM
08/18/23 01:44 PM
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Joined: Jan 2003
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440Jim
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It should be even more obvious 20-30 degrees after TDC on the balancer/timing marks; the cylinder on overlap will have the intake opening. This Comp Cams diagram might help you visualize what I said.
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Re: TDC Question
[Re: B1MAXX]
#3169099
08/19/23 09:14 PM
08/19/23 09:14 PM
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Joined: Jan 2003
Posts: 31,050 Oregon
AndyF
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Agreed I just take it one more step, after pointing the rotor at the right tower I fine tune the reluctor to line up. Yah, having a reluctor makes it a little more difficult. Back in the old days when I ran electronic ignition I would machine additional slots in the reluctor so I could fine tune the rotor phasing. That was actually a requirement for some performance engines with vacuum advance. The factory reluctor position wouldn't work on some combinations. I had forgotten about that since I haven't used a reluctor based ignition system in 20 years.
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Re: TDC Question
[Re: B1MAXX]
#3169159
08/20/23 10:17 AM
08/20/23 10:17 AM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
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Circle Track
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not a dealbreaker but I would run the plug wires in the OE order around the cap which lets em lay the neatest with the shortest lengths possible. this might help prevent a future mistake. EDIT this would be the #1 plug wire in the cap facing the front of the engine on a SB and at the 5 o'clock position looking over the pass fender on a BB. you can reclock the intergear to get it where you want it. be sure to check rotor phasing & with no vac adv I want it dead centered and with vacuum advance I want the trailing edge of the rotor tip at the trailing edge of the cap terminal as vac adv will pull it back against rotation as only vac adv not mechanical advance changes phasing. You can redrill the reluctor with a mini drill bit then break the edge out with a mini file to reclock the roll pin in the reluctor to change phasing and Echlin has a rotor with a longer blade (MO3000 iirc) that will help reduce the gap.
Last edited by RapidRobert; 08/20/23 12:25 PM.
live every 24 hour block of time like it's your last day on earth
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Re: TDC Question
[Re: B1MAXX]
#3169195
08/20/23 01:07 PM
08/20/23 01:07 PM
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Joined: Feb 2015
Posts: 2,079 CA
crackedback
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Where the slot in that drive goes is dependent on the distributor. MSD's have been known in some engines to be miles off with rotor direction/#1 tower when the drive is installed per the manual.
I usually identify where I want the #1 tower on distributor, figure out where the tang is pointing, get drive dropped in. Then when ready to fire it up and wired, hook up a timing light on #1 wire, timing mark in 15-20 BTDC area. On a BB turn housing counter clockwise, turn on ign, and twist housing slowly back clockwise watching for the flash. Should be very close to timed up.
Last edited by crackedback; 08/20/23 01:11 PM.
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Re: TDC Question
[Re: 6PAX]
#3169376
08/21/23 10:27 AM
08/21/23 10:27 AM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
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18 is excellent. pics are correct: rotor at 5 o'clock/reluctor dead even with the magnet no matter how the slot is clocked but in this case it is parallel which that is a good starting point & is correct most of the time. EDIT some dists have different bottom tang to rotor clocking
Last edited by RapidRobert; 08/22/23 11:01 AM.
live every 24 hour block of time like it's your last day on earth
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Re: TDC Question
[Re: Cab_Burge]
#3172509
09/03/23 09:07 AM
09/03/23 09:07 AM
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Joined: May 2005
Posts: 1,995 Apollo, PA.
B1MAXX
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Ditch the thermostat, try again a fan blowing at the engine compartment/grill is always helpful.
But that being said at 10 minutes the cam is probably broke in.
Did you check the timing during this time?
Last edited by B1MAXX; 09/03/23 09:10 AM.
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Re: TDC Question
[Re: B1MAXX]
#3172562
09/03/23 12:21 PM
09/03/23 12:21 PM
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Joined: Jan 2003
Posts: 5,632 Detroit area
6PAX
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Ditch the thermostat, try again a fan blowing at the engine compartment/grill is always helpful.
But that being said at 10 minutes the cam is probably broke in.
Did you check the timing during this time? No, I didn't check the timing. It was running so smooth I didn't think the timing was an issue. The engine is not in the car, it is on a dolly. I had a box fan blowing through the radiator and a couple of fans blowing on the sides of the motor. I tried running it again a little while ago without a thermostat and it only took 6 minutes to overheat this time. Again, with straight water. That being said, I think the first run with the t-stat I had in it it appears to have been a bad t-stat. Couldn't get it to open doing a test in a cup of boiling water. I am going to get another new t-stat to put in it. What temp t-stat should I get, 180 or 195?
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Re: TDC Question
[Re: 6PAX]
#3172577
09/03/23 01:05 PM
09/03/23 01:05 PM
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Joined: May 2005
Posts: 1,995 Apollo, PA.
B1MAXX
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180 But it should cool without a thermostat. I was just curious how close you where on the timing. What kind of fan on rad? Any shroud?
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Re: TDC Question
[Re: 6PAX]
#3172627
09/03/23 05:39 PM
09/03/23 05:39 PM
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Joined: Jan 2003
Posts: 19,375 Las Vegas
Al_Alguire
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If the timing is to retarded it will cause the coolant temp to rise quickly and significantly. Advance it some and see what it does, easy enough to try.
"I am not ashamed to confess I am ignorant of what I do not know."
"It's never wrong to do the right thing"
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Re: TDC Question
[Re: 6PAX]
#3173279
09/06/23 09:11 AM
09/06/23 09:11 AM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
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If it cranks/starts OK at 22 BTDC when hot I would limit the total (checked with vac adv (if used) plugged) at 34-36 with the FBO plate.
live every 24 hour block of time like it's your last day on earth
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Re: TDC Question
[Re: RapidRobert]
#3173283
09/06/23 09:17 AM
09/06/23 09:17 AM
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Joined: May 2005
Posts: 1,995 Apollo, PA.
B1MAXX
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I always set the total timing at 3000-4000. Usually with one hand on the throttle and the otter holding the gun (or get a helper). If you have 20 min run time its broke in.
Last edited by B1MAXX; 09/06/23 09:18 AM.
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Re: TDC Question
[Re: B1MAXX]
#3173318
09/06/23 11:59 AM
09/06/23 11:59 AM
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Joined: Jan 2003
Posts: 19,375 Las Vegas
Al_Alguire
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The more initial you have the happier it will be, and as stated limit the total advance when done. But give it all the initial it wants/needs. Most racecars have the timing locked out, so they idle in the 30-40 range.
"I am not ashamed to confess I am ignorant of what I do not know."
"It's never wrong to do the right thing"
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Re: TDC Question
[Re: Al_Alguire]
#3173321
09/06/23 12:05 PM
09/06/23 12:05 PM
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Joined: Dec 2005
Posts: 11,611 Fulton County, PA
CMcAllister
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The more initial you have the happier it will be, and as stated limit the total advance when done. But give it all the initial it wants/needs. Most racecars have the timing locked out, so they idle in the 30-40 range. Big cam, low vacuum, I don't even fool with it or band-aid around it. Lock it out and use the electronics to retard it as needed, when needed. Street car, small or stock cam? Sure.
Last edited by CMcAllister; 09/06/23 12:07 PM.
If the results don't match the theory, change the theory.
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Re: TDC Question
[Re: 6PAX]
#3173324
09/06/23 12:13 PM
09/06/23 12:13 PM
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Joined: Dec 2005
Posts: 11,611 Fulton County, PA
CMcAllister
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Looking at the top two pictures, would you say cylinder #1 or #6 is on TDC? With the balancer set on TDC, the top pic are the lifters for #1 and the bottom for #6. The second pair of pics are after I rotated the balancer 360 degrees. Again, #1 is top pic, #6 bottom pic. Watch the valves. As the engine rotates, the intake will open as the piston travels down on the intake stroke. As it reaches BDC the intake will close. As the piston comes back up it will be on the compression stroke. At TDC, drop the distributor shaft in it correctly and set the distributor in with the rotor on #1.
If the results don't match the theory, change the theory.
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Re: TDC Question
[Re: 6PAX]
#3173343
09/06/23 01:19 PM
09/06/23 01:19 PM
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Joined: Jan 2003
Posts: 75,047 U.S.S.A.
JohnRR
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Ditch the thermostat, try again a fan blowing at the engine compartment/grill is always helpful.
But that being said at 10 minutes the cam is probably broke in.
Did you check the timing during this time? No, I didn't check the timing. It was running so smooth I didn't think the timing was an issue. The engine is not in the car, it is on a dolly. I had a box fan blowing through the radiator and a couple of fans blowing on the sides of the motor. I tried running it again a little while ago without a thermostat and it only took 6 minutes to overheat this time. Again, with straight water. That being said, I think the first run with the t-stat I had in it it appears to have been a bad t-stat. Couldn't get it to open doing a test in a cup of boiling water. I am going to get another new t-stat to put in it. What temp t-stat should I get, 180 or 195? I had this same problem breaking in a cam a long time ago, my headers turned cherry red and it boiled over. Found out later about the timing issue causing it, once you get the engine running and you bring it up to 2000 RPM throw the light back on it and adjust the timing so it's at 34-36 degrees and run it there. Most distributors mechanical advance isn't high enough at 2k unless you've modified it yourself. Next cam I helped a friend with he saw the samething, fired it up and the headers were staring to glow at 2k , advanced the timing and the headers stopped turning red.
running up my post count some more .
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