Backfire through exhaust on initial startup
05-27-2014, 11:06 AM
#11
Registered
May wanna pull the dist cap and look for carbon tracking. I've seen that cause some really odd symptoms.
05-27-2014, 12:19 PM
#14
Registered
iTrader: (2)
Join Date: Aug 2005
Location: Between A Womans Leggs in IL
Posts: 6,306
Likes: 0
Received 1 Like
on
1 Post
BTW, thanks for all the input guys - all good suggestions. As of now, I think my issue is either initial timing or improper valve adjustment. I set them up one cylinder at a time, and rotated the crank 90* for each cylinder in the firing order. Adjusted intake and exhaust on each successive cylinder, with one full turn after zero clearance. Maybe I need to back them off a quarter turn. I just recall reading that the Morel's seem to work better at one full turn to center up the plunger.
05-27-2014, 12:31 PM
#15
Platinum Member
Platinum Member
iTrader: (6)
Those Morel's will rattle if there not a full turn down, believe me I know
05-27-2014, 12:34 PM
#16
Registered
iTrader: (1)
#1 cylinder TDC compression (both valves closed) bring pointer + line on damper to 10BTDC. Get your rotor to point dead nuts at #1 inside cap. Make sure carb is full of fuel. Start key and braaaappp, it's started.
Last edited by SB; 05-27-2014 at 04:59 PM.
05-27-2014, 03:56 PM
#19
#1 cylinder TDC compression (both valves closed) bring pointer + line on damper to 10BTDC. Get your rotor to point dead nuts at #1 inside cap. Make sure carb is full of fuel. Start key and braaaappp, it's started.
Intake just about closed, adjust exhaust. Same procedure as above.
Intake just about closed, adjust exhaust. Same procedure as above.
05-27-2014, 09:51 PM
#20
I went through and readjusted the valves using the procedure outlined by fbc25 - exh starts to open, adj intake, when intake is almost closed, adj exh. Started it again and it ran for a second then backfired hard thru the carb. Almost certain the power valve has to be toast after that one. Went through and double checked to make sure distributor is in the right position and not out of phase. It's right, and this time I set the mark on the balancer to the 10* adv mark on the tab, then made sure rotor is pointing to #1 as SB suggested. At this point I'm too tired to fool with it anymore and it's getting too late to fire up a big block with open headers and expect my neighbors to still like me tomorrow. Going to give it another shot tomorrow. If it's still backfiring I guess the next thing to do would be a leakdown test to make sure I didn't bend a valve, although I'm almost 100% certain that didn't happen. Pushrods were all fine and this thing just turned over too easily by hand to have any valve / piston interference.
