I have a mild built 390. When starting to adjust the valvetrain I brought #1 cylinder to TDC. The timing marks were aligned, but the piston was halfway down the cylinder. My original balancer was rough looking, so I thought that the outer ring must have spun on the hub. So I purchased a new balancer from Jegs and installed it last night. Brought it up to TDC and same problem. I removed the fuel pump, and can visually see the timing dot on the camshaft sprocket is pointing down when I visually bring #1 cylinder to the top of the cylinder. So that tells me that the cam and crank sprockets are alinged correctly. The part number of my original balancer is COAE-6316 B. Any suggestions will be greatly appreciated.
I've had this happen, a late timing cover + early damper or vice versa and the marks will appear way off. Look for a casting number on your timing cover if you can find it, there are at least two types and the timing pointer is in a very different spot. I forgot when it changed but it may have been 1963 or so.
Would it be possible to use an indicator and find the upper most travel of #1 piston, and just scribe a new line on the new balancer at TDC using the existing pointer?
It's hard to stop the piston at TDC exactly so I usually use a dial indicator and mark the damper when the piston is say 1.000" down, BTC, then thru TDC, then mark again at exactly 1.000" down, ATC. Then split the diff between the 2 marks and that is TDC exactly. (It should also "look" like TDC if you got it exactly 1/2 way between the two outer marks.
While you're at it I also mark 0-10-20-30-40 BTC to make it easier to check the advance curve later.
You are on the correct #1 cylinder, that is passenger side, all the way up front? Other makes, i.e. Chevy, #1 is in a different location.
Did the engine ever run correctly when you had it, or is this a rebuild or an engine build from a collection of parts and you are in the process of getting it running.
I'll also take a look at my collection of timing covers, to see what the difference are in timing tab location.
I have never had this motor running as it was apart when I got it. And yes, #1 cylinder is passenger front. When the balancer TDC mark is aligned with the timing pointer, #2 and #8 cylinders are at the top. Thanks for the responses.
OK, re #1 cylinder location I was just making sure that all the bases were covered. I figured if the engine ran ok by timing by ear, then you simply have the incorrect tab, assuming the engine was correectly assembled and the dampner pulley is ok.
I did check part of my timing cover collection. The C3AE-6059-A and C8AE-B's have the timing tab holes in the same location. I also have a couple earlier covers, I think they are C1AE's. From looking at the parts books, I believe the mtg. locations are all the same as the timing cover is common and the tab is different between certain engine applications.
Many years ago, I rebuilt a 427 engine and the car just wouldn't quite ET like it used to. I got home and rechecked the timing gear index and found out I was off by one tooth. I had a timing wheel in my toolbox and from then on I used it to verify camshaft phasing. Probably lucky I didn't bend any valves as I was running a .600" lift cam. There is no substitution for experience!
