Thread: timing troubles

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Hey everybody, got a situation that I think can be sorted out without too much difficulty Seems after new crankshaft install my timing is a little wacky. This is sbc 350 with Lunati cam- 218*@.050- .458 lift- anyway timing before was at 14*initial and idles decently. Now it has to go up to 20-25* to idle around the way it did before the swap. Will even seem smoother up around 30* btdc. Could being just a tooth or two off on the timing gears make this big a difference? Yes, this is with vac. adv. disconnected and port on carb plugged. Could there be something else I might have off that would cause this?

Yep, your chain is out a notch or two.

Find TDC and see if your cam is out or not for starters. You may need to degree the cam to fully evaluate it.

Kitz

Before you go crazy and pull the front off the engine apart, remove no 1 spark plug, turn the engine over by hand till the piston is at TDC, and check the balancer to make sure the timming marks line up. Could be the balancer has spun and the timming marks are off. D

I wrote this article about verifying TDC on the inertia ring after answering the question about how to do it so many times. Hope this helps.
Determining top dead center - Crankshaft Coalition Wiki

First, thanks for the replies- second, I put a new dampner on and double checked that tdc was on the mark on the dampner and thought I had the dots on the gears lined up but I went for 12 o;clock and 12 o'clock instead of
6 & 12 and then turning the gears to get #1 lined up. Guess I got the dots out of line more than I thought. Will go back and check it all from the get go before I start tearing into it, though. Also, with having to advance timing as much this time it sounds like the cam has more lope to it than previously had. Is this another sign that my marks are off from being put in straight up?

6 and 12 or 12 and 12, no difference, but you need a straight edge to be sure. More margin for error with the marks farther apart, all right. The cam seeming more lopey will be from the timing being out.

Did you put a new timing set in?

Well, timing set is not brand new but is only a few months old and has next to no slack in it. Have a double roller set from cloyes with the three keyways on the crank gear. Have checked it all again and have it on the "0" keyway and the dots match up with the tdc on the dampner and the timing tab lining up now. Have dist. set on #1 so will try to get things all set from here and see how it wants to run now- well, will see once mother nature stops making things so soggy as my driveway is my "open- air auto shop". Thanks and will post back when find out results.

Okay, things are not going as good as hoped. All marks line up like they should but can only dial in 12 in. of vac. or so and that has a jumpy needle moving 2 in. or so down then back up pretty rapidly. Used to get 15 in. of vac. and the needle only danced up and down about 1/2 in. which is about normal with not so stock cam, I think. Motor shakes and jumps like missing not sure where to look next? Should I start thinking about something screwy with lifters or valves? Maybe comp. check be next in line ?

All right, #2 intake valve gave me no reading on comp. check- re-adjusted and finally got 160# pressure in that cylinder. Re-set timing and checked vacuum and finally got 14 in. of vac. at idle. Seems to be running better now.

Thats good reading Tech, thanks for the tip

After putting some time on the engine I'd run the valves again and set them to Lunati's specs.