I just put a new GM engine in my 91z28 and it tries to turn over but wont. it rotates fine. it is making this backfiring noise as it tries to start. i smell fuel so it is getting fuel. i put a new dist in. could it be in wrong. i am 99% sure it is in right postion. please help it has been alomost 13 monthes since i had this thing running.

 

man, i feel you pain its been 3 for me and i am about to go crazy with it, but if it is backfireing thought the throttle body and that means that it is too advanced usally. have you checked you double check the base timing to see if it is correct. if it is not that you might want to see if you have a spark, have a friend turn it over wail you put a nail or something at the end of the spark pluge wire and put it next metal and see if there is a spark, if not you found your reason. if you cant figure it out my aol s/n is firbirdgta

 

Sounds like the dist is in wrong. Recheck how it's lined up.

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"So many Mustangs, so little time..."
ICON Motorsports

 

ok if the dist is in wrong then how do i start over and get it in right.

 

Okay, here's the procedure.

Remove the #1 spark plug and the distributor cap.

If you're alone you can wad up a piece of tissue and stick it PARTIALLY into the #1 spark plug hole; otherwise, with a helper, put your finger in the #1 spark plug hole only far enough to seal the opening.

Now bump the engine with the starter and wait until you feel pressure building against your finger or, if you're alone, until the tissue "pops" out. This puts the engine on the compression stroke.

Stop bumping immediately and look down at the damper and timing chain cover timing tab.

The TDC mark on the damper (balancer) should be aligned anywhere between 6 and 12 degrees BTDC (Before Top Dead Center) on the timing tab..

It may take a few times to be able to get damper to stop in this range, but eventually you'll get it.

Now, once the TDC mark is aligned with the tab properly, looks at where the rotor is pointing. It should be pointed directly at the #1 terminal/plug wire location.

If it's not there are a couple of ways to make the correction/adjustment.

Either remove the distributor and turn the rotor until it points at the #1 wire or the wires, themselves, can be moved one terminal in the required direction.

If you opt for the 'turning the distributor rotor method' (remove the distributor, turn the rotor a bit then re-install the distributor) then the oil pump drive/distributor tang will no longer align, so the distributor won't drop all the way down flush with the manifold.

There are a couple of ways to align them. The easiest is to drop the distributor in as far as it will go, then while holding your hand lightly on the distributor (be careful where you place your fingers because the rotor will turn), just bump the starter and at some point the two will align and the distributor will drop down flush.

The second way is to use a l o n g handled screwdriver to reach down into the distributor hole in the manifold. Engage the tip of the screwdriver with the oil pump drive rod and turn the drive until it's in the proper position to index with the distributor tang. This is more difficult because of being able to actually look down into the engine through the distributor manifold hole. It will probably also require installing and removing the distributor a few times to get it aligned correctly.

All this "bumping" should be done with the fuel pump fuse removed to keep from having excessive fuel enter the engine. Also remove the ECM fuse to kill any spark.

Don't forget to replace the fuses before you try starting the engine and lock down the distributor but not so tightly that it can't be rotated by hand for the final timing adjustment.

Now, when you turn the key, the engine will fire.

If you're starting a flat tappet cam for the first time, be sure to run the engine at a minimum of 2500 RPMs for at least 20 minutes to properly break in the cam. Lower engine speeds will result in wear to the cam/lifters and you'll end up doing this all over again.

Any adjustments, like fluid leaks, etc., should be made with the engine off, NOT IDLING.

After cam break-in, set the timing to its final setting using your timing light following the correct procedure (disconnecting the EST weatherpak connector, etc.)

Hope this helps.

Jake

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1986 Corvette Coupe, 415 CID, Edelbrock 6073s, ZZ9, TPIS Long Tube Headers and DynoMax Super Turbos (HATE 'em)



[This message has been edited by JakeJr (edited September 14, 2001).]

 

Good info Jake!

www.geocities.com/dzperf


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D&Z Performance
"Putting Power to the Pavement"

 

jake thank you very much for the info. i will gbe getting into it this weekend.