knocking mustang 5.0

[5150coupe]

i have an 89 coupe and just installed a new set of gt40 heads, e303 cam, and 1.7 crane rockers. when starting the car up for the first time there was a loud knocking noise. i thought the valves hit the piston since it was pretty loud, but the numbers show plenty of room for this combo. anyhow, i took one head off and found that everything looks fine and that there are no signs of the valves hitting. i put everything back together and still get a knocking. other mods are c&l 76 mm maf, bbk 70 mm tb, tf track heat upper and lower, and heads are port matched on both the intake and exhaust. i bought spark plugs based on a '93 cobra. even when i retard the timing it doesn't seem to have a possitive effect. any ideas?

[DaLe five OH!]

bent push rod? bad rocker? loose rocker? bent valve?

[Dark_5.0]

Take off all of the rockers and pushrods and inspect eveything. Look for bent pushrods or damaged rockers. The rockers are pedistal mount right???

[5150coupe]

i ended up finding out that it was just a timing issue. just backfiring...but now i have a couple other related issues. i can't seem to set the timing to 14 like it was before. at 14 i get backfiring and it won't idle or run well unless it is advance way to high at about 22-25. it doesn't seem to ping even though it is high, so i thought maybe the timing marker is off or something, but it looks to be at the same location as my friends coupe. i'm going to put it on the computer and start checking codes.

[USMC302]

Sounds like you a tooth off. Pull the dist, set engine to TDC, and restab it. Double check your ignition wires as well to make sure you don't accidentally have one crossed.

[goodyear1984]

13726548 firing order and i think u point the rotor to the ft drivers side upper intake bolt its like 1 oclock

[goodyear1984]

dont forget thats at tdc

[USMC302]

Originally Posted by goodyear1984

13726548 firing order and i think u point the rotor to the ft drivers side upper intake bolt its like 1 oclock

Negative. The rotor should point directly at the number 1 post on the dist, that's the one that's connected to cylinder number 1.

[goodyear1984]

the only way the rotor wont hit the number one is if ur off a tooth ..not negitive look up the rotor position and set it there with the engine at tdc.then if u have the rotor set right get the rotor to be as close to number 1 as possiable so it will start up the first time. then set timing, and if u set the rotor and have it at tdc of compression stroke it will be perfect.
goodluck

[goodyear1984]

also if u have the pedestal mount rockers make sure u check the valve lash most times u dont need to shim but u will get a back fire if u are in need of a shim.i had to shim only one of my rockers because of a backfire problem, and hopefully u have a good set of springs

[5150coupe]

-how do i know if it is on the compression stroke. what i have been doing is this: crank the motor till the damper is at 0 degrees and the 1 st piston is at the top. then i set the distributor pointer to the #1 post. it seems to start fine this way, but still won't run at 14 degrees or anything close. i will only run way past 14 degrees, but has no power and is hard to start. maybe the springs cause i left the stock gt40 springs on, but they are double coil and that seems fine for my conservative combo.

[5150coupe]

i guess it makes sense to just plug the spark plug hole with my thumb and crank till there is pressure...

[goodyear1984]

take out the number 1 plug.thats the passenger side front.have someone bump it over with your finger over the plug hole when u feel a big amount of air come out thats the compression stroke not a little amount but a good amount and 0 degrees should be close to the pointer on the balancer.line the balancer to zero degrees...now the the rotor has to be set .dont just slap the dis in there so its pointed to the number 1 spark tower on the cap thats the wrong way.now if u have the motor set at tdc on the compression stroke set at 0degrees your good.if ur not sure u can take the pass side valve cover and make sure the front rockers are all the way up if not then ur off and do it again.ok now set the dis in u want the rotor facing the intake straight back.it wont be perfectly straight back and will close to pointing the ft driver side bolt for the upper intake.now that the rotor is set bolt on the dis clamp not to tight ,u still have to set timing but u dont want the dis to move much when u start the engine .now u can set the dis so the rotor is just under the number 1 spark tower on the cap.check to firing order 2 or three times and make sure u have the right firing order the 302 ho is 13726548 and that is in a counter-clockwise order on the cap.now start and set the timing.put it at 15 and rember that each line 2 degrees. do this to the T and it will be right.
goodluck

[5150coupe]

...that's right about the rotor needing to point to the #1 spark plug post. if the #1 post is pointing to the upper manifold bolt at 1 o'clock that is probably a good position to have enough room for timing adjustment, but really it doesn't matter as long as the rotor points to the # 1 post and you give the distributer enough room for movement.

[5150coupe]

i set everything as described, but still have the same issue. the only thing i could be doing wrong is maybe not getting the compression stroke, but i basically cranked the motor till i felt a surge of air and then set the timing marker to 0 degrees. all i get is a slight amount of backfiring. tomorrow i will remove the passenger side valve cover to make sure it is on the compression stroke by making sure the rockers are both at their lowest point.