New engine assembled, won't start - backfires

[95formula383lt1]

i thought it was the wires lol ur welcome, ive done it many times before.

btw get some vids of that thing when its driveable. lol

[meissen]

Will do - only videos I have right now are on youtube: http://www.youtube.com/mifbody - can't post any videos yet because there's a few people on my site subscribed to my youtube account.

..then again, there's quite a few people from my site on here too and probably have seen this thread.

[ThreeHonks]

Will do - only videos I have right now are on youtube: http://www.youtube.com/mifbody - can't post any videos yet because there's a few people on my site subscribed to my youtube account.

..then again, there's quite a few people from my site on here too and probably have seen this thread.

Good to see its coming along!! so it will be at the meet and greet for sure now?? lol i just spun a bearing in my LT1 (most likely) so I will be going through kinda the same thing you had to do

[ThreeHonks]

I suspect you have a lifter preload adjustment problem. One or more is adjusted too tightly which is holding the valve open.

What procedure are you guys using to set the lifter preload?

If you're using the procedure listed in the Factory Service Manual or one of the Chilton books be warned, that procedure is very error prone. Using that procedure makes it really easy to make a mistake and cause the problem you're experiencing.

Use the IC/EO method that is now the recommended way to minimize the chance of making a mistake. If you need me to post the procedure, let me know and I will.

Jake

West Point ROCKS!

Could you please post this procedure for me??

Thanks,
Ryan

[meissen]

Good to see its coming along!! so it will be at the meet and greet for sure now?? lol i just spun a bearing in my LT1 (most likely) so I will be going through kinda the same thing you had to do

Haha like I was saying..

Ryan, no word on whether it will be at the M&G in all honesty. We got it idling on Wednesday but now it looks like we cracked the flexplate. There's a really loud banging noise coming from the dustpan area. Not to mention once we get the flexplate fixed it still has to be tuned.

When we were installing the transmission we tried to install it like everyone had told us we had to do - put the torque converter all the way into the transmission then line up the trans, bolt the torque converter on, and bolt the trans down. We heard a crack noise when we were trying to do it that way so that might have been the flexplate cracking.

Here's shbox's write up that we used - I find it to be the best way:
http://shbox.com/1/4th_gen_tech2.html#adjust_valves Method #3

[95formula383lt1]

Haha like I was saying..

Ryan, no word on whether it will be at the M&G in all honesty. We got it idling on Wednesday but now it looks like we cracked the flexplate. There's a really loud banging noise coming from the dustpan area. Not to mention once we get the flexplate fixed it still has to be tuned.

When we were installing the transmission we tried to install it like everyone had told us we had to do - put the torque converter all the way into the transmission then line up the trans, bolt the torque converter on, and bolt the trans down. We heard a crack noise when we were trying to do it that way so that might have been the flexplate cracking.

Here's shbox's write up that we used - I find it to be the best way:
http://shbox.com/1/4th_gen_tech2.html#adjust_valves Method #3

^wow that sucks^ sounds like u got about the same luck as everyone else on the site lol, i just lost the rings in my motor.

[flippy1974]

wires are so hard to get right on these cars , thats why i got me another set of cylinder markers ( jegs parts #121-3414) and put them on both ends then there is no guess work .

[JAKEJR]

Could you please post this procedure for me??

Thanks,
Ryan

First off let me say that there are seveal different ways to set lifter preload and all of them will work, but only if done correctly. The difference among the different methods is that one method is less error prone than the others. The least error prone method is the one I'm writing about now.

Okay, here's the procedure, it's referred to as the Intake Closing/Exhaust Opening (IC/EO) method:

The goal is to adjust the rocker arm adjusting nut enough so that it depressess the pushrod and thus the lifter plunger .030". Since it would be very difficult to actually measure that amount - requirng a dial indicator with a magnetic base, etc., turning the adjusting nut a certain amount will work just fine.

Most importantly, in order for the lifter preload to be set correctly, the lifer HAS TO BE on the base circle/heel of its camshaft lobe.
Since there's no way to actually SEE if the lifer is on the base circle/heel, you watch what its companion pushrod does in order to know. You watch the intake to set the exhaust, then watch the exhaust to set the intake.

May sound crazy but that's how it's done.

To begin with, install all the pushrods in their respective lifters and set the rockers and adjusting nuts loosely in place. Then you'll need a way to turn the engine in it's normal direction of rotation. I use a ratchet, extension and socket on the damper nut. Having the spark plugs removed will make the engine much easier to turn too.

Begin at the driver's side, front, very first rocker, which will be the #1 EXHAUST. We'll be setting that one first.

Grab the pushrod next to it, which will be the #1 INTAKE pushrod, with your thumb and index finger so that the pushrod can be moved UP and DOWN.

Turn the engine while feeling what the #1 INTAKE pushrod is doing. That pushrod will, at some point, begin to move up (indicating the INTAKE valve is beginning to open) and then down.

Just before that pushrod is all the way back down, STOP turning the engine. The actual point that you STOP isn't all that critical, just as long as the pushrod has moved more than half way back down.

With the #1 INTAKE pushrod in that position, the #1 EXHAUST lifter will be on the base circle of its lobe.

Now move your hand to the #1 EXHAUST pushrod and begin to gently move it up and down with your finger/thumb while at the same time begin to tighten the #1 EXHAUST adjusting nut.

When you reach the point that the #1 EXHAUST pushrod can no longer be moved up and down you've found what we call ZERO LASH.

It's now time to set the lifter PRELOAD on the #1 EXHAUST lifter. Most use 1/2 turn of PRELOAD, so turn the adjusting nut 1/2 turn more from ZERO LASH. This'll depress the lifter plunger and give you right at .030" of PRELOAD.

1/2 turn= handle of wrench at, say, 12 o'clock, then turn until the handle points at 6 o'clock.

If you're using Poly-locks, once that 1/2 turn is made, tighten the allen head poly lock with your allen wrench. Make sure it's tight!
That one's done.


Now we move on to setting the #1 INTAKE.

To set the INTAKE, we grab the #1 EXHAUST pushrod (the one we just finished setting) with those same two little fingers - or you can just watch what the rocker is doing - either way works.

Begin, again, to turn the engine over manually while watching the #1 EXHAUST rocker or feeling its pushrod. AS SOON as you see the #1 EXHAUST rocker begin to open that valve or you feel the #1 EXHAUST pushrod begin to move UP, STOP. You just found the point that the #1 INTAKE lifter is on its base circle.

Grab the #1 INTAKE pushrod with your index finger and thumb and begin to gently move that pushrod up and down as you slowly tighten its adjusting nut. When that pushrod can no longer be moved up or down you've found ZERO LASH for the #1 INTAKE.

Again, tighten the adjusting nut an additional 1/2 turn to set the .030" preload and tighten the allen head screw, TIGHT.

The #1 INTAKE and #1 EXHAUST are now set. Now move on to the very next pair, #3s and do the same thing. Continue working down the line to #5 then #7.

Once done, move to the other side of the engine and begin at the very first, front rocker/pushrod (#2 EXHAUST) and repeat, going straight down the line. After you're finished with #8 EXHAUST, you're done.

If you just do one after the other, straight down the line, you won't skip any and each will be set properly.

JUST REMEMBER: The valve arrangement is EIIEEIIE with E=EXHAUST and I=INTAKE It's important to know which valve you're working on, either an INTAKE or an EXHAUST.

Hope this helps.

Jake

West Point ROCKS!

[meissen]

Yup, that's pretty much what we did and 1/2 turn is exactly the preload we did too. Works great.

Happy to report the flexplate was not infact cracked - the counterbalance weight that looks like a handle was hitting the starter. No big deal, we just took the starter out, ground down the casting where it was hitting, and then reinstalled the starter. Lot easier than messing with the transmission!!!! That worked flawlessly - no more banging.

[ThreeHonks]

Yup, that's pretty much what we did and 1/2 turn is exactly the preload we did too. Works great.

Happy to report the flexplate was not infact cracked - the counterbalance weight that looks like a handle was hitting the starter. No big deal, we just took the starter out, ground down the casting where it was hitting, and then reinstalled the starter. Lot easier than messing with the transmission!!!! That worked flawlessly - no more banging.

Great to hear it! but honestly dont rush it to have it at the meet and greet, do it right the first time. I just dropped my motor out today and am planning on just doing things slow and getting it right. I cant wait to see it on WW soon tho!

Thanks a lot JAKEJR, I really appreciate it. Would u have any idea how much preload an LS7 lifter needs? I am using those for my build