Won't start after rebuild

[youdontknow37]

I've been trying to get my 93 Talon to start for about a month now after rebuilding it. We tried and tried but no dice until yesterday, when we discovered the crankshaft sprocket timing mark was 90 degrees off. Turns out the previous owner made his own timing mark on the sprocket where the #1 is at TDC, and we did it using the stock mark. So I redid the timing belt, going off of the previous owner's mark, and the #1 is in fact at TDC when that mark lines up with the mark on the block now. All the other timing marks were aligned, but when we went to start it it just cranked and cranked, backfiring out of the exhaust every 5 seconds or so. It did, however, crank over faster than when we were doing it with the timing off 90 degrees. I'm getting fuel (went through three sets of injector seals, fuel was spewing everywhere), spark, and I don't see how I wouldn't be getting air. I've flipped the CAS 180, and vice versa, but no difference there. The only other thing I can think of is a compression test, any ideas? Also, I run an AEM EMS, and under "Engine Start" in AEMPro, It says "Crank Advance - 14.99." Any idea what that is and why it's at 14.99? Thanks for the help.

 

[snox135]

I would strongly suggest you do a compression test. If you crank sprocket was 90* off you may have bent some valves. Not sure about the AEM, I would check there forums.

 

[youdontknow37]

If I bent some valves, wouldn't it be hard to crank over? When I put a breaker bar in the crank pulley and crank it manually there's really no resistance, other than from the cams turning over.

 

[snox135]

No it may still turn over like normal. I bent the valves on my laser and it still turned over fine.

 

[absolute_DSM]

If your crank sprocket was off 90* when you were trying to start it, you probably bent all your valves. Thats why you turn it over by hand first to make sure there is no resistance.

 

[B-Man]

I'd have to agree on the bent valves. 0 compression doesn't allow you to start. But why was the stock timing mark off in the first place?

 

[youdontknow37]

I'd have to agree on the bent valves. 0 compression doesn't allow you to start. But why was the stock timing mark off in the first place?

I don't see how the valves could be bent, because when I crank it with the starter it's perfectly smooth and stuff. But what happened was I first assembled the timing belt out of the car, lining up the stock timing mark on the crank. I later discovered that the #1 piston wasn't even at TDC at that mark; it was happening 90 degrees earlier in the rotation of the crank. It's a 2.4L crank, so that may have had something to do with it. But I then found another timing mark on the pulley, prob from the shop or the prev. owner, that was 90 degrees after the stock mark, and, sure enough, when it was lined up with the mark on the block the piston was at TDC. So I reassembled everything using that timing mark instead, but it still won't start.

 

[Thor06]

Just do the compression test, if I were a gambling man I'd put a pretty healthy sum of money on you having atleast one cylinder with really bad compression. None of them should be too good since the rings havent seated yet plus the head gasket hasnt settled. They dont need to hit real hard, it doesnt take much. When I bent my set of vavles you could only tell that 4 were bent and none were true. The only way bent valves would make it hard is if something went VERY wrong an one broke off in there or something. Actually, cranking will get easier when you have no compression as there isnt anything to resist the flow of air. You may have one popping, but that doesnt mean one or two of the others arent compromised.

If its not that, check over your wiring harness to make sure everyting is plugged in (CAS and transistor pack are my favorite to forget), check for spark, and check for fuel.

 

[absolute_DSM]

I don't see how the valves could be bent, because when I crank it with the starter it's perfectly smooth and stuff. But what happened was I first assembled the timing belt out of the car, lining up the stock timing mark on the crank. I later discovered that the #1 piston wasn't even at TDC at that mark; it was happening 90 degrees earlier in the rotation of the crank. It's a 2.4L crank, so that may have had something to do with it. But I then found another timing mark on the pulley, prob from the shop or the prev. owner, that was 90 degrees after the stock mark, and, sure enough, when it was lined up with the mark on the block the piston was at TDC. So I reassembled everything using that timing mark instead, but it still won't start.

By what you described right there, you again reassure to me that you bent valves.

 

[DSMfamily9295]

As stated previously, check the compression.
My wife and I have gotten three DSM's that were in good condition for real cheap. How? Because they all had thrown timing belts or the timing belt jumped a few teeth.
After rebuilding the first head, there wasn't even a question as to whether or not the second and third heads had bent valves. Just pulled the heads without even bothering to check the compression. Every time.... same thing.....Bent valves. Sometimes a little, sometimes seriously F###ed.
With that said, there is absolutely no room inside the combustion chamber for the valve timing to be off by more than a few degrees, and 90 degrees is a little more than a few.
An engine requires three things to run,
1- timed fuel delivery
2- timed ignition
3- compression
You say that Number one and two exist so check number three to be sure. A compression tester is relatively cheap (less than $25 for a functional cheapo at your local parts store) and the test is pretty easy to do on your own.
Don't drive yourself crazy over thinking the problem till you eliminate the basics.
If you do have even slightly bent valve stems, and it's quite possible you do, you will be lucky if you get a reading of 20PSI. More probable it will be zero.
Save your sanity, check the compression. If the readings are ok, then get ready to go insane. If they are low or zero, get ready to do some more labor.

One more thing, a bent valve won't necessarily cause the engine to become difficult to turn. If anything, it eliminates compression in that cylinder and makes it EASIER to turn the crank by hand.

 

[youdontknow37]

If I have bent valves, would I be able to hear the pistons hit them? If it makes any difference, I have a 2.3L setup with wiseco stroker pistons. We are trying to do a compression test right now, but the pressure release valve on the tester is leaking a lot of air, so we aren't getting any readings, even when we blow air straight into the tester using an air compressor.

 

[turboglenn]

No you wouldn't hear it, they would just be bent and you'd be standing around scratching your head. The thing that worries me is the timing mark the previous owner made. The crank pully has a notch to nly go on one way, so for the timing mark he made to be accurate he would have had to remove the pin on the crank like an idiot to have a mark that differs from factory.

I'm going to agree on bent valves. You MIGHT get away with the crank jumping one tooth (i've seen it) but you're not going to get away with being a full 90* off. The pistons hit the valves the first time you tried starting it, now you're screwed. It doens't make any noise and there's really no audible indications of bent valves. They just bend and that's it!

Get another comporession guage if your is leaking, if you bought it new take it back and exchange it, otherwise shell out the 35 bucks on a new one. As for the AEM saying you ahve e trigger issue, you might want to ensure that you wired up the cam and crank angle sensors correctly (or on a 1g, or when using a 1g CAS both signals are coming from the cam angle sensor) but if you're getting spark the sensors are fuctioning, maybe they are just way outta time or inconsistant. consult your AEM manual for the definition of the code

 

[youdontknow37]

No you wouldn't hear it, they would just be bent and you'd be standing around scratching your head. The thing that worries me is the timing mark the previous owner made. The crank pully has a notch to nly go on one way, so for the timing mark he made to be accurate he would have had to remove the pin on the crank like an idiot to have a mark that differs from factory.

I'm going to agree on bent valves. You MIGHT get away with the crank jumping one tooth (i've seen it) but you're not going to get away with being a full 90* off. The pistons hit the valves the first time you tried starting it, now you're screwed. It doens't make any noise and there's really no audible indications of bent valves. They just bend and that's it!

Get another comporession guage if your is leaking, if you bought it new take it back and exchange it, otherwise shell out the 35 bucks on a new one. As for the AEM saying you ahve e trigger issue, you might want to ensure that you wired up the cam and crank angle sensors correctly (or on a 1g, or when using a 1g CAS both signals are coming from the cam angle sensor) but if you're getting spark the sensors are fuctioning, maybe they are just way outta time or inconsistant. consult your AEM manual for the definition of the code

No he didn't take the crank pulley off and rotate it or anything, he just took a nail and scratched a little line on the pulley, you know? We're getting a new compression tester right now. Also, how can I tell if the CAS is 180 out? Are there marks that are supposed to line up? Since I can't warm my car up to operating temps before the compression test, if I do get a reading should I just assume the actual reading would be a bit lower?

 

[turboglenn]

There's a dot on the CAS body and a line or dot on one of the teeth on the CAS, they should line up when the motor is at #1 TDC. The reading when cold will be lower than the reading when hot, so if your numbers are only slightly low i wouldn't worry about it. But if you're seeing less than 100psi on any of them there's an issue with that cylinder

Here's a few pics, you can see the marks lined up on this CAS, this is exactly how it should go in with #1 @ TDC, and if the pulley wasn't moved and he made an "extra' timing mark, something is wrong. It shouldn't change from where the factory put it.

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[youdontknow37]

There's a dot on the CAS body and a line or dot on one of the teeth on the CAS, they should line up when the motor is at #1 TDC. The reading when cold will be lower than the reading when hot, so if your numbers are only slightly low i wouldn't worry about it. But if you're seeing less than 100psi on any of them there's an issue with that cylinder

Here's a few pics, you can see the marks lined up on this CAS, this is exactly how it should go in with #1 @ TDC, and if the pulley wasn't moved and he made an "extra' timing mark, something is wrong. It shouldn't change from where the factory put it.

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Thanks for the pics. We couldn't get any readings in any cylinder, so bent valves it is I guess.

 

[turboglenn]

That blows, but was kind of expected. If i were you BEFORE i put it back together i would either A.) get the correct pulley with a usuable factory timing mark. or B.) figure out what other part is wrongt or broken causing there to be a need to make your own timing mark or use some one else home made timing mark. If you can't use the original, start changing parts out till you can. Something is definately not right with that scenario.

So while the head is being rebuilt, get under there and figure out what the guy before you messed up that caused him to have to make his own timing mark. I can't emphasize enough that you should NEVER have to use a timing mark other than what is on the pulley from the factory, at least not on ANY DSM i've worked on.

When you line up the timing mark on the crank to install the timing belt. Place the pulley agains't the crank and see if the timing mark is where it should be. Also note if the locator pin for the crank pulley has been removed or if an extra hole was drilled in it to allow it to be rotated 90* off

 

[youdontknow37]

That blows, but was kind of expected. If i were you BEFORE i put it back together i would either A.) get the correct pulley with a usuable factory timing mark. or B.) figure out what other part is wrongt or broken causing there to be a need to make your own timing mark or use some one else home made timing mark. If you can't use the original, start changing parts out till you can. Something is definately not right with that scenario.

So while the head is being rebuilt, get under there and figure out what the guy before you messed up that caused him to have to make his own timing mark. I can't emphasize enough that you should NEVER have to use a timing mark other than what is on the pulley from the factory, at least not on ANY DSM i've worked on.

When you line up the timing mark on the crank to install the timing belt. Place the pulley agains't the crank and see if the timing mark is where it should be. Also note if the locator pin for the crank pulley has been removed or if an extra hole was drilled in it to allow it to be rotated 90* off

I'm debating whether I want to fix it or part the car/sell as is. I hydrolocked it in August, and just now got it back together. I've basically lost my motivation to fix it. The timing mark wouldn't have anything to do with the fact that it's a 4g64 crank, would it?

 

[turboglenn]

I'm debating whether I want to fix it or part the car/sell as is. I hydrolocked it in August, and just now got it back together. I've basically lost my motivation to fix it. The timing mark wouldn't have anything to do with the fact that it's a 4g64 crank, would it?

Aha! okay i don't know much about stroker engines, but if i missed that i'm sorry. It could be the crank that changed teh way the pulley is lined up but i wouldn't know for sure either way, but at least that's a viable explanation that hopefully some one can chime in on.

And don't give up just yet. Everytime i'm sick of my DSm and have just about run out of money i get it going and fall in love with it all over again. Case in point being my new TRE trans i didn't want to buy but had to have reliable transportation that could haul packages by the next week. Bought the trans with LSD diff and now i love my car again. DSM's are like a bad woman you love to have around, they'll beat you down, take your money and leave you stranded at times, but those few fun whips around the track when she is behaving makes it all worth putting up with And at least she can't cheat on you hahaha

 

[absolute_DSM]

And at least she can't cheat on you hahaha

And they dont talk back.

The 4g64 crank will line up the harmonic balancer the exact same way as a 4g63 crank.

 

[youdontknow37]

Alright I pulled the head today. Sure enough, a lot of the exhaust valves were bent. The pics were taken with the cam sprockets aligned so #1 piston is at TDC. All of the valves should be closed at that time, right? Also, I was told when I got the car that it had 1mm oversize valves, how can I check that?

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Here is the piston:

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[silver bullit]

You have to measure the valves using a micrometer.

You need to check the block, the cylinder walls from top to bottom, The pistons for any signs of stress marks from the valves, Roundness of piston makes sure the valve did not make the piston oval shaped in the area where the valves hit. You need to check and replace the head for broken valve seats all exhaust valves will need replaced and need to check exhaust valve seals. Check the dack of the head to see if it took a chunk out of the deck surface to.

Dude gimme a call or gimme a number that works so i can call you, i am the guy that is selling you your replacement head.