Wobbly crank pulley

androssyae86 · Postby **androssyae86** » Wed Dec 03, 2014 6:44 pm

Recently did an engine overhaul on my 4age bluetop. Long story short, while reassembling, we stripped the threads inside where the crankshaft bolt goes.. Ended up having to retap and use a different bolt. This other bolt however, can only tighten so far before turning pointlessly (I know). Anyway, I've just noticed that my crankshaft pulley is wobbly at idle, and I can move it with my hands when the cars off

Is this because of the bolt or could my harmonic balancer be the cause? Also, we had to use another keyway from another 4age BT cuz we ran into another problem there. My car's idle has also dropped to 500-600 rpm and I read somewhere that could happen because of my harmonic balancer. I plan to work on it this weekend but I just want some advice or pointers to look out for cuz I don't wanna mess anything up again

Thanks a lot guys

Ps just finished initial d & NOOOOOOOO... Lol

Resurrected · Postby **Resurrected** » Thu Dec 04, 2014 7:37 am

The bolt is your problem. If it just keeps spinning then it is not doing anything at all to hold the harmonic balancer in place. It needs to be torqued to spec.

androssyae86 · Postby **androssyae86** » Thu Dec 04, 2014 9:33 am

Oooh ok that makes sense lol. So just to be clear, an easy & lucky fix would be just finding another bolt to which I can fully torque, while, worst case scenario, I might have to take the motor to a shop to retap it properly so I can use an oem bolt if the other case doesn't work out?

Thx a lot for the reply, Ressurected

allencr · Postby **allencr** » Thu Dec 04, 2014 10:11 am

It's gotta be tight!
it's possible the wobble isn't from being loose but that the thing's bonding coming apart, it should still rotate true with or without being tightened down.
There just MAY BE enough depth in there to use the untouched threads at the bottom of the hole with a longer bolt or stud. If there are good threads, a length of them at least 1.5 times the diameter of the bolt, I'd try it if the preceding F'dup stuff is ground down &isn't going to harm the new bolt

Resurrected · Postby **Resurrected** » Thu Dec 04, 2014 5:06 pm

Sorry let me correct myself. The crankshaft threads are likely your problem. If it just keeps spinning and is unable to torque down that will need to be fixed. Just to be sure check the balancer itself for any damage. It's unlikely, but possible, you have more than one problem.

Postby **Moto_Club4AG** » Wed Dec 17, 2014 2:46 pm

You need a very accurate torque wrench for engine builds!!! It's not so that you don't strip bolts but more that every part needs to be fitted and torqued to spec, so things have the right tensile strengths and loads.
Guessing the torque by hand on any engine bolts and fasteners will cause leaks, cracks, fractures, and lots of harmonic issues later....

Use a very accurate torque wrench. And factory manual for specified torque specifications. Even 4A-GE, this is common sense for ANY precision metal parts.

If you're rounding threads and stripping tapped holes, you need to stop right away, that block might already be toast, as well as crank caps, and crank might be damaged too. Did you replace the bearings by measuring with crush gauge carefully? If factory specified bolts can't be torqued into any crank cap or retainer, you can't use that block anymore. It's done since it can't hold the heart of an engine, the crank, with even alignment or loads.

Sent from my iPhone using Tapatalk

androssyae86 · Postby **androssyae86** » Thu Jan 01, 2015 3:57 pm

Ok so I was driving up the local touge (lol) and long story short, my timing belt jumped. I'm assuming it's cus the crankshaft bolt wasn't correctly torqued and so on. Anyways, I took everything apart to reset the timing and found that my sprocket, harmonic balancer, key, and where the key sits in is pretty messed up.

Am I better off taking the motor to a machine shop to repair or just getting a new motor? And if I do take it to the shop, will they be able to repair it anyway? I'm a college student so my budget is really tight

Also, I have another motor but the 2nd and 3rd cylinders' compressions are reading 60-90 psi. I'm hoping it's a head gasket or valve issue and not my rings. Is there another way to confirm before I disassemble the head?

Thanks for reading guys

Andrew

Postby **yoshimitsuspeed** » Thu Jan 01, 2015 5:37 pm

Without seeing the crank there is no way for us to tell you if it's possible or practical to fix it but it's most likely not.
What is most practical will depend a lot on what's around you. If you can find a healthy motor for a few hundred bucks that may be the best option but they seem to be getting harder to find these days, even then putting a used motor in is always a gamble.

Whatever way you go make sure you do it right. This is exactly what happens when you try to cut corners and save time and money.

allencr · Postby **allencr** » Fri Jan 02, 2015 2:39 am

androssyae86 wrote:...assuming it's cus the crankshaft bolt wasn't correctly torqued and so on. Anyways, I took everything apart to reset the timing and found that my sprocket, harmonic balancer, key, and where the key sits in is pretty messed up.

The bolt, a tight bolt squeezing together flat smooth surfaces is what does it, NOT the key.
It is just an index for fitting it together in the right position and does next to nothing to hold it there except when the bolt is loose.
You could put it together WITHOUT the key and it would be fine for a long long time!!!
Also, it does NOT need any type of thread locker stuff!

androssyae86 · Postby **androssyae86** » Fri Jan 02, 2015 7:28 pm

Jus an update.. so I ended up picking up a 2nd gen. 4age + tranny cuz my t50 was going out anyways. Motor needs a new head gasket but that's fairly easy on these old gems. My old motor will have to be put on hold for now.. Making for sure I do things right this time! Wish me luck & thanks again Club4AG fellows for pitching in tips & information!