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I have seemed to have gotten myself into a slight pickle and wanted some opinions.
I installed my crank pulley bolt to use to turn the engine over while setting valve lash and when I went to removed the bolt for the timing cover to be installed I found out it was STUCK.
I have a pretty powerful 1/2 inch Dewalt electric impact that has never failed me before, but it will not budge the bolt at all.
I am trying to figure out how this happened. The bolt was not tightened any more than the force required to rotate the engine without the spark plugs installed. The bolt looks centered and not angle or cross-threaded. Does anyone have any ideas on how to remove it? Stronger impact, some way of stopping the engine from rotating and using a breaker bar with extensions, or possibly heat (Which I don't wanna use)?
I'm also praying the threads aren't damaged because if they are, then it seems like it may be a new crank which means machine shop fees as I do not have that equipment and may lead to the "While I am already in there" scenario....
The crank pulley center bolt is pretty long, and it has a massively thick washer on it, which then bolts over the harmonic balancer and the pulley center bolt hole. In other words, under normal mounted conditions only about an inch of that bolt threaded area sees contact with the center of the crank threads.
When you put it on without all that stuff adding thickness, and then you rotate the engine from it, I think what happens is that bolt bottoms out in the crank and the threads on the end get a bit messed up. This causes more friction when you go to remove it later on. If those threads near the end are messed up enough, it's possible that they can gall the other remaining threads on the way out. I hope that doesn't happen because like you said no one wants that.
I have no good answer here other than possibly spraying some light penetrating oil into those bolt threads that you see and then hoping that some of that oil wicks its way to the bottomed-out threads. Maybe then things will spin out with less trouble and the threads will be hurt less from the reduced friction.
I'm assuming that you've already put the plugs back in the engine? If so, this will help provide more resistance from the crank turning while trying to back it out....
The crank pulley center bolt is pretty long, and it has a massively thick washer on it, which then bolts over the harmonic balancer and the pulley center bolt hole. In other words, under normal mounted conditions only about an inch of that bolt threaded area sees contact with the center of the crank threads.
When you put it on without all that stuff adding thickness, and then you rotate the engine from it, I think what happens is that bolt bottoms out in the crank and the threads on the end get a bit messed up. This causes more friction when you go to remove it later on. If those threads near the end are messed up enough, it's possible that they can gall the other remaining threads on the way out. I hope that doesn't happen because like you said no one wants that.
I have no good answer here other than possibly spraying some light penetrating oil into those bolt threads that you see and then hoping that some of that oil wicks its way to the bottomed-out threads. Maybe then things will spin out with less trouble and the threads will be hurt less from the reduced friction.
I'm assuming that you've already put the plugs back in the engine? If so, this will help provide more resistance from the crank turning while trying to back it out....
Well, very quick update. I managed to get the bolt out....
Like your theory about it bottoming out and messing up the threads, you seem to be correct. I wouldn't say my threads are completely gone but I'd say a good half of it is pretty dang screwed. Definitely not getting a bolt back on.
I guess the next question is where the heck do I go from here? Any way to repair it or am I SOL
Last edited by Red89'-L98; Aug 8, 2021 at 06:28 PM.
Get a new bolt. It's 7/16" x 20 threads per inch, 2 1/4" long. I think Napa and others have it in stock as a crank center bolt / L98 / SBC.
Re-tap the crank by running a 7/16" x 20tpi tap in to clean up those threads. You've got nothing to lose by trying that in my opinion....
If you can't find that center bolt easily let me know, I have one I can give you.
I'm thinking I will try that option and see if they can clean up nicely since they don't look too bad. I figure if that doesn't work then I can tap to 1/2" if needed. Hopefully, I can get away without pulling the engine or at least not having to take it somewhere!
I think you'll be fine if those threads clean up, using a new bolt. If you think about it, you don't have to wail high torque on that bolt anyway. Before the bolt goes on, the harmonic balancer is pressed onto the crankshaft, the pulley is bolted to the balancer with those 3 smaller bolts (it's not going anywhere after that), and the function of that center bolt is really just to make sure that the balancer doesn't walk off the front of the shaft from vibration. The balancer is keyed to the shaft anyway so it won't spin on the metal, and that center bolt only has to handle tension load. I would go slightly less than the recommended torque value if you're worried about the strength of those threads. It's got a lock washer on it anyway as well.
On a sbc I wouldn't use the crank pulley center bolt to turn the engine over unless all the spark plugs were out or the engine was tired. Here's what I did, I replaced all 3 crank pulley bolts with studs and nuts. I keep this tool in the car with 3 extra nuts wired to it. I'll pop it on when I have to bar the engine over.
I think you'll be fine if those threads clean up, using a new bolt. If you think about it, you don't have to wail high torque on that bolt anyway. Before the bolt goes on, the harmonic balancer is pressed onto the crankshaft, the pulley is bolted to the balancer with those 3 smaller bolts (it's not going anywhere after that), and the function of that center bolt is really just to make sure that the balancer doesn't walk off the front of the shaft from vibration. The balancer is keyed to the shaft anyway so it won't spin on the metal, and that center bolt only has to handle tension load. I would go slightly less than the recommended torque value if you're worried about the strength of those threads. It's got a lock washer on it anyway as well.
That is what I am hoping for as well! I do have to use the threads to install the balancer as well, if it holds up to that then I know it will be fine or I can go old school and use the block of wood and hammer technique.
Originally Posted by ex-x-fire
On a sbc I wouldn't use the crank pulley center bolt to turn the engine over unless all the spark plugs were out or the engine was tired. Here's what I did, I replaced all 3 crank pulley bolts with studs and nuts. I keep this tool in the car with 3 extra nuts wired to it. I'll pop it on when I have to bar the engine over.
I did some research and found that what I did was a no-no. Sadly after the fact. I found this same tool along with a snout adapter that goes over the keyway and can be used to rotate as well. I am definitely investing in those before next time.
The engine was rotated with all plugs removed, but I guess that was too much.
Last edited by Red89'-L98; Aug 8, 2021 at 08:07 PM.
Also good news to hear. Sounds like I should be pretty well off then. I'm trying to save the machine shop trip for later on in life to build a bigger and better engine than the stock.
Thank you all for the quick comments and replies. I have a new tap and die kit along the way as my current one only had smaller sizes or coarse threaded in the size I need. Should be able to get the ball rolling tomorrow or the next day.
If you still don't have those tools needed and it's holding you up, let me know I have them and I'm nearby in EDH. If I remember correctly you're in Sacramento?
If you still don't have those tools needed and it's holding you up, let me know I have them and I'm nearby in EDH. If I remember correctly you're in Sacramento?
I am about 45 minutes or so from you more towards SF.
Also, thanks for the offer, however, I got the tools in yesterday and just got some time today. It rethreaded really smoothly and I was able to install the timing cover and have the harmonic balancer installed to what I believe is all the way. This leads me to a quick question.
I feel as if it bottomed out but am not sure how strong those rebuilt threads are to see if I can keep pressing it on anymore. Using a decent-sized wrench and oiled tool, I am unable to press it further without strain on myself and it seems to be all the way on. I measured the inside of the balance and get about a 1.125-inch depth before touching the snout and have very little shiny metal that I can see between the balancer and timing cover gasket itself.
Any opinions on this? I don't wanna pry too much more as I know those threads are not up to par but are easily holding the amounting force of me pressing it on.
I think you're good. If you see very little shiny metal that's about right. The timing mark tab on my (and yours I think) timing chain cover has a small hole behind the number markings. When your balancer is bottomed out on the nose of the crank, the back edge of your balancer rubber damper is just visible through that hole. You can see the hole here behind my timing markings - if you can see the back edge of the balancer through that hole you're good.
I think you're good. If you see very little shiny metal that's about right. The timing mark tab on my (and yours I think) timing chain cover has a small hole behind the number markings. When your balancer is bottomed out on the nose of the crank, the back edge of your balancer rubber damper is just visible through that hole. You can see the hole here behind my timing markings - if you can see the back edge of the balancer through that hole you're good.
I managed to get it to go on a bit further and let me say, those rethreaded threads are pretty good. It managed to hold enough to snap the tool itself which is fairly thick. Guess I won't be needing it anyways since it is on all the way. Thankfully it does have a warranty so maybe I will get lucky and they will replace it.
From: Liliha Bakery stuffing my face with coco puffs!
Originally Posted by Red89'-L98
I managed to get it to go on a bit further and let me say, those rethreaded threads are pretty good. It managed to hold enough to snap the tool itself which is fairly thick. Guess I won't be needing it anyways since it is on all the way. Thankfully it does have a warranty so maybe I will get lucky and they will replace it.
Glad you got that taken care of!!! Last engine I've rebuilt, had the same issue with the tool snapping...wanna say it was the cheap over the counter stuff you get from the big box chains.
It did help quite a bit. Gave me a good reference as my pictures did not include that when I took them and it’s been a while since I tore it apart due to work circumstances.
It was a fairly cheap tool so I am not surprised and hopefully I won’t need one again anytime soon or maybe they will warranty it.
Crank Pully Bolt Removal
