I just finished painting my engine, time to put it back together, i noticed the big bolt holding the crankshaft pully and harmonic balancer on has damaged threads. The threads appear to be fine on the crankshaft so i think ill be ok, i just need a new bolt. I checked at canadian tire but they didnt have any, where can i find it? The engine is a 71 350 4bbl in a skylark custom.
Crank Bolt If TA ships UPS/Canada it will cost more than that ! ou: Azeem - take your original to Ottawa Fastner Service in Bells Corners, tell them what it is, and they might be able to fix you up. :TU:
Ouch! When ordering from outside the US u always have to worry about the currency exchange and the shipping, thanks alot Randy, ill see what i can do. I still havent checked most smaller parts places, ill see if they have any.
Bad news bad news, i went to Ottawa Fastener Supply, they couldnt help me out. An employee at carquest suggested i try a place called Malmberg truck and Trailer repairs, they had the bolt but the guy was telling me how mine was metric and theirs wasnt? It was a grade 9 bolt, and they recommended i use atleast a grade 8 for the crankshaft pulley application. The only difference i noticed were that, when i hold up the bolts next to eachother, one had "sharper" threads than the other one. The grade nine bolt i purchased didnt fit. looks like i might have to get it from TA after all. Any ottawa folks have this part that i could pick up? Im not paying more than about $10 for it.
Crankshaft Bolt That's a real bummer Azeem ! I don't think GM Canada went metric till '77 or so - so your '71 should be non metric ? Are you sure the threads in the crank are OK? Hard to believe a simple bolt would be that hard to track down. o No: :TU:
I'd check my Buick dealer. Lots of things are still available if used many years in many applications, which I'm thinking applies to this bolt.
Your bolt is a fine-thread SAE (not metric) bolt. Most of what you will find locally will be coarse-thread.
no it shouldnt be metric im just trying to point out that the guy was a moron. When i meant sharper, ii meant thw threads were the same distance apart, and the bolt was correct, but as scott was saying they are :finer" or sharper at the tips. Yes my crank threads are ok, the reason i know that is because the damaged threads on the bolt are closest to the head, so when you put in the undamaged threads into the crank, they screw in beautifully by hand, up till the damaged part. The grade 9 bolt i purchased was correct, but the threads were too fat. As well, i dont know when canada went metric but my car was manufactured in the Flint plant, so it doesnt even know what metric means. Anyways, thanks for all the tips guys, i will keep checking around. The prob is alot of stores have this bolt but very few of them have it in a fine thread or a high grade.
I have spent a total of about an hour going through the crank threads, i have concluded 100% that they are not damaged. My bolt is however. Here is the surprising part, i went out to a wrecker today (very far from my house) and purchased 2 of these bolts for $20 cdn, off of 2 72 skylarks. both 2bbl. When i got home i was praying that they would work. I checked the size and thread pattern, and sure enough they were 5/8 X 18. I was a lil hesitant because the threads did not appear as "sharp" as the ones the came out of there from my bolt. And surely enough they were too fat, the bolt did not work. I have now tried, a fastener place, heavy truck parts place, 2 scrap yards and a dealer, what gives? Were there two different thread types for this bolt? (fine and not so fine?) or is there something wrong with my engine?
sounds to me that the crank in your car may not be the original, or the crank could have been rethreaded, but i doubt that. it really s/b 5/8" fine thread. see if u can find a 15 mm fine threaded bolt and try that.
Gerry beat me to it. Did you have the engine rebuilt or have any machine work done? Did the shortblock ever leave your possession?
I have not personally had it rebuilt, my budget or resources do not allow for it. Ive just done some cosmetic work, i will try a 15mm X 18 and see how that works out. The threads are 5/8 by 18 ive even tried a stock bolt out of a 72 skylark 350, but the threads were too fat. I will see what i can do. Im really bummed out about this.
I think ive figure out what happened. the bolt was not torqued properly before, or the washer was not correctly installed. The bolt must have been moving back and forth slightly when the car was running. Thats why my threads have gotten sharper. I was thinking of going out and buying a 5/8 X 18 fine thread tap, and running it through the crank to clean up the threads. Im guessing this will make them less V shaped and more U shaped, and hence will be more willing to accept that bolt i got out of the 72 skylark 350. Only question is, who sells a tap like that?
Problem solved my bolt was more V-shaped threads than the usual 350 bolts. As well there was a cone type thing at the end of the bolt, also not found on the regular bolts. SO, since the damaged threads were at the part where the washer goes, i bought an extra 5/8 washer, just ordinary one, and put it on the bolt, along with the big washer that is supposed to be in there. This way, only the undamaged threads went in the crank, there is a bit of a pocket of unbolted threads deep in the crank, but that shouldnt matter. I started the car up after 6 mnths, ran ok for crappy as gas, and terrible timing. Just needto get that fixed, and ill be cruising. Thanks for everyone's help.
bolt If it's a metric bolt it might be a 16 m.m.x1.5. 5/8=.625, 16m.m.=.6299 diameter. 18 is the thread per inch, each thread is .055555 long. closest metric to that would be 1.5 m.m.(.059 long). You won't find a bolt that's 16m.m.x18 pitch!
