I think I'm missing a nut.

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cruiser

cruiser

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MoBros and MoSis'
I recently acquired a stock 225 engine from a 1974 Dart, automatic with factory air. When I went to put a breaker bar on the crankshaft to see if the engine would turn, I noticed that there was no nut in the center of the vibration damper. I then checked my other very stock 1974 Duster, and the slant six in this car has a large nut in the center of the damper. I also noticed that the cavity on the Dart engine where the nut should be is threaded for a nut, but this cavity is empty (see photos). Is there supposed to be a big nut there? Is there something different about an a/c car? I noticed that it has three pulleys on the crankshaft to accommodate the compressor. The outermost pulley appears to be screwed onto the middle pulley. I'll be converting this engine to non a/c, so is there any problem with removing the outer pulley? Any ideas about the missing nut? What size is it supposed to be. Thanks, all!

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Nope. Not missing. It was never there. MOST slant sixes do not come with a crankshaft bolt, although all are tapped. You can certainly add one. I did on Vixen, simply because she loves to rev. If you don't plan on romping on it a lot, it's really unnecessary.
 
I would definitely add one, some of the old Chebbie 265s didn't have balancer bolts. A friend had one and I road to school with him from time to time in the 60s. We crossed a set of train tracks and he had it wound up tight. To make a long story short, the balancer hit the pavement, two pieces came through the hood and one of those came though the windshield. Luckily we weren't hurt, but we had to make a trip back home to change our shorts.
 
Literally tens of millions of slant sixes never had one. Unless you plan on sustained high RPM, it's totally unnecessary. IF you want to add one for convenience of turning the engine, OR if you plan on racing, or both, then by all means.
 
RustyRatRod said:
Literally tens of millions of slant sixes never had one. Unless you plan on sustained high RPM, it's totally unnecessary. IF you want to add one for convenience of turning the engine, OR if you plan on racing, or both, then by all means.
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Thanks, Rusty. I'm going to install one so I can turn the engine. What size bolt is this? My other 225 has one but I can't tell what size it is. Has a large hex head on it. Any suggestions? Should I use one from a junkyard, or will a generic off-the-shelf bolt do?
 
You also need a large thick flat washer. Mancini Racing Crank Bolt, 2.25" Long
As for the pulleys: The pully clossest to the timing cover is for the AC. The one built into the damper is for the alternator and water pump. The one on the front is for the power steering. Both the AC pulley and PS pulley bolt to the damper. To remove the AC pulley you must remove the damper from the engine to unbolt it. (don't throw it out, offer it for sale )
 
cruiser said:
Thanks, Rusty. I'm going to install one so I can turn the engine. What size bolt is this? My other 225 has one but I can't tell what size it is. Has a large hex head on it. Any suggestions? Should I use one from a junkyard, or will a generic off-the-shelf bolt do?
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The one Charlie posted in post #7 will get it did, sir. I added one to Vixen's engine and it does make it nice when I need to turn the engine. Also, since she has lots of compression, it'll zing up there real quick. It surprises me how quick a slant 6 will rev. lol
 
RustyRatRod said:
The one Charlie posted in post #7 will get it did, sir. I added one to Vixen's engine and it does make it nice when I need to turn the engine. Also, since she has lots of compression, it'll zing up there real quick. It surprises me how quick a slant 6 will rev. lol
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Is yours a 225 or a different combination. Is the balancer bolt a common part with V8's?
 
toolmanmike said:
Is yours a 225 or a different combination. Is the balancer bolt a common part with V8's?
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225. I cannot remember, but it is the same as one of the V8s. I THINK it's a big block, but I wouldn't swear to it. The one Charlie posted above will do it. I just happened to have one in a bucket of bolts. I don't know for sure which engine it came from. All of the slant sixes take the same size bolt, though.
 
I used a grade-8 bolt from one of the better fastener stores. They also had a grade-8 washer that worked - the thing has to be 1/8" thick and plenty big enough. Like the rest of you, I have them on all my slants to make it simple to roll them over as needed.
 
RustyRatRod said:
225. I cannot remember, but it is the same as one of the V8s. I THINK it's a big block, but I wouldn't swear to it. The one Charlie posted above will do it. I just happened to have one in a bucket of bolts. I don't know for sure which engine it came from. All of the slant sixes take the same size bolt, though.
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Just bought this at the hardware store. It is a Grade 8, 3/4 - 16 bolt that is 2 1/2" long. I just put it on the engine and it threaded on just fine, but wouldn't tighten all the way down. The second photo shows that I couldn't get it in any farther than in the photo. Any ideas? BTW, the good news is that the engine is not locked up and rotates. I hope I'm turning it in the correct direction (counterclockwise as viewed by the driver).

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RustyRatRod said:
I have one idea. It appears to be too long. lol
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Yes, I suspected that. Looks like the correct length would be 2". Whaddya think? Also, am I turning my motor in the correct direction, Rusty? Can I do any damage to it if I turn it the wrong direction?
 
cruiser said:
Yes, I suspected that. Looks like the correct length would be 2". Whaddya think? Also, am I turning my motor in the correct direction, Rusty? Can I do any damage to it if I turn it the wrong direction?
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You're turning it the right way if you're turning it clockwise as viewed from the front. And I believe from your convoluted description, that's what you're doing. lol And no, you cannot hurt the engine turning it the wrong direction. Clockwise as viewed from the front is how it runs.
 
RustyRatRod said:
You're turning it the right way if you're turning it clockwise as viewed from the front. And I believe from your convoluted description, that's what you're doing. lol And no, you cannot hurt the engine turning it the wrong direction. Clockwise as viewed from the front is how it runs.
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Thanks. Here's the right size nut installed. Total of 8 bucks for nut and washer at my local hardware store.

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Be careful getting too crazy turning the engine over this way. I wound up stripping the threads out of a crank one time by periodically turning it over while on the stand.
 
ESP47 said:
Be careful getting too crazy turning the engine over this way. I wound up stripping the threads out of a crank one time by periodically turning it over while on the stand.
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If you stripped a 3/4 x 16 bolt turning an engine, something was seriously WRONG.
 
ESP47 said:
Be careful getting too crazy turning the engine over this way. I wound up stripping the threads out of a crank one time by periodically turning it over while on the stand.
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NEVER heard of that before, and i was a wrenching auto mechanic, for decades, earning my living.
 
hemi71x said:
NEVER heard of that before, and i was a wrenching auto mechanic, for decades, earning my living.
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Me and you both! Now, I've seen it on a Chevy, but their bolts are only 7/16. Never on a Ford or Chrysler.
 
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