You guys are going to think I'm crazy... But I used a $10 Pittsburg torque wrench to tighten my Crower rods onto my Benson crank... Think I'll spin a bearing?

I have a KD Tools torque wrench, but it's never been calibrated in three years of use, and I know it reads a bit low. So instead of getting it calibrated, I just bought the Pittsburg wrench, which I figure comes calibrated.

I used it on my rods and mains, then threw it away. Think I'll have problems? It says it's accurate to 4%. The Snap-on's are accurate to 3%.

Who else has used a Pittsburg wrench? From what I've read (google research) I guess these things are actually pretty accurate, but they break all the time. Luckily mine worked.

I guess I wasn't worried until tonight when I was talking to an old friend. He says he used to work at Harbor Freight and people returned those torque wrenches every day because they'd break . But at this point, I'd rather get stabbed in the face than have to pull my motor and re-do everything. After six months, I finally have the motor built and ready to start, maybe as soon as tomorrow. Re-doing the bottom end would be a major setback.

 

i'd be worried about the accuracy. it's up to you to determine your risk.

i use the same torque wrench, broke one, so don't use it on heavy things anymore. as far as accuracy, for semi important things i go a few lbs lower than my target, then work up to my target. sometimes it doesn't click if you go right on target. after a while you get a feel for what should be right.

for critical engine internals, i wouldn't trust it. your internals are too valuable to risk it.

 

The calibration card I got with my digital snap-on gave the highest variance as .2% as tested from 20-100 ft-lb. But that is the difference between a $10 wrench and a $300+.

 

Well did you check any clearances, were they all checking out ok? Or did you just slap it together?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hybrid_KJ &raquo;</TD></TR><TR><TD CLASS="quote">The calibration card I got with my digital snap-on gave the highest variance as .2% as tested from 20-100 ft-lb. But that is the difference between a $10 wrench and a $300+.</TD></TR></TABLE>

Well the digital ones are different. I was told that none of the click-type wrenches can be made very accurate.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ScottEK &raquo;</TD></TR><TR><TD CLASS="quote">Well did you check any clearances, were they all checking out ok? Or did you just slap it together?</TD></TR></TABLE>

I spent months and months building it. It definitely wasn't "slapped together".

 

Well I just bought new ARP rod bolts and a Proform stretch gauge. Can I just drop the pan and re-do the bolts? Or do I have to pull the motor again...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EnzoSpeed &raquo;</TD></TR><TR><TD CLASS="quote">Well I just bought new ARP rod bolts and a Proform stretch gauge. Can I just drop the pan and re-do the bolts? Or do I have to pull the motor again...</TD></TR></TABLE>Your gonna have to take the motor apart and have the rods resized to use the new bolts.
I know you don't want to redo the engine but think how your going to feel about pulling the motor and having to replace everything instead of just retorquing it.

 

Resized?????????

 

I just spent three hours pulling the motor. It's sitting in my garage upside down with the pan and girdle off...

I thought the ARP bolts would fit!? I bought the Crower rods and bolts used, so I can't use the stretch gauge because I don't have an initial stretch value for the bolts.

So I need new bolts. Do I have to buy from Crower? They are a damn ripoff.

 

Rod bolt are normally pressed in.

 

Dammit, so ARP rod bolts are Thru-bolts? I thought they were cap screw bolts. I guess I'll cancel my order on the ARPs...

And I just checked with Crower. New bolts are $10.85 each

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EnzoSpeed &raquo;</TD></TR><TR><TD CLASS="quote">Dammit, so ARP rod bolts are Thru-bolts? I thought they were cap screw bolts. I guess I'll cancel my order on the ARPs...

And I just checked with Crower. New bolts are $10.85 each </TD></TR></TABLE>Even if they weren't thru bolts you would need to resize the rods the concentricity of the rod end is only good w/the bolts they are sized with.

 

I don't get it. You're saying the ARP bolts are a different size than the Crower bolts?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EnzoSpeed &raquo;</TD></TR><TR><TD CLASS="quote">I don't get it. You're saying the ARP bolts are a different size than the Crower bolts?</TD></TR></TABLE>No the bolts align the caps unless you have dowels installed in the rod caps,also the distortion caused by torquing the bolts is different for every bolt .That's why the rods are torqued and then sized you have to keep them as a set.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Ed’s Racing Heads &raquo;</TD></TR><TR><TD CLASS="quote">No the bolts align the caps unless you have dowels installed in the rod caps,also the distortion caused by torquing the bolts is different for every bolt .That's why the rods are torqued and then sized you have to keep them as a set.</TD></TR></TABLE>

Well the Crowers do have dowels. And I mixed and matched all the bolts during the balancing process... Hopefully it doesn't matter.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EnzoSpeed &raquo;</TD></TR><TR><TD CLASS="quote">Well the Crowers do have dowels. And I mixed and matched all the bolts during the balancing process... Hopefully it doesn't matter.</TD></TR></TABLE>IMO that's not a good thing.Don't take this the wrong way but seeing as you don't have a reliable torque wrench I'm guessing you didn't have a dial bore gauge to check the rod clearences.Even if you used plastigague it will only tell you the clearence from top to bottom not side to side which is where the distortion or nonconcentricity will show.If the rod end is distorted at the sides when the rod is under load in a running engine the side of the bearings can scrap the oil from the journal and you have major bearing/crank/rod damage from a lack of oil.

 

Eh, I guess you're just pickier than me . I don't care that much about any of that. It plastigauged fine, that's all I'm worried about. I don't think swapping bolts around will matter either.

 

So now it looks like I'm just going to get my good wrench calibrated and re-use my Crower bolts. I'm just going to hope that they didn't permanently stretch after their first use.

 

I hope for your sake your right,but it's an expensive choice.

 

Well I don't think they stretched, because they were pulled from a working motor. I'd think that if they did stretch, they would have spun a bearing on the old motor.

On a side note, where do I get my wrench calibrated at?

 

Your missing the point here.Even if the bolts are ok and they torque to the correct specs it doesn't mean the hole is perfectly round.

I don't want to **** the people off who build there own motor by any means but I see spun bearings on here all the time and this is one of the reasons why.And what do the majority of those people say -it's the bearings fault,not the person who assembled the motor.

This is why a professional build costs so much $ the time taken to make sure all the clearences are correct means having the proper tools and mock fitting of the parts sometimes several times to make sure everything is right.

In the majority of cases when the motor is put together correctly w/the proper clearences,unless there is a part defect,then there shouldn't be any problems with an engine unless there are tuneing issuses or your pushing the parts beyond thier breaking point.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Ed’s Racing Heads &raquo;</TD></TR><TR><TD CLASS="quote">Your missing the point here.Even if the bolts are ok and they torque to the correct specs it doesn't mean the hole is perfectly round.
</TD></TR></TABLE>

Why would it be out of round?

This whole motor build seemed so pointless. I mic'd all the crank journals and nothing was out of round. I plastigauged the rods a million times and everything was in spec. It seems like every "proper engine building" technique is just a "check" to make sure nothing is out of wack. And so far, nothing has been - and why would it be? The motor ran fine before.

I just don't see how the rods could be out of round. Even though I did move the bolts around, I can't see them applying uneven pressure to the caps to the point that it's a problem. I've talked to so many engine builders, amatuer and professional, and I never once heard mention of keeping the bolts with the caps they were originally torqued to.

 

So I'm pretty set now. I'm going to reuse the Crower bolts and tighten them with my Proform gauge.

Which is actually quite difficult. Since the bottom of the Crower bolts aren't dimpled, I just spent two hours coming up with a method to acurately use the gauge. And to get within the .005-.006 bracket, it takes quite a bit more torque than the Crower spec of 24 ft-lbs.

For what it's worth, it turns out the Pittsburg wrench was really accurate. It's about the same as my KD wrench, but my KD wrench reads about 5 ft-lbs low per 25 lbs of setting - pretty far off. That's what happenes when you never calibrate your wrench.

 

Which ever way you do end up doing it, make sure you are still watching your bearing clearances, dont go crazy chasing some stretch number and throw off bearing clearance.