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Topic Review (Newest First)
05-27-2005 09:49 PM
4 Jaw Chuck Torque angle analysis for critical bolted fasteners.
05-27-2005 02:32 PM
machine shop tom I thought "Real" mechanics could tell by the "feel" of a bolt if it was "tite" enough!

05-27-2005 02:02 PM
56Maynard lol, I was in fact responding to the nice young man screaming b.s. at the guy that took the time to research the subject and post his opinion based on his findings and conclusions, not you cold knock. I went back and scrolled through the thread and yeah, I can see now how you'd think I was talkin to you. I should have been more thorough in my reading. Sorry.

For some reason I cant open the carrillo link and i am sure its a good one from them as they have been at it for awhile now.

Aside from the obvious value in using a stretch gauge there is also the ability to capture the infrequent defective or "stretchy" rod bolt that could be/has been overlooked with a wrench.
05-27-2005 01:43 PM

Originally Posted by johnsongrass1

Sounds almost exactly like what i said,,,, and i never seen that write up before.....

05-27-2005 01:29 PM
johnsongrass1 Interesting read from Carillo
05-27-2005 01:13 PM
coldknock Please do, I have a few ideas on how to get to the bolts, especially the ones on the inside but any help would be great.

05-27-2005 12:11 PM

It's ok Larry i still love you!!!!! I think there was a mis-understanding here. I think 56 was talking to 347mustang and it was not a reply to your post about how your gramps taught you...... And i am only guessing here but i think it was because of his slam on me talking BS about what i found....

I made my own stretch gauges. I have a different one for when i am using my rod vise, like when rebuilding rods, or getting bearing clearances. Then i have another one for when i assemble the engine. It's real narrow to fit around all the other stuff in you way when your trying to get it on the rods..... I used a $10.00 indicator form travers tool and a small block chevy oil pump spring for tension.......

I really don't think i would pop for the digital one even if i had the money. I have found that alot of times those typs of indicators are just to sensitive and will bounce around all over the place......

if you do start doing the stretch deal be ready to invent some new tools!!!!! I can post pictures of the ones i built if you like????

05-27-2005 11:00 AM
coldknock I apologize for my outburst. It's seems that my late exposure to new engine building tools and technology was taken as ignorance.

K-Star, My comment was aimed at 56Maynard. His remark was uncalled for and it to be honest it pissed me off something awful.

Back to the subject. The one at the top of the page linked below is the tool I recently purchased. They have a digital version but I just couldn't justify a $600+ tool for two or three engines a year.

What do you guys use?

05-27-2005 05:56 AM
engineczar Like most people who have built engines for a while I never used a stretch gage until a few years ago. The failures I incured were very few. But for me if I'm going to charge decent money for my work, and I'm going to stand behind my work, then I'm going to go to every length to insure the motor doesn't fail. Especially due to something as simple as a loose rod bolt. I don't know about you, but I don't have extra cash lying around to replace customers motors and I also have a conscience that won't let me screw a customer. I feel like going that extra step is just cheap insurance.
05-27-2005 05:43 AM

I don't think this needs to turn into a fame job.....

I do have a hard time with someone tell me what i wrote is BS when i didn't see any results from there testing.....But it's ok they are allowed there opinions.....So i am trying my best to remain calm and not get into a fight over it...

I have not seen anyone tell me the reason why there testing proved that you do not need to stretch the bolt,,,,,

I know the troque wrench has worked for 100's or 1000's of engine builders and thats ok. But if you spend some time and do just some small testing on this subject you will very easly find out what i am talking about......I am amazed that every other engine does not have a rod bolt failure... but like i said before there must be engough safty built into the bolts that it'a a non issue.....

I am sorry if i offend anyone, but for me the tone was set in the post by someone telling me i am talking BS.........

The fact is you can do what ever you want when you build a engine your self. I was only trying to help.....

05-26-2005 11:15 PM
Rick WI The reason you use the stretch method is to get the proper clamping force on the fastener. It's as simple as that. If you don't have the proper stretch on the bolt it won't perform to specs..
05-26-2005 09:03 PM
coldknock I'll ask him if I make to heaven butthole.

Furthermore, I think every single person that's ever built an engine used a torque wrench and 30wt on the rod bolts until they learned of a better way to do it. Yourself included.

05-26-2005 07:22 PM
56Maynard If the nice man that engineered the fastener in question recommends/insists on 5 cycles, lube and a stretch gauge, why would anyone think to undo the engineering and put a torque wrench on it? Please ask Gramps that and get back to us.
05-26-2005 06:01 PM
4 Jaw Chuck I use torque angle myself, mainly because it works with blind fasteners and is unaffected by oil and temperature. Placing a fastener in it's elastic range is all thats important, it is a spring after all.

With 120 000 psi tensile strength fasteners commonplace these days the rod will fail in shear long before the bolt breaks anyway.

Accuracy of placement in the elastic range by measuring bolt stretch is not really necessary because of this fact, but if it makes you feel good it certainly won't hurt. Just make sure you do the same thing as the machinist that sized your rods.
05-26-2005 01:25 PM
NDNslicks4me Rod bolts don't stretch much from rpm, it's from the lack of...I'm not being clear. It's not falling from a building that hurts, it's the stop at the bottom. Any clearer? A drag engine doesn't use the engine for a lot of braking, a dirt track car does.

Metal will stretch a bit then become "stiff" right before it snaps. I think the idea is to take the stretch out so the rod cap doesn't "rubberband" the bolts. Lots of inertia there.
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