torque converter bolts

[RD73RT]

bought new torque converter & flex plate (B & M) for a 408 stroker. Should you buy new bolts for both or can you use old ones?

 

[moparleo]

I would never reuse a fastener twice that requires you to torque it. Also use loc-tite. Cheap insurance.

 

[74 challenger]

i thiny you can reuse them because you never get new ones when you do tranny work,the shops reuse them.just use locktite on them. I never had one come out.Thats like saying never reuse you flexplate bolts because you have to torque those down to.jmo

 

[Juan Veldez]

I wanted to respond to this also, but wanted to see what other people would say first. And as I thought, it could go both ways. I would say reuse them if they look like they are in really good shape and replace them if they have imperfections (or inexpensive) - better safe than sorry. I looked in a few of my books, it didn't say you should replace them every time. But I do recall being told that some drive train bolts should be switched out, just can't remember which one's, maybe the pressure plate ones. Anyone else know?

 

[moparleo]

My opinion comes from 35 years in the auto repair industry. Never assume that just because a garage uses your bolts over means that it correct. Do you use connecting rod bolts over ? Ask any major engine builder. I bet not. Basically you could use a flexplate bolt over because they are usually only 3/4-1" long and grade 8 or better. A fastener goes through 2 stages when being tightened, it goes from elastic to plastic. In other words the fastener stretches when tightened. If tightened past its designed stretch point it either stretches suddenly or breaks. Stretch gauges are very expensive and impractical for someone rebuilding only one motor. So we use torque wrenches. Ask a pro race team that builds their engines that has to last more that a few seconds.

 

[Juan Veldez]

My opinion comes from 35 years in the auto repair industry. Never assume that just because a garage uses your bolts over means that it correct. Do you use connecting rod bolts over ? Ask any major engine builder. I bet not. Basically you could use a flexplate bolt over because they are usually only 3/4-1" long and grade 8 or better. A fastener goes through 2 stages when being tightened, it goes from elastic to plastic. In other words the fastener stretches when tightened. If tightened past its designed stretch point it either stretches suddenly or breaks. Stretch gauges are very expensive and impractical for someone rebuilding only one motor. So we use torque wrenches. Ask a pro race team that builds their engines that has to last more that a few seconds.

Actually, yes I do reuse rod bolts, and mains, head studs, etc. I certainly do not carry your credentials and trust what you say, but I must have been very, very lucky. I've went hi 7's at 175mph in the quarter reusing these nuts and bolts over and over again (3 re-builds). None for breakage. And I'm talking 200 plus passes with 10,000 rpm's shift points, 4 shifts each pass. And I've raced super stock and super gas cars also. So you do not reuse carb studs, intake bolts, header bolts, valve cover bolts, etc.? I mean just about every bolt on the engine and drive train is torqued and would need to be replaced with each rebuild. Or are we talking fasteners in extreme shear or tension, or both? Seriously, I'm not trying to be a "Richard" here, I'm really curious?

 

[Juan Veldez]

Just "goggled" it. WOW, serious opinions on this subject. Some as strong as saying if you don't use a stretch gauge, your not a serious engine builder! Some (as me) say they built dozens of motors and never had a problem with using a torque wrench. But couldn't find anything about reuse after running the motor, just re-torquing them a few times prior to start up.

 

[moparleo]

We must use common sense. A valve cover bolt does not see the stress that a connecting rod bolt sees. The question was can I use the torque convertor bolts over or should I replace them. The answer was you can use all the old bolts again.
Of course you can, but there are reasons that we buy SPS or ARP head bolts and rod bolts. A weekend racer who is doing inspection teardowns every few race miles is different than a daily driver that should go 110K atleast before needing a major service.
Did you know that a 7 second run at 10,000 rpm's equals only about 1100 actual revolutions. Thats the difference between a NASCAR motor that runs 7-9k rpms for 500 miles and a Drag motor that only has to last for 10 seconds or less.

 

[74 challenger]

ok Im sorry if i was starting a problem here.I was just saying in my 18 years of back yard renching i never had a problem reusing any of my bolts. i rebuilt my 440 outside doing bearings with the wind blowing dirt around and didnt have a problem. USE THE LOCKTITE

 

[74 challenger]

Im sorry guys just it seems we all make something so small to something so BIG.Really torque bolts???

 

[moparleo]

So I guess the engineers who spend mega bucks designing and testing engine components must be knuckle heads for actually giving a torque value to each fastener. Some very important under a lot of stress and some not. Sorry, Its just that from what I can see, there are a lot of guys just looking for advice which is a good thing, new guys to the hobby wanting to learn. Some make sweeping statements with no explanation as to what they base their opinions on. This can be very confusing to the person just asking a question. I try to give answers based on a career in the profession. And I try to explain why I say what I do. Always with the other guys best interest at heart. It is easy to spend someone else money when making recommendations. I am now retired. In my professional life I started as a Service tech, worked up to Service Manager and finally to Store Manager. For a major worldwide company. I was also involved in professional drag racing in the AA/FC class for a number of years. So I have seen a lot of engine failures. Fasteners on a pro motor are throw away parts like the rods are. Only good for a few runs before being stretched and pounded to death. Street motors are built with longevity in mind, not how many times you can go cheap on a rebuild to see how many times you get lucky. I would not brag about building your motor in the dirt and you had no problems. I bet no one on this site would let you build their motors with that kind of bragging. If guys want to do that, fine, but don't recommend your bad habits to someone unless you are paying their bill for them.

 

[Chryco Psycho]

Common sense would say for the cost why not replace them , they are under high stress & often come loose when they are reused .

 

[moparleo]

Amen. All that needed to be said in the first place.

 

[RD73RT]

converter/flex plate bolts

thanks for all the input,to be on the safe side I will replace the converter & flex plate bolts. they don't cost that much and for piece of mind it's worth it. thanks again!!!

 

[74 challenger]

ok,but i wasnt bragging.i was never able to buy just any part i wanted or needed or be able to send my car to a shop.Not everyone on this site has money like that.

 

[moparleo]

Mr 74 challenger, My apologies for comming on strong, happens when you are starting to be an old fart I guess. I am not rich and when in my teens and early twenties my favorite place to shop was a place called Blair's Speedshop in Pasadena. They had a machine shop and did everything you could think of including Dyno tuning on a Clayton chassis dynomometer. Because of their reputation in So Cal a lot of racers went there so they sold a lot of used stock and racing parts. They also took payments. I was taught in the beginning that engines should be built in what they now call a clean room. Kinda like an operating room. I did plenty of work on my rides in the dirt on my back, but always was anal about engine building cleanliness. When I couldn't use the local high school auto shop, I would clean and wash the garage floor, close the door, turn on the lights and take all the time needed to make sure that I was confident that if there was a problem, it was the part and not me. My advice to any one reading this that wants to do engine work is clean,clean,clean . Clean bench, clean engine stand, clean tools, clean hands, good lighting and no smoking or beer drinking. You can never be too clean when working on precision machined parts. Have a plan before you start so you won't have to back track because you forgot something. And take notes just in case you have to do something over you have notes on what you did. Mopar or no car

 

[74 challenger]

moparleo I do agree about you should do it right and in a clean environment.I never meant to give anyone bad advice.My apologies to all.