Author Topic: Torque # for my Rod? (Read 3268 times)

Don R · « **on:** January 30, 2014, 02:04:46 PM »

CB750 stroker crank, I just had to see the rod bearings. They look OK, not shiney but no wear patterns, grooves, nicks or junk either. Aluminum Rods, the rod stud/bolt is 8mm and the nut wrench size is 13mm. MTC rods maybe? Does anyone know the rod nut torque? I'm ready to rock this Honda back together.

Neither MTC or Falicon has any info online. Falicon may have made them for MTC.

Bill/BentON Racing · « **Reply #1 on:** January 30, 2014, 03:24:39 PM »

I believe 22-25 ft/ lbs.

Bill Got some info somewhere.

Big Jay · « **Reply #2 on:** January 30, 2014, 03:31:21 PM »

Picture of the rod?

Don R · « **Reply #3 on:** January 30, 2014, 08:46:09 PM »

Obviously before anything got cleaned up. Check out the weld on the crank just above the rod.

Bill/BentON Racing · « **Reply #4 on:** January 31, 2014, 04:40:25 AM »

Be careful of that crank. Mflux it for sure.

MTC I think. Jay will know.
RC Golden rods torqued to 30 ft/lbs! Bill

MRieck · « **Reply #5 on:** January 31, 2014, 04:43:58 AM »

What is that white stuff on the rod parting line?

bear · « **Reply #6 on:** January 31, 2014, 07:35:58 AM »

New bolt's?

Cheers,
Brian

Don R · « **Reply #7 on:** January 31, 2014, 07:55:14 AM »

The white appearing stuff is just oil and a photo illusion, There's no goop in there. Kinda like the green stuff on the crank, just oil that wiped right off.

MRieck · « **Reply #8 on:** January 31, 2014, 08:37:50 AM »

Quote from: Don R on January 31, 2014, 07:55:14 AM

The white appearing stuff is just oil and a photo illusion, There's no goop in there. Kinda like the green stuff on the crank, just oil that wiped right off.

Gotcha.

I have found some very strange things in engines Don (as I am sure you have)...that's why I asked.

Don R · « **Reply #9 on:** January 31, 2014, 09:29:47 AM »

Strange things for sure, there was a stray o ring smashed under the copper head gasket, partly hanging into the cam chain tunnel and another one on the oil pump screen. It appears at least one of the sleeve o rings came out and got chewed up too. The sleeves were siliconed in due to air gaps between the fins. The nickel washers were folded in on themselves. It would have been an oil leaking pig. Hopefully the sleeves are sealed to the cylinder by the silicone.

Jim F · « **Reply #10 on:** January 31, 2014, 10:11:00 AM »

is that area that looks like its been welded an illusion also?

If it has been welded then please get it checked out

Don R · « **Reply #11 on:** January 31, 2014, 11:02:48 AM »

It's a welded stroker, that's how it was done back in the 70's. I pointed that out for educational purposes.
The bearings tell me everything is relatively straight and it's getting enough oil. I've crewed on an alcohol funny car and dragster, I've seen good and bad bearings, I'm going to trust what the bearings tell me. Thanks for the info so far guys. I'm trying to learn.

New bolts might be a good idea, finding suitable replacements could be another matter. I called my local shop, he'll mag the crank, might as well as long as I have the rods loose anyway.

MRieck · « **Reply #12 on:** January 31, 2014, 01:19:16 PM »

Maybe ARP has some bolts that will work Don. I have to assume they are standard issue size for some kind of car etc.

Don R · « **Reply #13 on:** January 31, 2014, 02:17:03 PM »

I took the crank to get magged, that's as far as I'm going. It was supposed to be relatively fresh when parked. My priority is my Daughters drag car and I have to draw a line somewhere on the Honda.

This is most likely going to be a cackle fest / show / memorial type deal anyway, Tom's boys want to buy it back and they aren't going to race.
Yeah, right.

Don R · « **Reply #14 on:** January 31, 2014, 02:57:41 PM »

Holy Cow! it checked good and cost me $10. That's good, since there's no plan B.

So, torque them 22-25 or 30? Too many things apart in the shop something needs to go back together.

MRieck · « **Reply #15 on:** January 31, 2014, 04:15:17 PM »

Quote from: Don R on January 31, 2014, 02:57:41 PM

Holy Cow! it checked good and cost me $10. That's good, since there's no plan B.

So, torque them 22-25 or 30? Too many things apart in the shop something needs to go back together.

You must lead a good life!

Don R · « **Reply #16 on:** January 31, 2014, 04:19:47 PM »

Makes up for the $12 o ring I bought this week. lol.

Don R · « **Reply #17 on:** January 31, 2014, 09:20:24 PM »

Anyone have a for sure number? I pulled them all and magged the crank, now they're all apart.

Big Jay · « **Reply #18 on:** January 31, 2014, 10:35:37 PM »

Those are MTC. I would use .005" stretch.

Don R · « **Reply #19 on:** February 01, 2014, 09:20:42 AM »

Thanks Jay. I've got a stretch gauge. Can do! I love it when I have a plan and it's coming together.
I stretched the bolts on my 383, it was WAY more twist than when I torqued them, almost scary.

Big Jay · « **Reply #20 on:** February 01, 2014, 11:31:36 AM »

I would test at least one. Measure the overall length. Tighten it until you have stretched it .005". Undo it, and it should return to the original measurement. if it doesn't, don't use them.

Post here if the bolts are no good, and I will see what I can do.

Jerry Rxman Griffin aka MuthaF'er · « **Reply #21 on:** February 01, 2014, 01:51:46 PM »

Quote from: Don R on January 31, 2014, 09:20:24 PM

Anyone have a for sure number? I pulled them all and magged the crank, now they're all apart.

It doesn't sound like you checked the torque they were put together with before you took them off?!?

Don R · « **Reply #22 on:** February 01, 2014, 03:02:59 PM »

They were torqued and locktited, I didn't think the breakaway torque would mean much loosening or over tightening.

Don R · « **Reply #23 on:** February 02, 2014, 03:09:54 PM »

OK. I stretched them .005". It's difficult to do this on old bolts. At least some newer rod bolts have a centered recess the stretch gauge centers in. These have a raised area in the center so you need to hold the gauge very carefully while tightening with a wrench and keeping the gauge block from moving. A two man job for sure. I'm more comfortable torquing.
I checked a couple, they do return to their previous length when relaxed. Fingers crossed.

Even though this motor is old, it wasn't raced much and has had new rods at least once. I know, famous last words. There's no plan to race it but it needs to start and sound good for cacklefests and shows. It's more of a tribute to the former owner. Hence my decision to re-use the bolts.

Big Jay · « **Reply #24 on:** February 02, 2014, 05:15:53 PM »

Dounds like you are good to go. Once you get one stretched with your gage, then you can use the torque wrench to see what that is in ft lbs.

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Author Topic: Torque # for my Rod? (Read 3268 times)