It’s an 85 SBF 302. Stock connecting rods.
Was tightening the last piston to spec and this happened. How do I replace it?
I just had a skid loader throw a rod and I suspect a rod bolt came loose. One bolt threaded out completely and the other one broke. I suspect the missing bolt is in the bottom of the oil pan. I've had that machine for a decade and have never had the engine opened up.
Congratulations on your new yard ornament
"Skid loader" you say, useful piece of kit, indispensable really. I'v been learning about heavy wrenching...it's a big time suck, but preventive maintenance like on a plane engine might be called for. $35,000 worth of used machine is hard to come by. Did it bust the block?
Sent the rod through the block and snapped the cam in half. I've been a pro mechanic my entire life and always keep the service up to date on my equipment. I don't know of anything that would of caught this. I'll know for sure when I get the engine tore down. Sometimes shit just happens.
I would buy a set of Rod Bolts myself & replace all of them.
I was gonna buy an ARP set and just replace all of them
Might need to have rods resized or at least checked after bolt swap.
Ditto 2
This
Meh, just hot glue the nut back on. It’ll be fine trust me bro😒
Fine you convinced me
Break out the welder. Welds shrink when they cool and it’ll suck that cap right up tight to the crank. Trust me bro, source: me.
I mean, they put 2 of 'em on there for a reason, right?
If you go ARP you're changing your clamping pressure. You're going to have to get them bored. Up to you if you want to go through that work
This!!! I made that mistake a long time ago and destroyed a crank because I failed to read the instructions.
There shouldn’t be any change in clamping pressure if the ARP bolts are the same thread pitch as factory and torqued the same. A quick check w plasti-gauge should verify this. Personally, if this motor is making more than about 150% of stock or more hp, I would invest in ARP head studs, as well.
I've never installed anything ARP that didn't have considerably higher torque spec.
I went down in a flaming ball of fire after 1 season on my stock car motor. ARP rod bolts are known for quality, however one nut came loose.
This is in fact the same exact day that I learned why I should patch ALL the holes in the firewall not just the big ones.
That is definitely the move OP.
Consider measuring bolt stretch as opposed to relying on the torque wrench.
I’m taking them to a shop to get the rods resized once I get the ARP rod bolts
Good luck my friend!
Before torquing any caps or heads I always stick the drive of my torque wrench in the vice and pit a zip tie at exactly 12” down the handle from the center of the drive and pull the zip tie with a digital scale. I test the click at 20, 30, and 40 ft/lbs. my favorite Mac tools torque wrench has been off by 2 lbs for 15 years.
Assuming the digital scale is accurate.
It’s easy to check, I just calibrate it to my torque wrench… aw shit.
Lmao. I literally just choked reading this exchange.
This is way too good to be buried in some reddit comment section. This should be in a show. Maybe a show about a mechanic shop in the style of The Office.
I'd watch that. Especially with content like this.
I would love a show like that or a scrubs like show about an apprentice becoming a mechanic
SHUT UP AND TAKE MY MONEY
and my 10mm
lol
They sell weights for scales
It was a joke, I calibrate my torque wrench with a scale and I calibrate my scale with weights.
But what if the weights fall out of calibration?!
You can tell by putting them on the scale...err...wait...
Wait so if I stand on a scale and attach 50 lbs of weight to my belt...my torque wrench will be calibrated to...(carry the one)....im so confused
How much do you weigh and how long is your torque wrench? I can do this math. 😂 I actually use the digital scale method on wrenches when a torque wrench won’t fit (compensating for the length of the wrench) and used to use it on a 5 foot cheater bar 250 ftlb axle nuts (pull scale to 50 lbs). But I own a giant 3/4” torque wrench now.
Some guys use a known volume of water as a sanity check, since 1L of water is approx 1KG
And you measured 12" correctly. And you're pulling perfectly perpendicular to the torque wrench. Etc. There are a lot of assumptions haha
Everything has a tolerance, even torque wrenches. +/- 10 % rule generally applies.
ANSI spec is +- 2% CW from 20 to 100% of scale.
I too like to stack tolerances 😂
on connecting rods you can just measure bolt stretch, torque is irrelevant as long as you meet the bolt stretch spec.
Mostly depending on the hardware, yes. Used stock hardware I don’t know if I’d trust either stretch or torque.😅
My shop has a digital crane scale… maybe I’ll do a quick and dirty calibration check on mine lol
Odd to have a rod bolt break like that. What was the torque spec? Seek advice from a machine shop.
From what I found online its supposed to be 45lbs
There’s your problem. 302 stock rod bolts (1/2” socket) torque to 24 lbs. I would replace them all with stock rod bolts. The problem with using ARP bolts now is that they are a tight fit in the rod and may require resizing the rods at a machine shop. Opens a can of worms.
Replace them all. They have been badly over torqued. 302 rod bolts are only 24 ft/lbs
24lbs!! Lol.
I sent you screenshots from the automotive engine rebuilders association spec website
Are you incorrectly doubting the correct spec?
Or are you correctly reacting to how badly that online guide screwed you? :)
Correctly reacting to how badly the online guide screwed me
You're so lucky that one of 'em broke during installation! Failure of those bolts during operation would be an unbearable agony.
I had a factory service manual for a motorcycle that incorrectly stated the torque rating for bolts on the cam caps by a factor of ten. That was a bad day.
You have a big problem , but it’s one that you’ll be happy you found now :
Was rebuilding a 77 302 and did exactly this because I followed a guide for the larger diameter ones. Replaced every single one and retorqued them.
5/16th bolts are 18-24 ft lbs Mains are in the 60-70 range
3/8ths HP are in the 40 range.
https://help.summitracing.com/knowledgebase/article/HE-04923/en-us
Were they re-used bolts?
They are the stock studs that came on the rods
I would maybe check and make sure your torque wrench is accurate…… or maybe you missed the click
could be wet vs dry too
It’s supposed to be wet, all the engines I’ve rebuilt have specified using oil to lubricate the threads, or using arp torque lube
Yeah, she oily.
Wet vs dry won't make the difference between the fastener breaking vs not breaking. OP was torquing to the wrong spec.
I bought the cheapest torque wrench I could find at harbor freight lol so it could be a bad torque wrench.
I bought the cheapest torque wrench I could find at harbor freight
if it was the PITTSBURGH 1/2 in. Drive, the torque range is a bit too large for an accurate 45ft lbs. And just Harbor Freight too
Uh yea man, buy once cry once for measuring tools.
I did use a Pittsburgh torque wrench to rebuild my 4age, but the thing is accurate for god knows why, I’ve tested it but I would never recommend it. Why spend so much on a rebuild to just trust a $10torque wrench?
I've definitely used my AC Delco angle torque wrench more than I thought I would after I bought it for the angle on my LS rod bolts.
Both of my HF icon click torque wrenches are within 2ft-lb of my buddies snap on click wrench @ 50ft-lbs when Tested with a torque dynamometer.
I'm thinking he got the Pittsburgh one. I had a problem with one tightening too much, and a coworker had a major problem with one not tightening even close to enough. I don't trust them at all.
Icon stuff is hard to beat for the price, though. I wouldn't be surprised if most of those are decent.
I bought the Icon digital torque wrench. Cashier hooked me up with a 30% coupon so I think I paid less than 150 for it.
Super happy with it, especially after making a similar mistake.
The Pittsburgh ones are truly garbage. You can get closer to a torque spec using a breaker bar and ugga duggas then those pitts wrenches
Please buy a little better one at least and recheck everything else you torqued. What size torque wrench was it?
you can measure 1 foot from the ratchet head and hang 45lbs to calibrate it
torque wrench I could find at harbor freight
Been there, done that. Almost snapped bolts on a 4.6 3v Ford Racing intake manifold with one of those. Harbor Freight has a lot of decent tools for the price , but the Pittsburgh torque wrenches are not one of them (the tool boxes are fantastic though, especially the Icon ones, and I am yet to have a problem with 99% of my Icon tools).
yeah I love my Icon torque wrench
I bought the cheapest torque wrench I could find at harbor freight lol so it could be a bad torque wrench.
Supposedly the Hazard Fart torque wrenches are pretty decent, but yeh it could be it's no good.
What are you working on? That sounds insanely high to me.
The Cylinder Head bolts on my 5.7 were 40 ft-lbs.
Edit: well sonofabitch, I just saw your photo caption, looked it up, and sure enough. Boss 302 is 40-45 ft-lbs. I guess I'm used to Dodge's x + 90 deg.
I’m working on a SBF 302. These were the stock connecting rod studs
Is 45lb right? I could be wrong but that seems too high.. 19- 24lb is what I understood em to be
You are correct 302 rod bolts are 19-24lb/ft
Yeah I just did a little more research and I kept seeing 19-24lbs.
You are very fortunate. That bolt started to fail prior to this. You overtorqued it, and it finally let go. The spec is 25 lb ft.
I almost always use a beam style torque wrench. They are very accurate and have a great feel.
You can buy new rod bolts from numerous sources. Stock, and upgraded. You might need to press the bolts out, and back in. You should inspect all the bolts for damage. And, consider replacing them all. Once replaced the bolts should be torqued up and the bearing bore measured. Verify the clearance too.
Click stop torque wrenches improperly stored will be inaccurate in a hurry. Never store without backing the torque setting all the way down. I'm not saying this was your issue, just throwing this out there. The old beam type torque wrenches stay accurate damn near forever, just not as convenient
I feel like a scientist when I use a beam type wrench.
Lol when I replaced my heads on my motor I didn't trust my old clicker so I borrowed an ancient beam style from an old timer i know and I haven't had a single issue
Better it fail now than later.
Go to sears online and get the craftsmen 1/2 inch digital torque on sale for 99$ regular price 300$ i bought me 1 today its flash sale after taxes it comes out to 115$. Dont tell the government i told u.
There's a Sears still open online?
They have a brick and mortar in the Seattle area...
I now have a fair amount of craftsman tools, including both the 3/8" and 1/2" digital torque wrenches. They're fucking sweet: beep beep beeeeeeeeeeeeeep
I don't think there is a Sears or Kmart open anywhere in Illinois. Last Sears I knew of closed maybe 3-4 years ago. You need to go to Ace or Lowes to find Craftsman, Menards dropped them. And it looks like Ace is going to Milwaukee tools. Napa had some but not much.
User deleted comment
2mo
It looks like you shared an AMP link. These should load faster, but AMP is controversial because of concerns over privacy and the Open Web . Fully cached AMP pages (like the one you shared), are especially problematic .
Maybe check out the canonical page instead: https://www.foxbusiness.com/economy/craftsman-factory-texas-shows-challenges-reshoring-manufacturing
I'm a bot | Why & About | Summon: u/AmputatorBot
Buy a lottery ticket with the money you just saved in RE-re-building the engine
Always replace the con rod bolts
Actual place where I’ll tell somebody straight up buy better
Push tjat piston out and knock the old rod bolts out and drive the new ones in.
Whenever rebuilding an engine, rod bolts, main bolts and heads bolts are a must have. Decades of use, thousands of miles, and thousands of heat cycles are best eliminated by and extra $200 for bolts.
This is the issue with online guides. You should source factory manuals for your vehicle. I prefer print, but the pdf’s are not very expensive.
Check your bearing also. If the bearing is the wrong size to start with your bolt will break before the cap seats
Start by replacing them all with arp studs and nuts
If you’re going to use a ”click” type torque wrench be aware they’re not accurate below 20% of scale. Your 150 ft. lb. 1/2 dr. shouldn’t be trusted brlow 30 ft. lbs. Better to use a 3/8 dr. wrench, beam, or digital. Check the paperwork that came with your HB tool.
well guess who now has the fun job of pulling the slugs back out of all the pots and replacing all the Bolts and buying a proper torque wrench. because i would not trust anything that's been tightened up now .
Are those rod bolts just a tiny bit short ? Looks like they're about a thread or two short. The difference in thread showing on two bolts.
I would, take the other nut off, push the piston out, replace Both Rod Bolts, and reinstall the pisto. Then go through all of the others and do the same. Better to do it now than risk one comming loose at 7000 rpms.
Cheap ass Chinese metal 😂
That is one of the most critical bolts in the entire assembly, I'd definitely recommend using ARP, and they probably have a few different variations depending on the application and budget. Luckily you can use a stretch gauge as opposed to a Torque wrench to get it safely within range. A quality assembly lubricant with generous application is going to be a must also.
Only apply a small amount as excess will affect your readings. ARP mentions that in the instructions included with the bolts.
Thx for that.. 🫤
That’s a connecting rod, or “rod” for short. Pull them out and start over with new rod bolts
Start over.
Meh, JB Weld and send it.
Nice quality “locking” nuts…
Remove the other rod bolt pull the rod cap off and you should be able to just grab the broken bolt with a pair of pliers and replace it with new hardware
Replace all of the Rod bolts that’s the correct answer. My guess is you probably need to replace your main cap bolts as well.
Damn I hatd when that happens.
While this is on topic, can you get away with upgrading rod bolts without getting the rods honed?
Punch the stud out before you in bolt the other one.
You’re lucky this bolt broke when it did. Save it as your good luck charm!
Didn’t give a proper offering to the grease monkey gods
The broken bolt looks like you can take it out with needle nose pliers.
Take the cap off and grab the piece with vise grips
No broken bolt is ideal. However, at least there is some meat on that thing to get it out!
If your torque wrench is working correctly change all the rod bolts.
From experience…carefully
JB WELD! you'll be fine 😬
Personally I'd use a sledge hammer...
Replace those studs with ARP bolts.
Replace them damn bolts
You should use a little oil while to torque
But I would probably replace all rod bolts, if that broke at 25 pounds
Consider yourself lucky. Now go back and inspect all your rod bolts. Or just buy new ones. They stretched to their breaking point. Oftentimes, they give measurements to critical hardware. Measuring thickness and / or stretch. You just avoided a catastrophic failure. If you are not sure what to do, go to a good machine shop that does engine work.
Take the piston rod back out, replace the stud and reinstall the rod.
Weld it
Did someone use ft-lbs instead of in-lbs?
Hahaha you actually got lucky on this one
It can't be stuck if it's liquid
Can use a fluted screw extractor, weld something else to it, or as a last resort you can drill it out and use a helicoil. After seeing that it’s sticking out some you can probably get some nejisaurus or vampire pliers on the shank and unscrew it
Switch to ARP bolts.
I would replace them all
Most our tools get calibrated annually, I work for a large County airport. Our tools aren't even used on planes just the Automated People Mover.
I think you tightened it too much
arp rod bolts. 😁
call metals tech
New Rod. No way around it.
Just order the new rod studs and tap them out one at a time .
Irwin screw extractors.....just drill straight, not a big deal. Tap to clean up the threads.
User deleted comment
2mo
It's a stud pressed into a steel connecting rod
Just be glad it was 'now' and not while running, then start over