I like going down the rabbit hole as well. Usually I learn Ive done it wrong my whole life, according to the internet, but if it works who is to say. Being as you had specs to the life of your British Bolts, I would have likely done the same I've only owned 5 foreign cars in my life, and only one British ,a 59 Jag. although I have worked on many, and if in doubt,I follow the instructions. At home, if it works as my training and experience say it should, it ships.
I think the idea here is that you get an assortment of recommendations here on the internet. Hopefully those recommendations are accompanied by an explanation as to why that recommendation works well/best. Even if someone doesn't follow the recommendation, maybe they learn something and can compare it with how they ultimately decide to do something. Its food for thought and maybe later use if not now. How many engines do you think have been assembled over the years where someone had a crank turned .010 and bought .010 under bearings and installed them.......never checked anything.....and never had any problem? Lots and lots. Does that make it the way all engine builders should assemble their engines............because it comes out right and OK a lot of times with no checking? Of course not. Knowing a proper way to do something never hurts, but each person has to decide for themselves how they will proceed ..........trust your luck or trust but verify.
The minimum I’ve ever done is plastigage not perfect however it gives the user at least a ball park idea Thanks again guys Dan
I understand measuring bolt stretch when the rod has bolt and nut. But when a cap screw is used there must be a through hole to check, yes? If a cap screw and blind hole do you drill through to make checking possible?
sep fontana when I measured the bolt stretch on the old bolts I made spacer and clamped in a vise to torque up to the various torques unbolted and measured the bolts at each stage.The new ARP bolts in the rod were torqued to ARPs spec On these rods one bolt hole is a through hole the other is a blind hole my opinion would be don’t drill through I don’t know if this would weaken the rod
You put them against each other and give them a twist. Clean blocks will "stick" together. Sometimes you can use a single block, like a .500" nominal block. Other than that your stack will be made of 2 or more blocks. Like a 1.0312" stack up. It will use: a .1002 block, a .131 block and an .800 block. Use as little blocks as possible. I was taught to use a piece of paper to keep track of what you will be using. This is what is in a standard 88 block set, it also lists the grades that are generally available. http://www.starrett-webber.com/GB10.html
It is actually on a molecular level, the surface finishes are THAT good. One class I was taking, we were split into 2 classes. The other class had a real old school instructor. He was good, but he went overboard on things. I heard that he spent 3 DAYS on gauge blocks. I think we covered it in 1. It comes down to simple subtraction. Get your "tenths" block, then the "thousandths" block. Then the "hundredths" one. The other will be a nominal one like .400 and so on. In the case a block is being used by someone else or is missing, there are alternate stack-ups that work. BUT... less is more when making a stack. Always check them with a good micrometer. Let me know when you are ready to get into sine bars.
The easy way to clean the gauge blocks so they'll stick together is to put a piece of paper on a flat surface and rub the mating surfaces on the paper. That's it for my tip of the day.
Just to clarify my farm implement reply above, let's add some context. Grumpy Jenkins would size his SBC rods with a .002 shim at the parting line. When the engine got pulled to max RPM (7,800) the rods would stretch at the centerline to round, he'd found they were stretching out of round and that was his solution. Perspective.
Another rabbit hole - cool stuff .Sure wish I had a mill and lathe at home. Since I retired I don’t have access to machine tools , only have drill presses, hydraulic press and belt grinders etc.
hello please? IF you are using cap screws - I can only presume that they have a circular head? how are you then fitting the oem style locking tabs?
I’m not using the locking tabs,the ARP bolts are 12 point with a special washers, ARP recommends using their thread lube, these bolts are torqued to 55 ft-lbs unlikely they will back out
Bit late to the party, but the A series motor in a 1964 sprite would have had all SAE threads, coarse and fine.
It's not just ARP bolts that make you have to resize the rods, it's the distortion of removing the bolt period that is as much of the cause itself. Replacing them with stock rod bolts requires it as well. I know over the years someone is going to say their grandpa did it all the time in his dirt floor garage with a hammer and punch and never had any issues....They just didn't realize how close to the edge they were....
I stand corrected the rod bolts are 3/8-24 unf threads not sure why I thought they were British Standard Fine still don’t know the grade of bolts the original rod bolts are no markings indicating grade. I do know that there are unf and unc threads on the manifolds, oil pan and timing cover. All bolts carrying a load head studs, main studs and rod bolts were ordered as direct replacements - never measured the threads on the replacements. That being said I was close to yield for a grade 8 unf bolt. Thanks for the info Now I know.
basic https://mechanicology.com/sae-bolt-torque-chart-grade-2-grade-5-grade-8 a bit more complex https://www.engineeringtoolbox.com/us-bolts-torques-d_2055.html I checked a few different sizes and they seem to agree.
I torqued the original rod bolts wet looks like I was past the limit if the bolts were grade 8 The original bolts might have been stronger than grade 8 but I don’t knowThe ARP bolts are of greater strength than grade 8 bolts
Fired up engine , broke in cam and tuned ran 1 to 1 1/2 hours blipped throttle to 5000 a few times oil pressure 40 at idle and 60 at 2000 rpm plus water temp at 180 (180 thermostat) no strange sounds oil looks good etc. I learned a bunch hope everyone else did too. Thanks to all for their input! Dan
1. no. not with 11 ft-lbs more, you might have stretched one or two but...seriously doubt it. the worse you did was MAYBE choke off oil supply. but since you caught it, you've probably worried more than you should have worried. If you have the time, back all the nuts off...let the bolts sit for a few days, come back and re-torque. They'll remember their state and return to it. If you find that none of them are stretching, while re-torquing, yeah, it might be time to replace the rod bolts. I did this, but more intentional, on a motor, I didn't get any stretch out of the rear rod caps and instead of 72, I didn't feel stretch until 78, so i kept it. the rod bearings starved for oil (my fault). but I used the bolts on the 'reset' after i had the crank weld-up and turned-down. the car ran for 25k after that (including 3 very long drives) before I sold it. Repeat to yourself 35, 35, 35, 35, 35, 35, 35. lol. best of luck.
Actually, measuring bolt stretch is more important than the actual torque reading. Bolts that can be measured should be measured before assembly while in a free state. Then the proper lube applied while assembling the nut and torqued till you get the proper stretch......which may be at a higher than recommended torque reading.
I can see measuring stretch on rod bolts, but how can it be done on mains or head bolts? Personally I just hope my wrench is accurate enough to make the spec range provided. Could you be thinking of TTY bolts by chance? I don’t know if anyone makes a spec or the proper bolt to used for old stuff. Then again I don’t have a clue if say a bolt used for TTY is the same as just used for a tq spec.
Generally speaking, you can't measure it, so its good to have the proper lube on the bolt if possible..........which then leads to the question about putting sealer on head bolts that go into holes that are open at the bottom. Rod bolts are probably the most critical item in an engine. Was just reading Hot Rod this morning and they talked about their newly built 350 Chevy failing during dyno testing. They felt that they had not completely seated the new bolts in the rods and that allowed the rods to seat the bolts while running.......which increased the clearance and destroyed their engine.....even though they torqued them. If someone was anal enuff, I suppose they could make a test fixture where they checked to see how much torque it took to stretch a head bolt and then apply that amount of torque when installing them. But, millions of engines have been built just using a torque wrench, so thats probably gonna be fine most of the time.
Yes stud or bolt stretch is the best method. I never have used the stretch method on an auto engine although I have used this method on industrial engines The industrial engine series that I worked on had a special hydraulic jig to stretch the stud. The nut was first installed then a special nut and cage was installed ,hydraulic pressure at specified amount was applied stretching the studs a predetermined amount then the nut was simply hand tightened then pressure was released and bingo bango done ,no wrenches needed for main studs ,rod studs or head studs I don’t recall any stud or stud related failures on these engines 250 mm bore turbo charged up to 10 psi boost with 10.5 static compression ratios and 1000 rpm’s + Oh you don’t want be anywhere near one of these beast when they detonate you’ll ruin your underwear. ARP has very good instructions and their tech support line is excellent
"(Hot Rod) felt that they had not completely seated the new bolts in the rods and that allowed the rods to seat the bolts while running.......which increased the clearance and destroyed their engine.....even though they torqued them. " The tear down of that engine would be mighty interesting. Loose or embedded bolts holding a housing together that is subjected to big loads ( like a con rod or main cap) allow a big rapidly progressing mess due to cap micro-motions that fret and allow further embedment. Maybe even worse the unloaded bolts are subjected to highly fluctuating loads that will cause fatigue, cracking and breaking in short order. https://www.boltscience.com/pages/fatigue-failure-of-bolts.pdf
The Jalopy Journal
