ARP rod bolt installation

brighton911 · 01-09-2014, 08:55 AM

I thought I would share my experience with ARP rod bolt installation on my 3.2 rods. Previous discussions about the need to re-size the big end after installing ARP bolts was a good excuse to buy a bore gauge. First thing I can say, the quality of the bolts is a thing of beauty. Installing them in the rods found the interference fit was not that great so I really doubted there would be a rod deformation issue. Bolts installed and clamped to 40 ft lbs using ARP lube found the rods to be round except for (there is always one) #6 which has a .0007" high spot. The rest were 0.00 to 2 ten thou out of round. # 6 will get sized of course.

On to the the stretch checking I bought the JEGs stretch gauge pictured below. The dial gauge spring is not strong enough to hold it in position but hooking your fingers around the gauge and pressing down on the top of the pin cured that problem. The rounded tip on the anvil could be a little more pointy but it still worked OK. As all that I was checking was the required torque to get the .0100 - .0105 stretch, I simply clamped the rods in a vice using soft faces. Made it so much easier. First checking the free length of the bolts and recording the value, I ran the nuts down 3 times each to ensure they were seated and burnished in. ARP lube was used. I found there was great repeatability in the torque and stretch values. All were all very similar to #1 with the lowest torque being 39, the highest 42 to achieve the necessary stretch value.

#1
Pre torque length number side 2.7443" plain side 2.7425"

40 ft lbs gave .0102" on the number side .0103" plain side

length after torques number side 2.7444" plain side 2.7426"

All in all, very good. Too bad about the small end bushings being worn out, delays the assembly just a tad.

KTL · 01-09-2014, 02:45 PM

Which bore gauge did you choose? I've found you've got to spend a good buck to get a nice bore gauge with a 0.0001" resolution dial indicator.

cgarr · cgarr's Garage

Quote:

Originally Posted by KTL

Which bore gauge did you choose? I've found you've got to spend a good buck to get a nice bore gauge with a 0.0001" resolution dial indicator.

Indeed!

Gordo2 · Gordo2's Garage

Quote:

Originally Posted by brighton911

... Installing them in the rods found the interference fit was not that great so I really doubted there would be a rod deformation issue.

I was also a bit surprised that the rod bolts didn't take more effort to install in the caps. They fit snug, and stayed in place, but only took a light tap with a rubber mallet to insert them. I guess for some reason I thought they were pressed in.

On this, I think most agree that the big end deformation and the recommendation to recondition is not so much due to the installation of the ARP rod bolts, but more so a matter of milage/wear.

I steered away from buying a bore gauge based on the same feedback you received from KTL and cgarr - that plus many seem to feel that accuracy (even with the best gauges) can be highly dependent on the user's proficiency.

Out of curiosity, how did you measure the rod's small end bore size - with the bore gauge you purchased?

Thanks Gordo

911pcars · 01-10-2014, 12:07 AM

Quote:

Originally Posted by brighton911

I thought I would share my experience with ARP rod bolt installation on my 3.2 rods. Previous discussions about the need to re-size the big end after installing ARP bolts was a good excuse to buy a bore gauge. First thing I can say, the quality of the bolts is a thing of beauty. Installing them in the rods found the interference fit was not that great so I really doubted there would be a rod deformation issue. Bolts installed and clamped to 40 ft lbs using ARP lube found the rods to be round except for (there is always one) #6 which has a .0007" high spot. The rest were 0.00 to 2 ten thou out of round. # 6 will get sized of course.

On to the the stretch checking I bought the JEGs stretch gauge pictured below. The dial gauge spring is not strong enough to hold it in position but hooking your fingers around the gauge and pressing down on the top of the pin cured that problem. The rounded tip on the anvil could be a little more pointy but it still worked OK. As all that I was checking was the required torque to get the .0100 - .0105 stretch, I simply clamped the rods in a vice using soft faces. Made it so much easier. First checking the free length of the bolts and recording the value, I ran the nuts down 3 times each to ensure they were seated and burnished in. ARP lube was used. I found there was great repeatability in the torque and stretch values. All were all very similar to #1 with the lowest torque being 39, the highest 42 to achieve the necessary stretch value.

#1
Pre torque length number side 2.7443" plain side 2.7425"

40 ft lbs gave .0102" on the number side .0103" plain side

length after torques number side 2.7444" plain side 2.7426"

All in all, very good. Too bad about the small end bushings being worn out, delays the assembly just a tad.

This ARP sheet says 50 ft.lbs. for M10 rod bolts (all 911 rod bolts up to 3.2 engine).

Sherwood

brighton911 · 02:38 AM

The 3.2 bolts are M9 and 40 ft lbs is the starting torque stated in the instruction sheet. The ARP part number is 204-6005

brighton911 · 01-10-2014, 03:18 AM

Don, I wasn't able to use the bore guage for the small end, it doesn't go that small. For a quick check, I cleaned the pin and rod of oil and inserted the pin and tried to rock the it. Once I detected small movement, I used a digital vernier to measure the pin and bore. Agreed, not super accurate however the difference between the pin diameter on the vernier and a micrometer was only .01 mm - pretty good.

brighton911 · 01-10-2014, 05:16 AM

I want Craig's gauge! For sure Kevin, one can spend big dollars on a high end gauge, mine is less so. The graduations on it are .0005" so I was estimating the readings, probably reasonably close.

KTL · 01-10-2014, 09:50 AM

I have a small economy bore gauge & it works OK for the rod small ends and the piston bores.

I got a more expensive Mitutoyo like Craig's for the bigger dimensions like rod bores, case bores and cylinder bores. I think the Miutoyo at ~$360 is a good deal because it's much cheaper than the really big dollar ($800-$1000 easily) comparator gauges but still a very good gauge that can last you for many many years. Plus the nice thing about the Mitutoyo is they make an extension for the beam so you can reach farther.

The reach is important when measuring main bearings installed in the case. A typical 6 in. beam length that the economy gauges use doesn't let you get all the way into the case from the flywheel end, to reach main #7. I think this is important to consider because you must have the #8 bearing insert installed on a typical 911 case when measuring the main bores or your bearings.

No. 8 needs to be installed because it aligns the case halves at that end. People who say they can use the economy gauges on all of the mains are doing so w/out the #8 installed. Which means you have to self-align the crank pulley end of the case and that is tedious or next to impossible. I say impossible because once you start tightening the bolts at that end of the case, it's going to go wherever it wants to no matter how well you've pushed & pulled on the case by hand to get the halves to align flush in the #8 bore.

Walt Fricke · 01-10-2014, 01:00 PM

Kevin

Could a guy machine a piece of steel tube to mimic the aligning effect of the #8, but still have a large enough ID so you could get a bore gauge through it?

Walt

cgarr · cgarr's Garage

Walt no need to you can use a rear main bearing from an old vw 1600 case. You need one?

JJ 911SC · JJ 911SC's Garage

Quote:

Originally Posted by 911pcars

This ARP sheet says 50 ft.lbs. for M10 rod bolts (all 911 rod bolts up to 3.2 engine).

Sherwood

As per step #6, its says 50 ft. lbs if you don't have a stretch gauge...

But I think that after step 4, it should read to do either step 5 (stretch gauge method) or step 6 (no stretch gauge).

KTL · 01-10-2014, 02:11 PM

Quote:

Originally Posted by cgarr

You need one?

I do! Then I don't need to use the beam extension.

I know, I can take out the no. 8 since my case is G2 super sleeved. The 1600 bearing will come in handy for other cases (Stefan). Of course, that bearing would only be needed if that magical engine of his ever needs a rebuild, knock on wood!

Walt Fricke · 01-10-2014, 02:20 PM

Craig - send it to Kevin!

I might have one in my VW bits box, unvisited for almost 20 years since my last VW engine build. But I only have aluminum cases now for my 911s, and tend to be trusting (and lazy) about worrying about dimensional changes in them. Maybe if I saw some asymmetry in bearing wear I'd be prompted to break out the bore gauge for this.

Elbowmotions Engineered? I love it. I style myself, when ordering parts, as "No Headaches Racing," because my wife's father used to say to his kids (I am told) "No brains, no headaches."

KTL · 01-13-2014, 08:11 AM

All those "companies" are sorta made-up.

Red Snail Racing is me. How convenient that its RSR, no?

The red snail came from talking smack in the DE "racing" days. Somebody said my car needed a name. Someone blurted out how about red dragon ('87 Carrera guards red)? Buddy Stefan said how about red snail, and it stuck.

MotoDelta & ProRaceStore are legit. Those are cstreit's companies. Good guy who's taught me a ton about racing & saved me a lot of $ over the years.

G2 Performance is cgarr's gig w/his brother (2 Garretts). Craig & Denny know their way around engines & suspension & have also saved me a lot of $ over the years. They can machine and fabricate just about anything. Two of the nicest and most fun guys to hang out with as well.

Elbowmotions is a joke. Our buddy Stefan "stole" the name from Souk. Souk used to run Motomotions. Stefan has become famous in our circle of friends for his use of the muffler delete/bypass pipe. Loud & loose is how he rolls. He decided way back when it all started that for track days he needed to ditch the muffler for more power & had a local muffler shop weld him a bend and a flange to hook up to the cat delete pipe. Little did he know how loud it would really be. Nonetheless The Elbow was born.

Whenever he'd pass somebody, he'd call it "giving somebody the elbow." Here he is giving me the elbow @ 1:10

Octoberfest BHF 10-6-07 - YouTube

We were joking around at a DE "race" one day and as usual he's talking trash with Souk (these two were always mixing it up on the track) how he was going to start his own company called Elbowmotions and put Souk out of business with his patented anti-oil consumption technology the Elbow provides. One of the ongoing jokes has been that his engine is magic. Just keeps on truckin' at 160K and uses virtually no oil. So he continues to use the Elbowmotions promotion any time he's talking trash about something that's so great (and secretive) on his car. Most of his "secrets" are usually stuff that's been given to him by one of us fellas at a sizeable discount!