about to put in my crankshaft, and have a few questions:

1. i was told that when bolting the main cap bolts, you should go in "thirds." for example if the torque spec is 75 lb ft, you torque the bolts to 30, then 45, then 75.

my torque specs (LS1) for my main cap bolts are 15 lbs ft, so do i torque them at 5 lb ft, then another 5, then another 5? or can i just torque to 15?

2. on a 350 small block chevy build i saw, they bolted the thrust bearing cap last. do i have to do this on the ls1 also?

3. also, how do i align the thrust bearing? i think that you bolt the inner main cap bolts to 15 lb ft, and then hit the crank rearward with a hammer, then hit it forward, and then start torquing the outer bolts. is this correct?

4. i know the caps are numbered; i'm assuming 1 goes in front and 4 goes in back? just want to make absolutely sure

5. i have arp studs for the mains. do i put their assembly lube on the threads that go into the block also?

Tons of thanks to anyone cool enough to take the time to help out a newb. I tried doing a search but didn't come up with the answers i was lookin for.

 

Wow that is a lot of information to touch on. Do you have any good books to read on the ls? There are so many minute differences to these motors that you need lots of knowledge. They are easy motors to work on but they are peculiar. I would research every single step on the forums before you do each step. Find out the pitfalls and quick tips that everyone else has gone through first.

Heres one to start you off. The torque specs for your mains are different than most motors. They are a torque to yield design. This means that you can only use these bolts once. They are torqued to the point right before they fail. They are so close to this yield point that they are unsafe to use again. Arp bolts are a different story.

You also need to understand that 15ft-lbs of torque will not hold your motor together. Gm uses a different method for torquing the bolts. After you have torqued the bolts to 15ft-lbs or whatever they are, then you have to use an angle gauge to continue torquing the bolts. The specification is in a angled measurement. After the 15ft-lbs you would tighten the bolt to read an angle of 75 degrees or whatever it has specified.

Hope this confused you enough to do some more research.

 

thanks for the response padre. i've read up on small block chevy books and chris werner's ls1 build book is on its way. i went through the 98 gm service manual and the books by chris endres and will handzel. i found a pic of a C5R block that had the number 5 main at the rear. i also found the gm high performance article on building a 383 ls1 stroker, and found a pic that showed the number 5 main at the rear also, even though it was a little hard to see.

The engine work was done by LME and they've given me the torque specs AND torque angle specs. They've done all of the pre-assembly measurements and cycled the ARP bolts 5 times, so that when I put it together, I just have to bolt it on (according to their specs, of course).Finally got my Snap-On torque angle gauge in, so I'm dying to install the crank.

Some of the things I read confuse me a little though, like this paragraph:
First, following GM's torque sequence, tighten the inner bearing cap studs to 15 lb-ft. Before the studs can be final tightened, the crank must be tapped with a hammer--first rearward, then forward. This aligns the thrust bearing, which again is located on the center main cap (between cylinders 4 and 5).
It says "before the studs can be final tightened." So does that mean after torquing to 15 lb-ft, but BEFORE the torque ANGLE spec? and do i torque just the inners before aligning the thrust bearing, and not the outers? or do i align the thrust bearing after tightening the inners and outers to 15 lb-ft?

Another example is using ARP assembly lube on the threads. I know you use them on the threads that go through the main caps, and underneath the stud head to reduce friction and get an accurate torque reading, but what about the threads that go into the block mains? I've read that you hand tighten those, but does the assembly lube also act as a bit of a threadlocker also? I haven't read anything about putting lube on those threads and just wanted to confirm.

Sorry for all the questions; I am aware I sound like an idiot. I spent a lot on this engine and really want to learn, so I want peace of mind on EVERYTHING and ls1tech is the only forum that has advice I trust for my LS1. lol

 

1. Tighten the main cap bolts to about 10 to 15 ft-lbs in order to seat the bearings; then loosen the cap bolts.
2. Tap the main cap toward the rear of the engine with a soft faced hammer.
3. Thread the main cap bolts in finger tight.
4. Use a bar to force the crankshaft as far forward in the block as possible, to align the bearing rear thrust faces.
5. While holding the crankshaft forward, tighten the main cap bolts to 10 to 15 ft-lbs.
6. Complete tightening the main cap bolts to specifications in two or three equal steps.



Crankshaft Bearing Cap Bolts (Inner Bolts-First Pass in Sequence) 15 lb ft
Crankshaft Bearing Cap Bolts (Inner Bolts-Final Pass in Sequence) 80 degrees
Crankshaft Bearing Cap Side Bolts 18 lb ft
Crankshaft Bearing Cap Studs (Outer Studs-First Pass in Sequence) 15 lb ft
Crankshaft Bearing Cap Studs (Outer Studs-Final Pass in Sequence) 53 degrees

 

AWESOME THANK YOU.

one last q...when i loosen the cap bolts, how loose should they be? all the way loose, or loose but still snug on the main caps?

 

The 15 lb/ft tightening is just so the cap bolts get seated into place. Once they are seated down you should be able to loosen them all the way and then proceed with the rest of the steps.

 

Does ARP recommend using torque angle specs also? I had thought that they used the standard torque technique. Don't forget that the assembly lube helps reduce friction so the torque values could be lower for the ARP bolts. Check with them for final confirmation.

Also are you going to use ARP bolts on the rods. If you do it would be wise to invest in a rod bolt stretch gauge. If you don't have one already that is. Rod bolt stretch is the most accurate way to torque but unfortunantly you can only measure rod bolt stretch if you have access to the front and back of the bolt. If you want more options Katech also offers a line of bolts that are supposedly as good or better than ARP. Sounds like you are doing it right. Keep us updated when its done.

 

Yes, ARP says that the bolt stretch method is the most accurate way, and that the torque angle method is next for accuracy. I do have ARP bolts for my connecting rods also.

Having said that, I am going to put together the engine exactly how LME, who is a very reputable shop and also a sponsor, told me to. They have had so much more experience with building these engines with ARP bolts/studs than I ever will, so since they told me to use the torque-to-spec-then-torque-angle method, that's what I'm going to do.

As far as aligning the thrust bearing, I was racking my brain over it because The GM service manual doesn't even mention it, unless I'm missing something (they do mention checking for crankshaft endplay though), but my Chilton's says "With all caps in place and bolts just started, tap the ends of the crankshaft forward and backward with a lead or brass hammer to line up the main bearing and crankshaft thrust surfaces." I'm assuming they mean GM bolts though, not ARP, but it does sound like the bolts aren't even threaded hand tight before you whack the crankshaft, that they're all the way out, just like Halloran said. So that is what I'll do.

Also, there's no mention anywhere that I have found of putting the ARP lube on the threads that go INTO block mains. It also doesn't look like there is any lube for the threads that go into the block in this photo of an LS1 build:



That image was for final assembly, not preassembly. I believe you just hand tighten the ARPs or bottom them out with an allen wrench when you thread them into the block.

I really do appreciate the responses guys; I will definitely keep you updated on EXACTLY how I put the crankshaft in. So you can tell me how badly I screwed up and that my engine is DOOMED. hahaha

 

Ahh! I understand now what you are asking about the lube in the block. You do not need friction lube in the threads in the block when you are using studs. I hope that you are using studs and not bolts. Or maybe you have a combination of both. Anyways if you are using bolts then just coat the bolt with lube and under the head. If you are using studs you need not coat the ones in the block but you must coat the ones on top that are showing when you spin the nut down. Also underneath the head of the nut and or washer if you are using them.

The studs are a better way of clamping things together. Instead of dealing with twisting forces that a bolt creates a stud eliminates this. The stud shaft itself never twists. You do experience friction when the nut is tightened. But more clamping force is being maximized when just the nut is having to tighten instead of the entire bolt. I'm probably not explaining this well.

Summary. Studs with washers and nuts are better at clamping than bolts. When you tighten the studs only go finger tight and go until they bottom out. Do not use the allen to tighten these studs except to get them to lightly bottom out. But with a clean block and new bolts there should be no obstruction to you going hand tight. If there is then something is out of whack. They just need to be engaged in the threads of the block. Their only purpose is to provide a force opposite of the applied nut being torqued. The nut is what does the clamping and it just uses the stud to pull back on itself. Again my explanation is probably insufficient. Maybe someone else will chime in and explain this better.

 

Dropping the crank in isn't as complicated as it may seem. It's very messy though. Just make sure to put plenty of assembly lube on both sides of your main bearings and then rest the crank gently into place. You will know when your caps are installed correctly and lined up with the block. It ain't no rocket science lol.DO NOT put any lube on the main studs or bolts. When talking about head studs and not bolts then all you have to do is just start hand threading the studs. Even with a clean block you may encounter some resistance when hand threading the studs. If so then use an allen wrench to get the studs to seat at the very bottom of the block. If my memory serves me right I do believe it is required to put some ARP assembly lube on the very bottom left and right head studs because they sit in water jackets. The rest of the studs require no ARP assembly lube when screwing them into the block. Then apply assembly lube to the tops of all the studs including the washers and nuts and torque them down in correct order in 3 equal passes (27 lb/ft, 54 lb/ft then finally at 80 lb/ft) . The smaller top nuts only get torqued to 22-25 lb/ft on the 3rd and final pass. You do not need to torque the smaller nuts in 3 passes.

Pic is credit to ls1howto.com

 

Great info, thanks again guys. The ARPs I have are studs, so I will just thread them in.

Ok I'm noticing that there are two notches on each main cap, but only one notch on the main cap bearings. Does it matter which notch I use?

 

Ok I went opposite on the notches. There was a thread that suggested to do that. Here are some pics before any torquing on the ARPs, if you guys are interested:

http://zigzautonotes.googlepages.com/crankandmains1.jpg
http://zigzautonotes.googlepages.com/crankandmains2.jpg
http://zigzautonotes.googlepages.com/crankandmains3.jpg

Going to torque to 15 lb ft now...

 

Yep looks pretty damn good to me. Are you doing a stock ring gap for your piston rings? Did LME already pre-assemble your pistons and rods? Have fun file fitting your piston rings if you are doing it yourself. It is by far the most tedious part of the entire job. I went .027 top ring and .025 secondary ring since I'm going to blow nitrous through my motor. Are you doing any FI with your motor or keeping it NA? Now is the time to decide what you want to do with your motor now that you are putting it all together. Don't kick yourself in the *** later on if you decide to go nitrous and blow everything up because you kept your piston rings gapped at stock. Just my $.02. Good luck with everything!

 

Thanks Halloran!

Yes, LME has already pre-assembled the slugs and rods. The rings are already around them so I just have to drop them in. Since this is my first time for everything, I'm keeping it NA. Would LOVE to turbo, but I think I need to crawl before I run...err....fly. lol

You bring up a good point though; EVERYONE says I will want to go faster with my build. I have a cam that will make a little more power than stock (TSP XS series 233/239), and other parts that will make a little more power than stock, like a FAST 78mm throttle body and FAST 78mm intake manifold. Heads are ported 853s, and rockers are Yella Terra. Headers will be FLP (I liked the sound of them).

Quick question, my torque angle gauge is 1/2" drive, and I coulda sworn I had 1/2" sockets, but apparently I just have 3/8". I left the bolts torqued to 15 lb ft last night, after aligning the thrust bearing. I assume they'll be ok overnight, cuz it's not a lot of torque force, or until I can make it to the store today to get those 1/2" sockets? So will it be ok or will I have to start aaaaall over?

 

You should be fine with them torqued to 15 lb/ft overnight. Just make another quick pass on them with your torque wrench at 15 lb/ft just to make sure you got all of them. The 233/239 tsp cam is a great cam. With a cam like that why are you putting ported 853s on when you could upgrade to the LS6 243 heads or the 5.3L heads and have those ported. I'm sure cost is a major factor as it is for everyone who decides to rebuild an engine. Next thing you know you'll be replacing your torque arm and or clutch if you have an M6, new suspension, the list goes on and on and on it seems. Projects like these like to nickel and dime you to death.

On another note, when you go to put your pistons in just do a quick double check on your piston ring chamfer (edge). The top ring edge should be facing up while the second ring edge should be facing down. Also, give all the rings a little squeeze, they should all go into their respective grooves without any binding. Get some oil and oil all the pistons and ring grooves as well as the cylinders before installing the pistons. It will make it much simpler. It is also advisable to make sure your oil rings are offset 180 degrees. The top and second rings should be offset too but it's almost impossible to get them offset perfectly so just do as best you can when you compress the rings. Below is where I used the compressor on my pistons. Once you get it started make sure your crank isn't going to be in the way of the rod when you go to pound the piston in. Get your rubber hammer and give the piston a couple hard whacks. If it doesn't go in the first time then don't keep hitting it, take it back out, reset the compressor and try again. Just have patience young padewan.

 

Got the crank in last night!!! The torque angle gauge was actually a little tricky. That "L" bar didn't really hold it in place very well. Luckily my neighbor came over and helped hold it in place. Once he did that I just torque angled everything to the specified degree, 80 for the inners, and 53 for the outers. I did 18 lb ft per LME's instruction sheet for the side bolts. I got a little ARP assembly lube on the crank, but the journals are still clean.

So next up are the pistons! I'll try to install those while waiting for my double roller chain to come in. I really do appreciate the info/advice you guys gave me.

Now that I think about it, if you're off a few degrees with the torque angle gauge, will that affect anything? Reason why I ask is because precise measurements to the thousandths of an inch are elsewhere on the engine, like rod/cylinder clearance, etc, so I now I'm wondering if you have to be that precise with the studs?

 

It's almost impossible to be dead on accurate with the angle gauge. If you had a friend help you I'm sure you probably had him tell you when to stop when you hit the degree mark while you torqued. When angle gauging it's best to use a breaker bar or something that will give you leverage that way you can hit your 80 degree mark in one pull. Try not to pull twice or reset and pull again to hit your mark. Nevertheless don't worry if you are off by + - 2 degrees. Again, have fun with those pistons and the compressor that will be your most difficult part of the job.

 

Ok I took a look at the pistons and there are four rings. A top one, a second one, and then two that are on top and bottom of the oil expander ring. The top ring and second ring are about 180° apart from each other. And then the first oil scraper ring gap is about 30° counter clockwise from the second ring. The second oil scraper ring gap is about 45° counter clockwise from the first oil ring gap. Here's a pic in case I sound confusing:



Do the rings/gaps look ok enough for me to install the pistons into the cylinder bores? Also, I noticed I didn't have piston pin springs (the connecting rod is already installed into the slug from LME). I heard piston pin springs were for higher horsepower cars, but I'm not sure, do I need to install them?

Thanks again guys

 

^^^^^^ Do you mean spring clips or locks? These clips are just to hold the piston pin on the piston. If you have piston pins that are pressed then you do not need the spring clips. They are more of a retainer than a go fast part. They are used when you have a low friction piston pin installed that requires them. Your pistons do not need these and cannot use them if we are talking about the same thing.

 

what i was thinking of were the little coiled up looking spring things that go into the piston pin holes to keep the pin in place. in the books i've read you just install them by hand.

could you tell by looking if i need springs or have locks? i took some pics this morning:

http://zigzautonotes.googlepages.com/piston1.JPG
http://zigzautonotes.googlepages.com/piston3.JPG