'70 Nova LSX swap LY6/TH400

[Chocflip201]

Fwiw I had my jeep engine hot tanked, it cost me $60 (i took it into them super dirty, straight from the engine bay) and had it back overnight, yes I had to replace my cam bearings but I was going to do that anyway. And I was super impressed with how clean the block was upon getting it back, it's the only way i'll ever go in the future.

[JaysinSpaceman]

Originally Posted by TheBandit

Someone on another forum said I would need to replace the rings if the pistons come out because they would be clocked differently when I put the piston back. Is that really a concern?

The more I read the more I'm thinking I will do the cleaning myself as you're suggesting.

This is all new to me. I've never gone deeper than a short block. It's awfully tempting at this point to spring for ARP stuff for the mains and rods, but I've also read the increased clamping can distort things just enough to need honing.

So much research to do.

If you start changing out fasteners then you will need to check for out of round on things like rods for sure, main cap not as much. I wont replace fasteners on critical components with out at least checking and I really prefer to re-machine when press-in fasteners are replaced like rod bolts. As far as rings go, I have heard of problems occurring when pistons are pulled, but to tell the truth I think it is more from people not marking what hole the piston came out of and swapping pistons around. In theory piston rings are free to rotate and usually do. I have taken apart motors, that I had assembled, and the rings had moved around a lot from the 180 degree ring gap alignment that I had originally assembled it with so I don't think there would be problems from ring orientation, of course a ball hone and new rings aren't that expensive either. Hope that's clear as mud.

Jaysin

[entropy]

Originally Posted by TheBandit

Someone on another forum said I would need to replace the rings if the pistons come out because they would be clocked differently when I put the piston back. Is that really a concern?

Somebody on another forum has not paid any attention to where the rings were clocked to going in, and where they were when they came back out. Unless the rings are pinned they will, and do, rotate around the piston at random and the top ring may be rotating the opposite direction of the second ring...

Originally Posted by TheBandit

The more I read the more I'm thinking I will do the cleaning myself as you're suggesting.

This is all new to me. I've never gone deeper than a short block. It's awfully tempting at this point to spring for ARP stuff for the mains and rods, but I've also read the increased clamping can distort things just enough to need honing.

So much research to do.

If you change anything you must re-machine that assembly.
The corollary is change nothing you can not afford to re-machine.

E

[TheBandit]

Thanks guys. I thought the same thing, but wanted to verify.

Originally Posted by entropy

If you change anything you must re-machine that assembly.
The corollary is change nothing you can not afford to re-machine.

I assume no remachining would be necessary if I swapped to a replacement GM fastener of the same design & torque specifications, right? Remachining would only be necessary for a change in clamping.

For marking the rods as shown below, is a number punch or engraver okay to use? I've read rods should only be held by a rod vise to prevent surface damage, but a punch is very counter to that.



I turned the engine over last night and pulled the windage tray so I could get a good look at the rotating assembly. There are definitely areas of rust on the crank and rods. I can't tell if it's in the bearing areas or not; it looks like the crank was splattered with water and it sat to dry & rust. I'll post pictures tonight.

I also moved all the pistons to BDC and inspected the bores. No rust or damage to be seen there and no cylinder ridge, so I'm happy with that.

[JaysinSpaceman]

I don't know what style rod bolt the late model SBC uses, if it is the type that has a true bolt then yes you can change them with factory or ARP typ fasteners but if it is like all the old style SBC rods with a pressed in stud and nut then you must re-machine the rod with ANY new rod bolt, factory or not.

I have always marked rods wit a number stamp. Only mark them where they are shown in you picture, never mark them where you would create a stress riser on the beam or cap portions (ie. on the balance pad on the cap).

Jaysin

P.S. Mark the rods before removing them from the crank with the rod bolts still tight.

[entropy]

Originally Posted by JaysinSpaceman

I don't know what style rod bolt the late model SBC uses, if it is the type that has a true bolt then yes you can change them with factory or ARP typ fasteners but if it is like all the old style SBC rods with a pressed in stud and nut then you must re-machine the rod with ANY new rod bolt, factory or not.

I have always marked rods wit a number stamp. Only mark them where they are shown in you picture, never mark them where you would create a stress riser on the beam or cap portions (ie. on the balance pad on the cap).

Jaysin

P.S. Mark the rods before removing them from the crank with the rod bolts still tight.

What he say. ^
OR in your case you could just used a felt pen on the top of the piston; always keep the cap on the rod finder tight with the nuts (or=).

[MeanMike]

Use some layout die and a scribe to put a number on the rod. Thats the more common practice with the engines I've seen come from high dollar engine shops. While I doubt stamping a number in the rod is going to cause a crack or make the rod go out of round, why risk it.

[sniperperformance]

this stuff may or may not of been coverd. iv built alot of ls engines mostly race engines. at the point your at i would upgrade the rod bolt with ARP's the rod bolts and rods are a weak link in any ls engine.
At this point in the game your just better off doing a couple of piece of mind upgrades. rod bolt and harmonic bolt are not reuseable. I always replace those with ARP also. then if i have any future repairs i dont have to go chasing those parts again. another is a trunion bearing kit for your rockers. other than that your doing a sweet job.

[sniperperformance]

Originally Posted by MeanMike

Use some layout die and a scribe to put a number on the rod. Thats the more common practice with the engines I've seen come from high dollar engine shops. While I doubt stamping a number in the rod is going to cause a crack or make the rod go out of round, why risk it.

your correct i never use a punch stamp for that reason. scribing is the only way to go.

[entropy]

Originally Posted by sniperperformance

your correct i never use a punch stamp for that reason. scribing is the only way to go.

This must be something in reference to the LS or perhaps Powdered Metal Rods.
However, I have never seen in more then 30 years a rod failure due to a stamped number. For a bunch of years I build a bunch of power out of predominantly GM products, this has never been an issue. BUT these were engines made with forged steel rods, not pressed metal powder.

[sniperperformance]

Originally Posted by entropy

This must be something in reference to the LS or perhaps Powdered Metal Rods.
However, I have never seen in more then 30 years a rod failure due to a stamped number. For a bunch of years I build a bunch of power out of predominantly GM products, this has never been an issue. BUT these were engines made with forged steel rods, not pressed metal powder.

you are also right. most these newer engines are supplied with powder rods and that creates micro fractures when you use a punch stamp. after enough heat cycles they tend to come apart. forged rods dont have that problem. and aluminum rods go out of round if not done while torqued and something to mimick the crank journal installed.

[TheBandit]

Thank for the continued advice. I will definitely do a scribe over a punch. My understanding is these are indeed powdered metal rods. They do not use a press-in bolt and they have a fractured interface for the caps. I am all for upgrading the rod bolts to ARPs, but what would that entail? Would the big end need to be honed or ? Please pardon my ignorance.

I flipped the engine over and took some photos of the top of the windage tray and the rotating assembly in two crank positions. Of course I'm going to disassemble and inspect further, but what do you think of what I'm seeing so far? Major cause for alarm or won't know until I look further?

[sniperperformance]

Originally Posted by TheBandit

Thank for the continued advice. I will definitely do a scribe over a punch. My understanding is these are indeed powdered metal rods. They do not use a press-in bolt and they have a fractured interface for the caps. I am all for upgrading the rod bolts to ARPs, but what would that entail? Would the big end need to be honed or ? Please pardon my ignorance.

I flipped the engine over and took some photos of the top of the windage tray and the rotating assembly in two crank positions. Of course I'm going to disassemble and inspect further, but what do you think of what I'm seeing so far? Major cause for alarm or won't know until I look further?

the only thing i see that is bad is rust. which turn into sandpaper in the oil. if it where me i would pull it apart and clean everything really good. again this is me, some would say slap it together the way it is.

replacing the rod bolts is not a big deal. ideally you would want the big end honed. but some have just thrown the bolts in. i dont want to take any chances so i have them honed. nothing can spoil your day like a spun bearing in a fresh motor.

http://www.summitracing.com/parts/ARP-134-6006/ - rod bolts
http://www.summitracing.com/parts/ARP-134-3609/ - heads bolts
http://www.texas-speed.com/p-128-arp...ncer-bolt.aspx balancer bolt

[Chocflip201]

Believe me when I say that I don't mean this in any rude way, shape or form, but it looks like cleaning the engine still together wasn't very good for it, and I learned not to do this from these pics. I'd do a complete tear down if it were mine, possibly just for the peace of mind because who knows, ya could put it back together and have everything be fine. But that seems like a big risk.

I'd keep tearin down.

[TheBandit]

Thanks guys. The rotating assembly is coming out, hopefully this week. I'm going to talk to a machine shop to see what it would take to have them clean it and replace the cam bearings. I'll also find out what honing the rods would cost.

[MeanMike]

How exactly do you hone a set of cracked cap rods and still have enough bearing crush? Maybe I'm missing something here, but I'm not sure you can even do that.

On standard type machined mating surface rods you have to grind a little material from the parting line on the rod cap. Then you hone back up to size. It's impossible to remove anything from the cracked surface and still have them mate back together.

I'm willing to be most people put new arp bolts in them and move on.

[entropy]

Originally Posted by MeanMike

How exactly do you hone a set of cracked cap rods and still have enough bearing crush? Maybe I'm missing something here, but I'm not sure you can even do that.

You replace the rods with forged steel units; or buy bearing inserts that have a larger OD.

[JaysinSpaceman]

First, I would definitely disassemble and clean the flaky rust from everything (I would not worry about the discoloration under the flaky rust though) and give it a good bath.

After that I think I would reuse the stock rod bolts (if they are not torque-to-yeild and they are, in fact, reusable) because you are not doing anything serious to the performance of this motor and I have heard of many people doubling (or more) the power these LS engines make stock with completely stock lower ends and not having rod bolt problems. Unless you are going to spin this thing to 8,000+ RPM I wouldn't worry about the bolts.

My $.02
Jaysin

[TheBandit]

Originally Posted by Chocflip201

Believe me when I say that I don't mean this in any rude way, shape or form, but it looks like cleaning the engine still together wasn't very good for it, and I learned not to do this from these pics. I'd do a complete tear down if it were mine, possibly just for the peace of mind because who knows, ya could put it back together and have everything be fine. But that seems like a big risk.

I'd keep tearin down.

I take no offense. Something certainly went wrong. I'm not sure if I would advise against cleaning the exterior of an engine - lots of people have done it successfully - but care must be taken not to let anything in. I thought I was very careful with blocking ports and leaving seals in place where appropriate, but I must have missed something or the problem must have been there when I received the engine.

Everything is coming apart for sure now. Going forward I can at least be very happy I caught this before something worse happened.

Originally Posted by MeanMike

How exactly do you hone a set of cracked cap rods and still have enough bearing crush? Maybe I'm missing something here, but I'm not sure you can even do that.

This is why I ask. I really don't know. Perhaps sniperperformance can offer some advice?

Originally Posted by entropy

You replace the rods with forged steel units

Backup plan: http://www.texas-speed.com/p-903-tsp...-assembly.aspx Too bad the wife would never go for it.

[entropy]

I've read the tech.
I've looked at the metallurgy.
I understand the theory... heck decades ago I even machine parts that went into orbit out of powdered metal.
If I have a choice I will not run rods make of powdered metal even in a stock application in your engine