JoeNova

So I pulled the pistons out of my L33 to check the ring gaps on the stock rings.

I started thinking about putting the rods back in. At first my thought was to get ARP rod bolts, but I couldn't find any local shop that could machine the stock rods that I could actually trust.

I've also had bad luck with new bearings. The first shortblock I ever bought I paid a fortune for. I even had them assemble the complete motor and do the break-in for me years ago. It spun a rod bearing within 100 miles on the street.

A second motor I put in new rod bearings, used a plastigauge, did a proper break-in, and ended up spinning a rod bearing on the dyno after a few thousand miles.


So someone mentioned getting new OEM replacement bolts, making sure the bearings are clean as well as the rod journals, and just re-installing the rods that way. Has anyone done this? I've never reassembled an engine without new bearings, and in this case I'll be reusing the stock rings and bearings with new bolts (they are less than $50 for a whole set).

1969x11

iTrader: (36)

I thought the rod bolts werent 1 time use? I have an lq4 on the stand right now and I was planning on reuseing the stock rod bolts.

Ratical

iTrader: (82)

It depends if you have the older rods with the bolt and nut or the cracked cap style with cap screws. You cannot machine cracked cap rods.

Rod bolts are not one time use like the head bolts are. If they are the newer cracked cap design with no nuts I wouldn't think you would need to machine them since you are not pressing bolts out and back in and I can't see why you would be applying additional force to distort them, merely using a bolt with a higher tensile strength.

As far as spinning bearings, it sounds like your clearances were too tight possibly.

JoeNova

The cracked cap rods are usually just line honed. There are bearings out there that are .002 oversized for this very situation.

My rods are 4th gen cracked cap.

I haven't looked into reusing the stock rod bolts yet. I wasn't sure if they were torque-to-yield or not.

Paul Allen

Should you open up the top ring gap like you are doing if you are going to run e85?

JoeNova

Even though it burns a little cooler and is let detonation prone, yes I would open them up. You have no idea how many engines blow from something almost trivial like a tight ring gap.

RonSSNova

iTrader: (3)

Joe,
I reused the stock bearings and rod bolts in my L33.
Regapped the top rings to .024".

Of course cleaned everything very well.

I have around 50 passes so far. Doesn't even have any blow by under boost. Oil pressure is rock solid.

Ron

JoeNova

Thats what I wanted to hear, Ron.

I had a couple of people tell me that the stock rod bolts were TTY. I honestly wasn't sure if this was the case. I've installed ARP rod bolts in 2 other cars without removing the bearings, I just did them one bolt at a time and used the stock torque spec to prevent an OOR on the big end. This is actually the first time I've completely removed rod bearings and re-installed them. I'll just wipe them and the rod journals down with rubbing alcohol and then a little lube before I put them back in.

Thanks, for the help, guys.

EDS01SS

iTrader: (30)

in the process of doing this right now and have installed the ARP rod bolts and no machining was necessary.

forcd ind

iTrader: (7)

when I rebuilt my LQ4, (05) I bought ARP rod bolts, kind of worried about how they would turn out when they were torq'ed
they said they could rebuild them, and then you use oversize bearings
anyway, after they installed and torq'ed the bolts, the rods were still true, so didn't need a rebuild
I didn't have to open up my ring gap with new rings, by the time I honed out the rust in the cyls, (burnt engine) it had good boost gap, lol
if I had know this project was going on this late, I would have bored it .005

JoeNova

I've installed ARP rod bolts before on a big block and it put the big-end out of round. They had to be machined. It might have something to do with the fact that the torque spec was about 25% higher on the ARP bolts than the stockers, but it happens. Thats why I usually torque to OEM spec with ARP rod bolts now. That might not be recommended, but I've had it last up to 7800 RPM on a 4" stroke for a few years before I sold it off. I just didn't want to mess with it too much since I'll be driving this car a LOT once its done, and most of the machine shops in my area do some pretty horrible work.

mp300zxtt

iTrader: (2)

I'm currently in the same predicament. I've got an LQ4 block that was assembled by a machine shop already when I purchased it from the previous owner. I have a set of ARP rod bolts I want to use, but I don't know if I should bother with it now, or when I forge the bottom end. Also, will I have to get some plastigage when reassembling the rods on the crank, or is that unnecessary?

I also need/want to re-gap the rings, so the pistons would come out anyways... I figured I might as well get it all done right now if I'm going to re-gap.

What gap are ya'll using for higher boost (18+) motors with stock rings? The 'Big Bang Theory' article recommends
"to increase the gap of the top rings from 0.015 inch to 0.028-0.030 inch"

Curious about ya'll.

Thanks!

JoeNova

I usually run .022 - .024 on E85. I did this in my old daily driver on 19 lbs.

For gas usually .026 - .028. If you use water/Meth injection, the water helps keep the pistons and rings a little cooler and keeps the from over expanding. I've always had better luck when using water and meth. Its an excellent safety feature for high boost.

Ryans99ls1

iTrader: (16)

Every time someone i know messes with their rod bolts, they end up spinning bearings. I didnt touch mine and i never planned on it, the only time i think you should consider upgrading them is if you really plan on turning some rpm, aka 7k+. Its just funny cus when people would find out how much power i was making the first thing they would ask is "on stock rod bolts?!" and i couldnt help but laugh cus it seemed ridiculous that they were most concerned about those out of everything.

IIRC rod bolts arent TTY, they are torque to angle, so they are reusable.

All that being said, I've seen far less issues when people run Katech rod bolts over ARP's

stock48

iTrader: (17)

Im with Ron. Anything on rings past .022~.024'' on E85 is costing power. I Reuse the stock bearings if possible and just clean everything really good. Id run new GM bolts as well. The GM bearing is better than about anything you can buy. I use new GM bearings in my built engines as well. If you replace bearings the crank needs a good polish and everything cleaned really well if you want it to live. It's kind of like putting old lifters on a new flat tappet cam if you don't. I have also had good luck with the federal Mogal oem A series replacement bearings. They are made by same manufacturer as GM I believe.

NoorJ

what do you guys use to clean the rods/bearings?

stock48

iTrader: (17)

Need to use solvent, gas, diesel, or jet clean on pistons/rods and Brake clean and a rag, or really easy with a worn green scotchbrite pad and simple green on bearings.
Id honestly have crank, pistons, rods, block etc ran thru an aluminum hot tank then disassemble and clean pistons etc one by one. It's takes a lot of hrs but if done right it will live.

RonSSNova

iTrader: (3)

We think alike Jarrett. Right down to the worn out scotchbrite pad.
I wasn't in any hurry, and cleaned everything by hand.
My engine was really brown inside. And that stuff is tough to get off. The ring grooves were pretty caked with gunk. Esp the oil rings. I was glad I didn't run it as delivered!

If you can find a shop with a cold tank for alum, it will save you a bunch of time.

Ron

mp300zxtt

iTrader: (2)

So.... what exactly happens if you don't gap the rings and run boost? This is all new to me, and I'm currently trying to decide if I want to even mess with pulling all of the pistons out or not.

ringgold

I have a set of the Wiseco Junkyard Dog series pistons that fit on the stock rods and will be using a set of Gen IV rods. I am about ready to gap the rings, and wasn't sure if I needed to contact wiseco or just use the equation to figure out what to run. I got these pistons because the block needed a slight overbore due to rust in a few cylinders that couldn't completely be taken care of with a hone.

I see people having good luck with stock rings on stock pistons gapped in .026" range. Would that also apply to Wiseco pistons even though they are a different material?

Was thinking about reusing the stock rod bolts, but I may opt for a new set of stock rod bolts. Also got a set Federal Mogul/Speed Pro standard main and rod bearings for it. Hope to get around to assembling it soon.