hansw3

Doing a rebuild on a Gen1 350. Bought new ARP WaveLoc rod bolts and am wondering if I need to hone existing connecting rods. Talked to a couple shops who have told me I should to be sure I won't spin a bearing. One of them sounded a little less adamant that I need to. I already installed all 8 pistons into the block and have the rod caps on. It was a big enough pain getting the caps off after confirming bearing clearance with plastigage that I'm wondering if there's more risk of dis assembly damage than leaving the rods in there. I can understand if this were a race motor needing to hone the caps, but damn- I pulled one piston out, torqued down the cap with the bearings out of it and I can hardly even feel the parting line in the bore of the rod. The motor wasn't trashed when I pulled it apart and all my bearing clearances are in spec.

Have other people replaced rod bolts without honing the existing rods and been fine? This budget build keeps increasing in price and I hate to tear all 8 pistons back out, drop $140 bucks on this and then have to stick them back in if in reality there's 99.99% odds I'm good.

InfernalVortex

iTrader: (4)

Youd be amazed what some people can get away with and it work fine. I know a guy who had a 305 he spun to 7,000 RPM all the time and had pistons from 3 different manufacturers in his car, plus a crank balanced for a 350... Still ran strong when he pulled it. You just do what your budget lets you.

But I on the other go out of my way to make sure my investment isnt wasted. If you can figure out a way to afford it I would have it done. How much is all the new stuff youre putting in it worth? How much is the machine work you've already bought worth? How much is the machine work to fix it if you throw a rod or spin a bearing? How much is your time pulling and rebuilding it again worth? You spin a bearing you need new cam bearings, new main bearings, new rod bearings, new rod machine work.. etc etc.

ASE doc

Honing the rod ends may not be necessary. The key is having them clearanced. In fact to assure a healthy long life for your build. I recommend clearancing the complete rotating assembly. My machinist charges an extra $100 for the service with a block prep. It's cheap insurance.

Then again, you've already got the motor together and your plastigage tells you it's all okay. Apparently this is a low revving motor you're building. I've done dozens of stock rebuilds without clearancing and never had a problem. I only go all out with the machine work on high performance applications.

Damon

If they are used rods you would probably want them resized/honed on the big end anyway. Having used almost nothing but stock rods all my life I have rarely found a used set that was round on the big end to begin with.

Add that to the fact that WaveLocs are particulary susceptible to moving the cap around a little from it's stock "home position" and you are in "definitely yes" territory.

hansw3

Well I'm leaning towards doing it for peace of mind. My concern is getting the caps back off without damaging anything. It's hard to do after installing them. They stick on the rod bolts intentionally I suppose to keep it located. How do guys take them off?

three methods I've used but not 100% success:
1. Used a pliers to catch the little tang on the cap and then the other jaw of the pliers goes on the loosened nut. This works sometimes but not always and sometimes there isn't enough space to get the pliers on the tang.

2. I've hit the end of the rod bolt with a brass drift pin to force the piston down. This works but once I moved a rod bolt down .25" and don't want that to happen again.

3. I've used a punch to hit on the little tang but it's not always possible to get at it with the angle required.

Is there a safer way to get caps off? Every time I take one of I lightly file any dents in the edges to make sure it has full face contact on reassembly and that the side clearance thrust surfaces have no burs either. I could build a dedicated tool if that would help since I have machining equipment at home.

If it clears up anything, this is essentially a stock rebuild and I will be running a torque cam. All but one of the rods are being re used on the new pistons. They looked visually good and still have the cross hatching from the last hone job between cap and rod. All the original bearings had even wear as judged visually. I bought the $200 Summit rebuild kit with pistons, rings, gaskets, etc. The only real wear was the ring end gap and about a .005" taper in the cylinder at the top so I had it bored .030 over and also decked the block .025 to gain a little compression. I am capable of modifying the intake manifold if I have fit up problems with the machine tools in my garage. I am currently checking piston to valve clearance before I pull the pistons back out.

ASE doc

The drift punch method is the only one I use. If a rod bolt backs out at all, it will quickly be pulled back in place when the machinist torques the caps to check roundness. Place sections of rubber hose over the bolts to prevent nicking the rod journals. I'm sure you did this when you assembled them.

sofakingdom

iTrader: (1)

Right: the rod bolt makes a sort of dowel pin arrangement to locate the cap. Change it, and now the cap isn't located in the same place.

Plus, the act of removing and reinstalling them, distorts the rod.

If you change em, you pretty much HAVE TO have the rods re-sized. Which is where they cut a couple of .001"s off the cap and rod, THEN install the new bolts, THEN re-create the round hole of the right size.

Sure, it's "possible" that it might work to do without it, and maybe once in a while, not have it explode. For comparison, I personally know someone who was skydiving, and his parachute failed to open; and he survived. Now does that "prove" that you don't need a parachute when jumping out of a plane? Really? So some one guy somewhere got away with not building his motor right once; does that "prove" all that stuff is unnecessary? I don't think so.

Do it right, and you won't have near as many chances for things to go wrong.

hansw3

I did get them re honed. Also discovered I had not done a good enough jobs chamfering the oil passage holes on the crank and some of the new bearings were scratched just from rotating the crank around enough during the piston install. The machine shop told me when I brough the rods in with the pistons on them that the wrist pins weren't floating in the piston holes freely enough either. So I paid them to press out the wirst pins, hone the piston holes lightly and re assemble too.

sofakingdom

iTrader: (1)

It's amazing how many details there are, eh??

This is why I don't buy motors from guys that have motor-building time trials, but rather, do it myself.