Your Rods hard enough?

by 77mali Fri Jul 26, 2013 1:37 pm

If you are considering an engine rebuild or have recently completed one utilizing Comp Cams "HI Energy" push-rods and are using guide-plates, be aware that the manufacturer is NO LONGER recommending these particular rods for use with said guide plates! Turns out they are not hard enough and are susceptible to scratching & gouging.

Ask me how I know?

I was in the midst of re-lashing my build when I noticed some light scuffing on some of the rods right where they travel up & down on the plates & I thought WTH is going on here? One of them was really bad and I haven't even broken in the engine yet- this wear was caused just by turning the crank using the starter. I called the engine builder and he said he had this happen a couple of times so he contacted his salesman and he confirmed that even though they had said it was OK for years (since the 80's) they decided to revise their recommendation based on many, many complaints recently.

I was able to return the Hi-Energy rods & replace them. They will give you credit for whatever you paid for the Hi energy rods towards the difference in price. I opted for the Magnums & the difference was about $88.00 for the set ($26.00 versus $104 or so).

BEWARE!! Here are the other types available:
http://www.compcams.com/Products/CC-%27Pushrods%27-2.aspx

by Bruisr Fri Jul 26, 2013 5:15 pm

That sucks, Good thing you caught that! My situation is almost the same. My machine shop used inferior rod bolts, when I started to torque them down, some torqued to specs while some went well past that and even broke a couple. I'm gonna tear down and completely replace rod bolts, head bolts and main bolts. Something I should have done from the beginning.

by 77mali Fri Jul 26, 2013 5:26 pm

Do yourself a favor & buy ARP Bolts...don't trust any other brand.

by Bruisr Fri Jul 26, 2013 6:07 pm

I meant to include that in my post. I firmly agree and will.

by pila Sat Jul 27, 2013 12:08 am

I never re-use rod bolts that have been torqued to spec., in a performance engine.
And I've never used guide plates (yet)

by Bruisr Sat Jul 27, 2013 8:44 am

I believe guideplates are mandatory for a big block. I'm thinking my machinist didn't replace the rod bolts when the rods where resized. I assumed that was part of the process, Apparently, I was mistaken. I know studs are better than bolts for heads and mains, but, this is a basic rebuild. Should I use studs instead of bolts? The price difference between studs bolts is almost doubled.

by 77mali Sat Jul 27, 2013 10:58 am

Are you talking on the cylinder heads for the rocker arms? Yes.

My heads are race heads- they need the guide-plates. I've read that in a stock or mild build you don't need them if the holes where they go through on the heads to mate with the lifter is "stock".

If the push-rods are now a larger diameter ie 3/8" vs 5/16" (which is stock for a 350 build) then the holes should have been drilled bigger- if that's the case then you should be using both plates & studs.

by Bruisr Sat Jul 27, 2013 3:09 pm

Sorry no, I hijacked the thread. I was talking about crankshaft main bolts, and cylinder head bolts. Thankfully the shop that did my heads does great work, they installed ARP rocker arm studs with new guideplates. All my posts have been regarding a 454 I'm currently gathering parts for to assemble.

by 77mali Sat Jul 27, 2013 6:02 pm

Mine is an SBC- 4 bolt main- no studs. I don't really know what advantage there would be in using those long studs- maybe someone can enlighten us both.

by pila Sat Jul 27, 2013 9:52 pm

Only time I use studs in the main caps is when adding a windage tray, which uses either 4 or 5 ( don't remember) long studs to attach the tray.
I know nothing about Chevy big blocks by the way Neutral

by Bruisr Sun Jul 28, 2013 12:41 pm

Here is my contemplation: I have 2 454's 1:1978 marine big block,2: 1990 chevy dually big block. The 78 454 had the windage tray attached the to main studs. The 1990 454 had the windage tray attached to the inside of the oil pan. I guess either would be fine, as long as there is a windage tray at all. Both 454 had 2 bolt mains, so I would assume either one would be equal to the other one. Both are original virgins blocks, never being overbored, yet. I chose the 1990 to rebuild for a daily driver/ limited modifications. The 1978 454, will be for my chevelle, and when the kids grow up and move out, will be my attempt to build a 5-600 horse big block, (yes, I'm dreaming outloud). This is my 1st attempt to build an engine and assemble it on my own. I've already made some bad choices, but am lucky enough to have discovered them during assembly, and I'm able to tear down and redo. Mostly trying to cut costs, having learned that cutting costs will only cost more in the end result! I've had to stop assembly to save up money to purchase the items to insure durability and longevity. A set of ARP bolts for the rods, mains, and heads will do wonders to durability and longevity!

by bracketchev1221 Mon Jul 29, 2013 5:25 am

If the block came with stock studs and you want to use the stock windage tray then go for it. But using aftermarket studs is not necessary. Just like repalcing rod bolts, when you change main bolts it is a good idea to check the mains and possible resize them as well. Studs improve clamping force and protect the threads in the block. However, unless you are making tons of power they are not needed. If you were making 600 or more I would recommend main studs in a 2 bolt block. But head studs, never in a car with fenders. You will shoot yourself if you have to pull a steel big block head off a set of studs in a car with fenders. I have run main studs in 2 bolt blocks between 6 and 700 hp with no issues. Both were 427's and I have main studs in my 540 in the Chevelle now. No head studs in any of my engines. As far as changing rod bolts in rod resizing, I would think any reputable shop would change the bolts. You have to in order to grind the rod cap mating surface. But unless he never resized them, or used cheap rebuilder bolts, I wouldn't think anyone would press the old bolts back in.

by Bruisr Mon Jul 29, 2013 11:54 am

The mains, crank, and the rods were machined, I think he used cheap rod bolts, and I was going to reuse the main bolts, and head bolts that were in the block before I had it machined. Will I need to have the new rod bolts pressed in or can I install myself with a mallet?

by Bruisr Mon Jul 29, 2013 11:59 am

bracketchev1221, Do you know where I can found out specs. on some cast iron heads for my big chevy? The casting # is 353049, I'm getting conflicting info. on the combustion chamber size. Some say its 122cc's, another says its 113cc's. I don't have the equipment to cc the heads myself. I'm just looking to see what my compression ratio is with 2 valve relief flat top pistons. Again, some say 8.5:1, others say 9.5:1. Really makes it hard to decide on a decent cam!

by bigredlaguna Mon Jul 29, 2013 8:27 pm

Ooooh, you're talking about engine parts. Shucks.

by 77mali Tue Jul 30, 2013 2:42 am

bigredlaguna wrote:Ooooh, you're talking about engine parts. Shucks.

Finally! LOL Very Happy

by bracketchev1221 Tue Jul 30, 2013 4:23 am

Bruisr wrote:bracketchev1221, Do you know where I can found out specs. on some cast iron heads for my big chevy? The casting # is 353049, I'm getting conflicting info. on the combustion chamber size. Some say its 122cc's, another says its 113cc's. I don't have the equipment to cc the heads myself. I'm just looking to see what my compression ratio is with 2 valve relief flat top pistons. Again, some say 8.5:1, others say 9.5:1. Really makes it hard to decide on a decent cam!

Unfortunately no. This is a common issue. I had the same issue with a set of 781 heads years ago. I cc'd the heads myself at home to check. Mine were 118. You can do it easily enough with a piece of lexan with a hole in it, and a 100 cc graduated cylinder.

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