Buying new block

Topic: Buying new block (Read 3097 times) previous topic - next topic

Buying new block

October 23, 2013, 09:03:28 PM

So I am buying a new block that I can build while I drive my car around. What are the weak points in the rotating assembly? I heard the rod bolts are one weak point. I'd like to shoot for 450hp at the motor on pump gas.

Buying new block

Reply #1 – October 23, 2013, 11:42:02 PM

Then I wouldn't look at a stock block.

Buying new block

Reply #2 – October 24, 2013, 12:52:15 AM

The stock block can handle quite a bit more HP then what I'm seeking.

Buying new block

Reply #3 – October 24, 2013, 05:22:55 AM

The rods and rod bolts are the weak point. Get a good set of rods that are floaters. I am assuming you are talking 2.3 the engine that i have been messing with since DAY ONE. Rods and bolts are the rotating assembly the crank and bearings are just that. Rods and bolts are the weak point in just about every engine. I spin my 2.3 well in to the 7800 Rpm band with no issues. Good luck

Buying new block

Reply #4 – October 25, 2013, 08:13:49 PM

Crower sportsmans will take almost anything you throw at them.

Buying new block

Reply #5 – October 25, 2013, 09:19:26 PM

Whatever block you buy, get it sonic tested to see where the thick and thin spots are before you waste ANY money on machine work. Four spots around the circumference of the bore, at the top, middle, and bottom of each cylinder. The core shift during casting is wicked on these. Find a machine shop who has, or has access to, a torque plate for a 2.3. Or be prepared to hunt one down for rent.

Buying new block

Reply #6 – October 26, 2013, 07:51:09 PM

Sonic checking is good but i am willing o bet you will never find a block out of speck. I have been checking these blocks for many many years and never found a single one that could not be punched 30 over safely. As far as a block plate that is a given but the 2.3 blocks must be decked then bored. This will help the HG live under 24-26 LBS. Because to break the HP numbers you are talking about will need high boost.

Buying new block

Reply #7 – October 27, 2013, 12:11:58 PM

"Out of spec" is not what you're looking for when sonic checking a block. You're looking for suitable wall thickness to support a selected power level. 2.3 blocks of all vintages have issues with thin spots in the cylinder walls from core shift at the foundry. The block I have the engine stand right now is only .115 at the rear bottom of cylinder #1. Knowing the wall thickness is critical as now I can tell my machinist to "move" cylinder #1 slightly forward during the boring process to maintain as much meat as possible for rigidity, even though I'm filling the block also. Had I just dropped the block off and told him to bore it .030 over, that cylinder would be down to .100.

Buying new block

Reply #8 – October 28, 2013, 04:39:03 AM

Rear bottom of the cylinder . Think about what you just said and then post back. Shifting forward is a fix but with the available HP that can be made with a low block you are wasting your time. A .015 increase in thickness in the lower portion of the block is not something i would worry about. And if you are filling the block you have nothing to worry about. Filling a block will make a street engine not feasible unless you live in the north POLE. Or just a slight fill. I am assuming the poster drives his 2.3 on the street. Once again i have never seen a 2.3 block fail. But i will admit i have only built a couple of hundred of them!!! By the way the THRUSH side of the block is the critical area JANGUS OR DIDNT YOU KNOW THAT!!!

Buying new block

Reply #9 – October 28, 2013, 04:52:22 AM

One of the first things you learn when using a sonic checker on a block is that the cylinder wall castings are not of uniform thickness. The cylinder walls are thicker on the sides facing the inner and outer parts of the block than on the sides between cylinders. The thick sides are the thrust surfaces of the cylinder wall, named that since they take the thrust load from the piston. In a motor that rotates clockwise, the major thrust surface will be on the passenger side of the cylinder, the driver’s side of the cylinder wall is called the minor thrust surface. Or coast side!When looking for an ideal block, we want one with thick, uniform thrust surfaces. More material on the major thrust surface is a nice touch as long as it doesn’t come at the expense of the other surfaces. Normally a thickness of 150-160 is very good compared to forward an aft. Normally forward and aft is perfectly safe @ 90-100. Most performance engine builders and racers like 160 on the thrush side. Just saying. But i would like to see a 2.3 that was blown up because of an aft thickness of under 100!!! POST IT I AM CURIOUS ABOUT ONE THAT FAILED AT THIS POINT OF THE BLOCK!!

Buying new block

Reply #10 – October 28, 2013, 08:13:02 AM

Tom, that "thrust" thickness applies to all blocks right wether they be 4, 6, 8, or 10 cylinders right? I know, kinda dumb question, but I've never thought about that. Makes a lot of sense though.

Buying new block

Reply #11 – October 28, 2013, 05:13:18 PM

It does we used to check blocks like MOPAR. The HEMI had a nasty habit of thin thrush side material. As the matter of fact they used to bust off the front lifter boss on the drivers side when they were thin, Basically Jangus has a very good point and is a knowledgable fellow. But he is a throw back from TF and NATO. They pounded me real hard and maybe with cause. But basically i have dun quite a bit of crazy stuff years back that some felt was BS. And i respect that. But this is not my first rodeo. Like i said Jangus is a sharp guy no question about that. But you have to know where to put your money when building an engine. Offset boring is great to compensate for thin walls and like i said is a good thing.

Buying new block

Reply #12 – October 29, 2013, 03:11:30 AM

Im not sure how far you wanna go with this, But i work for ROUSH and they will do custom work. It will take some time but im sure we could machine you a custom block to whatever specs you want.

Buying new block

Reply #13 – October 29, 2013, 07:17:24 AM

since rods came up, my machinest punched out the rods a tiny bit, the wrist pin pressed into the pistons but the road floated.

is floating rod better than floating piston in your opinion...
seems reasonable since a floating rod connection is one friction point where if the wrist pin presses into the rod, then the piston becomes two friction points.

Buying new block

Reply #14 – October 29, 2013, 02:27:17 PM

From everything I have ever read they always say the only weak point on the 2.3 bottom end are the rods.