I have a brand new siamese R3 48* tall deck that I just got back from sonic test, and I´m not very pleased with the results. This is 3.99" bore as it comes, and it seems to have core shift to every possible directions leaving some areas a bit thin. Thinnest spot is in front of cyl 1. Outer walls are thinner than inner walls on both sides, worst spot on major thrust sides is in the bottom of cyl 4.



Are these typical results for R3 block or do I have a bad one? I hoped that I could build a 4.185" bore 700-800hp N/A engine at first, but leave room for another rebuild, and if I decide to, be able to go forced induction and about 1200-1400hp power level. Not going to happen with this block?

I could fix some of the core shift by moving the bores away from the thin sides. My machine shop guy told me he could move the bore centers individually up to .060" if my head gaskets and combustion chambers allow it. I don´t think the combustion chambers will be a problem since I have untouched W9 heads and I will do all the headwork myself and I can fit the chambers to the cylinders. The head gaskets may be a problem, and I probably should get them first and do some measuring. I think the left side bores should be moved some towards back, and both sides should be moved inwards. Could this be done and which head gaskets should I get?

I could also do a smaller bore like 4.165" for the first build if required. Also I could do a partial fill since the thinnest spots are all in the bottom of the bores.

When I did my R3(very early block)it had at least
.200 walls or better even if it was bored to 4.22...
I guess you could slide that front cyl back .050 if
you work the head... even with the thick bores on mine
I had to sleeve 1 bore when it blew up

What block 673AC or AD revision? earlier?

My tall deck was also thin there. Can't remember how bad it was. We were wanting to bore 4.245".

Block filler is a wonderful thing. This what I did and it worked great. Or you could just sleeve #1.

Leon

how much of a hassel is it to return it & get another block?? lot of money spent for something that isn't rite. jmo, seeya.

RITTER XR1 WILL FIX THAT

It´s 673AD, shipped from chrysler a couple of months ago. It would be a bit hassle to change the block since I live in finland. Do you think they would change it if you got one like this?

If you move the bore centers as your machinist proposes you could solve that part of the problem. If you are willing to accept the spec out of blueprint.
Or a half partial fill:
An idea for you, as I know you are capable of doing the most: Fill the block with fat first up to the lower level of where you want the bottom of the block fill, let solidify, then cast blockfiller from that level up to the upper level (an inch thick or so would do!). You can add some tubes stuck into the fat, before blockfiller, to enable waterchannels from the lower level to the upper. In this way you can copy the watersystem from the R5 block, it has a manifold below, distributing water into the cylinder jacket from holes.
When block filler is stiff, you simply heat up the block and drain the fat, and you have a supporting band of blockfiller exactly where you want it, in the middle of the cylinder to support it (or higher up where the forces are bigger).
Do it all before machining is done!
Yoy can use cocos fat (melts at 29 dC), take car that it does not climb up to the walls where the blockfiller will go...
Better than baking for X-mas!!!
My

I would check to see exactly where the bores are at in relation to the crank centerline as well as each other (oposing 90*) and in relation to the front/back of the block (for/aft spacing). A real race engine machine shop can put the bore EXACTLY where they should be for maximum efficency and performance. If you must use that big a bore size and its gonna be thin AFTER correcting the bore spacing/placement, I would sleeve it but only after the bore is centered where it needs to go. Personally, I run a way smaller bore size and have no issues/worries about thin cylinders and it works for me. 8.92 @ 149.95 mph 2900lbs 360 inches N/A no power adders...

i bought a world hemi block from ray barton. rear seal kept leaking. after doing some inspection, i found out the groove for the rear seal was machined too wide & wasn't centered to the crank. called chrysler, they wanted the block back & shipped me a new one. as stated by other members here, u could have it corrected $$, or try for another. that would be ur choice. good luck. stay safe, seeya.

Find a a buyer for the block you have and order another block that will meet your requirements. If possible have a trust worthy machine shop check it out here in the US before it makes the long trip to you. You shouldn't have to change your plans and expectations.

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I think the left side bores should be moved some towards back, and both sides should be moved inwards. Could this be done and which head gaskets should I get?

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If it were mine I wouldnt do that....

find another block....

Why not? Bores would be done in line with crank centerline of course, but they still can be moved forth and back or rotated up or down around crank centerline? Whats the downside for doing that besides the head gasket/combustion chamber fitment? I would try the gasket on first and then make the call how much to move the bores. If I can work it out and it wont cause any other problems, I rather have that than walls that are too thin. I really don´t feel comfortable using this block without moving the bores.

I´d like to know what is the usual quality for these castings, is this really a bad one, and is it bad enough that I could require another block. If that´s the case I could discuss with my dealer about it.

If you plan on going boosted...don't go so big on the bore...will just cause head gasket problems later on....power will not be a problem later on with out the huge bore....

Mopster,

I feel your pain my friend. I have now been through 2 blocks and now waiting for the 3rd attempt. I must admit that mine are P5153478AB 59 degree siamese finished at 4.040" and I was aiming for 4.125" bore. However, you would think for what Mopar charge for these blocks they would get it right, not to mention the fact that we have them shipped half way around the world. The first picture is the sonic report of the first two blocks I recieved and the second is of friends 48 degree low deck for comparison. At the end of the day I may just go for a smaller bore to make way for a rebuild down the track. Pitty I already have the pistons.

Macka

2nd Sonic Report

going only by the sonic test reports alone is not the best way to approach a solution IMO. it's just the beginning step. we routinely sonic test blocks but we also follow up by fixturing the block in our CNC machining center to find out if the bores are in the correct location to start with. i can tell you on many of the R blocks and X blocks we've tested, they very often aren't. sometimes that works for you, and other times against you.
you do have the ability to move bores in the front to rear plane up to a point, but i don't suggest moving them away from the true 45 degree angle from the crankshaft/camshaft centerlines. quite often that crank/cam 45 degree angle is already out of spec as well.
if you have a shop with a CNC block machining center that can check all of the important measurements it would be a good decision to use them IMO. i probably have some pics i could post of different R blocks we've done where the bores were actually at 47 degrees as cast. some of the bores were considerably out of blueprint spec in the front/rear plane as well. when we corrected the geometry it actually helped the sonic numbers. like i said, you just never know unless you have the abilty to follow up with the newer type of equipment available today.

here's an example. this bore started out at 3.910. this pic was taken after the first .090" cut was done. as you can see it still didn't clean up the bores all the way. as i recall that block was almost 2 degrees off from the blueprint spec, which is a lot, but not uncommon.

here's another.

That block looks familiar...