Bad week at the homestead

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Cudaroy

Cudaroy

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Hi all,i just found crack in cylinder #2 on my 1990 318 block after a very trying week. it is getting cold up here in NH so last weekend flushed out the old coolant, hooked up the heater hoses, put new prestone in it and fired her up. Noticed after about 5 minutes the right side exhaust smelling kinda sweet and white smoke coming out. I thought maybe some sealer might work.NO! Then on Friday I replaced the head gasket and no change. I figured maybe the head was cracked so I went to a friend and he loaned me a set of 596 heads to try. I removed the heads and used a mirror to look at the#2 cylinder and lo and behold found what looks like a crack around the 12 o'clock position. Motor only has 6000 mile since the .030 over b
ore but the walls look very thin.The motor is a 1990 Truck block so beware! I didn't have the work done but bought the engine as a long block, tore it down, replaced the crank as #4 and#8 journals had spun and ran great until I flushed out the coolant.
Guess I'm in the market for another engine...........
 
Yea If thats all that wrong with it sleeve it that will be a lot cheaper than building another block and you will know what you have not just another long shot on someone else's build.
 
Lots of people needing money you might pick up a 340-360 cheap in good shape.
 
Sleeve it, and don't look back. Unless sonic-checking the other holes counts as looking back. Then do that.
 
I have the original numbers matching block that needs to be bored as well as a 69 block also needing a bore so it looks like that will be the direction going....
 
Cudaroy said:
Hi all,i just found crack in cylinder #2 on my 1990 318 block after a very trying week. it is getting cold up here in NH so last weekend flushed out the old coolant, hooked up the heater hoses, put new prestone in it and fired her up. Noticed after about 5 minutes the right side exhaust smelling kinda sweet and white smoke coming out. I thought maybe some sealer might work.NO! Then on Friday I replaced the head gasket and no change. I figured maybe the head was cracked so I went to a friend and he loaned me a set of 596 heads to try. I removed the heads and used a mirror to look at the#2 cylinder and lo and behold found what looks like a crack around the 12 o'clock position. Motor only has 6000 mile since the .030 over b
ore but the walls look very thin.The motor is a 1990 Truck block so beware! I didn't have the work done but bought the engine as a long block, tore it down, replaced the crank as #4 and#8 journals had spun and ran great until I flushed out the coolant.
Guess I'm in the market for another engine...........
Click to expand...

If this question was asked a week or so ago you would be advised to chuck the block in trash just like the members of this forum told another member who found a tiny crack on one of the valve seats of his heads, BUT a seat pressed in would have been the way to go instead of buying all new heads, or in your case a block. A sleave would fix your block, as so would starting with the other '69 block since you already have it.

Sleave it or start with the other block.
 
Thanks for the advice to all. Being a non matching 318 there would have been no way I would have sleeved the block as blocks are just too plentiful to come by and I have 2 extras already. I'll need to measure the cylinders on both the original 68 block and the 69 block as it looks like both will need at LEAST a 30 over bore and quite frankly am a little skittish after finding how thin the wall was with the 90 block. Also looking at going the magnum route as roller cam engines will make the zinc requirement issue go away.
 
Cudaroy said:
Thanks for the advice to all. Being a non matching 318 there would have been no way I would have sleeved the block as blocks are just too plentiful to come by and I have 2 extras already. I'll need to measure the cylinders on both the original 68 block and the 69 block as it looks like both will need at LEAST a 30 over bore and quite frankly am a little skittish after finding how thin the wall was with the 90 block. Also looking at going the magnum route as roller cam engines will make the zinc requirement issue go away.
Click to expand...

You will find that both of those early blocks have thicker walls.
All the 90's stuff was thin cast, automakers were trying to save money.
You can bore the early 318 blocks .090 over in most cases.
 
Cudaroy said:
Thanks for the advice to all. Being a non matching 318 there would have been no way I would have sleeved the block as blocks are just too plentiful to come by and I have 2 extras already. I'll need to measure the cylinders on both the original 68 block and the 69 block as it looks like both will need at LEAST a 30 over bore and quite frankly am a little skittish after finding how thin the wall was with the 90 block. Also looking at going the magnum route as roller cam engines will make the zinc requirement issue go away.
Click to expand...

90's blocks are not an issue....metaleargy is alot better in later blocks than the early ones.
But every block can have core shift no matter what the year.
I would suspect the machinist doing the work did not bore the block on the bore center line.
You said you already had to re-work the bottom end.
Salvage what you have, I would also use a free block than fixing one one with problems on a 318.
 
Cudaroy said:
Thanks for the advice to all. Being a non matching 318 there would have been no way I would have sleeved the block as blocks are just too plentiful to come by and I have 2 extras already. I'll need to measure the cylinders on both the original 68 block and the 69 block as it looks like both will need at LEAST a 30 over bore and quite frankly am a little skittish after finding how thin the wall was with the 90 block. Also looking at going the magnum route as roller cam engines will make the zinc requirement issue go away.
Click to expand...


The early blocks can handle a .030" overbore better than the "newer" ones....



Bummer on having to replace the engine.... :wack:
 
I've sonic checked dozens of SB Mopar blocks and have found that the earlier blocks are no better than the later blocks. In fact most of them suffer from bad core shift issues. The pre-Magnum roller cam blocks are far better, from a metallurgic and casting stand point.
 
Just bored a 71 4 ear 318 truck block 4.040.
I just like the early stuff, prefernece.

I'll take a pic
 
The one guy I know that tried that wound up with a motor that constantly over heated, ran like chit, and eventually windowed out a cylinder wall. Punching a 318 .130" over just to hit that magical 340 number typically never goes well. Not saying it can't be done successfully. To do it right you will need do a extremely thorough sonic check, and bore the block multiple times. By the time you weed out the blocks that aren't fit cylinder thickness-wise, and also pay for the multi step bore job. You could have bought a 340.
Not trying to be a dick, just trying to keep it real.
 
No multi step boring, no extra cost, no weeding through blocks.
Thrust sides are THICK.

This isn't your average passenger car block, real 4 ear truck blocks are cast with thicker cyl walls.
Now I'm not gonna go and say they have exactly the same cyl core as a 340, but they do go this big.

By reading this site, you would start assume every machine shop.has a sonic tester and every block gets tested before bore and hone. Reality 'not the internet' says about 95% of the builds out there on the street were not sonic tested. In my neck of the woods there is about 2-3 shops within 2 hrs of me out of about 30 who do sonic testing. Out of those shops over half build race engines of some sort.
Out of the 20-30 motors I've built...I have only had one sonic tested- ford 390 total pos, can't bore them .030 in most cases.

Sonic testing was something general motors and henry ford introduced by casting junk blocks.
Monkey ran the casting line.
Now I'm not against it, there is a place these days wether I like it or not for sonic testing, but the way people throw it around on here is ridiculous, its not something even a third of machine shops do.
 
Monkeys also ran the Mopar foundries - that's for sure. I agree a lot of engines historically were built without testing. And many shops that build performance engines don't sonic test. On top of that many that do don't have a quality tester or know how to do it properly. Some even charge for a test but don't have one. I built a 2nd 505 for someone after another shop built one. they charged him and told him his tested great. The first 505 made some dyno pulls, and had about 400 street miles before it split a wall that was .080" thick on the minor thrust where it cracked. I know the shop and know for a fact they had no tester. The one I built gives ETs that put it in the 550hp range and has been driving and racing for years now.
But - none of that changes two facts that have been proven by reputable independant sources over time:
1. - There is engineering truth, and production reality. Engineering did intend for some blocks to be stronger and thicker depending on the use. That's a fact. However - the production reality is that due to core shift and casting quality caused by any of a number of factors, the intended designs were compromised during production making them no better (or worse) than anything else. The "Low core number" and "four ear" small blocks are the same as the "230" B wedges and W5 heads. Good intentions - poor execution. You'll get some that are as engineered, but some aren't, and they look identical.
2. A proper sonic test can and does routinely stop people from making mistakes as far as putting money into something that has a higher risk of problems or failure.
If you haven't been bit count yourself lucky. Me, I'm not a shop, but I bought the best tester I could find at the time and it paid for itself on the 2nd block I tested. Since then the "failure" rate is about 30% where I end up sleeving one or more bores, or moving on to another block.

Time marches on. I no longer use a boring bar or manual tire machine either. You only need to be or have a person you know burnt once to be a believer.
 
Years ago I understood the fascination with the mythical 340...but in the days of strokers it is just a number that makes purists get a woody. If I were going to be using a Mopar small block it surely would not be a 340, tack on 100 or so cubes and now we are talking....
 
Big block chryslers are something special, they spin rod bearings at anything repeated much over 6800 rpm without oil mods, they have blocks with more main web than others so that you get instances of catostrophic failure. The 426 hemi when it came out was a crack'a lackin ****, blocks had all kinds of biffs.

Don't get me wrong, I love big blocks. I just can't put them in the comparison arena with the sb.
As for wall thickness, build dependent in my opinion. I'm not building a strip motor with a thin wall block. And at .080...that's something for under 9.1 comp and 5ooo rpm, not the dyno and drag strip.lol

One would think I hate big blocks after reading the above, truth is though Chrysler b/rb is a better large displacement design over the competitors.
Now that we've ventured far from the op , let's bring it back..
 
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