plymouth1937
Well-Known Member
Found cracks in the 318 la roller block around the head bolt holes in the left side i guess its doned or can it be fixt anybody tryed to repair it the crackes is running down to the water jackets
Not a good mopar day
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Rat Bastid
Dunamis Metron
Stick a fork in that one, it’s done.
plymouth1937
Well-Known Member
Yupp my opinion too
Dan the man
Well-Known Member
I've heard that a lot on the magnum blocks. I think that the auto manufacturers shouldn't worry about saving weight when it comes down to the design of their engines. I think that a engine should run as cool with a 0.06" over bore as it does with a stock bore.
Dan the man
Well-Known Member
From what I've heard, the magnum blocks are of poor design and quality
That’s not what I heard.
plymouth1937
Well-Known Member
Its an al block from a 87 van not a magnum but these engines are knowen to crack betwen the head bolt holes
Some cracks just flat don't matter. A lot of the later head castings crack and have been cracked for decades and never cause issue. Just HOW FAR can a crack go in a head bolt hole? Was it leaking before? I would have the block pressure tested. If it passes, coat the head bolts with high temp RTV when assembling and hit the road. It's probably been cracked for YEARS with no ill effects.
plymouth1937
Well-Known Member
Om gona pinn the block and use a head stund kit all the cracks are coming from the bolt holes and yes i had a leake internaly and found the problem but its duabole
It’s an ALUMINUM block? OR
It’s an “LA” block?
I quoted Dan the man making a mention to his statement of a Magnum block, that’s all.
Good luck with the project. Will you document it here?
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I'd spend the couple of hundred bucks on a block from craigslist, but that's just me. My '91 360LA was a craigslist find. $150 up in Reno. It had the 308 heads (one with a crack between the exhaust and intake seats. No biggie, another $100 for another set, where one was cracked. SO, yes those heads were both running fine with cracks, and NO I won't be using them. Is $250 a decent price for a block and a pair of good 308 heads? I put everything except for the block, caps and bolts in the shed. New cast SCAT internal balance crank $416 at summit, forged SCAT rods $250 from a member here, forged SRP pistonsand rings around $600, and machine work around $2k thanks to my HOA and I am not allowed to even change my oil, all means that a new (used) block is less than 10% of the cost. Hell, now I'm not even going to bother with those 308 heads, and instead going with a set of ProMaxx CNC Shocker 185's. Unless I can see some numbers from IMM down in Indio on their new import aluminum heads, I'm pretty sure that I won't be disappointed. Now the cost of the block drops to around 5% of the build.
Do you really want to cheap out on the build?
edit:
I forgot, add in a cam for $170 and lifters for around $250. Doug's headers $600+, an exhaust system from Summit around $300, Oil pan (was a truck motor), oil pump, intermediate shaft, bushing, freeze plugs, and a full ignition system from 4secondsflat.com
At this point, the cost of the block drops to below the level of the TAX on the build.
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Oh, you caught that too, the al block?
If it's aluminum, I get wanting to repair, and it can be welded up and the head bolt holes redrilled and tapped.
I figured it is an “LA” block since he said “87” for a year.
Dan the man mentioned Magnum missing the year listed.
I just added a laughing face to make sure it’s taken as just goofing.
Id like to see this operation.
Dan the man mentioned Magnum missing the year listed.
I just added a laughing face to make sure it’s taken as just goofing.
Id like to see this operation.
The OP is in Sweden. They may not have craigslist there. Maybe 318s are harder to find there than they are here.
plymouth1937
Well-Known Member
Sorry LA block my bad iv got an other engine coming in but this block is in exelt chape and dont need any macine work thats why im gona repair it
plymouth1937
Well-Known Member
Iv done this before whid good results
Dan the man
Well-Known Member
I've only had 1 magnum engine in my life but from what I've read and heard about them is that they are a thin wall casting and a 0.030 over bore is the limit is this true? Also I've heard that the magnum blocks are known for cracking. My experience has been with blocks from the 60's and 70's and they could take a 0.060" over bore. Also are the magnum blocks a 1 piece rear main seal block, would a magnum block be a better choice over a LA block? I'm looking for more longevity and mild performance build. Also what would be a good compression ratio for a 300-325 horsepower at the flywheel? Again I don't have any knowledge about the magnum blocks just what I've read and what I've heard. I thought that it be best to ask you guys that deal with engine's daily. I really like the a body site. Thanks for everybody's help and sharing of their experiences and knowledge.It’s an ALUMINUM block? OR
It’s an “LA” block?
I quoted Dan the man making a mention to his statement of a Magnum block, that’s all.
Good luck with the project. Will you document it here?
That was also said of every LA block in factory print. We now know that as untrue.
Ether block will do, even more so for that power level. Regular pump gas will do fine @ 9.0-1 w/iron heads. AKA, a stock Magnum engine’s ratio.
A lot would also be with what camshaft your going to use.
Start a separate thread to discuss.
Dan the man
Well-Known Member
Thanks. I'll do that.
plymouth1937
Well-Known Member
Pics on the crackes
Rat Bastid
Dunamis Metron
I wouldn’t pin that. Those pins won’t do well even with a stud in the hole. They aren’t structural.
I'd scrap it. You don't know how deep those cracks are, and you won't be able to weld them without way more cost in repairs than the CAST IRON BLOCK is worth.
MopaR&D
Nerd Member
Looks to me like the iron around the threads has been pulled up and started separating from the block around it, that's some structural damage if so... your head bolt or stud won't be able to get correct clamping force and I bet head gaskets won't last very long. I'd get a new block, and maybe double-check your head fastener torque specs...?
If the OP is interested on pursuing this path, I believe I have a set of 1998 Magnum heads with no cracks for sale. PM me if interested. Paul.
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