engine blocks, any year to stay away from?

[my98gsx]

Back around 2003, I ruined my 1998 4g63 block which was in my 98 gsx. At the time I sent it to slowboy racing to get rebuilt, and sent back. Well it took me 20 years but I finally ran the vin number on the block which appears to be a 1995... Now I cannot blame slowboy, my engine was used as a core I am sure. However this engine has failed numerous times on me and has been rebuild by very good shops since slowboys initial rebuild. I recently had the crank walk which is causing me to have to rebuild the bottom end yet again...

My question is - is there any year engine blocks to stay away from? Are 95 blocks not as good as 97-99? I do have a manly turbo tuff crank btw - if that makes any difference at all at this point.

If 95-96 year blocks are prone to walking more than a 97+ id rather just invest in another block to save in the long run.

Sorry if this post has been beat to death but my search has came up with no information regarding that I could find.

 

[1990TSIAWDTALON]

I actually like the split thrust blocks but I am not a usual 7 bolt guy.
Anyone else have experience with different blocks?

 

[DogWhistle]

Did your engine fail each time by crank walking? What are the engine mods you have done? What is your boost level? Are you running a heavy clutch? These are factors affecting the longevity of your engine.

A little internet search turns up some of the key differences in an early 4G63 (6 bolt) and a later 4G63 (7 bolt). At the risk of fanning the flames on a 6 vs 7 battle, here is their basic difference (credit HP Academy):

"On the 6 bolts, the oil gallery that supplied the center main bearing doesn't align with the hole in the bearing shell. Secondly, because these engines used a full 360 deg thrust bearing it was easy to misalign the cradle and essentially reduce thrust clearance. This misalignment then also resulted in the crank only being supported by half the thrust bearing. Also, there was insufficient oil flow to the thrust face."

Depending on your answers to the above questions and your uses/driving habits, even a 7 bolt could have issues. Describe your setup and let's see what others say.

 

[my98gsx]

I always run a act 2600 pressure plate spring 6 puck and an extended slave cly rod, which might be a main cause of my issues.

Hp was at 565whp, close to 30 lbs of boost give or take.

Engine block was manley h beam plus rods, turbo tuff 88mm crank and manley 8:5:1 pistons with clevite 77 bearings

Engines always fail with crank movement.

 

[Jonnyeclipse]

In 2003 my 95 crank walked on me. 95000 miles on it. I had Magnus build me a 6 bolt. I checked the # and it is a 90 out of a Laser. The 6 bolt lasted 500 miles after being broken in and tuned on the dyno by Marco. 6 or 7 bolt they all eventually break.

 

[DSMPT]

I don't know if this is applicable in the States, but actually the 7 bolt block can be converted from a non revised block to a revised block w/ split thrust washers. So in case you have a good 7 bolt block with one-piece style main bearing and you want a revised 7 bolt block with split thrust washers but can't find it, you should ask some machine shop. Maybe some shops can do that modification. That modification was common for the evo 1/2/3 and the early evo 4 owners in Japan.

 

[Devesh]

Hello i saw your post about modding evo3 block to use split thrust bearing, do u know exactly what is done

 

[DSMPT]

Hello i saw your post about modding evo3 block to use split thrust bearing, do u know exactly what is done

Here are some pics I borrowed from a Japanese website and edited. The block in the pic was originally a non revised block with one-piece main bearing that got crankwalk slightly. The pics are after converted.
Can't tell how many mm exactly it needs to be enlarged but basically you enlarge/widen the block side groove for the split thrust bearings and block off the cradle side grooves, or use one that originally came with a revised split thrust block. (Anyways this would probably require line hone/bore)

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