2G Evo 8 crankshaft on Eclipse 2g

[Jhusey]

Hi, I know this sound weird, but here in Peru is very hard to find a 2g Eclipse, mine is a 2g gst, my crankshaft got a wear (i think it is the translation to from spanish to english) and I broke a main bearing.

Getting a used 7 bolt crankshaft from a 2g Eclipse it is impossible, but a friend has a crankshaft from an Evo 8. I wanna know if this will fit on my motor, or I would go to repair my crankshaft?

Doing my research I found that I only can polish it at 0.010 inch without problem (sorry but i wanna be really sure before doing it)

thanks

 

[SBR Joe]

so if i wanna put the evo crank, i will need to machine my block because mine is in the 95-98.5 range to fit the evo crank??

No..... Like stated many times before, the difference is in the block, not the crank, so if you use an evo 7 bolt crank...its no different than a crank from a 95. The difference is in the BLOCK and that determines what main bearings you use. You have a 97, so it will most likely be a standart thrust engine.....if you want to send me pics when u have it apart just so i can confirm you can.


joe
SBR

 

[delta448]

You only have to do machining if you want to change the style of thrust bearing you're using. I really advise against doing any machining. Just use the regular bearings that go with your engine block.

Edit: I type too slow... nice Joe.

 

[turbodsmawd420]

Whoa whoa whoa, now you have sparked my interest in the thrust bearing. Are there any advantages/disadvantages to using the split thrust bearing instead of the std. thrust bearing? Are the std thrust bearings really more notorious to crankwalk like Joe said? or was he just referring to the 7 bolts in general, and not the actual type of thrust bearing.

To the OP, if you're only replacing the crank, the EVO8 crankshaft will fit right in (because they're both cranks from a 7-bolt 4g63 engine,and the 7-bolt cranks are all the same across the board). However, if you're going to be replacing the bearings also, you'll have to make sure the bearings are specific to your 7-bolt engine (because not all thrust bearings are the same across the board). Like Joe said you would have to open the block up to see exactly what kind of thrust bearing your 7-bolt uses, which shouldn't be a problem since you're gonna have to open her up anyways to replace the crank, so you can just take a look then, and send in a pic if you're still not sure.

 

[delta448]

The split thrust bearing is a superior design. Crankwalk can happen on any piston engine at any time, however the 4g63 and 4g64 engines originally equipped with the split thrust bearings have virtually no issues with crankwalk. Seriously, how many Evo 8s and 9s do you ever hear of crankwalk happening to?

 

[SBR Joe]

The split thrust bearing is a superior design. Crankwalk can happen on any piston engine at any time, however the 4g63 and 4g64 engines originally equipped with the split thrust bearings have virtually no issues with crankwalk. Seriously, how many Evo 8s and 9s do you ever hear of crankwalk happening to?

Spoken like a true prophet! !




Joe
SBR

 

[Jhusey]

right now i dont have a pic of the block (thanks joe), but the last time i rebuild it (5 months ago), i use acl bearings ACL 5M1186H (main bearings) and ACL 4B1185H (rod bearings).
I think if my block have the split thrust bearings i would have to buy this bearings (ACL 5M1219H + ACL 1T1219) but i only buy the ones i mention before

 

[talon187]

i dont want to sound totally stupid here but whats the biggest differnce in the evo motor from the 2g?

 

[SBR Joe]

right now i dont have a pic of the block (thanks joe), but the last time i rebuild it (5 months ago), i use acl bearings ACL 5M1186H (main bearings) and ACL 4B1185H (rod bearings).
I think if my block have the split thrust bearings i would have to buy this bearings (ACL 5M1219H + ACL 1T1219) but i only buy the ones i mention before

Ok, you have STD thrust bearing. NON split thrust. Got that problem solved! Just get the same bearings and the evo crank and you will be ready to rock!



Joe
SBR

 

[SBR Joe]

i dont want to sound totally stupid here but whats the biggest differnce in the evo motor from the 2g?

Nothing if youre talking about an EVO 1-3. 180* opposite in engine and split thrust in EVO 4-8 among many other things.


Joe
SBR

 

[turbodsmawd420]

Great, all of of my crankwalk nightmares are coming back to life . Is it enough of a concern that I should take the block back to the machine shop and machine it so I can used the split thrust bearing? Or should I be alrite using the std version?

The machinist took a look at the block when I had it honed,bored, and decked,and he said the block was in good shape,and all parts of rotating assembly are new(Eagle crank and rods, wiseco pistons, acl bearings.....it's a 2.3 stroker)

I know there's no way of avoiding crankwalk altogether, but I'd like to reduce the chances as much as possible before the engine goes back in.

Thanks for your help guys.
Pat

 

[delta448]

If the machinist says it looks good, I would take his word for it, especially if he has very much experience. If you're still worried, you could ask him to measure the crankshaft endplay for you and compare yours to the factory tolerance.

I would recommend NOT machining the block to fit the split thrust bearings. It's not easy to do because the surface is not easy to access and it requires extreme precision. Also, by machining the center mains you would be degrading the strength of the block slightly and possibly end up distorting the line bore/center main cap alignment or girdle alignment slightly. It would require complete disassembly of the bottom end, lots of double checking measurements and could easily ruin all the work that has already been done to the block if the machinist slips up even a little.

I strongly urge you to use the standard bearings at least until the block measures crank endplay as out-of-tolerance. Then, and only then would I risk machine work to the thrust bearing surfaces.

 

[turbodsmawd420]

If the machinist says it looks good, I would take his word for it, especially if he has very much experience. If you're still worried, you could ask him to measure the crankshaft endplay for you and compare yours to the factory tolerance.

I would recommend NOT machining the block to fit the split thrust bearings. It's not easy to do because the surface is not easy to access and it requires extreme precision. Also, by machining the center mains you would be degrading the strength of the block slightly and possibly end up distorting the line bore/center main cap alignment or girdle alignment slightly. It would require complete disassembly of the bottom end, lots of double checking measurements and could easily ruin all the work that has already been done to the block if the machinist slips up even a little.

I strongly urge you to use the standard bearings at least until the block measures crank endplay as out-of-tolerance. Then, and only then would I risk machine work to the thrust bearing surfaces.

Thanks alot Delta, the info is much appreciated. I'm just gonna keep the std thrusts bearings in there for now, unless the endplay on the crank gets to be too much, then I'll pull it out and take it from there. The machine shop is actually one of the best, the guy does work for Hahn Racecraft and AMS, but it just seems unessacery for all the risks involved.

Thanks again for the help Delta!

 

[jonbusa]

guess my 2g is going to have all evo 8 internals now

 

[96pos dsm]

Great, all of of my crankwalk nightmares are coming back to life . Is it enough of a concern that I should take the block back to the machine shop and machine it so I can used the split thrust bearing? Or should I be alrite using the std version?

The machinist took a look at the block when I had it honed,bored, and decked,and he said the block was in good shape,and all parts of rotating assembly are new(Eagle crank and rods, wiseco pistons, acl bearings.....it's a 2.3 stroker)

I know there's no way of avoiding crankwalk altogether, but I'd like to reduce the chances as much as possible before the engine goes back in.

Thanks for your help guys.
Pat

If your gonna spend all this money....why don't you just look for a 99 block that has split thrust bearings and not worry
On a second note I plan on doing a short block rebuild in near future and I have late 99 7 bolt , which bearings would be recommended for EVO crank. Acl, clevlit, oem?