105k on 7bolt How far should I take it?

[jspec]

I have a 99 gsx that has about 105k on the clock. Long story but I pulled the motor to do a clutch/ flywheel job. I figured I would do the head gasket and timing while I was at it. My question is this how far should I take it. New rings? New bearings? I found a deal on some 7 bolt eagle rods and weisco pistons. So I was thinking of going all out. My goals are really a 350 -400 hp daily driver. I believe the stock motor can take it so I am a bit confused on what to do. Cheap route is throw the HG and timing on and put it back in the car. Expensive long route is rods pistons and everything. Give me some thoughts? Thanks

 

[Defiant]

If the compression's good and the thrust bearing's in spec, I'd not crack the head gasket. Just do the belts.

 

[jspec]

Well that would make total sense but I made the rookie mistake of not doing a compression test before pulling the motor. I already have it stripped to the shortblock with oil filter and oil pan attached. Any way to check the motor out in that state?

 

[SBR Joe]

You have a 99, which means you have a split thrust 7 bolt. EVO's have teh same design, do you ever hear of an EVO crankwalking? I wouldnt feel one bit bad making 400whp on a stock split thrust 7 bolt. If you plan on doing 400whp, yo can probably get away with the stocker headgasket for a while but will evenstally fail. If you have it out and are doing timing components anyways, you might as well split the head and do a metal HG with some ARP's so you wont have to worry about it down the road.


Joe
SBR

 

[JaxTalonTSi]

You have a 99, which means you have a split thrust 7 bolt. EVO's have teh same design, do you ever hear of an EVO crankwalking?

Joe
SBR

Yes. If you read up on the UK/Euro Evolution forums, they have had the same issue with crankwalk in the III's and IV's as we have had in the 2g DSM. The split thrust is less likely to walk, but no guarantee. But the point is, Evolutions are not immune to crankwalk.

Regardless, I think most any 4G63T engine, regardless of where it came from, would be safe as a daily at 350-400hp without grenading anything in the shortblock.

 

[SBR Joe]

Yes. If you read up on the UK/Euro Evolution forums, they have had the same issue with crankwalk in the III's and IV's as we have had in the 2g DSM. The split thrust is less likely to walk, but no guarantee. But the point is, Evolutions are not immune to crankwalk.

Regardless, I think most any 4G63T engine, regardless of where it came from, would be safe as a daily at 350-400hp without grenading anything in the shortblock.

Yes, but the 99 DSM's and the EVO's (VII, VIII, IX) use the exact same thrust washer set and main bearings. I agree, not totally immune to it, but the chances are so much less of it happening that i wouldnt worry about it. Especially with 105k on it now.


Joe
SBR

 

[JaxTalonTSi]

I have a 99 gsx that has about 105k on the clock. Long story but I pulled the motor to do a clutch/ flywheel job. I figured I would do the head gasket and timing while I was at it. My question is this how far should I take it. New rings? New bearings? I found a deal on some 7 bolt eagle rods and weisco pistons. So I was thinking of going all out. My goals are really a 350 -400 hp daily driver. I believe the stock motor can take it so I am a bit confused on what to do. Cheap route is throw the HG and timing on and put it back in the car. Expensive long route is rods pistons and everything. Give me some thoughts? Thanks

Any engine which is "questionable", being that you don't completly know it's running condition should be gone through, but the difficult part is deciding to rebuild a 7 bolt or not. Despite what people have said about rebuilding 7 bolts and their individual account of how it ran, rebuilding one is still a role of the dice, and I wouldn't ever bother trying to rebuild it with a forged bottom end unless it's being done by somone who has figured them out a little more than the average DSM know-it all. It seems that Marco at Magnus Motorsports has the "secret" so to speak into building a reliable 7 bolt engine, but regardless, I think this is going a little far off from your goal.

If it was my engine, it would be completely torn down and inspected thoroughly. If everything checked out ok (read: using proper instruments and checking bore and crank clearances), I would probably have the block honed, reassembled with new rings and bearings, gaskets, ect, and drop it back in. Might as well do it right first rather than pull it out again later.

 

[delta448]

Yes. If you read up on the UK/Euro Evolution forums, they have had the same issue with crankwalk in the III's and IV's as we have had in the 2g DSM. The split thrust is less likely to walk, but no guarantee. But the point is, Evolutions are not immune to crankwalk.

I was under the impression that the Evo III used the same 4G63 block as the 95 DSMs. When did the Evos start using the split thrust? -Wasn't it in 99, like the Eclipse? What version of the Evo were they up to in '99?

 

[jspec]

Any engine which is "questionable", being that you don't completly know it's running condition should be gone through, but the difficult part is deciding to rebuild a 7 bolt or not. Despite what people have said about rebuilding 7 bolts and their individual account of how it ran, rebuilding one is still a role of the dice, and I wouldn't ever bother trying to rebuild it with a forged bottom end unless it's being done by somone who has figured them out a little more than the average DSM know-it all. It seems that Marco at Magnus Motorsports has the "secret" so to speak into building a reliable 7 bolt engine, but regardless, I think this is going a little far off from your goal.

If it was my engine, it would be completely torn down and inspected thoroughly. If everything checked out ok (read: using proper instruments and checking bore and crank clearances), I would probably have the block honed, reassembled with new rings and bearings, gaskets, ect, and drop it back in. Might as well do it right first rather than pull it out again later.

WOW guys thanks for the responses and the info. It is really helping me make a better educated decision. I really want to get this car up and running asap. I picked up this car in September and have put less then 1 mile on it. I have no idea how this motor was treated or what has been done to it. So if I decide to have new rings and bearings installed. You are saying I should send it up to magnus? I don't know of any local engine builders for 4g63's. I will ask on the local forum about it. Has there been any writeups on the pros and cons of the split thrust design?

 

[JaxTalonTSi]

WOW guys thanks for the responses and the info. It is really helping me make a better educated decision. I really want to get this car up and running asap. I picked up this car in September and have put less then 1 mile on it. I have no idea how this motor was treated or what has been done to it. So if I decide to have new rings and bearings installed. You are saying I should send it up to magnus? I don't know of any local engine builders for 4g63's. I will ask on the local forum about it. Has there been any writeups on the pros and cons of the split thrust design?

I'm not saying if you decide to reassemble with new rings, bearings and gaskets you should send it up to Magnus (unless that is, you live relatively close to them and rather fork out your cash to them specificly), but have a friend who knows what he is doing to help you reassemble it, or send it off to a reputable machine shop who is capable of putting a 4G63 together properly.

Here is some more info from Magnus's site: Read up ladies:

http://www.magnusmotorsports.com/tech/crankwalk.htm

 

[JaxTalonTSi]

I was under the impression that the Evo III used the same 4G63 block as the 95 DSMs. When did the Evos start using the split thrust? -Wasn't it in 99, like the Eclipse? What version of the Evo were they up to in '99?

I belive it was 1998 or 1999, though I'm not positive. The 1999 Evolution would have been probably a VI I belive.

 

[brandonzero0]

I thought it was all 2gb's

 

[jspec]

I have actually read that magnus article before. I kinda don't understand what his update means. Is he saying just use a stock clutch? Or make sure the clutch is properly adjusted.

 

[malern28us]

I don't claim to be a mind reader but I took it as the problems surfaced once people started to upgrade past the stock clutch assembly. Might give credence to the fact that most manufacturers spends millions on R&D. I just figured that just wanted us to always granny shift !
Eric