[Sabbasaun]

Well then at least drop the oil pan to see if it has the 4 bolt mains. That's one thing I'm very curious about, but haven't been able to find any answers on.

Kevin I just looked at the service manual, it looks like the Theta engine only has 2 bolt mains. I'm not sure what kind of difference 2bolt vs 4 bolt makes. Perhaps one of the experts can elaborate.

edit: a snippet from the service manual
---------------------

 

[OHGENESIS]

wasnt there a topic like this in another section of the forum about the rods and block girdle? sombody had said the bottom end is more beefed up than the evox and srt and showed pics.

 

[Tufast]

A 4 bolt main engine has a stronger crankshaft that doesn't flex as much, the block is also stronger & will not flex as much either. This engine will have less vibration than the 2 bolt main & is better for running at higher RPMs. So, the EVO & SRT4 4 bolts are better than the GenCoupe 2 bolt, but in today's engines, the difference between the 2 is not as big a difference as in the "old school" engines. Once again, we'll just have to see what these things are capable of.

 

[DayDreamer]

So by looking at this diagram of the main caps and bolts for the 3.8, I guess it would be safe to say that the mains on the V6 are 6 bolt? This isn't really my area of expertise, so I may be wrong...

EDIT: Crap, sorry I guess it's on a transparent background, but I think you get the point...

 

[OHGENESIS]

just looked at the manual its a ladder frame 4 bolt main system..

 

[Kevin DSM guy]

Kevin I just looked at the service manual, it looks like the Theta engine only has 2 bolt mains. I'm not sure what kind of difference 2bolt vs 4 bolt makes. Perhaps one of the experts can elaborate.

edit: a snippet from the service manual
---------------------

Was there anything showing the deck of the block? I'd also like to know if it's the semi-closed deck like the Evo, or open deck like the non turbo block.

 

[OHGENESIS]

i couldnt tell from any of the pictures if its semi -closed or open? you would think its semi-closed. we got are brocures yesturday if anyone local wants one and is close to brunswick, ohio i reserved about a dozen for friends.

 

[Kevin DSM guy]

So I finally got that HMAservice thing to work, and found this pic. Looks to me like it'll be an open deck block. Not good...

 

[Redline G Coupe]

Maybe it won't be so bad. The Caliber SRT4 is open deck and Realtune made 500+ hp on the stock block.

 

[Tufast]

sabbasaun HELP!

sabbasaun, I want to move all the info not dealing with Jrod's purchase of his new car to seperate thread in the engine/turbo section & title it 4 bolt vs 2 bolt main or something of the sort starting with the question from Kevin DSM about which this is, but I don't know how. Can you help me?

 

[Kevin DSM guy]

Haha yeah, sorry for taking this off topic. I'm done now. haha

 

[dboz1]

i couldnt tell from any of the pictures if its semi -closed or open? you would think its semi-closed. we got are brocures yesturday if anyone local wants one and is close to brunswick, ohio i reserved about a dozen for friends.

I live in Brunswick, hook my up.

 

[Tufast]

Haha yeah, sorry for taking this off topic. I'm done now. haha

Don't quit now, it's got it's own thread..LoL

 

[MSUGeoman22]

Open deck and 2-bolt mains are confirmed by redline's disassembly of the 2.0 theta motor. Personally, from the experience that I have had with various motors (a couple of 2.2 mazdas, 4g63 mitsu, 2.0/2.2 subie, and 1.5/1.6 honda motors) it all comes down to tuning. I have made solid hp numbers with no block integrity issues on open deck motors (245whp on a D15B honda) with stock components. I feel really confident in the design of the 2.0t theta and think that all of us will be pleasantly suprised with its potential.

 

[Kevin DSM guy]

Wow, way to bump a 10 week old thread...

 

[dboz1]

This will probably happen more as the site is attracting more members, who are probably doing searches and finding old threads as they scan topics.

 

[MSUGeoman22]

Yikes, didnt read the date stamp, my bad

 

[Tufast]

Yikes, didnt read the date stamp, my bad

it's cool, I'm one of the ones that promotes reawakening the dead threads when someone has new insigt or something to add. I would much rather rivive an old thread than starting a new one on the seme topic.

 

[os3q6]

on a 4 cylinder it more inportant how many main cap verses 2 bolt 4 bolt 5 mains gives a stronge bottom end.

 

[MSUGeoman22]

on a 4 cylinder it more inportant how many main cap verses 2 bolt 4 bolt 5 mains gives a stronge bottom end.

You're right to some degree. In all reality, balancing of the bottom end really is what matters here. Harmonic combustion is something that requires very delicate and precise tuning. With good tuning and a proper engine setup there shouldn't be much concern for the motor being 2 bolt mains versus 4. If anything, this should make people value a good tune/tuner just as much as the quality of parts they put in their car.