6 bolts on each 3.6 main boss. Were you planning to double the factory power and torque? I wonder if the engineers think the torque converter changes will make basic cross bolting unnecessary? Needs a cradle.
Were you planning to double the factory power and torque? I wonder if the engineers think the torque converter changes will make basic cross bolting unnecessary?
Triple+ eventually but now maybe not. If I would have to go through the trouble of a motor swap to achieve those kinds of numbers I might as well start with another platform.
Huh? No. Disappointing because I had high hope for this platform. I've never done a diesel build and I was looking forward to something new.
Now I think maybe I should just stick to the fuel I know and love.
e85
:wink2:
I really don't think 4 bolt mains are necessary unless the block itself is not exactly rigid and needs the bottom caps to help stiffen the whole assembly. things are plenty stiff without the caps....I don't think you would ever need more than 2 bolts. A lot of modern gas engine blocks made of aluminum need caps to add stiffness to the block as a whole and you end up with 4-6 bolt mains as a result of them being structurally needed by the block rather than just to keep the crank firmly in place.
Doubting this is a weak point though on this engine. Maybe though. Are the pans and covers missing here light pieces or more rigid pieces?
Two bolts or four, really depends on how big of a bolt your are talking about. Are these two adequately sized bolts? Anyone identified failures or deficiencies?
With two bolt mains the cap just wiggles around too much under rpm regardless of how good the bolts or studs are and it gets even worse with longer strokes.
The 2.8 is a LONG stroke I4. SDP just killed theirs with RPM. Coincidence? I think not.
We'll see. Not sure on what the stroke of this engine is, but a long stroke or short stroke isn't going to make a lot of difference. It's an overall design thing and whether packaging and weight savings and such forced them to need a lower end to stiffen the whole thing. It is completely possible this thing is good for crazy power with the 2 bolt mains. I'm not expert on engines...but am an engineer and would think 4+ bolt mains would tend to be a bigger gain for packaging and weight and such on V engines BY FAR than an inline engine. The opposing loads and such will try to twist and contort the block in ways that would be tough to stiffen without structural bearing caps that then need more than one bolt per side to help in stiffening things. With an inline engine the block is just going to be way less likely to twist and contort in operation....so as long as it's a pretty smartly stiffened block in how they removed material to keep weight down it should be good for a lot of power.
The reality is that if you actually needed 4 bolts on an engine designed in line like that....those bearing caps would need to WAY WAY WAY heavier looking also as they are going to go into extreme bending....while the bolts will stay in pretty pure tension with maybe a bit of shear...as is...that bearing cap might bust before the bolts just from my visual thumb based estimating take as an engineer and knowing how stresses build in bending compared to tension.
I came in here to say this. I will add that some engines with 2 bolt mains will add a girdle to spread the force along all the caps. The OP may want to look into this option. Would have to be a one off from a machine shop with longer cap bolts but doable.
Yeah, again, that's probably true for stock or near stock power levels.
I'm talking about double or even tripling the hp/tq numbers and for those kinds of power levels, even at stock red line, two bolt mains just will not be adequate.
You know what never mind. You're right.
Smile and nod. You betcha buddy, two bolt mains, the way to go, yup.
:wink2:
At double or triple stock power levels your prolly better off building an engine anyway. Going that high one would likely want to make improvements to oiling and cooling passages. And if your building you can come up with any type of main cap improvements you want, redesign, new fab'd girdle, etc.
GM had the engine designed for the power they marketed for. If you were expecting them to over engineer this thing because three customers are going to want ridiculous numbers out of it, you need to let us know what you're on.
The engine is in a midsize, light duty pickup truck. You can't expect them to be engineered for ridiculous numbers and still stay at the price point they are at. Want a rock solid foundation to build more power on? Go with a fullsize duramax. But don't expect fantastic out of mundane.
I love high hp diesels but this wouldn't make sense. It would be easier to slip a lightly breathed 600 hp 5.9 in there.
I will do a nice tune from GDE. whatever they determine to be safe, will be what it's going to have. I learned a long time ago to take the low hanging mod fruit then stop. It starts off being cheap and reliable to get a little more power but it quickly deteriorates from there.
V motors have two rods between each cap. Inlines have one. The caps and bolts don't need to be as strong because there are more of them in relation to the number of cylinders.
When I built the 468 Big Block Chevy in my Chevelle 22 years ago, I used a 2 bolt main block. It makes just shy of 600 horsepower and I turn it 7000 rpm. I did replace the bolts with ARP main studs and had it line honed. On a BBC the edges of main caps are indexed into the block, from the photo it appears the baby Dmax's are the same. Typically the shifting of main caps due to extreme loading (detonation on a gasser) is what causes main bearing failures.
I'd venture to say that main bearing failures on the 2.8 would happen only at extreme power and RPM ranges.
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