Hi I am rebuilding my engine for 300-400whp. I have read a lot of building threads but never seen anyone replace the main bearings bolts, I have torqued them about 4 times because checking the clearance to 52 Nm. The Honda workshop manual does not say that you need replace them.
If i should replace them go with oem or after markets?
Well, assuming this is a D16, ARP doesn't make main bolts. You will have to get OEM, which are 86$ for all ten with my Honda Employee discount. I bought them for extra insurance because the block I had was pretty tired.
I've never heard of them giving out, but given your power goals, I'd recommend replacing them with OEM bolts for insurance...wouldn't want to tear up a crank (or worse). They've got to stretch and fatigue like every other bolt, right? Feel free to set me straight if you know different. IMHO, FWIW...
yes you can use a set of bseries arp's. you will have to cut 3 of them for clearance issues.
i just for a block that has them. i do not know what be series ones they are tho. if you have to cut them i dont think it matters.
but if you get arp's you will have to line bore the block.
I would run them unless I had reason to believe they had been over tightened or tightened down on an uneven surface or been in an engine where a cap let go.
Remember Ds have a girdle that helps spread the load on the bolts a bit.
If you do, prepare to have sticker shock when you take the block in to get line-bored (which you MUST DO if you use studs for greater clamping forces).
If you dont measure them before you install them, and measure them every time you torque them, then you are just playing russian routlette.
ive had and seen ARP head studs pull apart on a regular basis, with the ARP recommended tq spec.
Fasteners fail. Its a fact. They will NOT last for ever and just because someone gets away with something thats not correct doesnt mean its a good way to do things.
Buying new bolts for extra insurance isn't a bad idea. They hold a rotating piece, not a piece that is having more force applied under it like head studs do. Yes I understand it too receives more force on the swing, but its force changes direction and if balanced is countered by the opposing swing of another piston and rod. You always have two up and two down, so you have countering weight on your side. The head on the other hand only has force trying to push it through your hood.
On the power stroke the rods push down on the crank. on the compression stroke the rods push down. At around BDC the rods are pushing down from inertia and at around TDC the rods are pushing up from inertia.
The inertia forces only have some tendency to offset each other, but the offset occurs further along the crank which sets up end to end rocking motions which is the main reason 4 cylinder engines in particular are prone to vibrations. These vibrations also hammer bearings and caps.
If you ever saw an engine fail by tearing a main bearing web out of a block you would realise just how much force the mains restrain.
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