which built motor?

[mike the snake]

When you do these multiple assemblies and disassembles, are you torquing everything down each time, or just lightly torquing them to check tolerances?

I ask because I know that some rod bolts and engine studs are "stretch" bolts and studs, which stretch when torqued and are only supposed to be torqued that one time. This is with mainly stock bolts and studs in my experience. Bolts and studs from, say, ARP are generally able to be torqued multiple times.

Originally Posted by Dustin@Dynosty

We use new OEM bearings. The bearings are not the issue, the oil clearance is. We have sold tons of built motor parts (pistons, rods) to shops along with one set of bearings and they just assume because Toyota/Subaru stamps the bearing "std" that they can just trust the measurement and roll on. That is simply not the case. Not every failure makes it on the forums... We have sold parts only to several race teams and shops that have had multiple failures at building this motor, due to improper clearances.

When we assemble a motor we have tons of OEM bearing sizes to select from (not just one set), it takes multiple assemble and tear downs of the short block to get the specs exactly where they need to be. On the shop motor we are finishing up, took 3 sets of rod and main bearings before we were happy with the specs. Proper machining also is key, if your engine builder did not use a torque plate when machining... good luck is all I have to say.

Micro polish crank is where the crank journals are polished to a fine finish. This aids in bearing life.

We have several fully built motors that are in their final stages that we will show off the results in the upcoming months when the rest of the car is done.

[mrk1]

Originally Posted by mike the snake

When you do these multiple assemblies and disassembles, are you torquing everything down each time, or just lightly torquing them to check tolerances?

I ask because I know that some rod bolts and engine studs are "stretch" bolts and studs, which stretch when torqued and are only supposed to be torqued that one time. This is with mainly stock bolts and studs in my experience. Bolts and studs from, say, ARP are generally able to be torqued multiple times.

Im not expert but I would think it varies by what hardware is being used. If it was me the price of sacrificing a few bolts would be worth it to make sure I had the correct tolerances.

That being said the last engines I built where just standard rebuilds of Rover V8's and those we just verified that what was printed on the box matched the part and then bolted it all together. Thats an entire different realm of engine building though.

[Fabron757]

Originally Posted by FullBlown

There are too many variable to what could cause bearing failure. Here are some..

-improper bearing clearance
-wrong weight oil for bearing clearances
-thermal breakdown of the oil
-unbalance rotating assembly
-motor not up to temp before heavy load
-detonation

Im sure there are more issues that could cause bearing failure. A properly tuned/built motor, should not have bearing to crank contact. A crank should glide between the clearance of the oil pressure, and never ride the bearing.

You can take any high end bearing in the world and pound them out with detonation. If you ignite the fuel and maximum cylinder pressure happens at or near TDC. It will force the rod down, and squish the oil out and wear/flatten the bearing.

A higher grade bearing will withstand that abuse longer but, its only a bandaid for the disaster that is coming if you do not address the actual problem.

Keep in mind, Oem bearings are alot better than they were years ago. We have ran oem bearings in many different platforms. I'm not saying that they are identical in quality to other makes but I wouldn't be quick to blame the OEM bearings.

ACL will eventually make a drop in bearing and we will more than likely use them but until then... We just don't feel the need to experiment with other bearings that weren't made for this motor.

Do you guys use a torque plate when machining?

[mike the snake]

It's just that sacrificing a few bolts can be a lot more expensive than you think.

Rod bolts and engine studs from aftermarket companies can run 2-3-$400 a set, but those are usually not "stretch" type. OEM bolts and studs aren't cheap either though.

I'd gather that when building and checking tolerances that the parts can be partially torqued so as to not fully stretch the bolts but still allow proper measurement.

Originally Posted by mrk1

Im not expert but I would think it varies by what hardware is being used. If it was me the price of sacrificing a few bolts would be worth it to make sure I had the correct tolerances.

That being said the last engines I built where just standard rebuilds of Rover V8's and those we just verified that what was printed on the box matched the part and then bolted it all together. Thats an entire different realm of engine building though.

[DAMotorsports]

@mike the snake to set bearing you have to torqued everything down like you would when you finish the motor. This step make or brakes many motors. you can have all the right parts but miss something like a clearance and your motor is junk. setting clearances is one of the most time consuming parts of the build and every builder has their on formula as to how they set the clearance.

[King Tut]

Originally Posted by mike the snake

It's just that sacrificing a few bolts can be a lot more expensive than you think.

Rod bolts and engine studs from aftermarket companies can run 2-3-$400 a set, but those are usually not "stretch" type. OEM bolts and studs aren't cheap either though.

I'd gather that when building and checking tolerances that the parts can be partially torqued so as to not fully stretch the bolts but still allow proper measurement.

That is why most companies don't go back with OEM bolts and they instead upgrade to ARP and why most rods come with ARP studs and nuts which can be torqued multiple times.

[mike the snake]

Thanks for clarifying. That's what I figured.

Rod bolts were the main cause of failure on the old Porsche engines I used to race, upgrading to ARP was standard procedure.

[Dustin@Dynosty]

Originally Posted by mike the snake

When you do these multiple assemblies and disassembles, are you torquing everything down each time, or just lightly torquing them to check tolerances?

I ask because I know that some rod bolts and engine studs are "stretch" bolts and studs, which stretch when torqued and are only supposed to be torqued that one time. This is with mainly stock bolts and studs in my experience. Bolts and studs from, say, ARP are generally able to be torqued multiple times.

http://www.frsmod.com/products/dynos...r-s-subaru-brz

We have had case studs and head studs available for close to a year now and we use them in all of our builds. But to also answer the question, they need to be torqued to the exact steps as factory and to the required torque specs in order to properly seat the case halves.

[Fabron757]

Well mind is made up going with full blown. Sending whole motor to them getting heads done also with ferrea valves and springs, ported with a cam. So i can get that nice 9k rev going with boost turned up to 30-35psi. My car should be a beast. New cams should be out by spring.

[Fabron757]

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These should solve my traction issue

[Ross]

They do hook pretty good

[SmsAlSuwaidi]

@Fabron757 running adapters or are they 5x100 ?


Sent from my IBrick

[Ross]

They are hub eccentric adapters till we can find wheels in 5 x 100 that are offset correctly.

[Dipstik-sportech]

Holy crap we're twins in the rim and tire department!!!! Mine are 16" though and I'm running adapters. What size tires are they?