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- Hemi Ram, 71 Plymth Scamp, 71 Plymth Duster 340, 69 Dart 340/4sp
Could this not be caused by improper balance or just plain fatigue? One motor proves nothing to me.
Wanted: Built shortblock opinions?
- Thread starter edaddeemsp
- Start date
Beau hasn't shot for the 400hp motor yet because he wants to build everything up. Actually, he's going for a lot more than that...he will probably find out how much these bottem ends can hold; he's getting a special turbo built for his app and I won't disclose more than that. The crankwalk problem can be seen in real life as well as in the design of our motor. There is nothing that prevents the crank from walking except half a thrust bearing!! That's it, nada, zilch, cero. You can't design anything less without the crank sliding through your block(remember, lowest bidder wins contract). Now, imagine every time you step on your clutch. All the force used in releasing the pressure plate is a lateral force that goes down the line of the crank. Conservation dictates that there has to be an equal and opposite force pushing back. Guess where all that comes from...the half thrust bearing. Now, this might be fine for a featherweight pressure plate on a 100hp motor, but when you upgrade your pressure plate you have a lot more lateral force pushing on that single thrust bearing. This does not bode well when you shoot for more power (Beau was close to 275hp on a non built up motor). I wouldn't be surprised if some of the spun bearing/thrown rod stories were helped along by this phenomenom (remember, most things are a culmination of little things).
On a side note, our engine is not perfectly straight and balanced like we would like. Why do you think you paid so little for the car in the first place? When I took my crank in to check the balance, it was not as nice as I had hoped...All that is taken care of now! Boy will I feel sheepish if I go and blow my motor now after I have talked it up so much....(confused)
On a side note, our engine is not perfectly straight and balanced like we would like. Why do you think you paid so little for the car in the first place? When I took my crank in to check the balance, it was not as nice as I had hoped...All that is taken care of now! Boy will I feel sheepish if I go and blow my motor now after I have talked it up so much....(confused)
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Yes it could, but fatigue can be caused by the lateral forces placed on the crank...BlkZoomZoom said:
Crank walk is just a term describing how much the crank moves because of the force. Look at some other 4-bangers (there were two Toyota 1.8s at the shop) and you might find the nicer ones have full thrust bearings to hold the crank in position.Also, the main that showed the fatigue happened to be the thrust main...
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I might add that having a full face thrust bearing will not help with the fatigue on the main, it will keep the crank sitting still though. Beau is actually planning on reinforcing the cast "webbing" of the thrust main so that it will support these increased longitudinal and transverse forces. A little professional welding and heat treating ought to do the trick...
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- Hemi Ram, 71 Plymth Scamp, 71 Plymth Duster 340, 69 Dart 340/4sp
One motor doesn't convince me. I've seen brand new heads and cranks that have shown cracks when magnafluxed. I've also seen some of these parts been used in motors that are still running strong. I just find it wild that one guy said 2.0's have crankwalk problems, apparently showing one cracked main. Then everybody is worried about it and ready to spend 400$ to correct a problem no one has actually blown a motor up from. I can understand if someone is going to build a 30k race motor to make every trick possible. Half the people that are planning to "build" these motors won't even come close to using them to there potential. I don't get it.
It's the same idea as the head gaskets, I have never seen a headgasket fail when used with the correct hardware and techniques. But one person said something and now everybody has to have an upgraded one.
But remember I'm stubborn and insanely cheap.
It's the same idea as the head gaskets, I have never seen a headgasket fail when used with the correct hardware and techniques. But one person said something and now everybody has to have an upgraded one.
But remember I'm stubborn and insanely cheap.
You are exactly right, it isn't necessary to build up your motor if your planning on staying below ~200hp. Beau is building the blocks to see major time and punishment. But since this is the FI forum I am assuming everyone is looking for the baddest stuff available. I am insanely cheap but not so stubborn. I am trying some things that Beau doesn't have an opinion on (like coating my piston domes).
edaddeemsp
Member
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- 2003.5 mazdaspeed
blkzoomzoom, I totally agree with what your saying, only cause i'm kinda cheap myself. Thats why I just want to pay for a properly built motor once, never hit the full potential of what I just paid $3000+ for, and hope that maybe since I'm only using the block for half the potential power, that it will last twice as long.
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- Hemi Ram, 71 Plymth Scamp, 71 Plymth Duster 340, 69 Dart 340/4sp
I do like the coating idea.... i wonder if it can be done without special tools?
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- Hemi Ram, 71 Plymth Scamp, 71 Plymth Duster 340, 69 Dart 340/4sp
I told you. lol We'll get your house into a performance shop one way or the other.
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- 2001 Mazda MP3
lol, save the convo for pms
Our short blocks are fully machined and deburred.
When we build our motors we do the whole nine yards.
Our short blocks come with:
CP Pistons
CP Gold ring package
Oliver billet rods
Toga bearings
ARP Main studs
ARP head studs
We address the crank walk issuse by having a second thrust bearing machined and installed($400), crank nitrated a second time($100) and then micro polished,line hone, square deck, bored, honed, plateau,all oil gallay's chaffered,full block debur,etc.
We do not bore & hone and put new rods in pistons in.Everything is done to spec and a full build sheet comes with our motors.The customer will know all tolerances and specs.
Our motors are $2995, plus core and shipping.
When we build our motors we do the whole nine yards.
Our short blocks come with:
CP Pistons
CP Gold ring package
Oliver billet rods
Toga bearings
ARP Main studs
ARP head studs
We address the crank walk issuse by having a second thrust bearing machined and installed($400), crank nitrated a second time($100) and then micro polished,line hone, square deck, bored, honed, plateau,all oil gallay's chaffered,full block debur,etc.
We do not bore & hone and put new rods in pistons in.Everything is done to spec and a full build sheet comes with our motors.The customer will know all tolerances and specs.
Our motors are $2995, plus core and shipping.
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- 2001 Mazda MP3
search button?
You know what, I have pictures of the block and the machine work but they are stuck on my brother's digicam, he can't find the usb cable! Anyways, at the shop there was a Toyota 1.8L block that the machinist modeled the top thrust tang with and I did some comparing between the two blocks...the Toyota has a much stronger main bearing casting. Ours only has a webbing whereas the Toyota is almost a solid piece. I believe this is why Beau wants to weld in another support to add some more strength.
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Aside from the obvious incresed tolerances the engine will be able to handle what other benefits would someone get from a built shortblockdaedalus said:
