Why does your motor blow thread, look inside.

[Lex]

Originally Posted by 06Speed6 John ran some simulations and it showed crankwalk, they are coming out with a 3/4" thick piece of billet that can be bolted to the girdle that will keep it from flexing.

I'm thinking it has less to do with flex and more to do with the amount of play that is usually taken care of by the thrust bearings. Seems on this car there is a lot of side to side movement of the crank after engine assembly.

[06Speed6]

Crankwalk is alot different than a thrust bearing failure. On my buddys v6 Mustang they have very weak main caps and in order to build that car you have to have the top of the mains machined flat and then bolt a fairly substantial girdle on top of them. As soon as I saw how weak our main girdle was I began wondering if our crank was moving around. I never really had any proof of anything because our engines just seem to grenade instead of trashing the bearings.

I did hear that the thrust bearings got an updated part number though. I would almost consider this to be a manditory swap if you go to a aftermarket clutch.

[ptperformance]

Originally Posted by Lex I have seen rods with quite a few wear marks on the side of the big end on the rods. This indicates to me the rods are touching the crank and this further indicates a lot of crank walk in this car. Do you have any comments on this?

Yes, we have seen oscillation in the crank during the simiulations. The rods have been hitting the crank on a few occations but I would have to say that this is from the weak griddle and crap rods. Its a combination of the two. I don't think that anyone has seen a billet rod failure as of yet, but I could be mistaken.

Originally Posted by 06Speed6 John ran some simulations and it showed crankwalk, they are coming out with a 3/4" thick piece of billet that can be bolted to the girdle that will keep it from flexing.

Its a little thicker then that but yes we are addressing the issue with the crank moving around, but the crank walk is something else that we are going to have to address, not sure whats going to happen when we start adding higher lb pressure plates to the mix. I can tell you that all our built motors are going to get tri-metal bearings and they will all be dry film coated, no questions about this.

[ptperformance]

Originally Posted by Lex I'm thinking it has less to do with flex and more to do with the amount of play that is usually taken care of by the thrust bearings. Seems on this car there is a lot of side to side movement of the crank after engine assembly.

There is but its more of a oscillation then a side to side movement. Once we have the billet strap kits installed this should keep the rotating assembly locked to the crank center line of the motor.

Originally Posted by 06Speed6 Crankwalk is alot different than a thrust bearing failure. On my buddys v6 Mustang they have very weak main caps and in order to build that car you have to have the top of the mains machined flat and then bolt a fairly substantial girdle on top of them. As soon as I saw how weak our main girdle was I began wondering if our crank was moving around. I never really had any proof of anything because our engines just seem to grenade instead of trashing the bearings. I did hear that the thrust bearings got an updated part number though. I would almost consider this to be a manditory swap if you go to a aftermarket clutch.

It will be, and we have to get a higher load pressure plate on the motor to do some testing. I can tell you that everyone of our motors will have tri-metal bearings and they will all be dry film coated from Calico... this will be a must with what we have seen with the crank movement.

[JimmyMac]

Originally Posted by ptperformance I don't think that anyone has seen a billet rod failure as of yet, but I could be mistaken.

Are you differentiating billet from forged? Because I remember you in the past talking about how you seem forged rods fail in this engine. And something about $7000 worth of blown motors. Just curious....

[ptperformance]

Originally Posted by JimmyMac Are you differentiating billet from forged? Because I remember you in the past talking about how you seem forged rods fail in this engine. And something about $7000 worth of blown motors. Just curious....

No, I am talking about billet rods. When I refferenced the forged rods I was talking about the stock rods which are forged, they are just cheap forgings (sp).

One stock block and one upgraded block, both set me back around $7000 total to find out what I should have been testing before I started building these motors.

[ztuner]

Originally Posted by ptperformance There is but its more of a oscillation then a side to side movement. Once we have the billet strap kits installed this should keep the rotating assembly locked to the crank center line of the motor. It will be, and we have to get a higher load pressure plate on the motor to do some testing. I can tell you that everyone of our motors will have tri-metal bearings and they will all be dry film coated from Calico... this will be a must with what we have seen with the crank movement.

How will trimetal bearings help with crank movement ? The only real reason to have trimetal bearings is because they are more forgiving in dirty conditions. Infact most tri metals are less resistant to pinging and higher cylinder pressures (read high boost). If your crank is moving around you need a girdle to improve rigidity. Bearings type will have no effect. Also higher end pressures from a heavier pressure plate can be negated by bypassing the clutch interupt switch. That is far more effective than bearing changes.

Harry

[ptperformance]

Originally Posted by ztuner How will trimetal bearings help with crank movement ? The only real reason to have trimetal bearings is because they are more forgiving in dirty conditions. Infact most tri metals are less resistant to pinging and higher cylinder pressures (read high boost). If your crank is moving around you need a girdle to improve rigidity. Bearings type will have no effect. Also higher end pressures from a heavier pressure plate can be negated by bypassing the clutch interupt switch. That is far more effective than bearing changes. Harry

The will not help with the thrust of the crank but they do have a thicker backing and allow for more surface impact than a non trimetal bearing. With the weak crank saddle that we have in the motor we are going to need every bit of help that we can get from the bearings.

I guess the trimetal bearings ran by Nasscar, NHRA top fuel, WRC rally cars, and on and on and on are just there because it sounds cool?

I am not saying swap your bearings out (where did I say that?) I am stating that if your going to build your motor you had better use trimetal bearings.