anyone figured out exactly why the rear irons crack?
'Tuna'
Joined: Feb 2001
Posts: 4,637
Likes: 3
From: Miami,Fl,USA
Originally Posted by DelSlow
Wouldn't it be possible to use external block reinforcement? I've been thinking about making a block girdle that would use a turnbuckle to pretension rods connecting the rear iron to the brace, distributing the force to other points on the motor, such as the motor mount studs. Has anyone tried anything like this before?
Because the rotor housings are basically a two peice design. I've seen the inner sleeve of the rotor housings the steel section completly out of shape from high horsepower applications where the outside was still at factory spec.
The rotor housings are trying to push outward on the sparkplug side and therefore result in the inside of the housing changing shape. Normally the top and bottom will come in a little and the sides goes out a little. It's so obvious that you don't actually have to measure it too see it. Some people also have problems with high boost/power applictions where the tips of the rotor contact the housing resulting in a stuck apex seal. Some say that's the result of E-shaft flex while others say it's housing deflection. I'll tell you back in the early learning days when that was occuring additional dowels solved that problem for me and a lot of other people that I knew. My veiw was that E-Shaft flex would cause other problems mainly associated with the side of the rotors contacting the side housings but that's another matter all together.
The way I see it additional dowels when done properly is mainly a reliabilty and safety mod. Also no additional dowels, larger studs etc. are going replace proper tuning. They just raise the level before something else breaks.
BDC Motorsports
Joined: Jun 2002
Posts: 3,667
Likes: 6
From: Grand Prairie, TX
Originally Posted by crispeed
Not really.
Because the rotor housings are basically a two peice design. I've seen the inner sleeve of the rotor housings the steel section completly out of shape from high horsepower applications where the outside was still at factory spec.
The rotor housings are trying to push outward on the sparkplug side and therefore result in the inside of the housing changing shape. Normally the top and bottom will come in a little and the sides goes out a little. It's so obvious that you don't actually have to measure it too see it. Some people also have problems with high boost/power applictions where the tips of the rotor contact the housing resulting in a stuck apex seal. Some say that's the result of E-shaft flex while others say it's housing deflection. I'll tell you back in the early learning days when that was occuring additional dowels solved that problem for me and a lot of other people that I knew. My veiw was that E-Shaft flex would cause other problems mainly associated with the side of the rotors contacting the side housings but that's another matter all together.
The way I see it additional dowels when done properly is mainly a reliabilty and safety mod. Also no additional dowels, larger studs etc. are going replace proper tuning. They just raise the level before something else breaks.
Because the rotor housings are basically a two peice design. I've seen the inner sleeve of the rotor housings the steel section completly out of shape from high horsepower applications where the outside was still at factory spec.
The rotor housings are trying to push outward on the sparkplug side and therefore result in the inside of the housing changing shape. Normally the top and bottom will come in a little and the sides goes out a little. It's so obvious that you don't actually have to measure it too see it. Some people also have problems with high boost/power applictions where the tips of the rotor contact the housing resulting in a stuck apex seal. Some say that's the result of E-shaft flex while others say it's housing deflection. I'll tell you back in the early learning days when that was occuring additional dowels solved that problem for me and a lot of other people that I knew. My veiw was that E-Shaft flex would cause other problems mainly associated with the side of the rotors contacting the side housings but that's another matter all together.
The way I see it additional dowels when done properly is mainly a reliabilty and safety mod. Also no additional dowels, larger studs etc. are going replace proper tuning. They just raise the level before something else breaks.
B
Senior Member
Joined: Oct 2002
Posts: 644
Likes: 1
From: scranton nd
I have a question.
It makes sense to me that because the fc engine mounts are on the intermediate plate vs the rear plate that it would add to the forces on the rear dowel pin....
Is there any truth to this? it was stated previously to look as the trany trying to turn one way and the engine the other..... and thinking like that, with the mount on the rear the twisting load of the transmission is held by the dowels of the bell housing and rear plate and the actual engine dowel pins just hold the engine's opposite force......
whereas with an intermediate mount, the opposing force of the tranny and part of the engine is transfered through the rear dowel pins till it reaches the intermediate plate......
I really can't convey what i am thinking as clearly as some of you guys
but maybe that is part of the reason the fd mounts are on the rear plate,
is there any truth to this, maybe someone mentioned this but i neglected to see it... thanks
I read this damn post the other day and so i looked at my rear iron ready for a build.... and sure enough it was fing cracked...S5
It makes sense to me that because the fc engine mounts are on the intermediate plate vs the rear plate that it would add to the forces on the rear dowel pin....
Is there any truth to this? it was stated previously to look as the trany trying to turn one way and the engine the other..... and thinking like that, with the mount on the rear the twisting load of the transmission is held by the dowels of the bell housing and rear plate and the actual engine dowel pins just hold the engine's opposite force......
whereas with an intermediate mount, the opposing force of the tranny and part of the engine is transfered through the rear dowel pins till it reaches the intermediate plate......
I really can't convey what i am thinking as clearly as some of you guys
but maybe that is part of the reason the fd mounts are on the rear plate,
is there any truth to this, maybe someone mentioned this but i neglected to see it... thanks
I read this damn post the other day and so i looked at my rear iron ready for a build.... and sure enough it was fing cracked...S5
