Spring psi question?
Thread Starter
Joined: Nov 2001
Posts: 7,303
Likes: 4
From: Delray Beach, Fl.
Spring psi question? We have a 236-242 617-613 112+2 sitting here waiting to go into a 402
The springs we are using are PSI 1511-ML's rated to .625
Now they rate the spring at a install height
1.800@120PSI for .625 lift
The lobes on this cam are XFI which I was told were alittle easier on the VT than the XER's so I figure the 1.800@120 is fine but would u shim this spring .010/.020 to bump the spring psi up to say 140 with this lobe?
PSI told me 1.800@120 would be fine with this cam and this is the manufatures recomendation but I just would like to be sure so thats why I'm asking for some info.
Persay some engine builders or from head builders on here or just one of u big brains etc...
The springs we are using are PSI 1511-ML's rated to .625
Now they rate the spring at a install height
1.800@120PSI for .625 lift
The lobes on this cam are XFI which I was told were alittle easier on the VT than the XER's so I figure the 1.800@120 is fine but would u shim this spring .010/.020 to bump the spring psi up to say 140 with this lobe?
PSI told me 1.800@120 would be fine with this cam and this is the manufatures recomendation but I just would like to be sure so thats why I'm asking for some info.
Persay some engine builders or from head builders on here or just one of u big brains etc...
The published coil bind spec is 1.100" and the published specifications for seat pressure is 130 lbs. @ 1.800". Shimming these to a 1.780" installed height would put you right at the minimum safe coil clearance and give you the following:
With the additional valve train weight, it's not a bad idea to install these at 1.780".
With the additional valve train weight, it's not a bad idea to install these at 1.780".
Last edited by 405HP_Z06; Apr 26, 2008 at 10:14 PM.
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First off, I would measure and check the installed height of every spring pocket. Sometimes you will find a pocket that varies from the rest which could cause an issue. It is also hard to find .010 shims, the industry standards are .015, .030, .060. Just be careful running the springs at minimum clearance (.060) from coil bind.
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Verdad Gallardo First off, I would measure and check the installed height of every spring pocket. Sometimes you will find a pocket that varies from the rest which could cause an issue. It is also hard to find .010 shims, the industry standards are .015, .030, .060. Just be careful running the springs at minimum clearance (.060) from coil bind.
Thread Starter
Joined: Nov 2001
Posts: 7,303
Likes: 4
From: Delray Beach, Fl.
I've seen that Isky kit before too 
TalonWS6 is checking every pocket
We're setting them up at 1.79@130ish.
This will give me plenty of coil bind.
Thanks for the help guys...
TalonWS6 is checking every pocket
We're setting them up at 1.79@130ish.
This will give me plenty of coil bind.
Thanks for the help guys...
Last edited by JS; May 3, 2008 at 12:09 PM.
Thread Starter
Joined: Nov 2001
Posts: 7,303
Likes: 4
From: Delray Beach, Fl.
Well I checked all the pressures..
They were ALL off so if u guys buy these heads I would check them.
They had 2 shims under each spring which made them all 1.76@155+ and this could cause coil bind on my 615 lift setup..
TalonWS6 played around with the shims and found 1.80@145 to be perfect.
We expect to lose 10lbs after a few heat cycles and dyno runs.
We feel this to be the best setup for our cam specs.
U might find u need more or less but be careful with coil bind..I believe 1.80@135 will be the final results after breakin and than supports .625 lift with plenty of could bind to spare.
If u are getting these heads again just make sure u CHECK THEM
The valvejob and bowl porting looked excellent from Dart.
This is one killer out of the box head for under $1600.
They were ALL off so if u guys buy these heads I would check them.
They had 2 shims under each spring which made them all 1.76@155+ and this could cause coil bind on my 615 lift setup..
TalonWS6 played around with the shims and found 1.80@145 to be perfect.
We expect to lose 10lbs after a few heat cycles and dyno runs.
We feel this to be the best setup for our cam specs.
U might find u need more or less but be careful with coil bind..I believe 1.80@135 will be the final results after breakin and than supports .625 lift with plenty of could bind to spare.
If u are getting these heads again just make sure u CHECK THEM
The valvejob and bowl porting looked excellent from Dart.
This is one killer out of the box head for under $1600.
Last edited by JS; May 6, 2008 at 10:39 AM.
Well I checked all the pressures..They were ALL off so if u guys buy these heads I would check them.
They had 2 shims under each spring which made them all 1.76@155+ and this could cause coil bind on my 615 lift setup..
TalonWS6 played around with the shims and found 1.80@145 to be perfect.
We expect to lose 10lbs after a few heat cycles and dyno runs.
We feel this to be the best setup for our cam specs.
U might find u need more or less but be careful with coil bind..I believe 1.80@135 will be the final results after breakin and than supports .625 lift with plenty of could bind to spare.
If u are getting these heads again just make sure u CHECK THEM
The valvejob and bowl porting looked excellent from Dart.
This is one killer out of the box head for under $1600.
They had 2 shims under each spring which made them all 1.76@155+ and this could cause coil bind on my 615 lift setup..
TalonWS6 played around with the shims and found 1.80@145 to be perfect.
We expect to lose 10lbs after a few heat cycles and dyno runs.
We feel this to be the best setup for our cam specs.
U might find u need more or less but be careful with coil bind..I believe 1.80@135 will be the final results after breakin and than supports .625 lift with plenty of could bind to spare.
If u are getting these heads again just make sure u CHECK THEM
The valvejob and bowl porting looked excellent from Dart.
This is one killer out of the box head for under $1600.
I agree, the Darts are a very nice head.
