matt030305
Well-Known Member
Hey FABO techs, this is my first time rebuilding a complete top end of an engine and I had a couple of questions on the lifter tolerance I plan on running.
1972 340 block that is being converted to hydraulic roller cam and getting trickflow 190cc heads (TFS-16094-16)
Here are the relevant specs:
They are Morel Hydraulic Roller Lifters
Suggested max spring pressure: 100-180lb seat pressure and 280-380lb open pressure
The preassembled heads I got from trick flow have 1.550” dual springs
138lbs @ 1.950” installed height
430lbs @ 1.250” open
420lb/in rate
.680 max lift
The Cam I purchased has valve spring requirements with my 1.6 ratio Harland sharp rockers of:
145lb @1.800” closed pressure (installed height)
345lb @1.250” open pressure
My questions are:
1. Will my lifters fail due to the specs of my springs and cam? For the lifters, is the max spring pressure based off of the cam specs or the actual valve spring specs?
(I.e. max spring pressure for lifters when valve is open is max 380lbs whereas the valve spring is rated for 430lbs. Cam is rated at 345lbs)
I just don’t want to damage the lifters as that will be an expensive mistake.
2. Will my springs be able to support the camshaft spring pressure?
Can’t thank FABO members enough for the knowledge that you guys have on here.
1972 340 block that is being converted to hydraulic roller cam and getting trickflow 190cc heads (TFS-16094-16)
Here are the relevant specs:
They are Morel Hydraulic Roller Lifters
Suggested max spring pressure: 100-180lb seat pressure and 280-380lb open pressure
The preassembled heads I got from trick flow have 1.550” dual springs
138lbs @ 1.950” installed height
430lbs @ 1.250” open
420lb/in rate
.680 max lift
The Cam I purchased has valve spring requirements with my 1.6 ratio Harland sharp rockers of:
145lb @1.800” closed pressure (installed height)
345lb @1.250” open pressure
My questions are:
1. Will my lifters fail due to the specs of my springs and cam? For the lifters, is the max spring pressure based off of the cam specs or the actual valve spring specs?
(I.e. max spring pressure for lifters when valve is open is max 380lbs whereas the valve spring is rated for 430lbs. Cam is rated at 345lbs)
I just don’t want to damage the lifters as that will be an expensive mistake.
2. Will my springs be able to support the camshaft spring pressure?
Can’t thank FABO members enough for the knowledge that you guys have on here.
