Engine head question
#1
Engine head question
Hey Guys,
I recently picked up a lunati cam as one of a couple things going on this winter.
It is a Bracket Master 2, here are the specs..
Advertised Duration (Int/Exh): 292/292
Duration @ .050 (Int/Exh): 230/230
Gross Valve Lift (Int/Exh): .554/.554
LSA/ICL: 109/105
Valve Lash (Int/Exh): Hyd/Hyd
RPM Range: 1500-5500..
What I didn't think of was if the stock valve train can take the lift this cam advertises. What else do I need to get for the valve train to safely run this cam? (springs/lifters?)
Any thoughts are appreciated.
I recently picked up a lunati cam as one of a couple things going on this winter.
It is a Bracket Master 2, here are the specs..
Advertised Duration (Int/Exh): 292/292
Duration @ .050 (Int/Exh): 230/230
Gross Valve Lift (Int/Exh): .554/.554
LSA/ICL: 109/105
Valve Lash (Int/Exh): Hyd/Hyd
RPM Range: 1500-5500..
What I didn't think of was if the stock valve train can take the lift this cam advertises. What else do I need to get for the valve train to safely run this cam? (springs/lifters?)
Any thoughts are appreciated.
#4
Wow I can't believe I forgot too include that.. thanks for the catch!
It's a 352FE, Holley 4b, Performer Intake, Headers..and now the above cam.
Your completely right, being a flat tappet hyd. cam, new lifters are required, and were bought with the cam. Whats tripping me up is whether I need heftier springs/ springs, or possibly different rockers.
I never thought of it before getting the cam, but I'd really like too get it right the first time and not need to tear it back apart because something I did got fubar'd
It's a 352FE, Holley 4b, Performer Intake, Headers..and now the above cam.
Your completely right, being a flat tappet hyd. cam, new lifters are required, and were bought with the cam. Whats tripping me up is whether I need heftier springs/ springs, or possibly different rockers.
I never thought of it before getting the cam, but I'd really like too get it right the first time and not need to tear it back apart because something I did got fubar'd
#5
Springs for sure, maybe push rods due to different geometry, travel, etc.
Make sure your rockers are in good condition.
Stock in good condition, they should live ok under 5500.
The spring change is due to the probability of coil bind with the higher lift, and because your springs are old and tired and don't want to react faster than they have all these years.....
Make sure your rockers are in good condition.
Stock in good condition, they should live ok under 5500.
The spring change is due to the probability of coil bind with the higher lift, and because your springs are old and tired and don't want to react faster than they have all these years.....
#7
I'm doing some reading on valve springs trying to learn about what I need to replace them.
I've read the stock rocker reatio is 1.73, can anyone verify this?
It confuses me when valve springs are advertised to a max lift, for example, I found springs to handle a .590 lift, or .640 lift. Is that after the rocker ratio is factored in?
Reason I ask is a .554 lift times a 1.73 rocker ratio is .95842.
Maybe its just late and Im having a hard time digesting the info on a new subject, but what springs do I need to avoid coil bind for a .554 lift cam with stock rockers?
yikes..bed time for me
I've read the stock rocker reatio is 1.73, can anyone verify this?
It confuses me when valve springs are advertised to a max lift, for example, I found springs to handle a .590 lift, or .640 lift. Is that after the rocker ratio is factored in?
Reason I ask is a .554 lift times a 1.73 rocker ratio is .95842.
Maybe its just late and Im having a hard time digesting the info on a new subject, but what springs do I need to avoid coil bind for a .554 lift cam with stock rockers?
yikes..bed time for me
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#8
Lunati should be able to tell you exactly what you need.
Here, I called them for you and they printed this up and posted it ():
Bracket Master II Cam - Ford 352-428FE 300/300 - Lunati Power
Here, I called them for you and they printed this up and posted it ():
Bracket Master II Cam - Ford 352-428FE 300/300 - Lunati Power
#9
With the small port size of the performer intake and stock heads, I do not imagine you will realize the full potential of the cam you have chosen. You may want to compare the spring pressure of the Lunati product to the stock spec; if the pressure is much greater I would suggest using aftermarket rocker stands as the outer rockers are unsupported with stock stands. I have read recommendations suggesting the stock non-adjustable rocker set up should not be used with cams having greater than 0.500" lift. Good Luck.
#10
Hey Guys,
I recently picked up a lunati cam as one of a couple things going on this winter.
It is a Bracket Master 2, here are the specs..
Advertised Duration (Int/Exh): 292/292
Duration @ .050 (Int/Exh): 230/230
Gross Valve Lift (Int/Exh): .554/.554
LSA/ICL: 109/105
Valve Lash (Int/Exh): Hyd/Hyd
RPM Range: 1500-5500..
What I didn't think of was if the stock valve train can take the lift this cam advertises. What else do I need to get for the valve train to safely run this cam? (springs/lifters?)
Any thoughts are appreciated.
I recently picked up a lunati cam as one of a couple things going on this winter.
It is a Bracket Master 2, here are the specs..
Advertised Duration (Int/Exh): 292/292
Duration @ .050 (Int/Exh): 230/230
Gross Valve Lift (Int/Exh): .554/.554
LSA/ICL: 109/105
Valve Lash (Int/Exh): Hyd/Hyd
RPM Range: 1500-5500..
What I didn't think of was if the stock valve train can take the lift this cam advertises. What else do I need to get for the valve train to safely run this cam? (springs/lifters?)
Any thoughts are appreciated.
The "gross valve lift" is just that, the gross, or total, amount the valve lifts off the seat. This number takes into account the rocker ratio.
The 1.73:1 ratio is correct for non adjustable FE rockers. Adjustable FE rockers had a 1.76:1 ratio.
As for springs. Use the springs recommended by the cam manufacture for the cam you choose.
Roger Carter
#11
With that much lift; you will need the factory style adjustable rockers. They will allow you to set valvetrain geometry much easier. The Performer intake won't do that cam justice as mentioned above. There are some good intakes out there that are much better. The Edelbrock Performer RPM is a great choice. Keep in mind that you want to match the compression ratio to cam. Lunati should list an ideal CR range. Auto or manual tranny? You most likely won't have enough manifold vacuum for power brakes but I run manual disc/drum and they work excellent.
Rear gear ratio? Tire size?
Rear gear ratio? Tire size?
#12
As a novice, fortunately have not had to deal with replacing cam on the flat tappet 390, but have on flat tappet 302, non adjustable type; recall there was no adjustment required on the 302 other than rotating engine to required degree's then tightening rods to zero lash??? Been awhile, recall it depended on the type of stud and how the rocker arm studs are mounted in the head? Hopefully a more knowledgeable member can enlighten?
#14
FE's have shaft mounted rocker arms, not stud mounted. The shafts are mounted in pedestals which bolt to the heads.
There is one "special" pedestal bolt on each side that needs to be in it's proper location for top end oiling. This bolt has a necked down shank where the others are full diameter shanks. Pay attention when removing the bolts.
A great book that addresses all the particulars of the FE engine is "How to Rebuild Your Big Block Ford" by Steve Christ and published by HP Books.
Lots of pictures and detailed explanations. I would strongly recommend getting a copy before you tear into your rig.
RC
There is one "special" pedestal bolt on each side that needs to be in it's proper location for top end oiling. This bolt has a necked down shank where the others are full diameter shanks. Pay attention when removing the bolts.
A great book that addresses all the particulars of the FE engine is "How to Rebuild Your Big Block Ford" by Steve Christ and published by HP Books.
Lots of pictures and detailed explanations. I would strongly recommend getting a copy before you tear into your rig.
RC
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