randy carlson

Does any one know the cam specs for the gen4 465hp 502, flat tappet cam thanks

Griff

I don't know the adv durations or lob sep. Flat tappet cam and lift is .560/.571. I used to have merc hp book when I looked that up.

http://www.offshoreonly.com/forums/s...ight=hp465+cam

rmbuilder

Randy,

The 465 HP 502 engine runs a Crane cam:

Dur @ .0042---- 300º/310º
Dur @ .050----- 240º/250º
Lift lobe .329"/.340"
Lift valve .559"/.578"
LSA 110º + 5º

The cam is still available through an updated part number.

Bob

randy carlson

thanks guys, RM what does 110 + 5 equate to in LSA my uneducated but reading tells me I want approx 112-114 LSA to prevent reversion is this cam going to be ragged edge of reversion, Is this too much cam flat tappet to expect longevity? thanks Randy

rmbuilder

Randy,

The 110º +5º is a 110º LSA ground with a 105º ICL/115º ECL, or 5º advanced. That is as the cam that was delivered to Merc.

If you were to spread the centers to 112º, keeping the +5º, your ICL would be 107º, ECL 117º.

There are multiple factors (both cam profile and non-cam) that influence reversion. I would not expect reversion to be a concern if the factory parameters are retained.

Regarding durability, core and lifter quality are the single most important considerations bar none. I would use only a Proferal/P-55 core in a flat tappet application with a high quality lifter. I would also verify crown and taper. I have yet to have one fail with these precautions and a proper break in procedure. Much of the emphasis on flat tappet durability is placed on the additive package of the oil used. This can easily be compensated for using the proper oil/additive. I can tell you that more flat tappet camshafts fail due to poor core/lifter quality than from lubricant related issues.

Bob

Griff

I know rm is is right. He is the cam man and is always right. Imagine my surprise to find out there was inaccurate info in merc manual

randy carlson

thanks again, the number I come up with from crane is 134551 236/246 .553/.571 lsa 110 grind h-236/325-2-10, is this the same cam? numbers very close, the core material you mention- does crane use this? or who does and what lifters would you reccomend, appreciate the help Randy

Griff

I would switch to a roller cam. It will perform better on all levels. rmb can tell you what you need. He is the cam guru.

US1 Fountain

My HP465 running straight Gil exhaust showed signs of reversion. I rebuilt that motor and went to a retro roller Crane cam xxxx741 and even added silent choice. Never had any reversion signs after the rebuild.
Have heard several say they had reversion with the HP465 cam.