[holorinhal]

Would it be safe to install new hydraulic flat tappet lifters on an existing cam, or a bad idea? If so would you have to go thru the same break in proceedure as a new cam/lifter install?
This is on the bone stock Gen 5 Junkyard dawg.

After having to pull the heads, the inside of the lifter valley was pretty nasty. The lifters still moved in the bores but were prety stiff from sitting for a long time.
I have got things cleaned up, and the lifters oiled and moving freely in the bores, but from cleaning, i noticed that a couple of the retainer wires that hold the the plungers in, had come out and now I am unsure about the integity of the lifters.

 

[carreradude]

If it was a roller, I would say yes. Flat tappet will most likely result in an early death of that bump stick!! I know some guys will say they did it and worked. They got lucky! Most don't don't. Are you willing to risk sending metal thru your motor over a camshaft that only cost a couple hundy or so??

 

[Moneypit]

Wedding bells.....

Hal, the easiest way to figure this is the cam lobes and the lifters were married the day it first ran. Using an old cam and the same old lifters CAN create a failure if the lifters are mixed up during re assembly. That is why they should be kept in order, using one of those cool little divided boxes the lifters come in. (mark front on the box).... So now you want to use an old cam, and new lifters... The cam may, or may not, accept the new lifters on ALL 16 lobes. It only takes one lobe that is unhappy, and usually, (I've seen it mare than once), the lobe that goes flat will infect those close to it with metal shavings, and you wind up with those shavings throughout the engine before you realize anything is going away. Once the lifter breaks through the lobe heat treat the cam can go flat in 2 minutes or less. Too late, take it all apart again and clean all the crap out of ALL the oil passages IF the polluted oil doesn't wipe out a few bearings along the way. (remember, once the filter is restricted it goes into bypass and all that crap is free to roam everywhere)....
Yes, others will say they "do it all the time"... OK. weigh the odds against the cost of a new cam and lifters. Hyd cam "kits" aren't that expensive, hell, you might want to upgrade the valve springs/retainers/keepers wile you have the heads off... AND, please tell me you're not attempting to run a junkyard 454 in a boat.... Sure, we'll hear about others that have multiple seasons on junkyard stuff, but the total failures far surpass the successes....
My answer to your question:
So NO, I would not put new, or mixed up lifters on an old cam....Too much to lose, not to mention the labor...

Ray

 

[Budweiser]

Summit cam and lifter kits are about $100, springs about another $60 IIRC. I ran this one in a junk yard 454 short block with unported 049 heads, performer manifold and a 750. For a cheap deal to get me back on the water, it ran fantastic in the flattie I had at the time. Spun about 5500rpm. However, it did break a wrist pin after about 30 hours on the water. )ThumbsDwn

Not sure if that particular cam is wet exhaust friendly, I ran mine dry.

Just food for thought.

 

[holorinhal]

Well, i knew the answer to my question before i asked it.
Fuck it, i am just going to take the whole motor down! At least that way i can check the bearings and rings.
I gues i will just do a complete rebuild. Hooegully , i can get away with just a clean ip hone snd not have to bore and buy new pistons. Other wise i might as well just sit out the season and save and spend the money on my original engine!

 

[ICECREAMAN]

Well, i knew the answer to my question before i asked it.
Fuck it, i am just going to take the whole motor down! At least that way i can check the bearings and rings.
I gues i will just do a complete rebuild. Hooegully , i can get away with just a clean ip hone snd not have to bore and buy new pistons. Other wise i might as well just sit out the season and save and spend the money on my original engine!

LOL!! Now you're sounding like me Hal.