91_rs-teal

iTrader: (7)

parting out

radical82

Problem is the govment took the zinc out of the oil and that is what protects the cam lobes... Go to a roller or get used to changing cams..... There are zinc additives, but they aren't foolproof either. I know of a number of engine builders who won't even put a flat tappet cam in an engine. Rollers because of their design have faster rates on the ramps and all around better grinds. Just spend the extra $$$$ and put something in their that will last.... Also, might want to mic your lifter bores, with all those parts going bad they can take a beating....

91_rs-teal

iTrader: (7)

with a max of .470 lift i cant get crap for a roller cam, is there a way to cut the relief in the piston a little deeper?

91_rs-teal

iTrader: (7)

also i even tried running mobil 15w50 and oil pressure was about half of conv. oil

ASE doc

Where do I begin? Are you breaking in these cams? 2,500rpm for 20 minutes, immediately after start up. Thats after installing the cam with lots of cam lube and adding a zinc product like ZDDP to the oil. Never use synthetic oil for engine break in.

Mobil 1 15-50 is standard in 700hp NASCAR small blocks and the only oil I allow in my high HP street/race motors. Dont blame a great oil on your failure to properly break in your flat tappet cam.

Im one of those engine builders who absolutely will not install a flat tappet cam in any engine today, unless racing class rules require it. Then I do so begrudgingly. For one thing, the advances in roller lobe profiles make the use of a flat tappet cam almost ridiculous.

Why do you think you have to stay below .470 lift? Your heads can certainly handle more. Are you worried about overlap clearance between the exhaust and intake strokes? Look at the cam I run. .560 lift and 290 degrees and I have no problem with interference, and thats on Twisted Wedge heads.

One more thing, before I went to using Mobil 1 synthetic, I used Valvoline exclusively for 20 years. In fact most of my race motors ran on 20-50 racing oil. I never had an issue with it. When cam lobes and lifters are being ground and beaten, due to lack of proper break in, they tend to get very hot. Thats what ruined your oil.

At this point, you really need to send the block in to be checked by a good machinist. It's hard to say what damage you may have done to it. Go with a roller cam. The extra cost now will come back in increased power and durability.

BTW, "duration" is the time in degrees of crank rotation that the valve stays open. A lobe with more duration opens the valve more quickly, not more slowly.

91_rs-teal

iTrader: (7)

the duration has the valve open longer if you have the same lift smaller duration cam has less open time

sofakingdom

iTrader: (1)

End the misery.

Go with a roller cam. Sell the other lifters to someone with a greater appetite for risk than yourself. (I must admit, my tolerance for risk is probably LOWER than yours, I haven't built a non-roller motor for about 12 years now, and probably never will again)

There's nothing wrong with Valvoline oil, as far as that goes, although I personally use Mobil1 exclusively like the above poster. I just use the regular stuff though; about the thickest I ever use is 10W-30, when I want candle wax. More I often I stick with 0W-20 when I can get it.



This makes no sense.

Yes there is. But piston-to-valve clearance is not an issue here. Not sure why you'd want to cut the valve reliefs deeper?

What induction system is on this? I'm guessing a carb, since it's in the deep 13s? (wouldn't be TPI) Or maybe HSR or other aftermarket FI?

91_rs-teal

iTrader: (7)

right, springs on the heads .600 lift with factory rockers

cam .470 lift with factory rockers

and yes a demon carb setup

and ill admit I was not aware of the cam break in.... but driving at 60mph for me is like 2500 rpm so a cruise to one place is not a good break in?

as for now i got a free cam so i threw it in for one last horrah. plan to get some kind of rev limiter setup and take it easy this summer. but meanwhile will most likely b lookin for a roller cam setup and a t56 setup.

vetteoz

iTrader: (13)

Did you not read what ASE Doc posted above
Immediately after start up. .
Not idle for 5 min in the driveway , back out and drive around the block for 20 min

You start new engine up and hold revs at 2K+ for 20 min to bed cam in

305sbc

iTrader: (3)

If I experienced an oiling problem like that I think I would pull the block and make sure every oil passage was clear and clean.
I'd also look for something else going on there like cam-bearing problem or too much cam end-play, etc...

The springs on your heads may also be for a roller camshaft, in which case there could be too much pressure against your flat-tappet cam lobes.
What are the open and seat pressures on the springs you are running?

cuisinartvette

Unless I misread youre running a flat tappet cam with afr 600 lift springs?

Arent those like 135 or 150 on the seat? That will kill a FT cam real quick.

91_rs-teal

iTrader: (7)

ok! ok! this cam was used but i still ran it at 2k for aleast 15 min's this time, i also have a cam button and just replaced the cam bearings... yes the holes line up to with block. AFR springs.... i dk were to get that seat pressure info at.....

91_rs-teal

iTrader: (7)

yes thats what im askin, do i need lighter springs? is this one of the reasons this is happening?

ASE doc

Those springs are too stiff for cam break in. They are not too stiff for a flat tappet cam to run. We have run stiffer springs than that in our NASCARs with huge flat tappet cams.

If you want this to work, install a new cam with new lifters, using lots of Comp Cams assembly lube, after you get your lifter bores checked for size, scoring or other damage. Remove the inner of your dual valve springs and fill the engine with 30 or 40 weight organic oil and a Zinc additive such as ZDDP. Then perform the cam break in. After the initial break in period, you may reinstall the inner springs. Or if you want added insurance, run the engine below 3,000rpm for 1000 miles. Then reinstall the inner springs and if you wish, switch to synthetic oil.

To save most of the above hassle and have a more powerful, better running engine. Just buy a hydraulic roller cam.

ericg83z28

yes , the machine shop can machine reliefs but only soo much can be taken out , money can do alot of stuff if u have it

8t2 z-chev

using new (flat tappet)lifters on a used cam will usually
result in rapid wear of both-i have gotten away with
using new lifters on a used cam before(back when i
didn't know better and oil had zinc) but once i didn't
get away with it-installed new lifters on a used cam
and a week later tiny metal particles were noticed on
the dipstick-the old,worn in cam ate the new lifters in
less than 150 mi.

Apeiron

"Used flat-tappet cam" is another way to say "stick of scrap metal". Good that you at least tried to break it in, though, you do need to do that with new lifters if try to reuse a cam. A cam button serves no purpose with a flat-tappet cam.

Kevman

This 'Go to roller cam' crap is kinda sick.. You cannot use a conventional oil with a flat tappet cam, GM makes an AC Delco additive that is nice, it's about $8 for a bottle.. Or you have other options.. Brad Penn oil, it's green, and it contains zinc, and other additives that benefit your late model engine..
Another one that I myself like is Joe Gibb oil, it has corrosion inhibitors in it, and it's safe for late model engines.

Flat tappet is fine, Just talk to some local hot rodders, they'll set you straight.