TheViper

i just put a comp 262 cam and comp pro magnum lifters in my 283. before i chaged it it was OK exept for the lobes rounding off on the #8 cylinder. now with the new lifters it hardly has any oil pressure at idle. in gear it has less than 5 and about 10 in park. it also has a lifter tap pretty bad. i've adjusted the valves about 3 times and it won't stop. it also dosn't idle good at all and when its at about 1000 in park it'l go down to about 500 and almost stall. it didn't do it unlill after i broke the cam in for about 20 mins. the only thing i can think of is that i got bad lifters.

sqzbox

Did you pre lube the lifters? Also, did you use some assembly lube on the cam bearings?

TheViper

yea, i lubed everything up good.

i'l try to explain what its doing a little better. it'l start OK and idle decent, then it will go down to about 500rpms and it sounds almost like the timing is way retarted but its not. now it taps a little all the time but every once in a while it will will do some serious tapping then stop for a while. it's also realy realy weak. it sounds OK when you rev it up though, it sounds pretty strong but its not. the reason i think its the lifters is because thats the only thing that i chnged that would have anything to do with the oil pressure.

sqzbox

How are you adjusting the lifters? It sounds like they are too tight. They have to come up far enough in the lifter bore to get oil.
I don't know about your cam and lifter combo, and the compatability with the 283. That could be an issue but we'll let someone with more exp. answer that question!

TheViper

i adjusted them first by turning then untill zero lash then 1/2 turn. then i adjusted them with it running and they ended up being about the same. wouldn't it have good oil pressure if they wern't adjusted right anyway?

also, the engine runs hotter at about 210* instead of 180 like it usualy does.

sqzbox

Any way you can get ahold of comp cam's? They should have a tech support line to help with this.

TheViper

i can try to get ahold of them, but do you have any ideas? i'd like to have this fixed tomarow and i doubt they'd be open.

sqzbox

I've suggested everything I can think of without looking at it. Just like a Dr. U need to come to the office, U know?

sqzbox

You don't think you might have knocked a cam bearing loose do ya?

TheViper

i don;t think so, the old cam came out real smooth and the new one went in smooth. i didn't force it or anything at all. it was tight too, i mean no play at all like it should be, not tight going in.

sqzbox

I can give you some ideas that could be wrong.
as far as temp. goes it's going to run warmer sitting rather than running down the road.
1. pushrod length
2. adj. on your new lifters
3. cam bearings not centerd
4. dist, 1 tooth off
5. oil level low
6. cam and crank gears out of sync. (not lined up in the chain)
7. intake bolts loose or gasket not sealing right
8. rocker stud pulled loose (use srtaight edge across top of studs to check height)That's about all I can think of right now! You really need to talk to comp cams and see what they say. I feel for you with a new cam and all but I wouldn't run it too much to keep from possibly damaging anything till you can find the problem!

radiateu2

try a mechanical guage to check the oil pressure dont rely on the guage in the dashboard......sounds like you didnt tune the carb for the new cam....do the exhaust manifolds glow...? did you preoil or prime the engine did you have oil flow out of all the pushrods at the rockers if ticking exist you might have a broken spring bad guides, flattened cam lobe or a hungup lifter poor oil pressure....you might have wiped out some cam bearings

AM Racer

Valve lash has nothing to do with oil pressure changes.
If the lobes were rounded , then the oil pump has been eating the shavings. Not too good for the pump.
As far as pre lubing lifters.
The manufacturer tells you right up front not to do it.
When you fired it up, did you keep the rpm up at least 2,000 so the cam and lifters break in or did you just let it idle?

Stekman

Dont confuse lubing the lifters (with cam lube) and pre-soaking them in oil.

Pre soaking them is bad.

Applying cam lube to the lifter faces is good.

Marc 85Z28

iTrader: (3)

Wow, that's first!

You're the only person I've ever heard say that. I've always soaked mine well before install. And so does everyone else I know - and that includes professional technicians, engineers, machine shop employees, and all kinds of amateur and professional racers.

Please enlighten us...

AM Racer

If the lifter's filled, how do adjust the preload before you fire it up?

TheViper

what would cause the lobes of the cam on only the #8 cylinder to round off?

also, when i started it up today cold it ran almost perfect. no tapping or anything so i took it around the block and it ran good, plenty of power. it also had 50psi at idle. then when it warmed up it started taping again and the oil pressure went way down realy fast.

i changed the oil to 20w-50 and it didn't stop either exept the oil pressure is at about 25 at idle now.

Marc 85Z28

iTrader: (3)

Tighten until all slack is removed from the pushrod, and a little drag is felt when you try to spin it, and then tighten and addition 1/2 turn. Why? How else would you do it?

radiateu2

its starting to look like you have excessive bearing clearance some where.....thats why the thicker oil is working for you...it probably wont last long though...have you considered a spun bearing could be making that noise?

Oh and most cam and lifter suppliers recommend to not pre-oil the lifters just use a pressure grease on the flat tappets for breakin....I do coat the sides of my lifters with oil just before putting them in the bores

TheViper

i'm pretty sure its cam bearings.

sqzbox

OK, I had close to the same problem with a 455 pon. once. My oil pressure droped to about 25-30lbs running W/straight 40 wt. and idled at 5-10lbs. Being my only transportation at the time, I continued to drive the car 18 mi. each way to work trying to figure out why? After two weeks, It suddenly went back up to 40-45 running down the road and 30 at idle???? confusing as it was,
I figured it was a gauge (mechanical) problem. A few months later,
I spun a rod bearing so I pulled the engine and #4 rod had indeed spun a bearing but I also discovered the #1 rod bearing
(from the scratch marks) had also spun but had gone all the way around and back into place. So much for the loss and reoccurance
of pressure. Your problem is consistant with exessive bearing clearence. The only other problem I can see might be a broken spring or stuck pressure relief valve in your oil pump. Particles from your worn cam lobe enter the oil pump before filtration so the pump is the first thing effected. I doubt that it messed with the clearance between the pump gears and plate that fast, so it could be a pressure relief valve problem in the pump.

TheViper

the guy at the machine shop said that theres metal shavings in it so i'm going to pretty much have to rebuild the entire engine. its just surprising because this engine only has about 5k miles on it, i changed the oil about every 3 months(less than 3000 miles) it wasn't high performance at all, and i never reved it much because of the small cam.

i also have a pontiac 455 that the rod and main bearings went out on and you could hear knocking, on the 283 its real quiet exept the rocker arm tapping.

sqzbox

I'm going to guess the one tapping is #1 or #2 cyl. (farthest from the oil pump).