Cam swap pressure dropped 20psi...
#1
Cam swap pressure dropped 20psi...
Well a heads up for those putting in cams, my cold start used to have my oil pressure at nearly 60psi cold start with a 40psi hot idle. After putting in a TR224-112 cam, I now have 40psi on cold start and around 30psi hot. She'll still climb in psi with rpm, but I think if you are already having issues with your oil pump a new oil pump is such a small investment. I didn't think I'd lose almost 20psi to just slightly looser cam bearing clearances but here I am. (mine's a 98, but damn strong I think)
As a side thought, I know I need a bit longer pushrods, I changed out to 7.4 inch but it's still a sewing machine under there. Anyone think that "short" pushrods may affect oil pressure? It's a longshot as it's pretty much the end of the line as far as where the oil has to go in the engine so I'm doubting it'd make a difference, only my hearing sanity.
As a side thought, I know I need a bit longer pushrods, I changed out to 7.4 inch but it's still a sewing machine under there. Anyone think that "short" pushrods may affect oil pressure? It's a longshot as it's pretty much the end of the line as far as where the oil has to go in the engine so I'm doubting it'd make a difference, only my hearing sanity.
#3
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If you changed your oil pump, you may have pinched the oil pickup tube o-ring.
Some nasty **** may have gotten in your oil while doing this. Ambient humid air, some dirt and stuff. Change your filter. It is often the cause of bad pressure.
Some nasty **** may have gotten in your oil while doing this. Ambient humid air, some dirt and stuff. Change your filter. It is often the cause of bad pressure.
#5
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My first cam install had the same problem but worse pressure.
Had to tear it all back down to fix the O-ring.
That was 4 years ago.
Now fast forward to the one I did a few weeks ago and no problem. Full pressure.
Just have to be patient with the O Ring.
Had to tear it all back down to fix the O-ring.
That was 4 years ago.
Now fast forward to the one I did a few weeks ago and no problem. Full pressure.
Just have to be patient with the O Ring.
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Something to consider...
If you changed to double chain setup.. you then removed oil pump and had to install spacers behind it...
When I did mine, I got pressure like you have, down to 20-25 psi and like 40-45 psi at redline.
I then removed oil pump to swap it to a neww ls6 oil pump and I noticed I installed the block oil feed side spacer (drivers side) upside down, so the feed hole was partially leaking oil back to oil pan.... I consider myself lucky to not have had any damage running her that way for .... 2000 miles!
If you changed to double chain setup.. you then removed oil pump and had to install spacers behind it...
When I did mine, I got pressure like you have, down to 20-25 psi and like 40-45 psi at redline.
I then removed oil pump to swap it to a neww ls6 oil pump and I noticed I installed the block oil feed side spacer (drivers side) upside down, so the feed hole was partially leaking oil back to oil pan.... I consider myself lucky to not have had any damage running her that way for .... 2000 miles!
#7
I kept my stock oil pump as it was working well (either the earlier pumps go or they run damn strong.) Mine was a freak. 100k miles and pushing 60psi cold, 40psi hot and around 50psi while cruising.
Oh well looks like I'm checking the oil pump... at WOT now it'll go to 60 psi by 3000rpm... I'm hesitant to go tearing into it as I had above normal oil pressure to begin with... maybe just a slight pinch.
Oh well looks like I'm checking the oil pump... at WOT now it'll go to 60 psi by 3000rpm... I'm hesitant to go tearing into it as I had above normal oil pressure to begin with... maybe just a slight pinch.
Last edited by SladeX; 08-04-2007 at 11:50 PM.
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#9
after observing more closely today, it seems I didn't lose 20psi, I lost around 10 psi, a bit less than I anticipated.
So I technically went from 60 psi cold to 50 psi cold, 30-35psi hot idle, around 50 psi when cruising so I think I'm well enough.
I'm going to go after the sewing machine issue with longer pushrods, seems 7.400 is too short.
My idle speed has been bumped from 825 to 900rpm.
So I technically went from 60 psi cold to 50 psi cold, 30-35psi hot idle, around 50 psi when cruising so I think I'm well enough.
I'm going to go after the sewing machine issue with longer pushrods, seems 7.400 is too short.
My idle speed has been bumped from 825 to 900rpm.
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You shouldn't have lost any oil pressure with just a cam swap. Since your rpm's went up you should actually have more oil pressure than before at idle. It could be the o-ring if you took the pump off. If so you will see the oil pressure fluctuate and you will get valvetrain noise coming and going.
#11
The oil pressure is consistent, just lower by 10psi as a whole. On the bearing portion of the cam, there was some lite pitting so we took it to a lathe and smoothed it all out which could explain the loss of pressure if the clearances opened up a bit on the cam. While inside the engine though there was no slop that I could feel turning the cam by hand.
There's no increase/decrease in valvetrain noise. When it's idling, it sounds like a sewing machine. With the hood closed it's not that bad. It's consistent with the dual springs and I've checked it and found the pushrods to be a bit short using the permanent marker test.
There's no increase/decrease in valvetrain noise. When it's idling, it sounds like a sewing machine. With the hood closed it's not that bad. It's consistent with the dual springs and I've checked it and found the pushrods to be a bit short using the permanent marker test.