VYClubby

Hi guys,
I have just had a set of ported and shaved heads fitted onto my 2004 LS1. It has a 220/220@112 LSA with .581 lift cam. The heads have been shaved 30 thou.

Since the heads have been on (2 days) at cold start it doesn't register any oil pressure for around 20 seconds on the gauge in the cabin, after that it seems to have normal pressure as I drive it, and at idle.

When the heads were installed they used the standard pushrods, not shortened ones, could my lifter preload be too much and could too much lifter preload cause this issue?

vettenuts

iTrader: (4)

No, this shouldn't cause an issue with oil pressure. I am wondering if the grounds are tight on the back of the head or the oil pressure sending unit got damaged in some way. Also, did they do an oil change and if so did they use a different filter or oil? Too long a pushrod could result in low/no compression but you would notice that immediately.

VYClubby

Thanks mate. It has new oil and oil filter. It has been suggested to me on a forum here in Australa that "with the shaved heads you put on, the pushrods may be compressing the lifter which can cause them to collapse internally and can drop oil pressure"

What do you guys think?

Greekey

iTrader: (3)

Anytime you change valvetrain geometry you need to recheck pushrod length.

VYClubby

They had shorter pushrods for the install, but they said they didn't need them after they checked. I am wondering if they made a mistake?

It is at the point that I have spent money on the heads and install, but can't drive it as I'm worried about the pressure issue.

I changed the oil and filter today, but it still takes 20 seconds for the pressure to come up. Then once it is warm the idle pressure is a tad low. SoI don't want to risk damage by the 20 second delay in oil pressure.

I am trying to see if it could be the installers mistake, as it's only been an issue since the heads went on? That way I can take it to them on Monday and leave it there until they sort it out.

Greekey

iTrader: (3)

I highly doubt your oil pressure problem has anything to do with your
pushrods. 20 seconds is out of this world crazy for oil pressure to come up. I think it has something to do with an electrical connection. Are you losing any oil? It could be a damaged oil pressure sending unit. I would not start that car again, until the problem has been found.

VYClubby

Would a damaged oil pressure sender stop the engine getting pressure, or is it's only function to operate the oil pressure gauge?

chrisfrost

iTrader: (8)

The pressure sending unit cannot affect the pressure in any way . I would look at the oil filter part # . I was buying an oil filter for my 5.3L and I saw that they have 2 different filters of each brand , 1 with the anti drain back valve and 1 without . If You have 1 without it's possible that is the problem . Like Vettenuts said , check You're gauge wiring also . Good luck

BlackZJ

I would use a mechanical oil pressure gauge to check if the sending unit works correctly. This should be the first thing to do. Otherwise you could possibly search for a problem that doesn't even exist.
When you start the engine, can you hear the lifters tick louder then usual while the pressure is/looks low or does the tick get quiet afer a short time?

To me it sounds like the oil drains back. Has the oil pan been removed while they were working on the engine?

VYClubby

Thanks for your help guys. I am taking it back to the shop that did the head install tomorrow so they can have a look. I'll let you know the outcome.

VYClubby

Well it was just a faulty oil pressure sensor. They used a mechanical tester today and it was fine, so they replaced the sensor and I have just restarted it after 5 hours of cooling down and it's all good!

Now tomorrow, Australia Day here in Aus, I can finally enjoy my new combo!

Thanks for all your help.