Rattling HLA's on startup

[fastivaca]

I've recently put a rebuilt head on my B6. The old head had the mechanical lifters but I had to switch to the hydraulic ones in the new head because I also installed an FMS performance cam.

On start up it sounds like the HLA's are not holding their pressure, particularly after sitting overnight. Is it usual for them to "drain down"? What could be causing them to do so? What should I be looking for to fix it?

I'm currently running Castrol GTX 5-30. Should I consider a different brand?

I may pick up some more HLA's from PnP next time I'm there and try them.

Thanks for your help.

[Festy46]

Make sure you have the rocker arm shaft installed correctly. There is an extra hole in the rocker shaft near the bolt hole for the center rocker shaft support that must line up with the hole in the head. If you have the rocker shaft rotated 180 degrees, the oil can't get to the HLA's except by squeezing around the rocker shaft until it gets to the hole. This could be the reason it takes a while to get oil pressure to the HLA's.

[fastivaca]

^^^ Thanks for that. I'll check it out and report back!

[fastivaca]

Checked the rocker arms this morning and they were/are installed correctly. Not sure what to try next. I'll replace the HLA's and see if that helps. Could this be a problem with the oil pump or oil filter?

[worfdog]

I changed my oil and used Castro 5- 30 for the first time about a month ago in my 89 with hla's. It has been making noise on start up ever since, but after a couple of minutes it quietens down. I am going back to the shell rotella oil on my next change in about a month and see if the noise stops. If it does it most likely means the oil was the cause.

[Festy46]

When the motor is cold after sitting for a while, have a light handy and start the motor and peek in the oil filler hole. You should see oil starting to run around on the top of the head almost immdeiately. If you do see oil running around on top of the head, then it is a good possibility the HLA's are gummed up and need replaced or at least cleaned. If you don't then get a mechanical oil pressure gauge and connect it where the current sending unit is attached. You may need an adapter fitting for the metric pipe thread on the engine. I'm guessing you will probably have good pressure. If you have good pressure at the gauge, but not much oil running around on top of the engine, take one of the rocker shaft assemblies off. Pull the coil wire so the engine can't try to fire and spin the engine over with the starter. Oil should come squirting up through the small hole in the head that you checked for alignment with the rocker shaft. If it doesn't, then it's possible the restrictor plug in the block may be gummed up with some gasket sealer or other junk.