Smitty's '04 GTO

iTrader: (5)

Ok, so about a month ago, while helping out on a heads/cam swap on an '04 GTO, we didn't pay attention to the orientation of the oil feed holes in the side of the stock lifters when we removed them. Upon reassembly, we put all the oil feed holes facing down (towards the oil supply galley that everyone uses to insert rods to keep lifters from falling in a cam-only install). To my knowledge everything turned out fine...

While tearing the LS1 apart in my GTO last week, I paid attention to and noticed that the oil feed holes were not uniform in their orientation during factory assembly. In my engine, 10 faced up towards the valley, and 6 faced down towards the oil galley. This leads me to believe that it doesn't matter about the orientation of oil feed hole, which may make the following question moot...

Now, one of the differences of the GMPP "Caddy" lifter (GM part# 88958689) is that the oil supply hole in the side of the lifter is located 90* rotated from the stockers. This means that the lifters can be installed with the oil supply hole facing either the front of the engine, or the rear. Anybody know which would be best? I'm guessing the front, as I think the oil is supplied via the oil galley from the front of the engine, where the oil pump is located.

Anybody got any other thoughts on this subject? Maybe I'm just "overthinking" it?

Would especially like to hear opinions of experienced engine builders, or those who've already installed these GMPP "Caddy" lifters... but all responses welcome!

Thanks!

Grimes

iTrader: (3)

Are you sure the oil holes are in different spots? The pics I have seen show them in the same area:

https://ls1tech.com/forums/generation-iv-internal-engine/580686-new-upgraded-hydraulic-roller-lifters-sdpc.html

Anyway, FYI, the oil from the oil pump is sent to the rear of the block, through the filter, then up from the filter up to the lifter galleys. (Travels in the lifter galleys from rear to front)

aNuBiS

iTrader: (25)

interesting question

DaddySS

I faced mine rear since the oil galley for the lifters flows rear to front.

blkbird

iTrader: (28)

I really didnt pay attention when I installed mine and have no issues. They have been in for about 5 months now....

Irocss85

iTrader: (1)

I paid no attention whenever Ive installed them in cars before. never had any issues. doesnt the oil go all the way around the lifter to continue on to the next lifter in the galley?

Smitty's '04 GTO

iTrader: (5)

Yes, positive. My stockers are different to those pictured in the link you posted. My stockers have the oil feed hole in the side above the face of the roller wheel. Also, my stockers do not have the body of the lifter surrounding the roller wheel but rather come down along the sides of the wheel like a pair of bicycle forks (another reason I think the GMPP lifters should be better / stronger than stockers...). I tried to take some pics, but they didn't turn out too well.



Anyway, thanks for the info about oil in lifter galley travelling from rear to front, I will orientate my lifters all with supply hole facing rear of engine, as another poster did. It probably doesn't matter as the oil under pressure surrounds the lifter in that center section of the body and like I mentioned, my stockers were mixed top and bottom as to which way they were facing when I pulled them, and they were assembled this way from factory...

Thanks much for the help guys!

Smitty's '04 GTO

iTrader: (5)

Here's the best of the lousy pics I took. The stocker is on the left, and the GMPP "Caddy" lifter is on the right.

http://memimage.cardomain.net/member...geQuality=Full

brad8266

iTrader: (23)

It doesnt matter just put the lifter in so the roller is on the cam lobe right. It will oil fine either way.

aNuBiS

iTrader: (25)

I also assume you let them soak in oil overnight before install...

brad8266

iTrader: (23)

That not needed either. Just dip em in oil right before you installe them. They pump up with oil quickly right after the car starts.

Grimes

iTrader: (3)

Yes - the oil will just flow around the body of the lifter and make it to the hole no matter what. You can see this if you look at the comparison picture.