Rb25/30 Top End Knock

[cuong nguyen]

Deleting the vct in the r33 rb25 head's is fine and won't starve of any oil I have done it on 2 of my motors.

[Scott Black]

deleting the vct oil feed passage on the bottom of the head to build a 25/30 without running an external feed to the vct starves the front journal of oil, might work ok for a while as the heads get a stupid amount of oil up there, yet its not good for the cam, the way to fit this is to take out the brass plug from behind the cam gear, and cut it off at the part where it things out before getting larger again, and then reinstall it, this allows the oil galery to goto the front of the head, if you dont do this the oil galary is blocked before the front journal.

[SkudR33]

Back on this discussion, I forgot to post my findings... I attempted to remove that brass fitting and the prick wouldn't come out.

As a move of desperation, I bought an oil squirting bottle thingy and pumped oil down those two holes on the front journal and it pushed oil into the main oil gallery along the side of the head. Not sure why it worked but as I was able to prove to myself that oil traveled straight through, I decided not to modify that brass fitting!

It's a very strange and debatable issue and I believe the best way to overcome it is to confirm using an oil can whether or not oil travels to that front cam journal.

Thanks for the advice from all the guys on here...

[Scott Black]

When you say the main gallery you mean it was comming out the other cam journals and such? If not then where. As I've had one home built rb30 come into my shop with the front cam journal completely stuffed and he hadn't done that mod when building it, and on the 3 I've done I've cut it down and havnt had any issue. I'll need to look into it more on the next one I build

[SkudR33]

When you say the main gallery you mean it was comming out the other cam journals and such? If not then where. As I've had one home built rb30 come into my shop with the front cam journal completely stuffed and he hadn't done that mod when building it, and on the 3 I've done I've cut it down and havnt had any issue. I'll need to look into it more on the next one I build

I pumped oil into the front feed and oil went though into the oil gallery. Refer to the photo, if you look closely you'll notice the oil.

I was so confused because Ben managed to convince me that I needed to do that mod...

[SkudR33]

This photo shows the amount of oil that went through after 2 squirts!

Guys also forgot to mention, that my mechanic who also builds engine had a spare rb25det head in his workshop and that head wouldn't allow oil to go through that passage when I attempted the same test! It is such a confusing, yet concerning matter!

[Ben C34]

Wow.

So there are differmves with the heads!

As Scott said he has seen, my engine builder has seen it yet people say its no worries, and now you have proven in your case your head is fine......

Very interesting.

Good on you for checking as it could have ended badly, now it has let others know that the heads are different somehow!

[Ben C34]

Do you know if one head was early and one late?

[Scott Black]

yeah thats amazing, hopefully i get to build another one soon then and look into it more, thats def not a neo head right?

[Scott Black]

http://www.sau.com.au/forums/topic/251669-rb2530-rb30det-vvt-internal-oil-control/page-2

this page here shows the plug we talking about and theres some drawings to show where it cuts off oil supply, so im really shocked it wasnt needed in you case. amazing

[SkudR33]

My head definitely a series 1 rb25det head... The engine builder had no idea what type of head he had, said it was a drop off from a few years ago.

It's such a weird topic because sometimes it works out for people and sometimes it doesn't. I believe ultimately all people should check with an oil can. According to my engine builder guy, if the mod isn't needed then it shouldn't be done as the last thing an rb head needs is more oil to it!

[SkudR33]

http://www.sau.com.au/forums/topic/251669-rb2530-rb30det-vvt-internal-oil-control/page-2

this page here shows the plug we talking about and theres some drawings to show where it cuts off oil supply, so im really shocked it wasnt needed in you case. amazing

I attempted this for hours man and the piece of shit wouldn't come out... Snapped a bolt in there and then tried using a tap bit and even snapped that in there. That was the point I raged and decided to test it for myself...