Mr.Matchbox

I discoverd or, let say exactly, can confirm a problem with the upgraded oil jet bolts . According to the workshop Manual from Honda, the oil jet bolts have a litte spring loaded ball valve inside, they should only open when the oil pressure exceeds 2 bar / 29 PSI. This helps to promote a healthy oil pressure for the engine when idling. My car was equipped with the upgraded oil jet bolts from the factory. I cant say exactly, but over he years the time it takes for the oil pressure light to switch off after i start the engine tooks longer. Almost 1 or 1.5 Seconds. This annoyed me to death, because oil pressure is critical and cold start wear is the biggest concern.

I stumbled across this noteworthy thread in the german S2ki forum, a member disassembled 2 damged engines and found 6 out of 8 oil jet bolts had the spring inside broken, makes them useless. https://s2k.de/forum/index.php/Threa...blem/?d2aba1fe

I bite the bullet and changed the oil jet bolts, 4 brand new ones from Honda. To my big surpise, when testing gently with compressed air or by blowing with my mouth, i discoverd that 3 out of 4 used oil jet bolts in my engine also had a broken spring, only 1 was O.K.




I dont opend them, i just made a picture in front of white background. You could cleary see straight through the damaged one, while the good one is closed by the tiny steel ball inside.
The only noticeable difference now is that oil pressure light gets off "in a blink of eye" when i start the engine now, compared to the 1 second it took before. .

I think this information is noteworthy, i just want to share this information. The engines seem to last neverthelss, but...

zeroptzero

That can be a common issue. The effect of decreased oil pressure at idle is debatable though, because at idle the engine is under very low load. I would be more concerned with oil pressure numbers at 3500 rpms when you refer to the spec. numbers. My Ap1 with factory oil jet bolts had low oil pressure at idle, but oil pressure at 3500 rpms was perfect. You don't need a ton of oil pressure at idle as long as oil flow is sufficient. I would be concerned with an engine that has low oil pressure at idle and low pressure at upper rpms, that would signal an engine / oil pump and oil flow issue. An engine with lower oil pressure at idle and perfect pressure at 3000 rpms doesn't bother me. Change the bolts if you can and for peace of mind when you are in there, but I don't know how critical that is if you don't and I suspect the new oil jet bolts will end up the same way after a few years of use if they have weak springs.

Mr.Matchbox

I am aware that the new oil bolts are likely to fail again. But i have peace of mind for many years now.
My biggest concern is cold-start wear and maybe to low oil pressure when the egine is really hot and the oil is thin. Engines die slowly from this.
A oil pressure and temp gauge is a good idea, i think.

windhund116

Where did the ball and spring go? Could you take a photo of the bottom of that banjo bolt?

Thanks!

Mr.Matchbox

The Banjo bolt is still in one piece, i guess that the ball and spring is pressed down at the bottom of the bore, frozen or jammed by the broken spring.
Just guessing... If i find the time, i will try to cut it open.

Mr.Matchbox

I just had a look through the holes of the bolt with my watchmakers magnifiers. My guessing was right, i could see the shiny ball inside the bolt, but stuck just below the outlet holes at the side of the bolt.
No for the fun part: I used a tiny drill bit and stick it upright throught the inlet hole, i was wondering if i could un-stuck the ball valve when i gently press it.
To my big surprise, the valve act like it should, i could press the drill bit down against spring pressure, and it came back with spring pressure. So, the valve is working, bit it just dont close completly again. It´s like the spring is a little bit to short. Must be broken... .

Mr.Matchbox

I just cut it open with my mini drill and a grinding disc. The spring is broken and winded inside themself.

zeroptzero

Damn good info, Looks like Honda has a defective part on their hands, but no one really knows about it as you have been the only one to look into this so deeply. Good work.

windhund116

Crazy! Another thing to keep one awake at nights.

Mr.Matchbox

Every time i serviced the front fork of my old Suzuki GSXR, i noticed that the fork springs get partially ground on the outside. This makes sense, the springs are long and if they get compressed they form a "S" like shape, grinding at the fork leg tubes from the inside.

The same effect happens to the springs inside the oil jet bolts. I have made a picture, you could clearly see that the outside of the spring in the middle section is partially ground. The spring wire is so worn on the outside, it has a "D" shape cross section. The ends of the spring are still new-round. So, the spring get weaker and weaker over time from grinding inside the bolt against the bore when moving until it brakes.