18psi

iTrader: (76)

9 out of 10 people that took it apart had issues afterwards, including myself with the last built motor I did. I knwo you said you cleaned it, but.......

patsmx5

iTrader: (16)

I've had mine apart twice, it's a pretty simple part. No idea if it works yet, will know soon though. I can't imagine any reason why it wouldn't work though, it's just a few pieces and seals/springs if I remember right, like baby apex seals...

stigish

It's apart now I'll see if I can hammer it back together soon. I WANNA DRIVE!

stigish

sad ain't it

stigish

Thought I'd update and bump the thread.

I picked up a new #1 cam bearing and oil pipe (adapter; the part with the o rings) and installed those with no change. Not that I was really surprised but I started doubting my diagnosis and thinking about just getting enough flow to the rotating assembly to handle some RPM without worrying about the valve timing but also ensuring lubrication makes it to the cam bearing and the actuator.

I made 2 block off plates which sandwich under the supply line. The first one had a 1/8" hole drilled into it. This drill size was arrived at by measuring and closely equivalent to the opening in the oil control valve that allows oil to flow past to the moving parts.

Sketchy huh?



1/8" made little to no difference in upstream oil pressure! But at least it confirms my suspicion that the loss is down stream.

The second plate has a 1/16" hole = 1/4 the area of the first hole. This provides enough oil to the VVT to lubricate while providing 20lb @ 830 rpm and 60lb all the way to 7k rpm with >210* oil!!!!!!

Although this does not provide enough oil for the VVT to function at any level it does

1. Prove the loss is the the VVT system.

2. Provide flow/pressure enough to keep the reciprocating parts happy.

THIS IS A TEMPORARY EXERCISE

Any thoughts?

What would you do next?

sixshooter

iTrader: (12)

1. It proves there is not enough oil volume coming from the pump to feed everything that currently needs to be fed. It does not necessarily villainize the vvt mechanism. The vvt mechanism does require a fair amount of oil, hence the size of the pipe compared to, let's say, a turbo oil feed line. The vvt may still be bad but I wouldn't consider this to be a conclusive deduction.

patsmx5

iTrader: (16)

Update, I got the VVT hooked up and it works fine in my car, and I disasembled/reassembled the VVT actuator before hand. Works fine! Maybe yours is messed up?

Regarding your engine, I'd still try a 50W oil next. It will not flow as easily, thus whatever(s) in your engine that is leaking too much oil will leak LESS and this will result in higher oil pressure. Worth a shot. Otherwise you gotta tear it down and find out where the leak is.

patsmx5

iTrader: (16)

Not true. You could also try this: Disassemble the engine and plug off all the oil holes to the main and rod bearings. Result? VVT will go to working! Cause now it will get plenty of oil!

Sixshooter said it well.

What you need to understand is that the pump does NOT supply pressure. All it does is supply FLOW. It pumps a certain amount of oil. All the restrictions in the system (bearings, oil squirters, VVT thingy, etc) present a RESTRICTION to the flow, and thus the pressure rises because of this restriction. You have a big leak(s) somewhere causing a lot of oil to go to one place and not much going everywhere else, and this also means lower oil pressure.

You can do the same thing with a turbo car. Unhook the blow off valve from the charge pipe and watch all the boost go right out the hole instead of in the engine. No restriction, no pressure.

stigish

Ok, granted guys. Using process of elimination, the squirters are installed with the copper washers and locating pins located and torqued to spec. The bottom end has a max clearance of .00225. The head has no cam bearings. So the head is left.

I guess clearancing all the saddles may point to a new head. Anyone know BP6D clearance? My search showed .006 max for 99 and before.

codrus

Have you considered removing the squirters and blocking off the feed holes?

--Ian

patsmx5

iTrader: (16)

Also I believe the oil pump has an O-ring at the discharge of the pump IIRC. If that O-ring is missing, bye bye oil pressure? Maybe this is your problem.

Joe Perez

iTrader: (8)

patsmx5

iTrader: (16)

Potentially he used the wrong o-ring then, and it's leaking, thus all these problems. Might be onto something!

stigish

I have only just considered blocking the squirters.

No massive puddles of oil on the floor to account for this much loss.

Joe Perez

iTrader: (8)

My VVT engine has adequate oil pressure with the squirters.

So do tens of thousands of others.

So did yours, before whatever went wrong went wrong.





I'm trying to remember exactly what this area of the oiling system looks like. In the absence of the O-ring, would oil be escaping from the engine onto the garage floor, or merely escaping from a high-pressure area of the engine into a lower-pressure area (eg: the pan)?

stigish

Yeah I know, new head or squirters? Or I haven't found the problem yet.

The pump outlet aligns with the block galley and seals with the o ring and/or RTV. If no seal then big leak.

sixshooter

iTrader: (12)

Did the machine shop remove the oil restrictor from the block when cleaning it and not reinstall it?

patsmx5

iTrader: (16)

You haven't found the problem yet. Removing the squirters will help, but it's not the problem. My VVT actuator works at idle in my miata. And I have squirters/stock vvt engine from the oil standpoint.

Try this: Put in 50W motor oil. If pressure goes UP, you have a leak after the pump. If pressure goes DOWN, you have a restriction before the pump (leaking/cracked/clogged pickup tube for example). Try something man! That or tear it down and start going through it.

patsmx5

iTrader: (16)

Curious what is this? I've never heard of it.

Joe Perez

iTrader: (8)

That plug goes in the galley which feeds oil up from the block into the head. It's present in every Miata engine from 1990 through 2005, be it HLA, solid or VVT.