hi guys:
I have a possible oil starvation problem in my cylinder head, I did the search but didn't come up with what I need. my intake cam lob over cyl #1 is a lil worn out, all signs lead me to think it's a oil starvation/passage blockage problem

exactly how can I check for oil passage blockage?

where exactly are the oil pick up and return holes on the head? There are 2 holes near spark plug wells on cyl# 1 & 3, are those the return hole? I cranked the engine with only starter motor, engine oil seemed to be coming out from a hole on the lower right ( exhaust side, closest to the radiator) of cylinder 1, is that the pick up hole to the head?

if u look at the cam rockers, every rocker seems to have a little flat head bolt on it, is that the oil squirtting hole?

where are the oil passages to the camshafts? r the passages internal to the cam holders?

if I crank the engine with just the starter motor, with valve cover off, spark plugs off, what should I see if I have a oil passage blockage problem?
thanks in advance

 

the oil passages are internal to the cam holders. The big gaps at the botom of the head are returns, I believe some of the round holes are supply to splash the valvecover. I always thought if you cranked the engine with the valvecover off you would have oil spraying everywhere so people plug up the round holes, but I've never done it.

How do you know that your cam is worn out ?, just by visual marks ?. The only way to tell is to measure the height of the lobes with a caliper and compare the measurements to specs. listed in the service manual. If you need the specs I can look them up for you. Going by visuals can be misleading as marks on the cams can occur for a number of reasons. I would think a blocked oil passage would be very rare unless a piece of metal was wedged in there, or the engine had sludge problems. A past problem with motor oil could have caused issues.

 

thanks jfusion. the intake cam lobe lobe in question has visable wear on it,
obviously different from all other lobes.
I know the problem from strange grinding noise from the engine, it sounds like bad bearing and it's from the head, after comparing with most other people's symptom with failed camshafts, it lead me to believe it's my oil passage but not my cams.
Interesting to know how hte oil is supposed to be splashed out, because when I cranked mine, the oil just "floated" out.
I t-bracketed a oil pressure gauge on oil filter, oil pressure reads fine.
ummm.

 

If you have an oil supply problem your camshaft journals would be stuffed.

The lubrication for the cams lobes is just the oil that splashes out from the rockers/shafts as the engine is running. They are roller rockers and do not require flooding with oil.

As your problem is with one lobe only my psychic diagnosis is that rocker had excessive valve clearance. The initial movement of the camshaft lobe is very gentle. If you have excessive valve clearance the rocker/roller is hit with a much more aggressive part of the cam lobe. This puts a lot more stress on the rocker/lobe and in some cases can cause the valve to break a stem as the valve is dropped rather than lowered onto the seat.

 

measure the height of the cam lobe in question and go from there, it might provide some peace of mind, check the valve clearance as mentioned above and go from there.

 

IIRC Billman posted pics of a cracked (and therefore raised) retainer being up that high it caused scuffs on a cam lobe.

edit:
Billman250 Posted: Dec 8 2006, 03:24 PM
Found here:
https://www.s2ki.com/forums/index.ph...=437271&st=150
Page 7 (with my board settings)
No pictures.
So the question is: is the rocker roller scored too?

Worth checking that out.

Any overrevving lately?
Revto10k?

 

yeah I had a problem of the passage being blocked, seized the entire cam and made my car come to an abrupt stop!!

 

if u have a worn problem on ur cams.. check ur retainers.. i had same issues.. all my retainers were cracked!!! cuaseing everything to be all messed up inthere...

roller rockers wore down causing cam to wear down... replace with tit retainers... wont have that problem.. its very common and then do a good valve adjustment and u wont have to worry about a lil wear and tear

 

thanks for all the input guys.
problem solved by changing oil filter!
had an experienced mechanic doing diagnosis, turns out something, don't know exactly what, blocked oil passage, no oil was delivered to the valve train. It was obvious enough just by looking into the oil filler cap with engine running, the mechanic thinks my cams are still good. one of the roller on the cam rocker may be bad, as he found a flat spot on it, along with a solid line (or crack). However it seems to me the line is manufactured in to the roller as some kind of marking. Retainers are all fine.
changed the oil filter, viola, sound was gone. the car is in the shop right now as they try to find out exactly what caused the problem.
As for now, I think we can dismiss the rumor that toda cams have quality issues, these cams survived without engine oil delivered to them.
Initial assessment is poor quality engine oil is to blame here, the funny thing is I stay with mobile 1 full sync 10w-40, always. I'll keep this updated.

 

You did use the 15400-PCX-004 filter?
Now and before?

edit

A guess: the filter was severely blocked and the bypass failed leaving just a little flow to only reach the crank but not enough to reach the valvetrain.
If this was with an OEM filter it would be the very first OEM filter failure.
Take pics!
I would cut the old oil filter open and if you don't find something completely wrong with it I would take a look at the heat exchanger & oil pump.