Bad Mystery Engine Noise

So, are we closer to a diagnosis? Dirty oil or contaminants in the oil which Bell first discovered in the oil resulting in the galling resulting in the chirp.

 

Unless close inspection of the lifter and its bore reveals something obvious --- such as a hard (particle) contaminant, a substantial surface (or structural) flaw, or a significant out-of-spec condition --- establishing direct root cause may prove impossible. It is very possible that whatever caused it is no longer present ---- leaving only the damage behind.

I would be inclined to replace the lifter with a known good one (either new or used), inspect the bore to confirm dimensional accuracy and acceptable surface profile (with rework as needed), and put her back together ---- new valve shim installed if appropriate --- and start her up.

Also, it's Bell's call.......but, if it were me, I would also change out the oil to a conventional product of appropriate viscosity.

All of this can be accomplished with the engine in situ and without need to pull the head ---- that is the good news

.....of course, if the "squeak" persists or returns shortly thereafter ---- now, poor Bell's got a bigger issue to deal with.

 

Also, as per Scott's expert suggestion ---- check that valve stem for tip damage and excessive lateral play......maybe pull the springs too for a thorough inspection just to make sure.

Good Luck

 

Fascinating - you look to have narrowed the problem down. I am envious of your spannering skills.
Hope the X1/9 is behaving better
Best of luck with finding the resolution

 

The only thing that bothers me (other then little knowledge) is that the chirp was always present and the bucket was free to rotation as he demonstrated . Wouldn't it be expected to have gotten stuck (the bucket)in one position to make such a consistent noise and show damage in one spot?

 

I assume you ment not always present? a cold bucket is going to have one dimension as it gets hotter it will expand. it may very well not be rotating when it's squealing, but it is running interference in it's bore with something.

 

Meant present again after he rotated the buckets by finger before reassembly and start this last time.


When all else fails read the damn manual. - wife

 

The other thing that is weird is that the bucket bore (Aluminum head) diameter should be expanding more than the OD of the steel bucket --- or at least enough to maintain clearance from cold to hot transition.

Makes me think that, unless he finds some crud stuck down there in between, that there may very well be something "wrong" happening with the way that bucket is interacting with either the cam lobe or the valve stem ---- causing it to bind only when it is under load from the cam.

Would not surprise me if the top portion of that valve stem turns out to bent or the tip is messed up --- could be something messed up with the contact area of the underside of the bucket too ??

Hopefully, Bell will continue to indulge us all with his comprehensive reports of his findings as he digs into it further....... 'cuz now..... I gots to know

Scott ---- You called it, Brotha' !

 

The tappet buckets have a Rockwell C of 55~60 or 15N of 85~95, that's on par with tool steel. it's also brittle, in other words the risk of a crack is high if they get dropped.

The aluminum head should expand more then the bore, however I'm not sure if that holds true if the exhaust valve is getting to hot and thru conduction is heating the bucket faster and with low volume oil cooling it may expand faster. It's very hard to determine at this point. further inspection of the bore will need to be done, unfortunately that may not be possible with the head on

Just today I dropped by my machinist to check on another set of QV heads, bank 1-4 had a taper of 3 thousandths! 0.003 from one end to the other, no idea why and a first we've ever seen. that head also was giving trouble. it'll be squared up and re-welded in some spots where the casting porosity leaves a lot to be desired. then I get to re-ream all the journals.

 

If it's an oil flow problem, how did it happen in the first place and, again, how did it start with an oil change? I can't imagine that there is a problem in the actual design of the head/oil passages - otherwise all these engines would be making the noise. It could be a defective head casting but again, what caused it to suddenly occur?

As far as oils - folks on this site are using everything from dino 20W-50 to straight synthetic 0w40 with no such reported issues.

Just curious...I have not worked on a Ferrari cylinder head; is the lubrication to the cam/valve area supplied by any sort of dedicated passage(s) to that area or is it "spill" from the cam bearings?

 

I was thinking that when I watched part 4 - much less oil to the exhaust side, at some points you can see it spilling down from the inlet side as that over flows but no sign of anything similar on the exhaust side on any of the valves.

At this point it might be instructive to remove the front bank cover & crank the thing again to see what a healthy oil flow to the exhaust side looks like (and possibly indeed have all the cams out & check all your buckets for any signs of wear).

The 328 owners manual has a picture of the oil system & seems to suggest that the oil reaches the cams in the rear head via a couple of passages located towards the front of that head - there actually seems to be relatively few passageways that it has to pass through to get there & most of it is the main gallery that runs down the middle of the block from the oil filter.

I think I'd also be wary of blowing compressed air back down the exhaust cam supply gallery because that leads back to the main gallery which also supplies oil to the crank bearings, so if you were to dislodge anything, the chances are its going to end up finding its way somewhere else to wreak even more havoc.

I wonder if that particular gallery could be flushed out by removing all the cams & blocking off the oil feed galleries that supply the other three cams & then cranking the thing over? The oil supply for the cams in the front head appears to reach the camshafts from the rear (distributor) end of the head.

 

I think he mentioned something about pieces of rubber in the oil near the beginning of this thread.
I have an Alfa Montreal, they have a well known problem with the rubber on the chain guides desintegrating with age and the small pieces of rubber get pumped around the engine, usually jamming the oil pressure relief valve.
I dont think the Ferrari engine uses this type of guide, but if he found rubber, there could be some partially blocking an oil gallery.

 

If possible, rather than compressed air, use some solvent or thin oil - something like ATF or Marvel Mystery Oil - blown through with a compressed air gun. It will be much more effective than just compressed air at flushing out anything that can be flushed out. The problem is that if something is lodged in an oil passage, it has already been under 70-80+ psi of pressure which may make it impossible to flush if you flush in the same direction that the oil flows.


FWIW silicone sealant is a tool of the devil; I try to never use it on an engine except in very rare - as in count those occasions on one or two fingers.

 

Ferrari engines have an oil restrictor in the deck of the block. It also acts as one of the two alignment dowels for the cylinder head. It has a very small hole in it to reduce the oil to the head. It was my understanding from Ferrari that the restriction was required to the head as Cosworth found out during the development of modern high speed belt drive motors that excessive oil actually acted as a brake on the cam journals and overtaxed the belt. That restrictor is the smallest passageway in the motor and is post oil filter. Silcone and other debris in the sump will never find their way that far but sealant used at the oil filter mount can.

BB's and TR's had quite a few failures from the silicone the factory used at the pan rail. It would ooze into the main oil gallery passage through the pan rail and find it's way to that restrictor. They eventually switched to a 518 type product to prevent that.

It has long been accepted that the cam followers are capable of operating quite well from just a little runoff from the bearings. There are areas around their circumference that trap oil needed at start up. The lower bank of either the BB or the TR motor have far less oil around their cam followers at rest due to the arrangement of the cylinder heads. We have never seen this type of problem on any of those.

 

I am not there conducting the tests so I don't know what is going on. Barring a crystal ball I can only say the only loss of lubrication issue I have ever seen in these heads and we have seen it quite a few times, resulted in bearing damage. I have seen lubrication issues so severe the motor was seized, the crank blue, the bearings crystallized and the rods welded to the crank with zero head problems.

If you suspect insufficient oil to the head it needs to come off. It is the only way to access the restrictor.

 

Brian, going off reservation here.. what are the chances it's a weak spring? my other thought is that at some point the valve made contact with the piston, a light kiss and the bucket took the hit rocking in the bore. course this could be speculated on fer days....

seems like the head may be coming off, but that's to be determined by Bell ultimately.

Bell I'm curious as to how you can see down the bore far enough, with the valve and spring assy in place there is no way to inspect the bottom of the bore skirt for debris or damage. have you tried fitting the neighboring bucket in the bore and noting if it freely moves about?

 

Good lord! I don't wanna say good find though! splendid investigation more! How is the bucket chamber/bore looking? Hope that is still OK!

 

We have seen broken springs on QV motors with no noise. In those cases there was never valve contact either. QV motors have huge piston/valve clearance. Not sure a floating valve can make contact.

We had a mechanic at the shop chasing a weird noise on a Countach once years ago. He had the motor out and partially apart and never found anything. We gave him a hard time about taking a car apart for an undiagnosed noise until he finally put it all back together, made it run then did a good, complete and thorough job of finding the noise. Had it fixed a couple of hours later.

 

I don't think a floating valve could either in normal circumstances, way out timing or belt jump teeth sure, or possible timing out enough to kiss under float. I was just hypothesizing that a weak spring may allow for just enough float.

Oh, the oil galley with the dowel pin with the needle hole is on the exhaust side of #4 btw. in any case the bucket has been rocking about a fair amount, as to why.....