Possible Vcis/Vtcs issue?

it def dont sound like piston slap its a fast thumping rattle and i only hear it under a lil acceleration say at 3k and if i hold it there it sounds like the head is gonna explode but if i rev faster or slower u dont hear it at all. not even at idle... Vtcs delete has already been done my nephew told me today that the cams had score marks on them where they ride the journal most likely due to the other oil pump failure when it spun the rod bearings and the PO still thinking he could still drive the car like an idiot. by the way on the old crank every bearing had score marks on them do i def believe the old oil pump failed but no damage to the block and cylinders were honed during rebuild. i really need to get a video of it

i will be posting a video tomorrow once i redo my manifold and find that damn vacuum leak. i can hear it n when i spray carb cleaner the engis rises but it could be in the injector area or the mani gasket which is new. i heard if u suck seafoam from the pcv valve it will pinpoint the leak but i dunno how it would do that can someone tell me?

OK there are many threads on here with rattle sounds just as you described, and nobody has come forth with a solution other than they replaced/rebuilt the engine and the noise went away. Mine has the exact symptoms and the only way I was able to quiet it was switching from the usual 5w30 to 0w40 synthetic. The noise is still there but barely audible when warm, and the cold start rattle was reduced to under half a second instead of the usual 3 seconds. I actually have to try to make the noise now instead of hearing it at the top of every shift and when I'm cruising. 0w50 would probably quiet it even more.

Trust me I know exactly what noise you're describing. People will say VTCS until they're blue in the face but that's not the issue, as you've proven to yourself already.

You are correct you just described noise I am hearing It is at the top of every shift and while cruising It's such an ugly sound. which makes me think about replacing the head with 1 of the ninety's models 2.0 heads I don't think those suffered from this issue

Yep, try the oil swap first. You might find that it's a good enough "fix" for now. To me it sounds deeper in the block and not the heads but again I haven't seen anyone prove exactly where the noise comes from. When people tear into the engine they usually replace everything. I might do the same soon as I like this car too much to let it go. The car looks almost brand new inside and out considering 155,000 miles.

008 said:

Yep, try the oil swap first. You might find that it's a good enough "fix" for now. To me it sounds deeper in the block and not the heads but again I haven't seen anyone prove exactly where the noise comes from. When people tear into the engine they usually replace everything. I might do the same soon as I like this car too much to let it go. The car looks almost brand new inside and out considering 155,000 miles.

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well i literally just rebuilt the bottom half on the engine with all new parts (crank,pistons,bearings,seals,rings,oil pump ect ect) so i know its not lower but the head was never touched except to remove and install and that is y i wonder if the cam journals being worn and maybe cam caps can cause this issue... the engine spun 2 bearings cuz the oil pump failed and all bearings in bottom end has score marks and the cam journal had marks on it too.... i dont think i can replace just the cams and cam caps cuz i believe the cam caps are milled with the head so a different set may b off slightly i dunno.

A long socket extension to your ear and carefully(!) listen at the head and the block. You soon discover where the noise is coming from...

P-Funk! said:

A long socket extension to your ear and carefully(!) listen at the head and the block. You soon discover where the noise is coming from...

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yea already did that that is y i keep mentioning the head. cuz i know for sure it is not the block but thank you

ah - ok.

whatusername said:

well i literally just rebuilt the bottom half on the engine with all new parts (crank,pistons,bearings,seals,rings,oil pump ect ect) so i know its not lower but the head was never touched except to remove and install and that is y i wonder if the cam journals being worn and maybe cam caps can cause this issue... the engine spun 2 bearings cuz the oil pump failed and all bearings in bottom end has score marks and the cam journal had marks on it too.... i dont think i can replace just the cams and cam caps cuz i believe the cam caps are milled with the head so a different set may b off slightly i dunno.

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have you checked the valve lash? It could be simple as that...improper clearance can create some wild harmonics at different speeds, particularly if there is too high of clearance (too little, not as much noise but burning oil and a very problematic idle/low speed...and it'll quickly fail)...its very easy to check...

i don't know about the cam journals, though...you're right, if they're out of round, it'll make some noise...but it will quickly come apart from that...its not something that could simply 'make some noise' for a while and nothing else...

i'd suggest picking up a solid lifter feeler gauage at a parts store...pulling the valve cover off, and checking valve clearance...you do not need to remove the cams for this...with a proper mic, you can also check cam thrust clearance...but you'll have to take the cam gears off...and therefor is a much longer job of undoing the timing belt and everything...

to check clearance, ONLY rotate the cams by turning the crank pulley bolt clockwise...DO NOT crank it counter clockwise, you'll load up the belt incorrectly and possibly skip a tooth...its much easier to do this by also removing the spark plugs, as you'll remove cylinder compression...and a simple ratchet will be all you need to turn the crank...also DO NOT turn the cams individually with their cam gear bolts, or the ground in hex on the cam shaft itself...that will also load the belt incorrectly...the timing belt's tension system is only designed to be turned clockwise from the crank itself...anything other than that should be avoided...

your clearance for stock cams should be around .012" for both intake and exhaust...you can easily check for bearing cap problems (if one is noticeably loose or something), but DO NOT just release those with the timing belt installed...the cam's hardness is many times higher than the aluminum head, and you will quickly 'dig' into the thrust cap and first journal area...possibly messing up the head even more...check to make sure the numbers on the caps are in proper sequence, and all are installed in the proper direction...if any of those don't line up, you'll quickly be narrowing down your problem...also, see if you can physically get any play in the cams just by grabbing it with your hand...when properly installed; those things are locked in so well they might as well be part of the head...ANY shifting or slop is NOT supposed to be there...and they should be very tight to rotate even with a wrench...

also, while you're in there...you could try loading up all the lobes and cap areas with big globs of assembly lube...that stuff will stick to those areas for at least a few minutes of engine operation...if this problem does have something to do with the weight of oil you're using; this will show it on the first start up...if there is no noise and you didn't change anything other than some assembly lube on there, chances are you have some form of an oiling problem...if it still makes noise with assembly lube, and with proper valve lash...the cam journals are probably toast, and it'll take either new cams...or a new head...to fix...

Do you have to use the SST to change out the solid valve lifter shims or is there some easier method ??

The SST is not required, but any other method adds risk to damage

^^yeah...

some have said that the 'toyota style' shim extractor tools will work with our heads...its just a wrench that will slightly push the valves down, away from the lobe's base circle, and allow you to pop the little shim out with a small pick or screw-driver...but, i've never seen it done, nor do i know which tool specifically works...as they seem to be available in several sizes...

obviously...you don't have to do it that way...by far the safest method is to simply remove the cams...but that adds considerable work to the project...making something that could be done in under an hour...a half day job if you're by yourself in this...

and forget about the SST from Mazda...some dealerships won't even sell those, and others will charge so much money its just an insult...it would be cheaper to just build your own SST...

I checked my valve clearance last year when I did my timing belt. All but three were within spec. and those three were only very slightly over (I don't remember exactly and didn't write it down). If it was as simple as loosening off a lock-nut adjusting the tappet then tightening it, like my last car, I would have done it. I'm figuring that it's close enough. I'm not hearing any excessive noise.
Am I correct in assuming that the shims are just sitting there on top of the valve once the cams are off and just pop right off??

No shield I have not Checked valve lash but you're right it could be that and I should and will check it I just didn't know how but thanks to your write up I should be able to do it. and as far as damage to the head you know howyou're supposed to put the cams in a entertain way? Well I did not do that I completely forgot about that And the manual says it will create a burr so I hope it did not. I think I am going to buy a spare head just in case I've only managed to put 200 miles on this car so far and thank God nothing has went boom

Loose valve clearances will cause noise at all RPMs. This is not happening here. Something is rocking back and forth at 3000+ RPM and no load. Creating a load removes the noise. Thinning the oil reduces the noise. The noise is there regardless of engine temperature. The noise sounds like marbles in a can, not tapping normally associated with valve noise. I'm all for trying anything but I don't see this as a valve-to-cam clearance issue.

008 said:

Loose valve clearances will cause noise at all RPMs. This is not happening here. Something is rocking back and forth at 3000+ RPM and no load. Creating a load removes the noise. Thinning the oil reduces the noise. The noise is there regardless of engine temperature. The noise sounds like marbles in a can, not tapping normally associated with valve noise. I'm all for trying anything but I don't see this as a valve-to-cam clearance issue.

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Yea but what? i swear when i hold the throttle to the point where it makes the noise at idle it sounds like there is something metal broken in there but there aint that i can see. i removed valve cover and checked to see if all caps n bolts r tight and they are then i took a magnet n stuck it in every hole it has and nothing came out.. this noise is enough to make me want to sell the car its so damn ugly. but other than the noise it runs fine

008 said:

Loose valve clearances will cause noise at all RPMs. This is not happening here. Something is rocking back and forth at 3000+ RPM and no load. Creating a load removes the noise. Thinning the oil reduces the noise. The noise is there regardless of engine temperature. The noise sounds like marbles in a can, not tapping normally associated with valve noise. I'm all for trying anything but I don't see this as a valve-to-cam clearance issue.

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loose clearance will cause noise at all rpm, but not necessarily noise you can hear once other engine noises increase...more importantly...EVEN loose clearance will cause consistent noise...but if you have some lobes tight, and some not...i promise, a lot of different sounds can start happening at different rev ranges...

you're right though, load on the engine shouldn't make a difference with valve noise...and temp definitely will make a difference, so its most likely not it...all i was saying was that it was worth checking, given its very easy to do...but if you're positive its a 'no load' problem, the only thing coming to mind would be crank walk...but you guys are positive its coming from the head?

yea im positive the bottom end is nice n quiet even when revving i used a long thick screwdriver to the ear and listened to the bottom in different places and the the head on different places and its way louder on the head towards the drivers side

Sub'n in hopes someone finds the cause of the noise. I have what seems to be the same noise, some days it sounds worse than others but it did seem to become more noticable when I switched from normal 5w30 to Mobil 1 5w30 synthetic oil. Maybe I am now just more aware it is there but sometimes it sounds like it is going to throgh a piston out the block. Other days it is not bad at all, first I thought it was an exhaust leak/hole in the header or something but it sounds more like a rattle.Car has 150,000km so maybe just old age.