Engine Rattle From Vvti Setup

[bedworthmotcentre]

Hi everybody - bit new to this & slightly embarrassed to admit I run a garage, but I have a problem that no one seems able to answer so any help would be appreciated.

We changed an engine for a regular customer after her's had seized due to oil loss from faulty oil filter seal (separate story but don't take a chance with a Wix or Unipart filter on this car). Obviously I accepted responsibilty for servicing vehicle as I have a good and respected reputation and wish to keep it, after recently servicing her car. Basically we opted for a 'Reconditioned engine' rather than second hand to give the lady some warranty that she had got a better engine than her original unit. That's where my problems started we paid almost £2000.00 for a unit from UK Engine Parts, which was supposed to be fully recon'd, but to our cost found out that it was simply a cleaned up used second hand engine - after a lot of hastle from borth customer & no communication with UK Engine Parts - located in west midlands, we decided to repair all the faults we found on the replacement engine, oil seals mostly.

Got it all running, tested it & found that the head was leaking - I managed to get a so called recon'd head from Uk Engine Parts after they p***ed me around for about 4 weeks, put all back together & tested & monitored car for 2 days before I was happy enough to return back to a very miffed customer ( we had lent her a car in the mean time ).

Told her that after approx. 1000 miles would like to have back in & change oil & filter.

Great I thought problem finally sorted.

After we had the car back to change oil & filter customer rang 2 weeks later & told me she had had to put about 3 liters of oil in.

Alarm bells !!

Asked her to bring it straight in - checked for leaks - bone dry, no smoke comming out back, sounds lovely - could not fatham it out.

Took it for run great until it hit approx 3000 revs then black smoke billowed out - we obviously assumed at least rings gone possibly piston wear.

By this time we obviously knew that it had not been recon'd - so I agin lent customer a car & told her that we would strip the engine down ours selves & get all bits needed properly replaced - you can tell where I going of the overall cost of this can't you - but hindsight is great if you've got.

we had 1 piston replaced, full set of rings, etc & found out that the head supplied had not been skimmed at all.

I forgot to mention that when we put the replacement engine back in 2nd time we caught the oil continuity valve & broke so put new one in.

Anyway put engine all back together for about 6th time ( i lost count ) , on tick over sounded so smooth & quiet, however on test run it had developed a rattle on top end at around 1700revs that stayed there, I mean it did not go away through the rev range until dropped to below 1700rpm. We took it down to the enginers who had put the internals in for us & they tested oil pressure = 75psi which they said was great, maybe valves hitting pistons ?

On way back we felt something go in engine & towed back - stripped head off & found valve seat had dropped out of 1 & broken valve head off another! - Resulting diagnosis from us that it had been skimmed too much - so got another full second hand head complate with cams & VVT unit.

Put it all back together after skim & pressure test on latest head & guess what top end noise still there !

Noise stops if you unplug ther oil continuity valve that controls VVTi.

Local Toyota agents sent me test info. on valve = OK.

So my problem lies in VVTi set up , have put new VVTi cam end counter weight & still have problem.

PLEASE ANYONE HELP I USED TO HAVE A FULL HEAD OF HAIR !!

[Jamesbelfast]

Hi Bedworth - you have all my sympathies - it's one of those jobs sent to try you.

I have came across similar problems on a different brand of engine (a Renault) EEK!! - I hear you say.:)

After numerous rebuilds using 3 diferent cylinder heads the top-end rattle still persisted - eventually it was discovered that all 3 heads had been skimmed beyond their safe dimensions. In fact I was able to discover that the heads were unsuitable for skimming. The manufacturers state the head should be renewed. Have you been able to check if the latest head is still within the manufacturers specifications. My reason for asking is that your second head seems to be displaying similar symptoms to the first.

The above information may be totally useless bit it may be worth a shot.:)

Good Luck!!

[bedworthmotcentre]

Thanks james, yes engineers checked this when sent replacement head.

I think the problem lies within the VVTi - even thought about fitting standard cam sprocket & doing away with VVTi ?

[Jamesbelfast]

Thanks james, yes engineers checked this when sent replacement head.

I think the problem lies within the VVTi - even thought about fitting standard cam sprocket & doing away with VVTi ?

If you fit a standard sprocket the ECU may throw a hissy fit and throw its dummy out of the pram.:)

From what you say it seems there is definitley a fault in the VVT aspect but knowing exactly can be difficult to trace. But if the noise disappears when the activating solenoid is disconnected may be a clue. My understanding of the sytem is that when the system needs to adjust the control unit allows more pressure to go to the adjusting system. Could it be the control unit is faulty and allowing full pressure when it shouldn't or is the unit on which the oil pressure acts be furbarred.

Maybe I'm grasping at straws here.:)

[anchorman]

I don't think you will have any success in removing the VVTi sprocket. I do think like you it is related and would go back over it. If you remove the plug the oil pressure will drop and the inlet valve timing will be retarded which silences the rattle suggests it is there somewhere. Just have a look at this diagram and check that the timing marks align on the sprockets AND the VVTi unit;

timing_marks.pdf

[daveh_rav4]

Wow... a nightmare job from hell all caused by a non genuine mal-fitting oil filter seal :o :(

Fourty years ago I worked as a mechanic and vehicle technology was obviuosly a lot simpler then and vehicle repairs more forgiving! You could skim a head two or three times (normally to increase the compression ratio for more BHP). With all these modern engines (with there granted benifits in certain directions) we seem to have boxed ourselves into a corner... they are exorbantly exspensive and difficult to repair if at all! I have a 10 year old Rav4... if the engine went on that it would probably be uneconomic to replace and in many circumstances a vehicle only a few years old would be scrapped because of the complexity and expense of repairing it! I never agreed with this ten year scappage scheme where perfectly serviceable vehicles with many years of useful life left in them were being scrapped for economic reasons. Maybe we should be looking to simplify vehicle design extend there servicable life and preserve the earths resources. Dispite recycling... it still takes a lot of (carbon) energy and addional resources to build a replacement vehicle. CLUNK... opp's, that was me just falling off my green soap box! :D

Now that's what you call a decent thead drift eh!

DaveH

I don't think you will have any success in removing the VVTi sprocket. I do think like you it is related and would go back over it. If you remove the plug the oil pressure will drop and the inlet valve timing will be retarded which silences the rattle suggests it is there somewhere. Just have a look at this diagram and check that the timing marks align on the sprockets AND the VVTi unit;

timing_marks.pdf

[in_the_no]

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[anchorman]

Interesting thoughts Dave H.

There is no doubt you are correct but it seems to be legislation that drives development these days. Manufacturers are forced to create hugely complicated devices these days mostly to meet emmission standards. When you think about the cars we cut our teeth on (Minis, Cortinas etc) it is mind bogling how far we have come..........

We'll be driving about in cars that absorb radiation from a depleted ozone layer before you know it (sealed for life!!!).

[bedworthmotcentre]

Thanks, to all that have responded to this query, we have checked all that you have advised - I personally think the fault is in the oil continuity valve but according to Toyota's test data it should open one way with Battery voltage & close without - it does this, so am I to believe it is working OK or does anyone know about what pressure it should operate at ?

[bedworthmotcentre]

HI ALL,

HAVE NOW FITTED NEW OIL CONTINUITY VALVE ( 2ND ONE ), AND NOW DOES NOT RATTLE AT ALL UNTIL ENGINE GETS WARM ?

DOES ANYONE KNOW WHAT RUNNING PRESSURE THESE UNITS WORK ON ? I'M GETTING 75PSI AT OIL PRESSURE SWITCH ON THE HEAD - WHICH TO ME SOUNDS PRETTY GOOD, BUT THEN I'M NO EXPERT & AFTER THIS CAPER I MIGHT GET jack IT ALL IN & BECOME A FLORIST OR HAIRDRESSOR !

BY THE WAY ONCE ENGINE IS WARM IS EXACTLY THE SAME - GET TO 1700 RPM & RATTLES.

[dave.m]

You might be better posting a link to this thread in the General Discussions forum. There are a few members of TOC

who work for Toyota, but dont frequent the Rav forum very often (Moonstone Mart springs to mind) They may have

come across this problem before. Try doing a new post on there under the heading of VVTI problem and post the link

to here. Save all the typing again, good luck

[anchorman]

Good suggestion Dave, I understand the theory of VVTi perfectly but have never come across this problem.

BedworthMC - are you sure you have got ALL 3 timing marks right as in the diagram? That is the 2 on the sprockets and the 1 on the VVT hub. It sounds like the valves might be contacting the pistons when the revs and the oil pressure are high enough.

Just look again at that diagram.

[bedworthmotcentre]

Thanks Anchorman, yes we have checked all timing marks line up about 3 times, the noise was present on the original strip down & rebuild & again after head replaced & timing again refitted.

[bedworthmotcentre]

Would turning back timing on VVti unit 1 tooth have any damaging affects - I know in the past we have had to do this on diesels regardless of timing marks ?

[anchorman]

Well that is a good question. Before you go down that route, have you checked that there is nothing wrong with the sprocket fixings on the cam? VW/Audi have a known problem where the key on the crankshaft wears and lets the timing drop back. I suppose to test your theory you should turn the engine to 90 deg BTDC to get the pistons away from the valves then connect it up and ease it forward to make sure there is no contact. If you can also work out the equivelant amount of advance the VVT hub gives and then do that as well by knocking it back more teeth it might tell you but do it all by easy easing the engine around. If I want to do that carefully, I take the plugs out and jack up the OSF wheel so I can put it in gear and ease it round in 5th gear.

Do this at your own risk!!!

[in_the_no]

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