96 Q: Valve flutter

[chuckphx]

Hello: I just had my 96 Q KS's replaced along with the EGR tube cleaned of carbon and all vac lines under plenum replaced. Car is 1000% better, but the valve flutter on acceleration is still there. It also has a slight miss in the feel of vibration when revving engine. Not a massive problem, but want my baby to be purring and it's just not there yet. Could this be injector related?

[maxnix]

Doubt it. Wish you could describe more fully.

Did the plenum get totally cleaned, including the EGR inlet? Lower runners?

[chuckphx]

My mechanic stated that the EGR tube was partially clogged and is 100% unobstructed. He stated that he checked all under-plenum vacuum/soft lines were checked and must have been replaced at some point due to their great condition. He said he did inspect and clean up the interior of the plenum...said it was a small amount of build up but nothing serious. He said the lower runners were fine and again the last owner must have had work done with plenum off as the overall condition was good. He also changed the oil and said that the oil coming out wasnt burnt or degraded too severely. He is not an Infiniti only mechanic, but he strictly works on Toyota and Nissan products incl. Infiniti.

The noise upon acceleration sounds like that of an old GM v8 with bad lifters. It is noticeable and it the r/r of both KS's havent improved this particular noise. My mechanic did tell me that with 154k miles on it that it does appear to be in fantastic condition from his perspective. Is there any valve-train maint. that is part of the Q's schedule? What, other than the EGR or KS's, cause the valve flutter noise? I bought this car as a long-term project to bring back to mint condition and am afraid that this noise may be a symptom of expensive times ahead.

Your thoughts/ideas are most appreciated and welcome.

[99q45t_vl]

How's the transmission fluid? Replace it with Redline D4

[chuckphx]

You will have to pardon me for possibly being ignorant here, but what would the transmission have to do with valve-train flutter?

[Q45tech]

HLA clatter noise [not valve flutter] caused by abusive oil change intervals?

Oil varnish can partially clogg tiny hole and reduce oil pressure which pumps up HLA. thus they make noise which sounds similar to noisey worn injectors. One uses sthethoscope to differentiate between cylinderhead and injector on lower runner.

BG Quick Clean for Engine treatments can remove some HLA varnish if instructions are followed precisely.

Abusive wear noise that took 13 years to create cannot be solved in a few months or even years .

[chuckphx]

Q45Tech:

Okay and thank you. I will give the BG treatment a shot and hopefully it will help. How often can this treatment be done? Is it recommended to be performed multiple times within a specified time frame?

Being that this engine is very sophisticated and the oil passage clearances are most likely very precise and small, will this treatment potentially flush 100% of the varnish/grime deposits over time if performed on a regular schedule over a year or two+?

I just bought the car in August and have done quite a bit of work on the deferred maint side of things, but am a little hesitant to tackle a larger job if needed. I am mechanically inclined and would love to be fully adept in r/r of the Q inside/out...just not confident enough at this time...so that said, the wallet tackles the jobs for the time being.

The service that was done this week was r/r KS's, r/r EGR system lines, r/r drive belts and oil change again (3rd oil change since August). It still needs some other jobs to be tackled, but am wondering if I should just buy a working replacement engine with higher miles and rebuild it with some of the mods that are suggested on other sites/articles re the v45 engine.

I baby the car and will until I know that all systems are in normal functioning order and little noises and vibrations always make me paranoid. More than likely I am my Q's hypo-condriac alter-ego.

[qship96]

Does the valve clatter{ HLA noise} go away after car has been running a few minutes and is warmed up?

[maxnix]

BG Quick Clean is ingested 15 minutes before immediately performed oil change. Do not let it sit after engine shut off and do not drive at WOT, above 2500 rpm, or very far. Idle is sufficient.

If they didn't remove the plenum and clean thoroughly, then there is a chance the EGR entrance into the plenum is still obstructed. Lower runners should have been cleaned also.

[chuckphx]

Qship96:

Yes, the noise is still prevalent even after full warm up.

[chuckphx]

maxnix:

The plenum was cleaned and the lower runners were cleaned as well. All EGR ports were fully cleaned and serviced.

[99q45t_vl]

You sure the noise you hear is the valve-train flutter ?

[Q45tech]

It is still a good idea to pull the passenger side valve cover to examine what might be gleened from looking...............take quality pictures with a reference color chip* [so we calibrate our cideo card and monitor]. So we can analysize the exact color of varnish and view any black/brown sludge and wear on cam billets and faces.

Please measure the hot idle fresh oil and filter PSI accurately at 750 rpm

* piece of pure white evelope = visible in each photo.

Finding a NEWISH JDM 1996 Engine is very difficult and time consumming [we have found 4 in the past]...............2 of which took 4 months to acquire after rejecting dozens of US junkers.

[99q45t_vl]

Or Gretag Macbeth Color Chart: http://gretagmacbethstore.com/...r.htm