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JeffAmentSlash

The Dreaded SR20 VCT rattle

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Hey guys

 

This is my current situation, so maybe 3 months ago my engine got rebuilt, while going through all the stuff that I was upgrading they said do you want a new vct gear and solenoid, I said with the amount im spending at the moment i really cant afford to.

 

Later down the track i decided that i would get rid of that dreaded rattle and bought a new gear. They put it in with the old solenoid as the old solenoid was functioning fine. I got my car back and for about a week the noise was completely gone then it returned, I had the workshop look over it , they spent 3 days searching for answers and were completely stumped. Everything was working fine oil was getting where it needed to, the solenoid was still working. They tried different oils

 

After been completely stumped i stumbled across a forum post on here talking about how someone just replaced the gear without the solenoid and within a week had the rattle back. I thought well ive wasted money on this gear maybe that solenoid somehow is screwing up. So i bit the bullet spent more money on , A brand new gear (again) and this time a brand new solenoid.

 

Both replaced and again the rattle has been gone for this time bout 3 weeks. This morning i noticed what i believed to be the vct rattle again, it was while the engine was semi cold and when I got back home after about 40 minutes the rattle under slight acceleration could not be heard. Im hoping I was hearing things but I wanted to know everyones thoughts on what the hell is going on with my sr.

 

I warm up my car, i don't push it until its warm, There is only really those two components that can cause it so surely replacing them should eliminate the problem but obviously we are missing something. Just need some help finding my next steps, ive searched a lot and i cant seem to find anyone that has had similar issues, replacing the gear and solenoid seems to always work.

 

I have got upgraded cams, Nissan , Kelford, my engine builder and workshop are completely stumped.

Any suggestions would be great.

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How big is the lift on the cams? If you're over 11.5/12mm, that could be it.

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I wouldn't expect cam's of that lift to kill your VCT that quick.

 

Are you running aftermarket valve springs? Stiffer springs like the BC ones can shorten the life of the VCT I believe.

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I put BC springs in my car against the better advice of my tuner and it cooked a brand new VCT in about 10k kms.

 

I put the standard valve springs back in and a brand new gear which then failed completely after a couple of weeks (it never became noisey - it stopped working altogether).

 

I ended up putting the noisy VCT gear back in and funily enough it was completely dead quiet and remained that way for approximately 20k kms.

 

The car now has another brand new gear in it and is dead quiet.

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Fuck this is exactly the next step the guys were thinking of, keen as to try it out, I reckon I still have my stock Springs too!

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Its interesting that the valve springs have such and effect, just out of curiosity would you know why? I find it interesting that a gear that makes noise will stop when valve springs are changed, they held my old gear for me so pretty happy that i have a spare one or that i don't have to go get new ones straight away again. Ive only gone about 700km since my vct was installed so thats obviously quite a difference though.

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I believe it's to do with the extra pressure on the cam and then cam gear causing it to wear

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Thanks guys, I have 85lb Springs wonder if this Is the issue, Is it worth just looking at new oem Springs. Also how long has your new gear been in the car for now with no rattle

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Okay so, we got in contact with kelford about the possibility of it being my Springs, they said oem are definitely not a good idea and that my Springs should be fine and they believe theirs a bigger problem elsewhere, back to square one now �� any other thoughts?

Edited by JeffAmentSlash

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Well they are definitely not going to say " oh yeh, it's our valve springs causing it" even though it might not be. Are you using a decent oil and the correct grade?

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We have tried using different oils of different grades. The cams actually come packaged with recommend springs, so considering they are the recommend springs and the chances of that being the root problem? I don't know I am totally up to being like yes cool lets change em, but if I am just going to be back in the same spot in 3 weeks id like to see if there are other opinions. I am almost at the point where I have to VCT delete which in my opinion is just absolutely ridiculous. Ive contacted other workshops and they have never heard of such a problem. Replace VCT gear and solenoid problem solved. One workshop said VVCT should never be used after upgrading your cams due to the extra pressure the aftermarket springs needed put on to the unit. I tend to disagree knowing that many others have upgraded cams with vct still.

 

I was talking to the guys to find out what deleting VCT would do and they said it would feel a little bit less responsive. Has anyone removed VCT from their sr20 for any reason and how did they find it. Obviously I want this to be the absolute last resort but I really do feel like I'm running out of options. These are guys who work on imports day in day out for many years, if they are clueless I am beyond clueless. Everyone I have spoken to has never heard of it coming back that quickly. Like i said 700km? Surely there is a bigger issue here.

 

Appreciate the help sxytime ;)

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being a less commonly used cam, its a bit harder to pinpoint exact cause.

 

but yeah grade of oil. springs and grind of cam can all play a part.

 

from what i very loosly remember. how hard the cam ramps down can play a part ? could be wrong, but someone had a theory on agressive cam lobe design once many years ago, and stiff springs to stop valve float, combined buggers teh VCT?

 

 

good oil plays a big part.

i got about 7000kms from my stock vct before it started playing up after i put in procams and type a springs. need bigger springs though, as getting valve float.

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Thanks for the reply man. We have played around with the oils, spending another week just trying to come up with things before we make our next move. Really keen on finding the root problem. Theres surely only so much that can affect the vct?

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