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5 GT Turbo EFI - GT Turbo

Update, so the old C1J is playing silly buggers.

After a bit of advice on what could be the cause as its baffling. I am pretty certain it has something to do with pushrods, cam followers, head work that's been done. @Clarkey will probably have something to add to this so here goes.

So top end is sounding very tappy, much more tappy that it should and we all know they can be sewing machines at the best of times. So checked valve clearances and all sorted and within tolerance, tapping still very evident after a run warming car up etc.

Today swapped 6 out of 8 push rods for good condition unmarked and straight ones. Some of the ones I swapped were not in the best condition to be fair, quite a few witness marks and many discoloured. Also using a straight edge many slightly bent. Once changed re-set valve clearances and out for a short drive, on start up still tappy, out for a run and seemed to clear once getting a bit of heat in the oil. Then opened car up for a bit of a blast, very short one mind through 2nd and 3rd.

Anyway, back on the drive and tapping is still quite evident. @StavFC copied, Steve will be able to add his 2 pence worth.

@Fordy mentioned cam followers to me the other day? Any thoughts people?
 
I've nothing much to add, aside from I was 99% sure, once warmed up, on the gentle drive the engine was as quiet and lovely as I've ever heard a C1J, even when stopped at idle at lights etc, super quiet sounding.
BUT then Mark gave it some a couple of mins before got back, and then after that it DID sound a bit too tappy at idle for my liking, which, when it didn't before that, points towards something changing after he put it under load.

Small witness marks on pushrods 2/3 the way up on some where they'd hit the head as they're close to the holes, not severe though, none bent bent, but with a straight edge I'd say at least 5 of the ones changed had a slight kink on the bottom inch. Some visible by eye (carefully), some not.
Personally, if I was having head work, I'd be opening the holes up so that doesn't happen.

Do followers knacker up much on C1Js? I've no idea, but it's tappy top endy noise which is usually blamed on a sticky follower on most engines.

It's not bad bad, someone less paranoid than Mark prob wouldn't notice, but it's not how it was, so I'd be inclined to try and solve the mystery.
 
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What a ball ache !!!!!
Somethings not right, was all good before the headwork, right.
What valve springs you got on there now?

As you know, had this all year. Once I set the clearances the engine sounds sweet and pretty quiet to be fair.
After a session, it starts to get tappy and we re adjust. This year forever checking/changing clearances!!!

In the past with BP285 and RT300 hardly ever got tappy , we would check after every couple meetings but very rarely adjusted anything.
I have put all our issues down to the cam with the added lift, maybe spring pressures if you got the same now.
Pushrods flexing?

Looking forward to taking my engine out and sorting this.

On the plus side I'm getting somewhere on pushrods :)
 
@StavFC - You were saying the same about the high lift cam weren't you ?

@Clarkey - The CTM invoice just states race spec springs not duplex. Charlie did ask me about which cam I was using and as I wasn't 100% sure I told him to assume Piper 285, that of course may not be the case. I'm not sure if anything else other than the push rod could be the culprit ? Cam follower ?

Odd thing is on the way up to Scoff's car was quiet, on the rollers car was quiet, then bent push rod (we fixed it) car was quiet, all the way home car was quiet. It's only been since our recent stint of timing the car that this particular issue is evident.

I'm not sure on the next step to take to be honest? I could give Charlie a call and ask for his advice ? Perhaps a spring change and to ask if he can add a bit more clearance where the small witness marks are/where push rood "seems" to be hitting. I'd love to see what cam is in there, if I do that I might as well refresh the whole lot.

As a next step I will check the new push rods we put in today as they were very clean so any obvious marks will show nicely.
Any other pointers/opinions would be appreciated.

Also, no this didn't happen with old head.
 
I said to you when we was doing your car what someone has before on here, maybe on that Pushrod thread, that the more lift you have, the closer the pushrods get to the head, and yours are close, hitting slightly going by the slight witness marks.
The fact they're close but NOT touching normally when turning the engine by hand, but clearly have, suggests, as Clarkey mentions, that they flex under load, which is when they hit.

Also, you've got bigger valves, so more surface area for the cylinder pressure to be pushing against, making it harder for the pushrods to open them under full boost, meaning more likely to bend the cunts now, than with your old head with stock size valves, when there was never an issue.
More power and boost is more cylinder pressure too, again making it harder to open, again giving your pushrods a harder time than it used to be at 23psi.

IMO it's not valve springs as the root cause, and even IF it was you'd be taking the head off to sort that, and then you'd be far far better off just enlarging the pushrod holes and fitting them Isky rods, rather than fitting weaker springs.
Weaker springs is like putting a plaster over something rather than actually fixing it in my eyes.

Considering how mild the witness marks are, that in itself isn't the issue, but the fact some seemed slightly bent at the bottom 'may' be, but even that I'm not convinced as we checked the valve clearances prior to that and they were a little tight if anything, not loose how a bent pushrod would do.

It's about look at this logically rather than changing bits willy nilly.

The only part not checked, and a part well known on engines for being noisy, is the lifters/followers. But on 5s I've no knowledge of them.

First up, have a look at the pushrods again before making more decisions.
 
I can only say what I've experienced.

Cam followers wear one side of the lifter bore and can dome on the face, but this would of been there before.

Middle rocker shaft bolts pulled out the head after some high rev's think it was from selecting wrong gear that caused it,

Cracked valve collets causing tapping noises and valves sunk and rocker arms run on collet.

Exhaust valve's stuck or sticking in guides straight after CTM worked on it (they fitted new guides claimed my valves expanded more than normal)

Now something i don't think would effect you but i'll say anyways,
I used titanium retainers to suit my wider catcam valve springs.... now my retainers where very close to the rocker arms at low lift so i expected at high rpm they would move around a little. So I put more of an arc on the bottom edge with my mini belt sander. Weather or not yours are similar i don't know.

Could be push rod flexi, lets face it everyone at high boost/power has bent a few at some point, but for it to happen at idle? i'm not convinced
 
Thanks Adam,

I'll check the new push rods that I've put in and go from there. To be honest after that I am not sure what to do next ? Leave it and cope with sewing machine 5? Take head off to check valves or sticking guides and get it checked by CTM? Source different rods?

Dunno ? Bit frustrating to be honest, just want to use it without incident.

Longer term, let's say that I do go ahead with bottom end refresh and change cam I am going to want to use the head I've just paid the best part of £1000 on but then would be annoyed if this issue still remains. What I find interesting though is as I've pointed out before, is the fact that when head was first fitted, clearances set, driven around for a while, head re-torqued, up to EFI and back - almost silent despite bent rod. So what's changed since the weekend ?
 
Blowing manifold gasket will make it sound like a sewing machine. I would check that as you may have lost some nuts after refitting it all.

Yeah all checked and done up Mark, double checked intlet/exhaust bolts too.

I'm working from home tomorrow so will spend some more time investigating.
 
Blowing manifold gasket will make it sound like a sewing machine. I would check that as you may have lost some nuts after refitting it all.
Also a cracked manifold would too. Manifold related ticks often quiet down when it gets hot though.

Mark do you have a stethoscope?
 


So I think I've found the issue with tappy engine, it's still blowing at join despite all 4 bolts done up. I've checked both faces and they are clean but it doesn't look like they are flat. I've ordered a metal 200SX gasket this time so hopefully will fix it.

@DaveL485 - I may need your advice on ecu to adjust idle afrs slightly.
 
Mines worse than that on a cold start up.....
I don't run a gasket, when it warms up, seals together nicely.

Mine is sometimes noisy with the paddle clutch......depress clutch and all quiet again:)
 
Not sure if its normal Mark but mine does it so bad you can hear it blowing.

Does it not seal its self once its warmed up ? Mine never sealed with gaskets on....
 
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