K series tick tick ticking...

[V7 SLR]

I spent Saturday at DVA Towers. My intention was to shim the bloody engine the way Dave does it, rather than my (obviously) crap method.

 

Upon reassembling the engine, Dave helped me time in the cams. We actually spent a good while doing this because upon my initial reassembly we both discovered that I’d got it out by one tooth. Don’t know why but it was definitely out by that one tooth. Eventually we had an almost perfect 130/110 (Dave’s good – he got it to a repeatable 129/108) and all the marks on the cam pulleys lined up too (double confirmation). Dave explained that my cam tensioning was inadequate too. You have to push the tensioner past the maximum once you’ve had the head skimmed, effectively resting the outside of the tensioner’s backplate against the retaining bolt. I hadn’t done this before so I was running waaay too slack.

 

4 weeks earlier, at Emerald, I timed in the cams using their 3 dial gauges on their little brackets but having subsequently suffered with crap throttle response and flat performance I am now convinced that the belt must have jumped a tooth. As it was never really satisfactory after that session I went down the road of investigating shims, thinking cam timing would be affected by very bad shim gaps. Hadn’t occurred to me that it may have jumped a tooth.

 

Anyway, on Saturday, when we rolled V7 out of the garage and fired it up it exhibited the smoothest sounding idle it had ever had. Even from new it was slightly rattley, but on Saturday evening it sounded fine. The shimming technique had worked.

 

Dave adjusted some of my map settings (too much fuel compensation at start-up in the “warm” regions) so that it now starts on the button without the need to feather the throttle. I like that. Gives it a “production” feel. ;-))

 

On the way home V7 simply felt electric again. All the lost throttle response had returned. Blipping the throttle when changing down was back to the lightening response it used to be. No more bogging down. Bloody cam timing..!!

 

 

One problem has surfaced though which I need help with please. As V7 warmed up on Dave’s drive a single tick became audible. I thought perhaps I’d messed up one of the shims (wouldn’t have been the first time eh?)… so I left it as it was. It couldn’t be that far out. I’d checked and checked again when building, and the tick wasn’t that loud. Perhaps I was being over-critical?

 

Anyway, drove home and put V7 away. This morning I was due at Hoopy Hall to help him rebuild his car but had to stop when the ticking became extremely obvious. I had fitted a new dizzy cap yesterday as I’d broken the old one (long story and not relevant) so I took it off to check and (shag..!!) broke this one..!! Called RAC and waited 2 hours (I specifically requested recovery – I hate them messing with my car). Got home eventually and bought a new dizzy cap from Halfords. Then I set about checking the shim gaps again (I've gotten good at taking and rebuilding the head over the last 2 years). One was slightly tight, so I took the cams out and juggled a few shims around until I had the required gap on number 5 then reassembled.

 

Started V7 up again and BINGO, it sounded perfect… until it warmed up when the loud ticking resurfaced.

 

It can’t be top end can it? If it was it’d rattle from cold… probably worse when cold, no?

 

Forged pistons slap a bit, but that’s supposed to get better as the car warms up. There is no noise when cold. The ticking appears to be in time with the rotation of the engine.

 

Question is, could it be big/little ends? Wouldn’t they be noticeable from cold?

 

Please help. I’m at my wit’s end with this engine. A gallon of 4-star and a match seemed appropriate whilst I waiting for the RAC in Kidderminster.

 

Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours

 

[V7 SLR]

It's been noted that this type of ticking might be caused by a knackered exhaust gasket. Although I changed it when I rebuilt the engine after the Winter, I have loosened the manifold up to 4 times since to allow my fitting and removal of the cat for the MoT.

 

I'll buy and fit another new one and test again.

 

Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours

 

[F355GTS]

Leaking Exhaust manifold?

 

Mark

[Jason Plato]

loose spark plug ?

 

 

[Slarty Blat Fast]

Injector?

 

Absolutely no hitchhikers

[V7 SLR]

Manifold ought to be OK. Not really a "wear" item. Gasket sounds likely as does whether or not the lambda is screwed in properly (it's in only one branch of the manifold).

 

Spark plugs should be fine too. I cleaned out their seats on Saturday. The new cam cover is so low that the spark plug leads stand proud, meaning dirt and grit falls into the holes. Perhaps I need to check those seats again, just in case. Does anyone know whether the thread on the plugs forms the seal or the seat?

 

Injectors are fine. This is far too loud to be one of those.

 

All suggestions gratefully accepted. Thanks.

 

Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours

 

[Peter Carmichael]

The "washer" on the plug deforms to form the seal. It doesn't necessarily deform more than once perfectly, but nipping them up always seems to work for me.

 

Could it be something to do with throttle body balance. This makes quite a pronounced ticking sound at idle. When I adjust butterfly position and bypass I get a veriable amount of hiss and tick tick sound. Get the old bit of rubber tube down your lughole and localise the problem.

[Rob Walker]

Remove the cam cover and check if any of the inlet cam lobes are hitting the ali cam carrier. IIRC you have installed 1227 cams. if so the head needs fettling to give clearance. If insufficient metal has been removed it may only contact when hot. Look for a shiny wittness mark or check with feeler gauges when hot.

[V7 SLR]

I'll give that a check Rob. DVA got me to fettle the head, so I went a tad overkill I think. Probably too great a gap by the side of the lobes if anything. Worth another look definitely. It (the ticking) only surfaced on Saturday... read on.

 

Found what may be the problem last night. Alloy shavings in the cam pulley area. Had to push the tensioner up a looong way to get the required tension and it seems it's been rubbing on the inlet pulley. This is a likely candidate. I pushed it that far up for the first time on Saturday which leads me to believe this might be the cause.

 

I have pulled apart the engine (again) for a number of reasons (leaking cam seal, replace the belts now covered in both oil and alloy shavings, yada yada yada) so when I put it back together I'll check all gaps around the cam lobes and pulleys.

 

Thanks.

 

Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours

 

[CHRIS CLARK]

Keep on like this and you'll join that exclusive Mick Smith/ Peter C club of 100 engine in/out/in bits per year!!!

If you are using the std. cam belt tensioner pulley fitted into the thin steel retainer with a cut out slot it is possible to remove the pulley from the carrier (it can be pressed/tapped out), moved around slightly and refitted to gain more offset which allows the locking bolt (not the centre socket head cap screw) to operate in the middle of the slot rather than right to one end!

Easier to do than explain!!!

[V7 SLR]

I've heard that it is possible to move the tensioner backplate, but my experiment of clamping it in the vice and tapping it with the hammer to move it round didn't work. It appears very firmly fixed in.

 

I now have a re-welded one which gives me more travel... a cut and shut affair. If you didn't know, you'd never know it wasn't made that way. Chap who made it for me has blended in all the radii so it looks perfect. Took me a while to find a common point to compare it with a normal one.

 

Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours