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K engine problems just before Haggis :-(


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[Also posted to the Sevens list.]


I buzzed my engine after fluffing a gear change from 4th to 5th. I think

the revs went somewhere over 8,000 rpm (the engine's not normally revved

over about 7200 - standard bottom end with 633(?) cams, Lotus Sport 135 head with Jenvey DTH TBs).


Now it's making a nasty tappy valvey noise, here:



(The recording makes it sound worse because the noise-canceling

microphone that I used did a good job of filtering out the rest of the

engine noise.)


There are more crackles and pops than normal when I drive it, and I

think it's down on power (but no slower because I rarely get chance to

use all of the power on my commute, so perhaps I'm going just as quickly

by using more throttle?).


Bent valve?


And recommendations for people who know their K stuff near Reading, and

are likely to be able to take a look and hopefully fix it on Wednesday

or Thursday? Otherwise I'll start phoning the usual suspects, starting

of course with DVA but he's bound to be booked up, and it's a long way

to drive a poorly engine.


I'd be happy enough if somebody could (truthfully) tell me "yes, there's

a problem but you won't damage the engine any more by driving it, so go

off to Scotland and fix it when you get back".


I'm currently a bit depressed. I'm really looking forward to Haggis, but

so is my brother who's coming as my passenger, and I really don't want

to let him down. :-(


I'm going into the garage to fix some niggley little problems just in

case the tour's still on for me...



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This might turn out to be a case of the blind leading the partially sighted, but ... Apart from taking the head off, you could check the cam to tappet gap in case one of the tappets has "lost" oil. Do a search and you find some info on this ....


Or could the cam belt have slipped a tooth?? Think I saw the photos on how to check the cam timing on your site. Maybe a good idea to check?


Sorry I cant be of any more help ....


Edited by - Adam on 17 May 2005 23:01:51

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Assuming you changed down from 4th to 3rd, you'd get the following resultant revs with your diff and gearbox - can you remember what you happened to change gear at?


Change @ Gives:

7200 9144

6500 8255

6000 7620

5500 6985

from here


Could be a broken valve spring or follower?



Phil Waters


Edited by - philwaters on 17 May 2005 23:09:25

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Go to halfords at lunch time and get a compression tester this is your first move.


Do a compression test you will find out from here how but easy enough whip the plugs out and stick gauge in each plug hole and spin the engine on the starter WITH THE THROTTLE FULL and record the results on each unit.


Post the results here and the wise ones will tell you but basically you are looking for variation.




The happy handle made me do it

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Max ever revs, according to Emerald: 7456


Compression test shows (in bar):

1: 16.5

2: 16.7

3: 16.5

4: 15.8 rising to 16.8 with 1 teaspoon of oil down the bore


They seem very high compared to the Haynes recommended minimum pressure of 10 bar. The maximum difference between cylinders is quoted at 1.5 bar, so in theory that 15.8 should be OK?!


I'm just waiting for the exhaust to cool down so that I can move the Apollo tank and remove the front cover to check whether the cam timing has changed.

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Jason 16 bar is normal for a K series, mine had 16, 5, 16, 16 and 100% leak on no 2 comapred with 8% on the other cylinders that we measured.


If the engine is just very tappety could it be air in the oil in your followers ?


if you only revved to 7450 then I can't see you breaking anything.


The oil making the compression figure rises just means worn rings I think. You'll need a compressor to do a leakdown test.




See willfly.net for more info.

If you don't spin you ain't trying *smile*

Happiness is knowing you have just a tad too much power *wink*


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Bummer. It sound pretty much ok on Monday evening.

If it's getting rapidly worse I would think it could go terminal pretty soon.

Dropped or snapped off valve or totally compressed tappet.


Compressed tappet would not be too bad.


Roy's offer of a head would be the quickest way if you can find someone to do the work.


Hants (North) and Berkshire Area club site here

My racing info site





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I've checked the cam timing, but I'm not sure whether it's OK or not. The clearest way of showing it is:


Crank lined up (confirmed with a mirror to eliminate paralax):



Pulleys out by ~ 0.5 tooth:



It could be down to the fact that when DVA timed them he used true TDC (measure on a piston) rather than the mark on the cover.


It maybe / sorta looks like the vernier may have slipped? Not really sure about that though.


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Your crank is at 90 deg BEFORE TDC there. You need to line up the mark on the rear of the pulley with the TDC mark which is with the group of marks on the cam belt cover at sort of 10 o'clock on the pulley.


see here




See willfly.net for more info.

If you don't spin you ain't trying *smile*

Happiness is knowing you have just a tad too much power *wink*


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Ok, I bow to superior knowledge, I thought you were trying to check the timing not get the pistons in a safe position.


What's Dave's verdict on the noise ?




See willfly.net for more info.

If you don't spin you ain't trying *smile*

Happiness is knowing you have just a tad too much power *wink*


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The hopefully final, anticlimactic update...


Phil came round this evening. Immediately reckoned that the noise was the injectors and perfectly normal. Checked a few other things over and then drove over to Phil's to a) try to provoke the real problem, b) collect appropriate tools if a) happened. Car was fine - top form, in fact.


Here's my theory / excuse for being an arse: there really was a problem on Tuesday, possibly aerated followers, probably unrelated to me buzzing the engine (because that happened on Monday, and both Phil and Steve heard it then, and thought it sounded OK). Wednesday, start engine, all geared up to hear a poorly engine, and I either do hear the remnants of aerated followers, or I hear the injectors and make up the rest. Spend the rest of the day pissing about and wasting peoples' time.


After I left Phil's place I went for a vigorous blat, on the basis that I'd rather blow the engine up down here rather than in Scotland. It didn't miss a beat. So the plan is to drive it to work and back home tomorrow (total ~50 miles). If it's OK then drive up to Scotland. If not then quickly hire a cheap hatchback, and drive up to Scotland.


Thanks to everybody who helped today, both on the various lists, and off. It was very much appreciated, since I didn't feel comfortable taking a "problem" K-series to anybody local.




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If you want to hear what a noisy injector sounds like I can bring my car over... *eek*


I presume your recording was at tickover? I'd say the ticks are more frequent than with my car. (Assuming my MEMS and your Emerald both do only one injection per revolution. Plus I have only one noisy injector.)

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Tony, yes it was recorded at idle. I think the MEMS (EU2, non VVC) uses batched injection, so it fires twice per rev. I think the Emerald is the same. My idle might be higher than yours, and as you say I might have more than 1 noisy injector.
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