VX Sounding "Tappety"

[J7HPC]

Hi All,

 

Just bought myself an HPC after a long time of wanting a Caterham and I've just posted a question to Chit Chat asking if anyone knows a good place near me to take it for servicing and TLC. Overall the cars great BUT it seems to have an intermittent nasty "tappety" sound and was wondering if this is something common.

 

Essentially I'm being very careful to warm up the car properly etc and it runs fine but after my first long trip the other weekend it started to sound like it was ticking a bit but then cleared.

 

I've driven it a couple of times since, only local trips and it's fine but then just occaisionally will sound tappety.

 

Oil level and pressure is fine.

 

I was wondering if this is common with VX engines or if I should get it checked over as a matter of urgency?

 

Cheers

 

Rupert

 

[pussycat]

Hi

 

I had exactly the same issue with mine. I did cure it by putting on a different sump bought from caterham. However the new sump was so low I have literally just worn it away and am about to put the old one back on so expect the 'tappety' issue to return. I am hoping to go the whole hog and fit a dry sump later in the year.

 

I was told not to worry too much about the noise but as I do track days I wasnt happy with it either!

[kenny.]

I had it too with my HPC years back.

 

2 issues solved it.

 

1) I stopped using 0/40 Mobil 1.......I switched to 10/40 Valvoline, ran quieter when very hot.

 

2) Oil pressure relief valve. I'd fitted the after market fibre jobbie after I thought original may be sticking. On advice from Mr.Webb I switched back to a new original item...........no tappety noises any more.

Car was running 42H QED cams on standard oil lifters........is your Swindon kit solid lifters or normal?, if normal check which oil you use.

 

Oh, and forgot to say. If it's a standard VX Caterham sump I found a 1/4 inch overfill helped things too

 

Good luck,

Kenny

[pussycat]

That was interesting reading! I do use the 10/40 and like you find slightly over filling helps. Now going to check out the oil pressure relief valve when we put old sump on this afternoon!

[Paul Deslandes]

Hi Rupert, welcome to the world of Vx engined 7s.

 

The cause is lack of oil in the hydraulic cam followers which can happen after a spirited drive, especially on the track, when the oil disappears up into the engine and can't get back down into the sump fast enough. This can be helped by changing the oil type, as suggested. As the car is new to you, and I assume its wet sump not dry, check that the dipstick is correctly calibrated. Because of the shallow sump, the oil level needs to be a bit higher, but not too much higher, than the standard level. There should be a line scribed on the stick and you should see that the face of the stick has been ground flat to remove the word 'MAX'. You may find that just adding a bit more oil will fix the problem.

 

If you're happy to get into the engine a bit, there is a very worthwhile modification to the inside of the cam cover that involves removing most of a baffle plate. The plate was originally fitted by Vauxhall because the engine was designed to be transverse mounted in an Astra and the plate stopped oil surge. All it does now is give the oil somewhere to hide! Details can be found on the SBD website or by searching on blatchat back to the beginning. If you get stuck and want to have a go let me know and I'll point you in the right direction. One clue that oil is disappearing is that when you've been blatting, the oil pressure drops a bit but when you stop the pressure slowly rises again over ten or so seconds as the oil drains back into the sump. Adding an Apollo tank, which increases the amount of oil available to the engine, will also help, short of going dry sump.

 

If you search back in the archives here you'll find this topic covered many times over.

 

Paul

 

 

[Lotus Boy]

I did the SBD mod late last year. Well worth doing as Paul says.

 

It's not too difficult but a couple of useful (sensible) tips is when removing the plate, which can involve a fair bit of levering, is to start at the end which you don't need to keep and obviously make sure you remove ALL traces of silicone sealant. You can get sealant remover - I used a Unipart product which did the job fine.

 

and the result...no more plumes of smoke out of the exhaust on hard cornering

 

Definitely check your oil grade. Ideal is something like Mobil Motorsport 5w50 though I always use Comma Syner-G 5w30 which is the recommended and has been ok though I do get a tappety noise every now and again. Don't think it is much to worry about if your oil pressure is fine.

 

Dave

 

ps - sorry to hi-jack the thread but is there much involved in checking and replacing the oil pressure relief valve?

 

[kenny.]

Lotus boy. No!, The main problem I always had was getting enough pressure on the spring when refitting to get end plug back on..........I used to swear a bit I remember

 

Kenny

[Paul Deslandes]

The trick with the relief valve is to press (very hard) with your thumb and turn the nut with a ring spanner. It helps if you can find the right position for the nut so that it 'starts' as soon as you start turning. It also helps if you can get the car off the ground, rather than lying on your back.

 

TBH if your oil pressure is ok (60psi 'ish at normal revs) I wouldn't touch the relief valve. If you need to raise the pressure, bearing in mind that you should check it with a known good gauge rather than relying on the unreliable VDO/CC unit, you can pack out the spring using washers, one at a time. Its about 2 - 3psi per 1.5mm washer from memory.

 

 

[kenny.]

It also helps if you can get the car off the ground, rather than lying on your back.

 

Absolutely right, only ever done it lying on the concrete and used to think to myself just how much easier it would be over a pit or on a ramp.........I could never see what I was doing, it was all by feel to put it back.

 

Funny thing is though, when my HPC went in to "tappety mode" oil pressure would indeed waver when on the move and oil pressure on tickover would be a lot less than it should. The 2 symptoms always went hand in hand on my particular motor.

 

Kenny

 

 

[Lotus Boy]

Thanks for the words of caution.

 

Reason I ask is that last year I also fitted an mechanical OPG. After fitting it, I have noticed that when pulling away and the oil pressure picks up from idle it suddenly spikes momentarily up to say 80psi and then shoots back down and settles around 60psi.

 

I just wonder if the reason why it is spiking is because of a sticky oil pressure relief valve???

 

cheers

 

Dave

[Paul Deslandes]

One other thought, the Caterham Vx sump uses a horrible foam insert that acts as a baffle. These should be changed at least every 3000 - 4000 miles or every other year. They clog or, worse, break up. It has been suggested that synthetic oil causes the latter to happen quite quickly. You don't want bits of it finding their way through the engine.

 

We changed one in a Vx a couple of years ago. It looked fine but the car was suffering from low oil pressure (30 - 40 psi) so we changed it and everything was hunky-dory afterwards.

 

One last point, when the sump's off, make sure the oil pickup pipe isn't touching the sump surface. If it is you might see a shiny witness mark on the ali. A mod worth doing is to file four semi circular slots about 4mm deep at 90deg to each other in the end of the pipe so that oil can get into the pipe, even if its touching the sump face.

 

 

[Paul Deslandes]

Dave, that does sound like a sticky valve. Take it out and clean it.

 

 

[kenny.]

I seem to remember making an airtight seal for oil pick up pipe into block was a must too. I was always advised to put a miniscule of sealent on the face which I did without any issues.

 

Kenny

 

PS Foam baffle does go horrible and starts to break down, good point

[Lotus Boy]

Thanks Paul, will have a look and clean it then.

 

Yes I change my foam baffle every other year. First time I did it though it became apparent that the previous owner (of 10 years) wasn't aware of it and that it was a serviceable item. It was like chinese seaweed when it was removed. Did a full engine flush and am counting my lucky stars! All is ok.

 

Cheers

 

Dave

 

 

[J7HPC]

Cheers for all the advice guys, despite the noise i'm somewhat comforted to know that it's a common thing and i'm not on my own with it!

 

I'll be looking into a dry sump and the sump mods at some point soon....

[Mavic82]

Seems to be a comon problem. If you search through last years archives you will find my posts on the same issue. I changed to solid lifters which stops the noise 😬 but not the issue.

 

I have a head with drain tubes added, the cam cover mod, a better grade oil, slightly over filled sump, new baffle foam, carefully adjusted pick up and slightly raised oil pressure. Even so when I run a of 5k engine revs for a a prolonged period oil pressure drops a few PSI (and when I had hydraulic lifters) the tappety noise started. A short period at low engine speed and all would return to normal.

 

I have just fitted a dry sump so hopefully that will cure the issue. Although not a huge concern it is an issue. If it is tappety then the cam lobes are hammering the lifters not good in the long run.

 

Cheers

 

Guy

[pussycat]

Just fitted my original sump back on after wearing away the previous Caterham part! (Think she is riding too low and needs new shox and springs - wish bones arent horizontal?). I took the advice given on here and slightly over filled with oil. Took her for a test run and she spat a fair bit out on the screen under alot of throttle. I have heard they can do this, it doesn't seem to have any issues?

 

I will now have to wait and see if the tappety noise comes back, and save for a Dry sump kit :) Was great to follow all your good advice on this thread :)