K Series Engine Noise

[Tigs]

Morning all

Looking to tap into the fountain of knowledgeable K series engine people on here! I currently have a Superlight R which I picked up almost a year ago. It has got a VHPD K Series engine in it that has been fettled by Dave Andrews and is now pushing 216bhp. It's a dry sump engine.

I had my first track day this week with the club at Castle Combe and the car ran like a dream pretty much the whole time but, occasionally, there was a slightly worrying noise on start up. After a session on track, and after a period of rest before the next session, when starting up it sounds terrible as if it has no oil in it. After about 10, maybe 15, seconds it settles down and the noise goes and the engine runs perfectly with no other signs of issues. Occasionally it has happened at other times after some spirited driving. It's as if it is taking a short few moments to pump the oil around the engine. 

Is this normal behaviour for a dry sumped VHPD K series engine? If not, any suggestions on what to look at?

If it is normal 'd rather be slightly paranoid about the noise than ruin an engine! 

Thanks

[SM25T]

Have you checked the oil level ... in the required way ?

[Tigs]

Yes, oil level checked and all seems fine in that regard

[revilla]

Is the noise a rattling from the top end of the engine? Like the valve gear is all slack and lacking lubrication? If so, you could have a problem with leaky hydraulic lifters. When you then leave it standing some of the valves will be open and those lifters will be under pressure from the valve springs. After some spirited driving the oil is hot and thin, so if the lifters are a bit leaky, they can bleed down leaving you with very wide clearances. Next time you start those valves will knock and rattle until the oil pressure inflates the lifters correctly again, which takes a few seconds as you describe. You see it routinely on engines that have been left standing for a long period (over the winter) without turning over. I would make sure you've got the right amount of the right grade of oil in and make sure the oil is clean (if not, do an oil and filter change). You can get oil additive products which claim to clean sludge and deposits from the lifters but I don't know how well they actually work. Sometimes they will flush naturally after a couple of oil changes. In the meantime I'd just let it idle until it settles after start or maybe run it at a fast idle of about 2000rpm to bring the oil pressure up a bit and make it a bit kinder on the cams.

[Tigs]

The noise is certainly top end of the engine I think and to my untrained ears it sounds like it is a lack of lubrication. The oil is Comma 5w50 so the right grade and the level is correct. There was a bit of extra oil in the catch tank than usual but not enough to reduce the overall level in the engine. The noise is only apparent for the first 10 or 15 seconds until, it seems, enough oil has reached the whole engine. Will get my home mechanic (aka Dad) to try starting it with some extra revs and see if that helps at all. 

[revilla]

Can you or your Dad manage to record the sound on a mobile and put a video on YouTube?

[SLR No.77]

Unless it's been converted to hydraulic lifters, a VHPD engine should have solid lifters so oil drain will not occur. Do you know which cams are fitted?

What oil are you using?  Do you get any sign of a drop in oil pressure when cornering or breaking hard? (I mean properly hard!) (Edited to add I must type faster and you're using the correct oil for a VHPD with solid lifters).

Does it exhibit anything similar on start-up after being stood after normal driving, i.e. full cold normal use?

Stu.

ETA: You really need to know whether it's original VHPD cams/followers or whether they've been swapped to something like the Piper 285H with hydraulic followers.

[Tigs]

He has strict instructions to do that - I am not with the car as it lives in his garage. Will post a video once he has done it

[revilla]

Yes as Stu says my suggestion only makes any sense if it's on hydraulic lifters, sorry I didn't make that clear.

[Tigs]

No obvious issues with oil pressure on braking or cornering but whether on my first ever track day I was doing either hard enough to notice I don't know!

Off the top of my head I can't remember the engine spec but have it at home so will confirm later.

On cold start ups it's a little lumpy and soon settles down but doesn't make the horrible sounds. PGM haven't noticed anything on cold start up and in fact commented on how well it idles on start up but that's only every really cold the times they have had the car!

[Tigs]

Have checked the engine build spec and the lifters don't appear to have been changed so assume they are still solid lifters. Cam is a 1444 with Piper double springs

[SLR No.77]

1444 cams would be used with solid lifters.

Stu.

[Tigs]

As a bit of a follow up on this, having sent a video clip of the issue to the guys at PGM, we think that the starter motor is not disengaging properly when starting up. Instead of disengaging immediately it seems to stick for 10 to 15 seconds and will run at engine idle speed before disengaging. 

Will replace the starter motor and see what happens. 

Many thanks to the guys at PGM for their help and remote diagnosis