K series let go

[p.mole1]

Has anyone ever thrown a rod on a K series? Yes it was me that left the huge oil trail at Anglesey. I have given it a quick once over and there is at least one hole in the block. Up until it failed I had 60psi oil pressure, I did hear some very light metalic noise ay very low throttle openings less than 5% at around 2500 to 4000 which I thought could be pinking but as soon as throttle was applied it disappeared. With hindsight it could have been the little end? Just as the noise started to increase and I was going back off it let go at 6000rpm in top at over 100mph. I think the bottom end a pile of scrap. I hoping my DVA VVC head is ok or it's game over.  

[p.mole1]

I have a paid for a track day at Croft if anyone would like to make me an offer for it? With hindsight I should of waited till till Anglesey was out of the way!

[p.mole1]

I have just pulled out the spark plugs and number 2 plug is soaked in oil, looking down the plug hole I was expecting carnage but all of the pistons are where they should be expected? The crown of number 2 is covered in oil but seems intact. There  is at least one hole in the block below number 2 piston. I'm going to hazard a guess that I've spun a bearing or a rod bolt has gone? Judging by the prodigious amounts of oil smoke pouring out the bonnet i must have holed a piston. How is possible to put a hole in an engine and all the pistons are still in the correct place. I'd like to thank the person that lent me the trolley jack so I could get my car on to the recovery truck and apologize for spoiling a track session. Looks like it's end of track days for me this year and possibly for good!

[p.mole1]

I have had another quick look at the engine before I drown my sorrows! 2 more holes found in the crank ladder which has also cracked along with the block, I tried a screw driver down number 2 spark plug hole and it was coincidence that the piston was in the expected position as it moved down the bore with a horrendous scraping noise unattached to the crank. I'm assuming that would have hit the cylinder head with enough force to wreck it although I still seem to have a full set of inlet valves. I looks like all I'm going to be left with is a pair of camshafts and a set of tappets and a sump pan which seems to have survived.

[revilla]

Hi Phil, really sorry to read this. From the pictures and description I would guess it's a big end failure, possibly rod bolt as you say. Looks like the crank has punched the floating end of the big end of a rod outwards through the side of the crankcase. Like you, I can't imagine there's much left of the bottom end but I wouldn't give up hope on the head until you've had a look. If the piston has remained intact you may be OK. I've seen an engine with two dropped valves resulting in a badly bent con rod where the resulting scarring of the head was only cosmetic. I think you need to just get the head off for a look and see what's what.

[p.mole1]

Thanks, I'm going to drop the sump today just of curiosity to survey the damage. I should have the head off by Wednesday and then I'll decide what to do. I should end up with interesting paper weights.   

[Tony Whitley]

Bugger

[Jonathan Kay]

Sorry to hear this.

Email sent.

Jonathan

[p.mole1]

The fragments in the sump are the remains of the piston skirt! I traced the problem it's oil starvation number 2 bearing has spun in the rod as the rod is blued with the heat only piston crown is left in the bore. I was lucky the car didn't catch fire as all the oil was dumped onto the exhaust manifold.

[Wrightpayne]

Was the car on standard oil system or was an Apollo added?

[p.mole1]

The upper photo is what is left of the big end bearings, they are blue with the heat and all of the white metal has gone, also you can see the where the conrod has been getting hot! Ignore strange noises at you peril! If I had noticed a drop in oil pressure I would have done something about it but it was showing 60psi when it let go

[p.mole1]

Last year I did a couple of track days with no Apollo but I did have an Accusump fitted and it seemed to work,oil pressure never dropped below 35 psi. However I think the problem is not oil pressure it's fact the bearings are probably being supplied with froth and this causes damage to the white metal. At the begining of this year I managed to locate and fit an Apollo but the damage was probably already done?. This combined with 195 Bhp this year finished them off

[SLR No.77]

Sorry to hear about your woes Phil, not good :(

If there's oil starvation no.1 & 2 big ends are the usual ones suffering the most damage ... I've been there done that made the video etc, except mine was at Oulton and I got away with just a new crank and subsequent rebuild. I feel your pain though, it's not nice.

But .... and I could be wrong ,.. I'm surprised that you managed to break a rod and mangle the piston if the big end bearing was the start of the problem, the K-Series bottom end is pretty tough even in standard form and oil starvation at no.2 usually causes massive knocking and a very noticeable loss of oil pressure, but the rest of the engine will hold together. I think getting the head off is going to show whether it might have been something higher up that started the destruction, maybe a valve that went first.

I know it's easy to say, but at this stage just relax, take your time and work it all out, there's nothing that can't be repaired, you just might want to take it slow.

Stu.

[p.mole1]

Thanks it's nothing that can't be fixed,at least the bottom end didn't cost me too much, I'm going to take my time to find out what has caused it and will inspect all of the bearings, I hope someone caught on video as it was spectacular, unfortunately I didn't have my camera on

[p.mole1]

Cylinder head seems ok apart from 2 bent exhaust valves, but if look at the piston you can see an imprint of the small cutout in the combustion chamber! The combustion chamber is unmarked apart from some tiny pits it squish area so hopefully it will be ok

[TomB]

That’s one impressively broken engine! Stronger 160 pistons lunched. Have you got to the bottom of the cause yet? 

[revilla]

In your pictures the exhaust valves have clearly taken a clout, but the piston has fractured across the pockets on the inlet side, not the exhaust side. Is there any sign of contact on the inlet valves? I'm just trying to imagine the sequence in which things failed. I'm wondering if the piston crown maybe fractured first. I'm sure I read somewhere that it was a weak point and a known failure mode fracturing across the valve pockets like that.

[p.mole1]

Thanks you can see where the piston made contact with the exhaust valves, I should have the engine out tomorrow and will strip the bottom end. I still think it is a lubrication/oil starvation issue. The inlets seem fine and the valves show no contact marks. I will be rebuilding the bottom end with steel rods and forged pistons, but I need to make sure I have no lubrication issues.

[Wrightpayne]

Arhhh but which steel rods - Max Speeding?

[SLR No.77]

What sort of power are you hoping to get, or put more simply, why do you think you need steel rods? If your problems are lubrication related you need to fix that first, before deciding on forged pistons / steel rods ... dry sump needed.

Stu.

 

[rj]

The Chineese rods are as cheap as ordinary rods.

[p.mole1]

My engine was putting out 195 Bhp at 6900rpm, on the limit for VVC pistons. To be honest the engine is producing way more power than I expected but a quite a low rpm limit. I had set my rev limiter to 7200rpm but I only hit it once

I will need a set of fully floating rods to enable me to use forged pistons, I want to avoid Chinese stuff unless I can be convinced it's ok. I don't know if the bearing spun due to lack of lubrication, I will have the engine out today and will inspect the rest of the bearings. I am running with an Apollo supplemented by an Accusump and when I was at Cadwell Park in May the oil Pressure never dropped below 40 psi in any corner. 

I did run the the engine last year without an Apollo, albeit at much lower power ( 150bhp at 5800 )and that could have damaged a bearing? I did have an Accusump and it held oil pressure in the corners but I am sceptical about useful it actually is 

My car is not set up as track car so the ride height is relatively high the suspension is quite soft and I running on 185 track day tyres so my cornering forces shouldn't be too bad? Unfortunately a dry sump is a luxury I can't afford.

Oil pressure on this engine has never been an issue other than the fact I thought it was a bit high 80 psi cold 60 psi at 100 degrees and 40 psi tick over hot with 5/40 ester synthetic. One theory I have is my big end bearings purchased on Ebay could have been fake crap with the wrong clearances, too tight,( I never measured them ) causing to over heat due to not enough oil flow and the causing number 2 bearing to spin in the rod,my rods had the double tangs. The rod looks like it has been getting hot around the bearing surface, although the crank looks fine

  

[rj]

AFAIK does Dave Andrews sell conrods, which I believe are made in China - like so many other "European" products...

[StevehS3]

Could it simply be a case of working on the limits of the pistons/engine. Every component will have a manufacturer’s tolerance and would only be batch sampled on manufacture. Perhaps some pistons rated at 160 won’t be reliable at 195 @ 7,200 RPM?

[m1 se7en]

DVA's steel rods are manufactured in China to Dave's own specification. I know he has spent a considerable amount of time working with his supplier to perfect the design and enaure consistent quality.

The fact he puts his name to every set he sells/fits is good enough for me!