Seans engine failure a Spa

I think this is an interesting thread.

At the end of the day a customer bought an uprated and inevitably more expensive [than original] product and ran it. Something went wrong and either directly or indirectly the product failed.

To be honest this is just engine development. If you have the budget then hopefully you do all this work in-house and no-one else see’s it. Ultimately the design theory is only half the battle with other irritating things that require ironing out being the other 50%.

I hope you get to the bottom of this Simon - as everyone has always said general development of the K is a great thing that is widely endorsed.

On the opposite view, if you have a pocket full of money then you have the choice - build a high spec K with aftermarket parts, or spend the money on an alternative relatively stock engine engine using a different installation. All options have merit depending on budget and performance required, but aside from having an alternative source of K-series parts I don’t think the outlook has changed (yet).

All very interesting Simon, however you didn’t address the question about the torque on the verniers that you said had slipped. It’s a pretty important question because there are hundreds if not thousands of sets of Piper and other verniers fitted out there and it is not in anyone’s interests to have uncertainty or doubt cast on their safety.

I have seen a large number of Piper verniers, many of them after thousands of miles of action and never seen one slip. In spite of your comments I have never seen one broken as in the photos of your vernier. I have seen a cracked one where one of the bolts had been missed out by the owner as he had mislaid one.

I have seen one damaged as a result of a ladder bolt coming out and wedging under the cam lobe, interestingly the verniers didnt slip at the clamp bolts, but at the main pulley bolt , shearing the roll pin as it did so.

It is worth clarifying the situation WRT the slipped vernier if you have the relevant information. Piper should also be given the opportunity to respond as you have been.

If it was not a Piper vernier that slipped, please say so categorically here… I’m sure I am not the only one who has made that perfectly natural assumption based on your description of the ‘latest three bolt’ vernier.


Dave

Although the technical element of this thread is way above my head, I’d like to thank the participants for their informative posts so far, & for the manner in which the various issues are being considered.

Although the technical element of this thread is way above my head, I’d like to thank the participants for their informative posts so far, & for the manner in which the various issues are being considered.

Absolutely Pesky - well said. I for one am enjoying reading this thread.

Lets hope that the desire to imporve the K and to genuinely learn when things don’t go according to plan remains the primary focus of this thread and it doesn’t end up with…

Its time to play the music, its time to light the lights.
… on the muppet show tonight.

To extend my point above, the question then becomes what happens if you build a high performance and a component breaks, what do you then do?

The normal practice is that the individuals and the supplier come to some agreement and everything moves on. Of course, the other method (and one that as an engine developer I genuinely wouldn’t endorse or agree with) would be for a rival company/developer to get hold of the parts and then publicly discredit the original manufacturer. Of course, the problem with the latter is that this is awkward (and arguably unethical) practice, and is likely to come back one day to bite you on the backside should ANYTHING go wrong with one of your own publicly in the future. You pay your money, you take you choice. Or to put it another way, you live by the sword, you die by the sword.

No-one has pointed the finger or criticised you over the breakage of the verniers. We have simply made some observations based on information you have supplied.

However during the course of conversation you volunteered criticism of another companies products and by implication that company is Piper. I just want to clarify the situation ; from what you are now saying it appears to be simply hearsay as you have not seen the verniers in question, are you telling us that you have not seen the verniers? are you telling us that the person telling you the tale did not know their origin? Are you saying they were from another manufacturer?

Dave

Please don’t let this thread go that way… It’s great so far.

Hear, hear. It’s fascinating.

No-one has pointed the finger or criticised you over the breakage of the verniers. We have simply made some observations based on information you have supplied.

However during the course of conversation you volunteered criticism of another companies products and by implication that company is Piper. I just want to clarify the situation ; from what you are now saying it appears to be simply hearsay as you have not seen the verniers in question, are you telling us that you have not seen the verniers? are you telling us that the person telling you the tale did not know their origin? Are you saying they were from another manufacturer?

Dave

I havn’t credited the verniers that slipped to any company - there are 5 different sources of verniers for the K that I am aware of, what I did do was raise the issue of design, and FYI the bust engine was brought to my attention by the engine builder that built it.

I still think that is needs some clarification…

Dave

Looks like the webs are bit thin to me, probably suffered a fatigue failure due to “ringing”

Do you think this failure mode is a possibility Simon ?

Bernard

Sounds like a balancing issue then

however people keep coming up with this “resonance issue”

firstly resonances are nothing to do with dynamic unbalance

Except that dynamic imbalance will exacerbate them.

Imbalances can occur in other places than the crankset.

Run out or out of parallel between the cam bearings and the crank plane or between the cams can cause all sorts of nasty issues.

k is a belt driven engine - johnboy/bernard may not have noticed, but it is

Try to keep it nice, Bernard was building 230BHP K series engines in 1999, well before you had even looked at porting your first ‘K’ head. I think he knows the K better than you give him credit for. He (amongst others) has afforded you respect and constructive comments at a time when it would be very easy to offer ridicule, try offering him the same.


Dave

There is no mention of his engine on that website, only on the kengine one and the graph has no date. The point still stands, he had extensive K series experience before you had even become remotely involved, certainly enough to know that the cams are belt driven.

Bernard went on from his first engine to build a much more powerful one in quick succession before moving on to Audis, as mentioned, well before you ported your first K head.

The point remains, be polite in response to politeness.

Dave