Volvo Penta KAD 43 intake valve failure

[Latestarter1]

One for Volvopaul.

I have been asked about the cause of VP KAD 43 intake valve failure and consequential damage by owner in the U.S.

Remember discussion re: 4 valve heads and lack of lubrication during low speed operation, however cannot find the thread.

 

[[2068]]

KAD43 has two valves per cylinder.
KAD44 and KAD300 have the four valve heads.

 

[Latestarter1]

KAD43 has two valves per cylinder.
KAD44 and KAD300 have the four valve heads.

Thank you, the very reason why I stay away from Green engines.

KAD 43, 1,000 hours fails inlet valve, insurance company claiming due to corrosion??

 

[volvopaul]

Thank you, the very reason why I stay away from Green engines.

KAD 43, 1,000 hours fails inlet valve, insurance company claiming due to corrosion??

Before we comment , is it def the 43 two valve or the 44/300 4 valve per cyl head. Valve do corrode on Volvo engjnes, the 61 a was a big problem in the early years it was introduced. I've never seen a 43 failed valve, Pistons yes.

 

[spannerman]

Be interesting to know the cause of the corrosion it that's actually the case, another reason could be the valves haven't been adjusted on schedule or correctly, a too large a clearance will allow the valve at high rpm's to fall off the back of the cam lobe a resulting in a very hard close which can stress the valve stem causing the valve head to break off.

 

[springer]

Los of early failures of valve gear on 4 valve per cylinder VPs when 1st launched. 44 and 300 engines. VP pointed to lack of adjustment at 200 hour service intervals as per owners manual. With multiple drive belts and tensioners these have become a significant revenue stream for VP dealers and competent independent engineers.
John

 

[[2068]]

Thank you, the very reason why I stay away from Green engines.
KAD 43, 1,000 hours fails inlet valve, insurance company claiming due to corrosion??

Never heard of one failing through corrosion.
As above, valve clearances that were waay out could cause a problem.

 

[Latestarter1]

Be interesting to know the cause of the corrosion it that's actually the case, another reason could be the valves haven't been adjusted on schedule or correctly, a too large a clearance will allow the valve at high rpm's to fall off the back of the cam lobe a resulting in a very hard close which can stress the valve stem causing the valve head to break off.

Spannerman,

You are spot on, failure to adjust valve lash is very common in engines operated by bus companies. As clearance increases over nominal the valve closing velocity increases dramatically. Valve beat in on bus engines is often so severe that I am amazed that the mushrooms have stayed on!

Thanks to everybody for input.