F36

[kimhollamby]

Re: Volvo 44 series etc, look at the facts

Yes, I'm sure about the 30/40 series info. They've subsequently been adapted for all sorts of things since, a lot of them industrial low load stuff.

Regarding 44-series, engines use a 24-valve head that is, as far as I am aware, is unique to marine engine. The engineering problem, outside of the rocker cover gripe, lies in the fact it is mechanically adjusted yokes that do the pushing; they do seem to widen very quickly. Hydraulic tappets would be a solution I suspect.

It's not a uniquely Volvo Penta thing however; I remember checking with most of the major builders of engines of that size immediately afterwards and found that virtually all need regular tappet adjustment...on the equivalent Mercruiser it was every 100 houirs at the time.

 

[kimhollamby]

Re: Volvo 44 series etc, look at the facts

Ah...this was an interesting one.

What happened as the valve clearances opened was that the springs then didn't cushion the opening and closing correctly, causing higher than anticipated impact forces with the valve seats that in turn bent the valve faces. It was a broken piece of valve face that did the damage, not a broken valve stem.

One puzzle solved once the bending was found was the valves that were closer to normal clearance...they were the ones that in fact had gone wide, then closed up again as the faces bent and reduced tolerances.

What we also found out afterwards was that a common practice by often experienced mechanics was to listen to the head and, if they didn't hear a tappet rattle, not to check the tolerances. Several readers reported back that this was what they had found. With Missing Link's engines there never was a noticeable rattle and, I guess because we were running them well of maximum for much of the time, no noticeable performance drop-off either.

 

[kimhollamby]

A lot of boat diesels a nightmare to work on. My current gripe...the increasing number of engines that have impeller pumps facing back into the block in order to save all of an inch on the front. Guilty parties include Yanmar, Volvo Penta and Cummins. I have actually seen a couple of engines now where I wouldn't know how to pull the impeller without major demolition.

 

[ChrisP]

Kim
I realy feel for you mate.

I used to boat with a bloke who wrote a motoring collum for the Evening Standard. I once asked him why all the car write ups always said good things about the car even when it was a real dog. His reply was that if they told the truth about it the manufacturer would never give them another car to test.

Here we are all giving you a dogslife over a subject where if you were given a free hand you would loose IPC thousands in advertising etc. Keep up the good work mate. Some of us know where you'r realy at.

Chris

 

[hlb]

My wife has a J reg. car. My son an E reg car. Both in excelent condition. First one Toyota second one BMW.
Work the year out for yourselves. Neither has had any other than service parts.
Now they cant get away with. Ah, its a bit slower than the rest, but it lasts longer. Or well, its small and fast but only lasts five minutes. Afraid time is catching up with Volvo. Up to now we could'nt actually talk to others to see if all agree.
Apparently we do.

Haydn

 

[Guest]

Look at Yanmar.

Kim Yanmar has had a 24 valve engine out for sometime now, the 300 based on the Toyota Landcruiser engine.

Paul js.

 

[kimhollamby]

Re: Look at Yanmar.

Sorry, to clarify, meant 24-valve head is unique within 40-series engine apps (ie they only use it on marine version).

Do you know what valvegear system Yanmar use? I can check anyway, just being lazy.