VW - TBO's?

Paul Gibbs · Post by **Paul Gibbs** » Mon Jul 11, 2011 8:24 am

Hello All,
Was looking to pick the brains of the community to get an idea of typical tbo's for the VW conversions.
My 1834 is running very sweetly on 140 hours since top end overhaul, and is giving no sign of issue. But I am conscious of TBO's and wonder what I should expect, or any areas I should monitor more closely.
It is a well cooled 1834 fitted with a stromberg CD150, and Leburg, currently used 30-50 hours per year.
Any advice would be much appreciated.

Paul.
G-NIPR.

Nigel Ramsay · Post by **Nigel Ramsay** » Mon Jul 11, 2011 9:10 am

Paul, I'm not sure there is an official TBO for VW engines. I would think some form of scheduled monitoring and service routine would be far more important than worrying about fixed hours (which applies mainly to specific aircraft derived components).

Consider a Beetle, on the road, in it's day, 140 hrs at say 40mph average speed = 5600 miles. I ran a garage business in the early 70's and regularly had knackered beetles in with engine mileages of 30K or more. (remember that oils weren't as good then and a car engine was knackered at 45k!).

Also, a car engine is subjected to constant torque reversal as you change gear, especially if you are hammering it, going from say 2000rpm to 4000 rpm (we're talking beetle here), which is extremely punishing.

Checking Valve clearances regularly is most important, monitor oil pressure and keep records. Not so easy to record compressions with a hand swing engine but you can take individual pressure readings from each cylinder, when hot, though they will e on the low side as you are only hand swinging, but it will show when one compression is low compared with the others (don't become paranoid by a couple of pounds difference though because your swing may account for that, but you get the picture?) Malcolm McBride (or was it Francis) wrote about this recently in LA.

cardiffrob · Post by **cardiffrob** » Tue Jul 12, 2011 7:58 am

I've heard it said that the crankcase is a 'lifed item' in the opinion of the engine designer and that 100,000 miles is the expected limit for a road car (inc 2 rebuilds). I've been to Brazil a few times where the engine is still in regular use and they said that the cases eventually crack and leak oil before they die. Keep the case clean and as free from corrosion as possible, especially around the head stud holes in the block.
Problem is, how old was the block that was used to build your engine? New, one careful owner or 'thrashed'?

Rob Swain · Post by **Rob Swain** » Thu Aug 04, 2011 4:17 pm

You say its 140 hours since a top end overhaul. What about the bottom end?

As has been suggested: put decent oil in it, keep on top of the valve clearances and pay attention to the oil pressure. Oh yes, and enjoy your flying!

If it's doing 50 or so hours a year I'd say it was fine and will probably continue to be. Biggest problems with any aero engine are caused by lack of use and many VW powered aircraft only seem to do around 10 hours a year so it's not surprising they have problems.

The Leburg probably plays a big part in her flying regularly. Many magneto'ed VWs don't get flown because people can't face the battle to get it to start, which then causes problems due to lack of use, that makes it difficult to start, which leads to it not being flown.... and so the downward spiral continues!