Thread: 3.9 V8 vs. TDI - does one generally last longer than the other?

the tdi generally outlasts the v8.

the camshaft WILL wear out in the V8, generally after about 100,000 km i've heard

Originally Posted by jazzaD1

the camshaft WILL wear out in the V8, generally after about 100,000 km i've heard

Maybe so, but they will keep on going anyway.

The killer for both is overheating.
Regular maintenance will see both engines running for 1/2 million km or more.

the camshaft WILL wear out in the V8, generally after about 100,000 km i've heard

Well I just changed mine at 197KK and it was still servicable although worn and the lifters were concave rather than convex.
I bought my car at 67KK and it had had few oil changes, I guess at 10KK intervals, as there is still a black deposit on the bottom of the dipstick. I have changed oil at 5KK intervals since and I believe that is the secret.

On the other hand I bought a 3.5 81 in Saudi with 76K miles and by 120K miles the cam was breaking up at the shoulders. But the rest of the engine was OK even with daylight through the aircleaner housing.

It depends on the maintenance.

I agree that IMHO most engines die from overheating which comes down to no maintenance of the radiator or hoses or belts. I am amazed at some who post and ask why their car overheats with a 10-20 year old radiator that has never been rodded!!
Even Toyotas do radiators in 10 years or less, sometimes much less.
Regards Philip A

To expect a car to run and never have some sort of failure is like humans never getting sick.
I drop oil on all my cars at twice the recommended intervals and do a radiator flush/rodding if needed every 2 years.

Prevention is better than curing I figure, that way if I want to drive to Brisbane at a drop of a hat I can.

We have a little shack at Moonta bay here and our neighbour has a old Toyota ute, he drives to 1000km's almost every week.
Car has now done close to 900,000 km's and he says the oil has been changed only a handful of times. The oil cap has think black crap under it but starts easily and takes his cabinets to town 3 times a week.
He has no plans to get rid of it as he wants to see it back on a 000000 reading on his odometer. Funny old man he is but it just goes to show, some motors will do huge miles and others are cactus even if serviced very well.

Some people have heart attacks even if they have been looking after themselfes, eating well, exercising etc.
Some cars are the same.

Originally Posted by BigJon

Maybe so, but they will keep on going anyway.

The killer for both is overheating.
Regular maintenance will see both engines running for 1/2 million km or more.

Originally Posted by PhilipA

Well I just changed mine at 197KK and it was still servicable although worn and the lifters were concave rather than convex.
I bought my car at 67KK and it had had few oil changes, I guess at 10KK intervals, as there is still a black deposit on the bottom of the dipstick. I have changed oil at 5KK intervals since and I believe that is the secret.

On the other hand I bought a 3.5 81 in Saudi with 76K miles and by 120K miles the cam was breaking up at the shoulders. But the rest of the engine was OK even with daylight through the aircleaner housing.

It depends on the maintenance.

I agree that IMHO most engines die from overheating which comes down to no maintenance of the radiator or hoses or belts. I am amazed at some who post and ask why their car overheats with a 10-20 year old radiator that has never been rodded!!
Even Toyotas do radiators in 10 years or less, sometimes much less.
Regards Philip A

i didnt mean to sound so drastic, i have just pulled down 2 3.5's last weekend and they both had quite worn cams and lifters, one of which ran out of oil, and the other that was still running

i'm about to rebuild one of them to go back into my discovery, but ill post a seperate thread for that

Originally Posted by big guy

To expect a car to run and never have some sort of failure is like humans never getting sick.
I drop oil on all my cars at twice the recommended intervals and do a radiator flush/rodding if needed every 2 years.

Prevention is better than curing I figure, that way if I want to drive to Brisbane at a drop of a hat I can.

We have a little shack at Moonta bay here and our neighbour has a old Toyota ute, he drives to 1000km's almost every week.
Car has now done close to 900,000 km's and he says the oil has been changed only a handful of times. The oil cap has think black crap under it but starts easily and takes his cabinets to town 3 times a week.
He has no plans to get rid of it as he wants to see it back on a 000000 reading on his odometer. Funny old man he is but it just goes to show, some motors will do huge miles and others are cactus even if serviced very well.

Some people have heart attacks even if they have been looking after themselfes, eating well, exercising etc.
Some cars are the same.

Spot on analogy Big Guy!

Originally Posted by jazzaD1

the camshaft WILL wear out in the V8, generally after about 100,000 km i've heard

The secret to a flat tappet cam in any V8 is the correct oil, they need an extreme pressure lube un like more modern roller tappet engines. Most modern oils have had the zinc and phosfer removed to increase CAT life. A flat tappet cam needs about 80-100parts per million to stay a live. You can by cam additive from Comp cams etc or just run Penrite 40 it has heaps of zinc. My D1 has 225k on it now, has no tappet noise and is not down on power, it has had changes at about 5-7k km since I got it in 98. I will put a cam in it before 300k though, wether it needs it or not I think.

When you change a cam always spray it with Molycote, spray on lube, let it dry and then cover it and the lifters with cam lube, bed it at 2000 rpm for 20 mins and it will be fine, as long as you use the right oil.

I have a Comp cams XE268 Extreme engery ford windsor cam on the bench at the moment, that didn't even last 10k km, 2 lobes are completely gone and the base of one lifter is iron filings in the sump, because it didn't get run in nor did it have the correct oil in it. Oil and bedding is the key.