Rails

 

Nice work! That's some serious carnage on the old motor. Any ideas on what the initial failure was?

 

Are you asking what might have caused the lifter failure?

 

Looks like a stout build! Keep the photos coming!!

 

Sorry, should have stated that a little clearer.

 

The lifter needle bearing imprints are clear. Why lifters fail to begin with isn't exactly clear (or at least not singular in nature) - at least not to me.

 

In my experience, abrasion/dirt is the cause. The bearing of the lifter roller is too weak for a 4-valve engine (the load of 2 valve springs weighs on one lifter), a design weakness in these engines, especially in the exhaust valves due to the longer lever of the rocker arms. The needles are only 1.5mm in diameter!
The dirt particles in the oil lead to wear both on the lifter bearing needles and on the surface of the camshaft.
Every time I change the oil in these engines, I drain the oil into a clean container. I always see the tiniest residue on engines with long oil change intervals. Of course, a certain amount of wear is normal, but the dirt particles are passed through these bearing points again and again, resulting in even greater wear.
I also like to use the Johnson lifters, but the load on the camshaft remains the same no matter which lifter you use. With 100lbs valve springs you also increase the load on the entire valve train.
I can't imagine that stronger springs are necessary for an engine that is built for pulling. The only plausible reason for me would be high revs. I always install springs with the original spring rate. However, I also make sure that the piston protrusion is at the lower tolerance limit.


this is a cam from a 06 truck engine with 65000mls / 105000km. You can clearly see when the bearing of the lifter roller gets load (i.e. when the valve starts to open)









a 6.0 bus engine with ridiculous 115K

 

Totally agree on oil cleanliness playing a big part. I also think that high oil temperatures does as well. High hp tunes. etc also probably impact the failure rate. Then you have issues like fuel dilution of the oil, or even coolant contamination. Both can also play a part in the failure. Then there is cam design and quality. Lastly, I like an oil that flows well quickly, but has the higher viscosity and film strength at temperature. I can manage the minor shearing. No doubt these engines are not very forgiving in many respects.

Engine design is clearly a bit lacking, but there have been some high miles achieved without lifter failure (400k range), so there are steps worth taking to mitigate the design risk.

 

I think it's a combination of minor debris in the oil leading to surface fracturing of the needles (I've shown this) and degradation of the cam lobe surfaces. You can have one or the other, but often, when it goes bad, it's hard to tell which was the first. I agree that excessive oil temperatures from a failed cooler are a contributor. All the guys with long-lived engines are good at maintenance and use good oil and filters.

It's also common for the barrel-shaped rollers to spread the contact as the load increases during the ramp. This is also when you can get some skating of the roller on the lobe, which causes the most distress to the lobe surface.

 

 

Be aware with those BD up pipes. The small stud that holds the coolant pipe on the firewall could contact the bellows.

I installed them and found out later it was rubbing while in gear and motor torque. I was fkng pissed and made it work to alleviate the minimal contact. Shame on those aholes for not mentioning that in their instructions.

Either remove the stud and secure the pipe differently or cut it down as much as possible.

I have to come up with a way to do this with the zero room left after mounting.

 

Thank you for mentioning that. I will trim them down before putting the motor in.

 

It is only one stud....hard to miss. I am still pissed writing this.

Great up pipes.... $h*t company for not mentioning that