Putting Fears of Premature Engine Wear to Rest

 

TL;DR Fear not.

Very interested and curious about the intricacies of the R06A engine that powers the Caterham 170, I stumbled upon a series of YouTube videos by 赤シルの休日 @akasil. In that series, our man Akashiru shows a complete engine rebuild of the Suzuki Alto HA36S he plans to race.

Beside those videos, he also got an interview with Izumori-san, president of OS Giken.

Wondering about the differences between the K6A engine (the one from the Caterham 160/165 as far as we are concerned) and the newer R06A (in the 170), they inform us that emissions compliance and fuel economy were driving most of Suzuki's engineering decisions. 

While the K6A is 'square' (bore=stroke), the R06A is a long stroke engine (smaller bore, longer stroke for the same displacement), giving more torque and helping with emissions and efficiency. This a overall better suited to use with a turbo. 

Side note, the "longer" engine also explains the lower rev limit : 7000 RPM vs  8000 RPM for the K6A (not to mention that crazy video of a Suzuki Cappucino that goes up to 11 000).

To achieve that and improve geometry, the crankshaft is offset from the pistons slightly. This in turn leads to more wear of the thrust bearing that keep the crankshaft centered in the block (gross simplification from me).

In the interview, it is said that those bearings should be replaced around 100 000km, and the only preventive measure is to run a little more oil. Since hearing this, I have been running 0.2 to 0.3 liter oil over the "max" mark.

I think I learned about that while on holiday, so between July and August. The topic came back to mind with my car reaching 38 000km, as I told my mechanic that he should be ready to get the engine out for preventive maintenance at 100 000km.

Looking for more information, I found a few videos that show what the issue looks like from the outside, with the crankshaft pulley moving by a few millimeters when clutch is applied, and oscillating by itself, with some racket when the engine is running.

I finally stumbled upon this blog post from Tastes like Petrol that gave the full picture : Suzuki issued a recall and extended the warranty to 10 years and 200 000 km on cars built from 2014 to 2018-19.

It was established that thrust bearing on those engine series were somewhat too soft and suffered from premature wear. The solution is a pair of more durable thrust bearings, they can be swapped from underneath the car, no engine removal required.

So no fear for us with the Caterham 170, as it began production late in 2021, we should be safe.

Then again, it does not cost anything to check the pulley for any axial movement when applying the clutch or the listen for unusual rattling.

Read it all on Kelvinator's blog post on Tastes like Petrol.

You could as well watch the job done by Nori : https://www.youtube.com/watch?v=gd-mL8XY2Wo

That won't help my very recent issue with the thermostat though... or the lost turbo stud I just saw on the cover image from the previous 'lambda sensor' post.