Different Colour cams

[suprasteve1979]

Hi just in the process of doing my valve stem seals on my Jspec tt supra, I was wondering why the inlet side of the Head the bearing caps are a lot blacker than the exhaust side of the head.

 

[Digsy]

There will be more coolant flowing around the exhaust side. The water jacket typically extends above and below the exhaust ports (i.e. comes right up under the oil deck) but normally only sits under the intake side. That could be a contributor.

 

Have you got any blocked or modded breather lines coming from or going to the intake side cam cover?

[Chris Wilson]

The exhaust cam on a DOHC engine typically runs a lot hotter than the inlet, add cheapo oil and you get the very noticeable oxidisation on the exhaust cam and pedestals you see here, and not as much on the cooler inlet cam. Quite common, and a sign it's been run on poor oil at some time.

[suprasteve1979]

Thanks for that Digsy breathers all standard.

 

Will giveyou a ring in the week (Chris) about some parts.

 

Never gone for the very expensive oil, last time I serviced the car, I used Morris oil which I thought wasn't actually that bad.

am I wrong?

[Chris Wilson]

Turbo engines need a decent fully synthetic oil, especially road engines with a recirculating crankcase breather system.

[uk-rich]

crikey thats filthy, here is mine, just changed the inlet cam, it looked like this when i pulled the cam covers off

 

i'd suggest some oil flush and then some good oil