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Posted

While the exchange rate is good I'm halfway tempted to chuck some JUN cams in it too... 

As it's a bitch to change them over later while the motor is in the car. 

But I'm also quite curious to see how well it will go just with factory 1NZ cams and ITB and the high comp. 

Definitely cams at some stage though. As I can buy a pair for cheaper than just one for 3S :( 

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Posted

Another reason for gunky combustion chamber is low tension piston rings. If you've got it that far apart it's probably worth reringing it with better rings

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Posted

Missus has one of these so can happily look at bits you might need to figure out.  They do run a heat exchanger in the exhaust after the cat

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Posted

What's the story with refacing the lifters/buckets on these when you get a new cam? Would it still be cost effective getting them from pick a part  vs brand new once you pay to get second hand ones refaced (and result in the clearance changing)?

Posted

What do you mean by getting them refaced? 

Here's what I'm planning: 

Measure clearances, not them all down including the number on the buckets

See if I can move them around to get as many as good as possible to spec 

find/buy the remaining bucket sizes I need. 

In the engine manual there's a look up table which says "If you have XYZ bucket, and you're out by this much, use number 32" or whatever

Not planning on doing anything to the top face of the buckets. 

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Posted

I'm just thinking along the lines of the process of installing a fresh cam in other engines, they always say to regrind the lifters so the cam beds in properly without being wiped out.*

 

*This is for OHV engines, no idea how it is for OHC stuff or if it even makes any difference in any situation

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Posted
41 minutes ago, sentra said:

Does it not run hydraulic lifters?

Nah you need to shim them to tolerance. 
So if the tolerance was good from factory AND the factory cam and aftermarket one had exact same clearances, theoretically I dont need to do anything at all. 
But I'm guessing that's unlikely. 

 

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Posted

It's interesting how a lot of modern engines have gone away from hydraulic lifters. Harder wearing surfaces, less thermal expansion and better oil technology means there's much less need for them.

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Posted

Maybe also improvements in automation for setting the valve clearances on day 1

I remember old mate Ken telling me about how he visited the Toyota factory in Australia. 

The block would come along, and a robotic probe would touch each of the valve stems (or whatever) then it would autopick the right bucket to suit the distance it measured. 

Like maybe as tech evolved it was just more economical to spend the money on the magic fingering machine, and less on parts for each engine (assuming hydraulic is more complicated, dunno) 
 

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Posted

A cursory glance on the internet indicates that there is significantly less load on modern buckets than the old ohv lifters. Bigger diameters, large contact patch etc coupled with lower valve train mass, supposedly less stiff springs and no rocker ratio.

End result is just less wear, effectively eliminating need for self adjusting systems

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