ef7 crx ati pulley

The ATI pulley project for a safely revving honda engine

This entry is part 34 of 41 in the series TrackDays EF7 HONDA CRX

The ATI pulley project : why ?

As for many japanese vehicles, reliability of Honda’s sports cars is now well known worldwide and it is usual to see 150,000 or more kilometers cars driven really hard during a trackday.

And all this still often with a stock engine having only regular maintenance done on it !

Running a stock B16a 1L6 bottom-end on my CRX, I try to be more and more careful about the reliability of this engine mainly because of its ‘high revving’ aspect !

This kind of engine is factory equiped with a dampered pulley meaning that it has two main steel parts separated by a kind of, let’s say, rubber piece.

This rubber piece is really important as it links the two steel parts together and then allows for filtering all kind of frequencies (idle, accelerations, …). For example, compared to this kind of OEM pulley the well known B16a EK9 N1 crank pulley is just a one piece pulley that do not have this mechanism on it.

The ATI damper

Ok so what’s the target of this damper ? It is able to filter and helps reduces stress sent to your crankshaft under various load conditions and so, increase general reliability of the bottom-end. But as for everything in the automotive world, this system is not perfect and cannot filter everything from 1 rpm to 10,000 rpm.

It is efficient in a range like in between 2,000 rpm to 5,500 and this is right when the damper is new. And if you own a car like mine, your damper is now let’s says around … 25 years old !

ATI dampers (or other brands doing similar products ..) uses performance materials to enhance a wider frequencies filtering range and then reduces stress on crankshaft and bearings. With a 25 years old engine running at 8,000 rpm all day long … well, this can be a good way for keeping the engine alive !

AltImage.jpegHere is a view of an ATI damper. This damper is fully rebuildable but unlike the OEM damper can’t just be slided in position just by handed.

3D CAD design of the hub installer

Because this pulley is fully balanced from factory, you need to ‘press-in’ the main hub on your crankshaft with a specific tool. And of course this tool is a little bit expensive for one installation only !

ef7 crx ati pulley

Because it is NOT possible AT ALL to modify the hub in order to not loose the factory pulley balancing, I decided to start designing my own ATI hub installer.

Here are views of the 3D CAD design hub freshly finished. The installer can’t just be a bolt tightened on the crankshaft to press-in the pulley because there is a huge risk to damage the crankshaft thread.

So next step : finishing installer design !

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Category: CarEngine and Transmission

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Article by: yogi