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Choosing a Geo Tracker Camshaft Grind


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I can't seem to find any anecdotes one way or another for this engine.

I've driven full-size trucks that had an RV cam grind, and they ran great.

I'm looking to rebuild a 1.6 8v and wondering about a Stage 1 or Stage 2 cam grind.

If anyone has done this, I'd really be interested in hearing about your results.

...also considering refurbishing the head...maybe a 3 angle valve grind.

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  • Moses Ludel changed the title to Choosing a Geo Tracker Camshaft Grind
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Knyte...There are a variety of camshafts in the market, I looked a several profiles.  For me, the Isky Torquer 260 would be a possibility if you don't want to lose bottom end power.  My target for overall drivability and decent fuel efficiency would be a camshaft with improved/increased valve lift and only a mild change in duration.  This will provide better low-end torque like your RV camshaft experience and not target power at the high rpm end. 

The Isky camshaft has more than enough valve opening duration, especially if your 8-valve is working at all off-pavement in 4x4 mode.  Most suppliers recommend a header and cylinder head port matching to support their camshaft change.  This should be a consideration, especially if you do cylinder head work.  I would not get carried away with any of the "high performance" camshafts for this engine unless you plan to drive constantly at high interstate speeds.  You won't realize bottom end improvement and will be burying your foot in the throttle to get any value from the camshaft change.  Fuel mileage will suffer.

The 3-angle valve seat cutting is common with all contemporary machine shops, so finding a shop will not be an issue.  The engine is small displacement with a big job to do.  I would concentrate on reliability and good fuel efficiency.  On that note, your TBI system would not work well with a longer duration camshaft, another reason to stick with a valve lift increase and mild duration.  Long duration camshafts reduce manifold vacuum at idle, affect tip-in throttle and reduce bottom end power...They also throw off the MAP and other EFI readings.

Moses

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Interesting input; thank you for that write-up.

You're right, I don't expect much highway time with this vehicle.  As it is - stock - it's not really a highway vehicle.  I plan on towing or trailering to the trails where possible, or otherwise short highway trips to trails. 

Fuel economy is somewhat tertiary - I chose a Tracker because of it's small displacement, but full-frame toughness.  It sips fuel as it is.  No need to get carried away - I'm not going to the drag strip.  I'm after a bit more oomph, but don't need to go deaf or overstress anything.

Again, thanks for the advice.  That helps heaps!!

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Knyte...For your needs, a camshaft with more valve lift would be valuable.  For trail use, you want the highest manifold vacuum possible at idle.  This will make trail running sensible by providing more torque at throttle tip-in.  Again, I would avoid the longer duration camshafts, idle vacuum falls accordingly.  You'll have good power to 4500 rpm with a torque/shorter duration camshaft.  Can't imagine the need to spin this engine beyond 5,000 rpm—ever.

A torque/RV camshaft will also keep a lid on fuel consumption.  When we drove 1.6L 8-valve Geo Tracker 2-doors over the Rubicon Trail in the mid-nineties (a publicity stunt for Chevrolet), I was surprised how much fuel these engines consumed while performing low range rock crawling.  The small fuel tanks had us filling up with spare cans of gas.  When trail running, it's gallons per hour, not miles per gallon.

The header would be a minor improvement in the idle-3,000 rpm range.  Beyond that engine speed, there would be a noticeable improvement.  Most "gains" from a header reflect the less restrictive exhaust flow.  For low speed performance, the stock exhaust manifold and piping are adequate.  

I like your plans for short drives to trailheads and towing the Tracker on longer trips.  We're 710 miles from Moab.  A drive there in a short wheelbase Jeep or Geo 4x4 would be daunting.  We tow our trail vehicles on trips beyond a hundred and fifty highway miles each way.  

I'm a fan of trailering a 4x4 as opposed to flat towing.  This is less stressful on the 4x4's steering gear/system.  (Never flat tow a vehicle with its steering column locked!!!)  A two-wheel dolly also works well...It's easier to back up a flat deck trailer or dolly than a four wheeled vehicle on a tow bar.  Depending upon the wheelbase and other chassis dynamics, some flat towed 4x4s are impossible to back up.  

Moses

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Fantastic info, thank you.

2 hours ago, Moses Ludel said:

When trail running, it's gallons per hour, not miles per gallon.

This is a bit of a surprise.  Granted, I've only done (many) day-trips, but once we arrived we were in 4L most of the day until the trip home.  I'll have to keep better track of MPG, but from what I recall it wasn't crazy.  I guess the trails weren't challenging enough :)

You read my mind; after a cam / clean the head, a header would be my next upgrade.  From what I've been able to find, and you're echoing this, that's about all I'd realistically need to do.  Simple list.  I don't see swapping to a 16v for eg or a crazy  2.0l mod or adding boost.

I've been looking at trailer dollies, only because I don't have room for a trailer.  Flat towing, while considerably cheaper, doesn't appeal to me for all of the reasons you listed - difficult to back up; extra wear and tear.  There are some very compact vehicle dollies out now.  Tantalizing.

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Calmini offers a camshaft, too.  The profile is not listed, you might seek out the lift/duration specs on the grind...As for dollies, they come up used all the time.  A good friend bought a brand new Demco Kar Kaddy, the company's top drawer dolly ($$$) with disc surge brakes and auto steer feature.  He kept it for less than two years and towed less than three thousand miles.  This is similar to his unit:

https://www.amazon.com/Demco-9713046-Kaddy-Dolly-Brakes/

A lightly used dolly in good condition should sell for $1000-$1500 (USD).  As you note, they store easily.  There's little to wear out, so "restoring" a used dolly is not costly.

Moses

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