2002 chevy express 5.7L vortec, L31 swap help

114155 Views 698 Replies 41 Participants Last post by Rinny, Sep 25, 2020

Rinny

Discussion Starter · Jan 22, 2017

I was wondering if you guys could help me out with my 2002 L31 swap out of a chevy express
It has 100,000 miles on it.
I am putting it in a 2003 awd astro van 2" lift, that I use for surf fishing up here in rhode island (putting that motor in is quite a feat in itself for me, but within my capabilities!!)
I want to do the smart things before I install it,I am going to go with electric fans, http://www.ebay.com/itm/CHEVY-ASTRO-SAF ... 5w&vxp=mtr
thinking about an EFI intake upgrade
Radiator http://www.jegs.com/i/Champion-Cooling- ... 6/10002/-1
oil cooler not sourced yet
can the fuel injection be improved upon, I would like to keep it.. Not racing it just want responsive driving on the high way and sand.
any input is welcome.
I don't mind spending some money but don't want to do things that are not nesc for my application
cold air intake also?
water pump
timing chain
oil pump?
Cam ( mild and which one?)
what head work is required on the vortec heads if I do a cam?
valve covers?
I have the motor Mounts and I have cast iron exhaust manifolds that work for this application, courtesy of Captin Crunch
Should I put new pistons in and should I do any head work on the vortec heads if I leave the cam that is in it now?
crank polish and bearings?
Hone cylinders or bore 30 over? (is that a good number to bore over?)
I am going to have the machine work done and probably lower end, pistons, heads, EFI intake assembled by the same shop if I go that far into it.
I can wrench but have limited abilities.
Thanks

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Lumpy

· #2 · Jan 22, 2017

I'll comment on the elec fans -

Professor Maher, math-a-billy extrordinare, explains how TWO fans can't give as much surface area as ONE larger fan. Something about his pies being square.

Also, those RED fans, that brand/vendor gets a lot of negative chatter from people who have considered or bought them here and elsewhere. I generally don't worry too much about negative reviews until it comes from someplace like here and/or there doesn't seem to be any positive press.

Their link on the eBay listing is 404 but at least when I went to their index page I'm happy to see they lost that seizure inducing red text on black background that they used to have.

That package on eBay seems pretty expensive. My Taurus/Lincoln fan with shroud was 100 bucks. Controller was 30 bucks. Blows hard enough to sweep the leaves in the driveway.

Several of these guys here have dropped extra iron in their astro. They'll know all the quirks.

Thin, aluminum, low cost radiator replacement is a popular change for both 6s and 8s.

Lump

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1lowcab

· #3 · Jan 22, 2017

I've wondered about that fan kit myself, if it was worth it or not.
It says in the listing "This controller will also allow the fans to be turned on automatically when the air conditioning is turned on."

They don't show the controller or explain how it does that, they just say "Very simple hook up, less than 1 hour for people with basic automotive skills."

They do say the temp sensor is a probe that slides through the radiator fins, don't know if I like that either.

CopperFiremist

· #4 · Jan 22, 2017

I used the 1993-2002 Camaro E fans on mine I think DRZ talked me into them, they haven't skipped a beat! I used a Camaro fan relay box I stole from a donor. Though I don't think the L31 PCM has E fan control I could be wrong. Most the time on GM its a green and blue wire that control the fan relays.

http://a.co/1ND1IrP

1lowcab

· #5 · Jan 22, 2017

This controller here doesn't look to bad, it threads into the water jacket which I think is better and it has the AC over ride. Is there an empty 3/8 NPT port on the 4.3...... sorry for the thread jack

http://www.jegs.com/i/Derale/259/16...210019240631&gclid=CMzik4Pk1NECFcm3wAodMiEEvg

markmitch

· #6 · Jan 22, 2017

That will work on a single efan but on a double you would have to do something different.
I bought an aftermarket single fan off ebay but have not tried it except to power it up but being from ebay I am a bit skeptical about its longevity. I may do something different if the future. I can always use it in the garage window in the summer lol. I think the dual Camaro fan set up is a great idea math or not if GM did it there has to be a reason is all I can say.

1lowcab

· #7 · Jan 22, 2017

Definitely the Camaro fans, they look like they would work great.

That controller says it will activate up to 2 fans with a total maximum draw of 25 amps, if the draw is over that then you'd need to find another.

AstroWill

· #8 · Jan 22, 2017

Or just use the controller to activate a relay.

Rinny

Discussion Starter · #9 · Jan 22, 2017

So it appears the 1966 to 2000 Camaro fans might be the ticket. I will need a controller unless I can get it out of the Camaro? Or I will need a separate controller because my PCM will not operate the fans with the Camaro controller? Will it come on when the a/c is on? The controller from Jegs above looks to be a good set up with the thread in temp sender. That wont eliminate my temp gauge? There must be another place to thread it in besides the temp gauge sender? This is exactly the feed back I need to complete this swap the rite way. Thanks

Lumpy

· #10 · Jan 22, 2017

Thread in or stick through the fins, I think either style probe is fine. Ultra precision isn't a factor. You just want the thing to turn on when you tell it to. For the thread in version, you buy a pretty simple T adaptor that goes inline on your upper radiator hose. Look at GlowShift.com for that. Once it's all hooked up, you simply wait till the temp reaches your desired turn ON point, then adjust the little trim pot on the controller.

The A/C connection is simple. It simply taps into the compressor 2 pin connector (or takes it to/from the ECC).

Controllers typically include a relay. Mine was a pretty standard 30A. I sent it's signal to an 80A relay just so I'd be sure and be over rated.

I always recommend installing a simple switch and BRIGHT pilot lamp so you can disable the fans (and light so you'll know they're off). You'll want to disable them when you're working on the engine and what not and you don't want them suddenly coming on. Some people turn the fan OFF at highway speeds and I think MusicMan has a design to make it shut off automatically at freeway speeds. My van doesn't seem to cool naturally at highway speeds, perhaps because of my big bumper interfering with air flow.

Here's my switch/indicator lights/gauge built into an A pillar. RED/YEL/GRN LEDs indicate fan manually OFF/normally ON/normally OFF -

The Taurus/Lincoln fans (and lots of others I think) are two speed. I switch the speeds manually by just plugging the connector into the "other" position during the hottest time of the year. Rest of the year it's on low speed. Controller does the same in either position. On high, skinny people have a hard time approaching the van. The high velocity wind blows them away. I guess I'm safe if I'm attacked by coke addicted zombies. I'm in Phoenix, the temp gets over 110 for maybe a month during the summer. Sometimes I don't even switch it over to the high speed. The low speed seems to do just about the same as the high speed. I have not perceived any need to have the two speed thing switchable on the fly from the dash or automatically from the ECM or a thermostat. It simply needs to come ON.

Then there's the shroud. My fan came with a plastic shroud that covers nearly 100% of the radiator surface. Maher runs withOUT a shroud and his cools just fine. So that might not be the most important factor in choosing which fan. I'm stupid to V8s but I'd think that simple CLEARANCE between the radiator and the engine would be a more important factor than anything else. And again, plenty of experts here have addressed that.

Lump

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Rinny

Discussion Starter · #11 · Jan 22, 2017

Lump thanks for that answer which brings me to more questions, lol. But really
The Camaro fans and shroud are available on rock auto, 3 different brands I do believe. I will be on the sand a bit so I think the 2 fans are a positive?
If not I prob can get the tarus fan and shroud there also, which year?
Which controller did you use or is the one from jegs fine?
Why turn it off at highway speeds if the temp dosent come up enough to send a singnal for them to come on.
How many cracK heads have you found stuck to your grill ; )
I am sticking with the single core radiator that is in the van now after doing some radiator research.
add an oil cooler and trans cooler or will they interfere with the engine cooling?
Ad yes, what digital gauge and switch combo are you running?

chevymaher

· #12 · Jan 22, 2017

I would look into a bigger radiator. Chevelle radiators are almost the same exact dimensions. But come in a 4 core. Cooling is a issue in these vans.

Lumpy

· #13 · Jan 22, 2017

Rinny said:
Lump thanks for that answer which brings me to more questions, lol. But really
The Camaro fans and shroud are available on rock auto, 3 different brands I do believe. I will be on the sand a bit so I think the 2 fans are a positive?

In my view, the two fan option does two things. 1) it moves less air than a single fan would. 2) it might give you a backup in case one fan fails, if it's wired that way. I've never had and I don't think I've heard of, a fan failure to make that "failure" component a factor for me.

Shutting the fan OFF for some off roaders is a function of getting through high water or maybe blowing sand, as you suggest. I can't really imagine dual vs single to be a factor for the sand question.

Rinny said:
If not I prob can get the tarus fan and shroud there also, which year?

Mine, from RockAuto, is "1993 FORD TAURUS 3.8L V6 OHV" their part #620101 (620-101). I think that style will fit all AstroSafari radiators.

Rinny said:
Which controller did you use or is the one from jegs fine?

Mine was a simple $30 blob from the LAPS. I think they're all about the same.

Rinny said:
Why turn it off at highway speeds if the temp dosent come up enough to send a singnal for them to come on.

The temp might get high enough for the fans to come on. But at 65 MPH your vehicle speed might be moving air faster over the radiator than the fan could. So you could save some pretty high current draw by turning it off. With a gauge and a switch, you can experiment in real time. Get up to speed, note the temp, turn it OFF and see if the temp stays there or climbs.

Rinny said:
How many cracK heads have you found stuck to your grill ; )

Not too many here but when I drove to LA to visit CargoCrawler, I was picking out zombie tweakers from the grille for weeks.

Rinny said:
I am sticking with the single core radiator that is in the van now after doing some radiator research.

I wouldn't anticipate any problems unless you think it's clogged up, DexCool boinked, not cooling enough or not enough physical clearance for your 2 xtra pistons.

Rinny said:
add an oil cooler and trans cooler or will they interfere with the engine cooling?

They won't interfere. Lots of people have bad luck with leaking OEM oil coolers. Perhaps whatever version your new engine will have won't suffer that.

Rinny said:
Ad yes, what digital gauge and switch combo are you running?

Gauge is GlowShift. Switch and LEDs have been in my junk box for decades. It's simply a DPDT switch that enables or kills power to the fan relay and lights an LED when the fan is OFF.

It's all really pretty simple. Pretty much any fan and any controller will be fine. Just figure out a way to turn it OFF when you deliberately don't want it on. And experiment for a couple days just after install to get the thermostat turn ON/OFF point where you want it. Really simple.

Lump

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Rinny

Discussion Starter · #14 · Jan 22, 2017

I am getting less scared about doing this swap every day!! Thanks so much for all the info Lumpy!! Motor is on a stand and the van is half apart.

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kennysmoke

· #15 · Jan 22, 2017

Rinny said:
I am getting less scared about doing this swap every day!! Thanks so much for all the info Lumpy!! Motor is on a stand and the van is half apart.

Nice looking van. Looks like more than a 2 inch lift, is the motor still in it?

Rinny

Discussion Starter · #16 · Jan 22, 2017

kennysmoke said:
Rinny said:

I am getting less scared about doing this swap every day!! Thanks so much for all the info Lumpy!! Motor is on a stand and the van is half apart.

Click to expand...

Nice looking van. Looks like more than a 2 inch lift, is the motor still in it?

Yes the 4.3 is in it in that pic.
It has the 2150 lb springs made for astros and safaris (Sd spring I think) Big boost!!
Journys off road spring hangers and shackles
Reindexed Keys but they are not tweeked too much
2" body lift

Rinny

Discussion Starter · #17 · Jan 24, 2017

I think I should have started off with this question. Is the electric fan mod required to do this swap? some "experts " say you cannot get the cooling capacity out of an electric fan set up that you will get from a belt driven fan? I know I will get an increase in HP and fuel mileage but how much will that be do you think? All in All is it worth the time and effort and the $$? should I put the $$ into the motor and try to get it up to 330 Ponies?
Making progress on getting the clip out. Maybe this weekend it will be out.
The 5.7L is about 1/2 stripped of all the stuff on it, taking it down so the heads are off and the lower end is exposed for a good inspection.
For what I am gonna be doing,GM's Ramjet cam(#14097395) is a good choice? It won't require any headwork,however,I would use better springs than the stock set.The GM LS6 springs with Comp 787 retainers would be a good budget friendly choice? The cam runs approx. $170 new.Springs are $60.Retainers run approx. $55.
This cam will give me great lowend torque (approx. 400 ft/lb) from 1800 out near 4800 rpm.It will run ok on the stock Vortec tune,but,tuning will really bring a lot better perfoirmance & not cause codes in the system? I can get it on a dyno for 400.00 and get it dialed in? ( This info was courtesy of Hotrodders, Bunch of great guys over there and they know their stuff!!)

If I find wear in the cylinder or lower end I will bore it 30 over , polish the crank and have it put togeather with a new spider and possibly intake? So if the elect fan is not going to give me a good bang for the buck I would rather put the $$ into the motor as I said. I can always add the elect fan set up later?

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AstroWill

· #18 · Jan 24, 2017

Rinny said:
I think I should have started off with this question. Is the electric fan mod required to do this swap?

It's not required, but in my opinion it is worth it.

Rinny said:
some "experts " say you cannot get the cooling capacity out of an electric fan set up that you will get from a belt driven fan?

I don't know who those 'experts' are that you are referring to, but you can get all the needed airflow that you need from electric fans, and in some situations even better flow than mechanical fans.

Rinny said:
I know I will get an increase in HP and fuel mileage but how much will that be do you think?

Unknown, there are too many variables, but it's going to be a tiny difference that you won't notice

It doesn't eliminate all drag on the engine, because it will increase the load on the alternator. The real benefit is that you gain clearance, flow at lower speeds(think stopped in traffic), better AC performance when stopped, quicker warm up, and more.

Rinny said:
All in All is it worth the time and effort and the $$? should I put the $$ into the motor and try to get it up to 330 Ponies?

I think that it's worth it, but it's something that is easily changed later. Putting money into the engine tends to be a whole lot easier when it's not in the vehicle.

Lumpy

· #19 · Jan 24, 2017

The V8, is not "Required"... :driving:

Lump

Rinny

Discussion Starter · #20 · Jan 24, 2017

Lumpy said:
The V8, is not "Required"... :driving:

Lump

Of course it is otherwise its no fun!! :banana: :banana:
"Not necessary." "What could be more Necessary"

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