weinerschizel

Anybody here installed an LS3 pump on an LS1? My pump went out and I heard that the LS3 pump is a nice upgrade. Has anybody here performed the upgrade can tell me of any tweaks need done to pull this off.

Thanks!

KCvetteowner

It fits perfectly but you also need the LS2/LS3 thermostat and thermostat housing as they are not integrated like on the LS1. Remember you also need the gaskets for tstat and the waterpump. 4-5 lbs lighter than the LS1/LS6 pump and less rotating mass.

Last C5

Is there an improvement in cooling and flow? Will the 04 LS1 separated thermostat and housing work?

KCvetteowner

The LS2/LS3 water pump cools my 418ci forged LS3 motor very nicely. I haven't noticed any coolant temps above 192. My oil temps hit 230 regularly I can't see GM making a pump that doesn't cool/flow better for the LS2/LS3/LS7

I'm almost certain the separated thermostat and housing for the LS1 won't fit. As I recall the thermostats were too deep for the LS2/LS3 shallower tstat cavity in the water pump. Please let me know if you try it and it does work.

lucky131969

So in other words....you don't know....

KCvetteowner

Correct. I switched motors and water pumps at the same time so although I see cooler temps I have a different engine.

You still can't argue less rotating mass and 4 to 5 lbs lighter.

lucky131969

Yep, there was less rotating mass in the C6 Z06 halfshafts too......

KCvetteowner

weinerschizel

So you have an LS1 with an LS3 pump on it? I want to make sure and get this right as every time I work on the car I have to drive 600 miles to where it's stored. Long story...

I called summit racing to order the pump which I have along with all the parts by this weekend. The guy said it comes with the thermostat housing, thermostat, and gaskets. They in turn ordered the part through gm performance parts for me. Although the guy seemed confused and didn't have all the answers up front for me so I'm a little skeptical.

OhioC5

Weiner I sent you a PM

weinerschizel

Are the LS2 and LS3 pumps the same? Summit sold me a thermostat to go with the LS3 pump but it doesn't list the LS3 motor as something it's compatible with.

http://store.summitracing.com/partde...w=1&N=700+150+

Next, they charged me $280 for the pump. I did some shopping but not a lot as I'm strapped for time. Have to have the pump by Friday. Is $280 a bit much???

KCvetteowner

I had an LS6 with LS1/LS6 water pump on it. I upgraded to a 418ci forged LS3. LME built the motor and said all the LS1/LS6 front accessories will bolt right up. I already had 43k miles on the car and wasn't about to put my old water pump on a 510rwhp motor. So I looked around at options and this is the best option short of spending a lot of money for an Evans unit, etc.

I compared the two pumps side by side, weighed them and saw the gaskets are identical they both line up identical and the tensioner mounts the same exact way. Your stock belt fits perfectly.
Here is a link to more information on the LS1/2/3/6 differences:
http://nookandtranny.com/Info_LSx.html

OhioC5

The link I sent you came from KCvetteowner I was close to spending too much on a pump myself. When I decide to do it he saved me 180.00 bucks

KCvetteowner

I just pm'ed you the same link

weinerschizel

Thanks! I called race parts direct. He explained to me their website had a typo. The pump will not fit an LS1. However, he told me the pump I ordered through summit was wrong as well! It had the wrong pulley. So I went to summit and had them reorder the pump with the right pulley! Yahoo...

So apparently the latest revision small block pump as used on LS2, LS3, LS7 is part number NAL-89018053 using the older version pulley as seen on LS1 and LS6.

Otherwise it's part number NAL-89018052 using the newer version pulley as seen on LS2, LS3, LS7.

Although the pump was $270

KCvetteowner

I would have to disagree. The LS1/LS6 water pump bolts right up to the LS3 but the LS3 water pump won't fit the LS1?? Yes, the LS1 for F-body /GTO won't work because of the serp. belt pattern uses the outer edge of the bell.

Rob's 73

I can tell you that my ls6 pump bolted right up to my LS3 417.

xizor

Did you ever get your pump and install it?

weinerschizel

Yeah I did a dumb thing...

Thought there were two versions of the LS3 pump.. one with bell shaped pulley and another with a regular pulley.

No there's only one version of the LS3 pump... it has the regular pulley. I thought you had to have the bell shaped pulley on the LS1 vette so I bought a factory replacement pump that I thought was an LS3 pump with bell shaped pulley.

When I pulled off the old pump I realized it was the EXACT same as my replacement pump. So the long and the short of it... only difference between the LS3 pump and LS1 pump is the LS3 has a smaller lighter pulley.

So if you want to do an actual LS3 upgrade on an LS1 you have to have the corvette style accessories. And it will give a slight performance increase (probably won't notice though) because the pulley is lighter on the LS3 pump.

That's it... oh and don't buy the factory pumps. They are a bloody fortune

xizor

to clarify, you mean you can't fit the ls3 water pump on a non-corvette LS1 because the accessories are different between the LS1 variations?