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1998 Grand Prix GT Engine Swap (to the L26)

J

jasonbernard

New member
Ok, here is the new thread.

Quick background: Bought car for daughter, knowing it had a spun main bearing.
Was going to rebuild engine, but the fellas here set me on the better choice of an engine swap: http://www.grandprixforums.net/thre...rix-GT-Coupe-Bad-Main-Bearing-Rebuild-Project
(many thanks to Buck531, ScottyDoggs, WarStryker13, and many others for setting me on the right path!)

My daughter and I will do the work together.
She gets her license later this year, so we can take our time, label things and photograph as we go.

Old Engine: L36 with spun bearing



New Engine: L26, 18k miles, long block+ (see pic below)


First question: what is that next to the EGR on the new L26 engine, but doesn't seem to be on the old L36 engine?
Do I need to keep it or toss it?
 


That is part of the air pump system, that motor came with cali emissions that you do not have. Remove it and toss it.

You won't be using that wire harness either so it doesn't matter. Swapping your top end over with new gasket is really all you need to do and the oil pan and various mounts or odds and ends.
 
I'm pretty sure he's keeping the L26 intake, so after doing the full gasket set on the L26, he's just gonna drop the entire block in with a TB adapter and route the PCV properly.

It's more of a teaching exercise than a matter of making it work, so he's going through it the long way. Kudos, jasonbernard.
 
Thanks guys, you can see I am a weekend mechanic at best. :rolleyes:

Yep, we're keeping the aluminum L26 intake, but I don't know about a full gasket set.

I'm thinking we may stop at the UIM and LIM gaskets (replacing with metal reinforced one).
Of course, if we do that we will probably do the IM coolant port plugging mod...

This replacement engine looks like a brand new crate motor.

We are looking forward to doing some triage on the outgoing L36, can't wait to show her how to pop off the rod and main bearing caps...
 
jasonbernard said:
Ok, here is the new thread.

Quick background: Bought car for daughter, knowing it had a spun main bearing.
Was going to rebuild engine, but the fellas here set me on the better choice of an engine swap: http://www.grandprixforums.net/thre...rix-GT-Coupe-Bad-Main-Bearing-Rebuild-Project
(many thanks to Buck531, ScottyDoggs, WarStryker13, and many others for setting me on the right path!)

My daughter and I will do the work together.
She gets her license later this year, so we can take our time, label things and photograph as we go.

Old Engine: L36 with spun bearing



New Engine: L26, 18k miles, long block+ (see pic below)


First question: what is that next to the EGR on the new L26 engine, but doesn't seem to be on the old L36 engine?
Do I need to keep it or toss it?
Click to expand...

What year is that replacement engine? I might give you 20 bucks plus shipping if it fits mine.


Sent from my iPhone using Tapatalk
 


That is a VERY clean engine. lol

Also, don't forget to switch to the aluminum coolant elbows, sometimes referred to as heater hose elbows, the factory plastic ones tend to split or even shatter.
 
Next question: Old fuel rail had 2 fuel lines going into it, the new one only has 1.

Keep the old L36 fuel rail and fit it over the new L26 intake?
 
id think the l36 rail should fit, if it dont you'll be best to use the l36 intake. or make a custom rail.

i chopped mine up and made it custom. best 25 bucks ever spent in parts lol beats the hell out of 300 dollar fuel logs :th_laugh-lol3:
 
progress today: L26 wire harness, fuel rail, throttle body, and rear exhaust header all pulled off.

Got the aluminum TB adapter plate from sseilmnop - looks like great workmanship, nice flat & smooth metal.

Interesting thing for my application though is that the L36 intake kept it's gasket recessed, and so does the L26 Throttle body.

So, looks like I may have to make my own gaskets, or do you guys just RTV it on both sides?
 


Before you go too far, make sure to plug the coolant ports on the LIM and open up that side passage. Otherwise you could get a coolant leak at the spacer, and it will also make removing the intake or TB, for any reason, much simpler. :th_thumbsup-wink:

I would suggest the 1/4 NPT tap and brass plugs, because those are simply nicer and prettier. Since your daughter is wanting this kind of experience, it would be a good way of showing her to take pride in the work she does. And teach a little about working with machining tools.
 
Yep, way ahead of myself, and no, the L36 didn't have a paper gasket, it had one of those red rubber ones recessed into the intake face to the TB. Maybe because it is aftermarket?
 
Last edited:
Wouldn't the paper gaskets with the rubber lines embedded in them work? Those should be able to create a good seal, especially if the mating surface on the adapter plate is clean and smooth.
 


you should take the H bar out the side. sealing the two ports cuts some flow, opening the side up helps the flow to the rear head.

i used a large dual carbide cutting bit and just ground it out to what you see.

048_zpshv8jun0i.jpg
 
Thanks Scottydoggs, did you use an air tool grinder to do this?

With this mod, is it recommended to use a lower degree thermostat (i.e 165* F)?

Looks like I may have to buy one of those OBD2 displays: oil pressure, oil temp, individual CHTs, coolant temp, coolant pressure
(not sure if all those are available)...
 
i ran a stock 195, still run one but my fans are tuned to a lower temp. t stat dont really matter it will always work its way up to 200.

if you have a droid tablet or phone get the torque app and a obe2 blue tooth reader, it gives you a long list of stuff to scan, more then you know what to do with.

i phones got another app they use. it dont show kr, but your na and kr dont matter.
 
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