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Crazy Stroker Thoughts

belize1334

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Nov 18, 2003
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Bozeman, MT
Ok, so I've got my flame suit on and I wanna poll people's opinions.

I'm getting ready to do an engine build off of the profits from my 90 TSI partout (see upcoming FS thread). I've got a nice 1G head that I'm gonna use but I'm gonna have to source a crank one way or another (spun rod bearing = nasty rod journals). This started me thinking about strokers again. After some poking I found that I can get a low-mileage 4g64 short-block for pretty damn cheep (like same price as reusable 2.0 crank). That'd mean that all I'd need is a set of pistons since I've already got a spare set of 1G rods.

Here's the hair-brained part. I'm thinking since the 2.4 deck is 6mm taller, I could just use 1G or 2G pistons in there. The only problem that I can see is that I'd need to get 0.6" overbore since it's a 86.5mm bore instead of 85mm like the 4g63. So I'd have to assume that the block doesn't need a rebore.

Now, I know that most people who do a stroker go w/ aftermarket rods and pistons but I'm not building to make a power monster. I just want my easy living 300whp but w/ super fast spool up and a really low boost threshold. Something like Evo3 16g on 2.4L would hit full boost at like 2300rpm and have instant spool. And 1G rods w/ 1G or 2G pistons have made 400+whp time and time again so they should stand up.

So what are your guys thoughts on this? 2.4L block w/ 4g63 head. 1G rods and 1G or 2G pistons 0.6" over. Good for up to about 400whp w/ amazing turbo response. It'd be the autocross hawtness but buildable for the same price as an OE rebuild.
 
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a2vr4

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Aug 13, 2005
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Ann Arbor MI
That would be a de-stroke if I am not mistaken, and to do this correctly I think you would need custom rods/pistons. Someone confirm this? I have wanted to build a de-stroke myself, but it was going to be way too much for basically a novelty, at least for me being a broke weekend warrior. /ubbthreads/images/graemlins/dunno.gif
~Brian
 
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H05TYL

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Jun 9, 2007
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Wgtn, NZ
er, de-stroke is using a 63 crank in a 64 block, he's talking about using both the 64 crank and 64 block with o/s 63 pistons (to suit the bigger bore of the 64 block whilst having suitable valve cutouts for the twin cam head).
 

belize1334

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Nov 18, 2003
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Bozeman, MT
^^ Yes...that and also the fact that OEM pistons are durable and cheap. The only issue is finding them in 0.06" overbore (85mm + 1.5mm overbore) = 86.5mm (stock for 2.4L). So far I can't find them from NPR which is the OEM manufacturer.
 
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i would go for it if i were you, good luck /ubbthreads/images/graemlins/applause.gif
 

This would be a straight 2.4 build not a stroker or de-stroker. I'm having a brain fart but how are you going to compensate for the extra 6mm deck height again /ubbthreads/images/graemlins/dunno.gif
 

belize1334

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Standard 1G rods w/ standard 1g or 2g pistons. Then the 100mm crank means that the piston tips out 6mm above normal. But the 2.4L block has an extra 6mm deck height anyway, so it should work out fine. I looked up specs for the 2.4L pistons and they have the exact same wrist-pin locations as 4g63. And the 2.4L rods are the same length as 4G63 (though not as beefy obviously).
 

GIjoe

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Budapest
Quoting Sw4n3e:
i would go for it if i were you, good luck /ubbthreads/images/graemlins/applause.gif



Yeah, definetly sounds interesting.
 

prove_it

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Sioux Falls, SD
It sounds feasible. Isn't the 2.4 block cast weaker? I know your not for huge power, but I was just wondering. Also will the head bolt up to the block with no passage issues? What about timing components, will they be the same and will the cams degree properly once the belt is on? Just some thoughts I had. Sounds like a great build, if it works I'll be jealous and just might have to build my own.
 

belize1334

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Bozeman, MT
Well, for me it's all speculation and internet sack-riding /ubbthreads/images/graemlins/cool.gif. Basically, from the research I've done, it seems like the crank, rods, pistons are a no-brainer (though, again, I can't seem to find OEM 0.06" over...maybe they don't exist). The head SUPPOSEDLY bolts right up as per a the image below (found at ZeroG) which shows ALL of the holes and passages being identical. The timing components are all the same except for needing a 4g64 dohc belt which came on the 93(?) Galant which was the only one to come w/ a DOHC head (it was a 7-bolt I believe). It also requires adjustable cam gears or else DOHC gears from that same year DOHC Galant. There's one final issue which is that the entire head/turbo assembly sits 6mm higher which can be an issue for things like the oil-return line, turbo coolant line, and down-pipe. I'm thinking that this last issue is easy to solve w/ a 6mm spacer between the manifold and the turbine housing but I haven't seen any documentation yet so I can't say for sure.

 

prove_it

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Good point on the turbo distances. The spacer idea should take care of that though, That's how I would tackle it instead of AN fittings for lines, and rebuilding the exhaust. Obviously you won't be able to use the intake manifold brace. Let's see, what else?

Oh you may what to check into the head alignment dowels since there could be a difference in size there, which may require drilling the head or block to accept each other. I kinda doubt there would be, but just thinking hard on this one. What about the timing covers? I would think you'll need covers off the 93 DOHC engine too.

What about head bolts or studs? Would standard 4g63 bolts work, or would the 2.4l bolts be needed? I say this cause the step in the head may have way different heights.

I'll keep thinking about it. Sounds like it should be feasible. Big thing would be the passages and alignment dowels.
 

prove_it

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Wait a minute....
I was looking at the picture and my brain maybe over seeing something, but if you look at the pics like they sit then yes the ports are identical, but your looking at the bottom of the head so you actually need to flip it and to me it looks like the ports would different.
 

turbowop

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Apr 29, 2001
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Yakima, WA
Flip it up/down, not left/right.


Has this never been done before? I could swear people have used this block in the past right? I've never really studied strokers and 2.4liters, but this is all stuff I figure somebody has already done before. /ubbthreads/images/graemlins/dunno.gif
 
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prove_it

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Yea yea, I'm sure it is, been a long day and my critical thinking is gone.
 

boostedinaz

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Apr 20, 2006
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Scottsdale, AZ
Yes 2.4s have been done before. I think the only issue would be finding stock style pistons in the correct size.
 

belize1334

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Nov 18, 2003
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Bozeman, MT
I talked to RoadRaceEngineering and they said that the head-block matchup is common and simple. It's just a question of piston choice. According to them you CANNOT get 60 over OE pistons. They just don't exist. You can get aftermarket stuff for this build but they cost the same as other aftermarket pistons ($450+) which negates the whole "OEM parts" idea. So, I did some looking and I think I've come up with a solution, but I doubt it's worth the trouble.

The EvoX 4b11 engine has a stock bore of 86mm. That means that you could get 0.02" overbore pistons for the 4b11 and they'd be the correct bore for an untouched 2.4L block. Likewise, 0.04" overbore 4b11 would work for 0.02" overbore 2.4L block. But there's still a problem, the wrist pin is located 1.75mm closer to the dish on a 4b11 than on a 4g63. Link . As such, they could only be used with HIGHLY custom rods or else with the block milled down 1.75mm. You'd also have to have the rods machined to accept the 23mm pins. As such, I think it IS doable, but it's just not worth it. OE EvoX pistons aren't cheap the way DSM pistons are, and once the machining work is done you'd have dug deep into the bank account for an OE part rebuild.

So, I think that unless someone gets NPR to make a 0.06" over piston, you might as well just buy aftermarket. In many cases people would want to do that anyway...I just thought that if one COULD build w/ OE parts then it could be done cheep for a moderate power car w/ better response. Also, the RRE guys maintain that the 4g64 isn't worth building since the piston walls get too thin which results in head-gasket failures. I'm not sure if that makes sense since most HGs are 87mm bore anyway but that's what they said. That's just they're opinion of course, but they've built more engines than I have so...take that for what it is.
 

prove_it

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That's what I posted about eariler. I thought the 4g64 has some block differences that made it weaker somehow. I know I've heard it before. I was thinking it was something to do with the bottom end. If RRE is right then I would think since your building a low power engine I would think that ARP studs with a MLS head gasket would hold up to it. Yea it's not a OEM build, but sounds like your past that point anyway. I would think you should be more worried about cracking the cylinder walls if they are thinner. I'm sure 15lbs of boost through a 16g would not cause that kind of damage though.
 

slugsgomoo

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Oct 16, 2003
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Tacoma, WA
there are a ton of people who have made 600+ AWHP on the 2.4L and a handful that have made 850+ It's not that much weaker, and in this case, it definitely doesn't matter. If you really care about block longevity with the 100mm crank, a kiggly girdle is going to be the most important piece anyway. /ubbthreads/images/graemlins/dunno.gif
 
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