Dumb question here: I thought your 3.8L stroker was unsleeved. But I was looking at your engine packages ( https://my350z.com/forum/product-announcements/239093-gt-motorsports-short-long-blocks.html ), and you have the 3.8L stroker listed as a sleeved setup, why?

 

I thought he had a 3.8 stroker with a 100mm overbore to make it a 4.1 liter. Obviously sleeved to get this.

 

My bad. By "your", I meant GTM's 3.8L stroker motor setup. Not specifically George's.

 

Yeah your right, they have a unsleeved 3.8 stroker. I think they have both sleeved and unsleeved though. I can't remember.

 

This is correct, with the 3.8L you can go sleeved or unsleeved, up to you, but if you are going to sleeve it might as well go 100mm bore like me, unless you want to use HKS gaskets, then you cannot do a 100mm bore.

-George
GT Motorsports

 

thats the one thing i was wondering...cuz if you go HKS you are stuck with a 97mm bore. im guessing then george you just went with a cometic ??

 

I couldn't use HKS gasket regardless because of my 14mm head studs, so yes I went with a Cometic gasket to accommodate my bore and large head studs.

-George
GT Motorsports

 

Thanks for clearing that up George.

 

Do sleeves also cause an NA motor to run hotter? I guess it stands to reason that they would. I don't really understand why sleeves increase the temperature of the motor. All the block material that is removed is replaced by the sleeves.

I live in Florida and am trying to determine if the 4.1L version would be acceptable for a daily driver. It gets pretty hot down here in the Summertime.

 

the sleeves make the engine closed deck instead of open deck. Instead of the coolant completely surrounding the cylinder chambers, with sleeves, they only have little channels the coolant can flow through.

They're also not made of aluminum, but steel which traps in more heat

 

Iron

 

oh I was wondering that after I wrote that. Iron's even worse that steel with trapping heat

 

since he said:
Do sleeves also cause an NA motor to run hotter?

...i dont think he needs to worry about it anyways with going with darton sleeves... if he is stroking his engine but keepign it N/A

werd

 

So you're saying that when they bore out the block for the sleeves, the outside diameter of the sleeves is so large that boring the block for it removes some of the water jacket that normally surrounds the cylinder?

I'm not sure what open/closed deck means.

Of course. I hadn't thought of that. It makes perfect sense now that you all mention it.

I am thinking of boring and stroking... hence the sleeve questions. Is Darton the only/best sleeve manufacturer?

I've been planning to bore and stroke a new RevUp NA motor for quite a while, but I never considered the possible overheating issues you all brought up in this thread. Very interesting.

 

The engine running a little hotter is not to be confused with overheating, we haven't had any overheating issues with our cars, also as mentioned a properly upgraded cooling system will take care of the higher temps.

-George
GT Motorsports

 

Great discussion! I'll be building my motor soon (staying NA), and am weighing the pros & cons of stroking to 3.8.

 

just look at some shortblock pictures of a stock VQ35 and some darton sleeved short block pictures and you'll see

 

Sleeving an NA motor would be OVERKILL IMO. 3.8L stroker, nice heads, and some spray for "special occasions" it would be a bad b!tch...

 

Would only sleeve an NA motor if I was going 4.2

 

+1

and even then I still think I'd rather just go V8 for the money