What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

L18 8.1L swap resource thread

I have a york on my big block, works great for pressure and volume and is relatively light and will run air tools and fill tires no problem.

I just have to keep the oil very low or the air is full of frothy oil, the only thing I don't like about it. Great for ait tools, not so great for inside your tires or blowing stuff off, makes a mess.

Tried the block off trick at the top, still does it. The only thing that doesn't do it is if I let the oil get low enough it stops. But I feel eventually he pump will die that way.
 
Depends on how much brake you use, and if you have leaks. Not supposed to lose more than 3 or 5 psi in 1 minute applied test.
Compressor cuts off at 125 psi and had better cut in at 65ps.
There is build up spec x amount of pressure in x amount of time, that escaped me atm. These test have to be done every 90 days and documented , for commercial trucks. Not motorhomes
 
Last edited:
folkenheath said:
Wow, that seems like a waste of fuel to pump air the whole time. Also sounds big and heavy, nevermind. Thanks for the info!
Click to expand...
there HEAVY AS HELL and in the CDL air bake world its better to pump full time to make air for brakes ass needed and bypass the extra = the WHOOSH you here next to big trucks running . my gmc 7000 i just got back together was a engine hose to help hold it in place as i set it up on the head of the 366 bbc tall deck engine .

getting in to the medium duty / heavy duty world is a LOT DIFFERENT than the stuff 98% of us are use to playing with for sure .
 
folkenheath said:
I have a york on my big block, works great for pressure and volume and is relatively light and will run air tools and fill tires no problem.

I just have to keep the oil very low or the air is full of frothy oil, the only thing I don't like about it. Great for ait tools, not so great for inside your tires or blowing stuff off, makes a mess.

Tried the block off trick at the top, still does it. The only thing that doesn't do it is if I let the oil get low enough it stops. But I feel eventually he pump will die that way.
Click to expand...
med / big trucks have a WET tank and dry tank to help filter this out . . . i found out on my gmc 7000 i just fired up ........ i found the WET tank and it was NOT fun at all . . . what a mess .
 
For when you do get it running. Sounds like previous owner didn't know either.

How long have you had this truck? That wet tank might be compromised
 
Wes Harden said:
For when you do get it running. Sounds like previous owner didn't know either.

How long have you had this truck? That wet tank might be compromised
Click to expand...
Nov 2016 . Not sure how long it sat before . Had a lot of oil and moisture mix . Just flipping the truck so not my problem . Fine details will be new owners job .
 
I went looking but, couldn't find it.
Will a Big block intake manifold bolt up to the 8.1 litre?
Seriously, thinking about a tunnel ram, modified for injectors. If it will bolt up.
 
BoondocK5 said:
I went looking but, couldn't find it.
Will a Big block intake manifold bolt up to the 8.1 litre?
Seriously, thinking about a tunnel ram, modified for injectors. If it will bolt up.
Click to expand...
The only downside to the 8.1 is the fact that the intake is unique to that engine only.

There are some aftermarket options but none are cheap.
 
BoondocK5 said:
I went looking but, couldn't find it.
Will a Big block intake manifold bolt up to the 8.1 litre?
Seriously, thinking about a tunnel ram, modified for injectors. If it will bolt up.
Click to expand...
I have converted Darts 8.1 Intake to MPFI for some customers, doing another one next week. Its setup for a carb but the bosses are cast in for the fuel injectors, I machine the injector bosses and the rails, and make rail mounts.

20210128_113504.jpg
 
Last edited:
Then you'll be better off with a traditional BBC, even if you convert it to MPFI. I don't think anyone makes a tunnel ram for the Gen7, which means a custom sheetmetal intake that would cost more than the engine, from someone like Marcella or Hogans.

Raylar makes something in between, but it's not cheap either.

Vortec 8100 8.1L EFI GEN7R Intake Manifold - 496cid GEN7R Intake Manifold - Intake Manifold Porting - Raylar Engineering

Vortec 8100 / 8.1L / 496cid GEN7R intake manifold. 8.1l GEN7R intake manifold.
www.raylarengineering.com

raylar-coolgap-unlimited-intake-twin-1000cfm-throttle-bodies.png
 
folkenheath said:
I have converted Darts 8.1 Intake to MPFI for some customers, doing another one next week. Its setup for a carb but the bosses are cast in for the fuel injectors, I machine the the injector bosses and the rails.

View attachment 423665
Click to expand...

That’s bad ass! I’m assuming that’s using a Holley system? Is that using the stock crank and cam sensors?

I’m curious how that intake changes the power production over the stock intake.
 
ZooMad75 said:
That’s bad ass! I’m assuming that’s using a Holley system? Is that using the stock crank and cam sensors?

I’m curious how that intake changes the power production over the stock intake.
Click to expand...

Thank you, and yes, they used a Holley system to control it, I created a starting tune to work with it too, so it was "plug and play".

It does utilize the stock cam and crank sensors yes, it's the same 24x pattern as many LS engines, and this one next week is reusing the stock injectors too it appears, they are the mid length truck injector/connector. That one in the pic was some short LS3 style injectors.
 
Last edited:
You must log in or register to reply here.

Latest Posts

Top Bottom