MG Sports Cars

engine swaps and other performance upgrades, plus "factory" and Costello V8s

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BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5600 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: 340 upgrade
Posted by: BlownMGB-V8
Date: November 17, 2017 01:44PM

IMG_0006.JPG

IMG_0007.JPG

IMG_0015.JPG

You can see here that there is at least 1/2" of allowable travel before the yoke hits the transmission.

IMG_0016.JPG

Continued:


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5600 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: 340 upgrade
Posted by: BlownMGB-V8
Date: November 17, 2017 01:50PM

The slave is an Isuzu part available for $40 from Amazon.
Dorman CS360032 Clutch Slave Cylinder

IMG_0008.JPG

I used banjo fittings and put a hose on the bleeder that reaches the reservoir for recirculation bleeding, works a treat. I may have had to re-tap the bleeder port to a larger size, not sure on that. The push rod that came with it was exactly the right length. Bore is 3/4" and stroke is 2".

And that's all I have for you guys at the moment. Should have it completed today or tomorrow.

Jim


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5600 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: 340 upgrade
Posted by: BlownMGB-V8
Date: April 20, 2018 11:55PM

So I've been testing and tuning and trying to use this much delayed spring as an excuse to get the car ready to drive. There was (and may still be) an oscillation at any idle below 1200rpm that I've spent countless hours trying to resolve yet it has resisted all attempts to date including extensive remapping of all injection and ignition parameters. The most recent datalogs show a steady idle and then it will drop into oscillation. The way it begins is that for no presently discernable reason the revs will climb then drop. George Van Horn has looked at the datalogs with me and we have drawn a complete blank on why that happens so at his suggestion I have reloaded the firmware. But I think I already tried that way back at the beginning so it may not change a thing. Tomorrow's test drive should tell.

But it is plenty drivable and the good news is that I've finally begun to use Autotune and get some usable results. When they first came out with that it was kinda buggy and didn't work very well. Mind you this was, what? 15 years ago maybe? I decided at that time that I could tune the VE map as well as I could the AFR table, and after getting used to that saw no real need to try it again. Anyway now it works pretty good. Turn it on for awhile, push the button to smooth the map a time or two and repeat, tweak the outlying areas and do it again. I'm happy with the results so far.

Finally ordered a new rear bumper. One of the old overiders was touching my new gas cap, couldn't have that. So I cut those off and installed a set of LED bolts for the tag lights. But man, that bare bumper is sure gonna uglify the car til the new one comes in what with the dents and scratches that were covered up, as if it wasn't already ugly enough anyway.

I did Glen's zerk fitting mod on my door hinges and have swapped out the passenger's side, which meant the door had to come apart of course and this was a good excuse to refinish the door panels, caps and pockets. I just finished up one side and have the other yet to go but it really spruces things up inside the car. That got me thinking about speakers so I ordered a new set of 6 x 9's. I used to have early Altec-Lansing Voice of the Highway 4A 6 x 9's mounted on the doors below the window cranks. I knew they were extremely good but did not realize quite how special until the long fruitless search for adequate replacements. But, maybe these will come close: Morel Maxima Ultra. They are supposed to be pretty good, we will see.

There's a local car show tomorrow. So, the first actual hand wash in many years in the morning and a stop by in the afternoon. With the top down. YAY!

Jim


Jim Stabe
Jim Stabe
San Diego, Ca
(666 posts)

Registered:
02/28/2009 10:01AM

Main British Car:
1966 MGB Roadster 350 LT1 Chevy

authors avatar
Re: 340 upgrade
Posted by: Jim Stabe
Date: April 21, 2018 02:16AM

Pictures coming I hope. Have you had a chance to really stomp on it yet?


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5600 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: 340 upgrade
Posted by: BlownMGB-V8
Date: April 21, 2018 02:24AM

Not really hard but I've gotten into it enough to know the power is there. However it seems I may have been a little conservative on my valve spring pressure so won't be wringing it out until that is upgraded. Meantime I'll be keeping it under about 4500rpm. Not that this creates a problem you understand. It's a very frisky engine.

Photos... yeah, that'd be a good idea.

Jim


Jim Stabe
Jim Stabe
San Diego, Ca
(666 posts)

Registered:
02/28/2009 10:01AM

Main British Car:
1966 MGB Roadster 350 LT1 Chevy

authors avatar
Re: 340 upgrade
Posted by: Jim Stabe
Date: April 21, 2018 03:59PM

"Frisky" - Great description, I'll have to remember that


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5600 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: 340 upgrade
Posted by: BlownMGB-V8
Date: April 21, 2018 10:31PM

I'm sure you've experienced much the same thing.

You know, I used to say that at 300hp you could do anything with the MGB that you wanted to. And that was true enough. Now it's just, well, more so.

I took it to a local car show today, that was fun. Didn't stay very long, just enough to wander through once or twice and answer a few questions but I had a good time. The idle oscillation though? Yeah I've still got that. Maybe it'll go away when I switch to MS3. I also have a plan in the works to remove the intercooler. Don't need it at my level of boost and it'll drop the inlet 3-4", vastly improving my sightlines. That will probably happen over the winter. Maybe I'll add the IC condenser to my A/C system and boost it's efficiency (once it's finished that is). Seems like a good choice since it is already installed. Anyway, if the oscillation is somehow related to induction volume that should change it for the better.

Jim



MG four six eight
Bill Jacobson
Wa state
(281 posts)

Registered:
10/23/2007 02:15AM

Main British Car:
73 MGB Buick 215, Eaton/GM supercharger

Re: 340 upgrade
Posted by: MG four six eight
Date: April 24, 2018 11:37PM

Jim,

What are you running for air/fuel ratio at idle? The reason I ask, is because I have to run a slightly richer fuel mixture at idle.
I tried and tried to get it to idle at 14.7 to 1 without it surging. Finally I resigned to just giving the motor what it wants and it idles nice and smooth in the 13.2 to 13.5 to 1 range. It also produces the highest vacuum reading at idle with a 13ish to 1 fuel mixture as well.
At cruising speeds I can get away with a leaner mixture no prob. However I'm thinking that the motor likes a slightly richer mixture at idle due to the parasitic draw from rotating the supercharger.

Bill


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5600 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: 340 upgrade
Posted by: BlownMGB-V8
Date: April 25, 2018 10:15AM

Thanks Bill, I think just about any engine is going to need a little richer mixture at idle. In fact I'm not yet down to 14:1 anywhere on the map just yet. So that's not the problem.

Jim
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