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tips, technology, tools and techniques related to vehicle driveline components

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Moderator
Curtis Jacobson
Portland Oregon
(4308 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
custom plenum and fuel rail on Rover EFI manifold
Posted by: Moderator
Date: August 18, 2012 02:07PM

Well, my little project is starting to take shape...

My good friend Scott McRoberts (McRoberts Machine Shop, Longmont) helps me with machine work...
ScottMcRoberts-MachineShop.jpg

Throttle body aimed rearward for cowl induction / cold air induction.
Plenum-Base-and-Fuel-Rail-1.jpg

I'm reworking the Rover fuel rail, and I plan to have it nickel plated.
Plenum-Base-and-Fuel-Rail-2.jpg

Wraparound plenum wall will be TIG welded to base. There will be a flat, removable lid...
Plenum-Wraparound-Wall.jpg

Now I have some details to work out... and I wondered if you guys might have tips.

I need to add ports for PCV, vacuum advance, and the vacuum sense line on the fuel pressure regulator... There isn't much room for threaded-in barbed hose nipples... should I use some sort of press-in, weld-in, or glue-in vacuum hose ports, and if so is there a good source for them?

What's the right physical location for the vacuum advance port? On the throttle body?

A question for people who have installed Rover EFI manifolds on Buick engines: what did you do about the thermostat bypass hose? Rover flipped it from left-side of the thermostat to the right-side. (Third photo.) Did you cut and weld, so you could use a straight hose? Source an S-shaped hose?


roverman
Art Gertz
Winchester, CA.
(2863 posts)

Registered:
04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

Re: custom plenum and fuel rail on Rover EFI manifold
Posted by: roverman
Date: August 18, 2012 02:21PM

Curtis, Nice work. Scott and the camera person, "both" need safety glasses. Cheers, roverman.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5329 posts)

Registered:
10/23/2007 12:59PM

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

authors avatar
Re: custom plenum and fuel rail on Rover EFI manifold
Posted by: BlownMGB-V8
Date: August 18, 2012 05:46PM

Put one or two 3/8"npt holes and as many 1/4"npt holes as you have room for in the base plate and a few 1/8" as well. Better to have and not need them, you can get hex socket plugs to fill the spares. If you need to put any through the side wall, tig an internal boss for it.

Consider splitting your fuel rail in the front. It's a real pain to install and remove as one piece.

Jim


Moderator
Curtis Jacobson
Portland Oregon
(4308 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: custom plenum and fuel rail on Rover EFI manifold
Posted by: Moderator
Date: August 19, 2012 06:31PM

"Put one or two 3/8"npt holes and as many 1/4"npt holes as you have room for in the base plate and a few 1/8" as well..."

Alas, so very little room to work with, both in terms of surface area and also height!

VacuumPorts.jpg


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5329 posts)

Registered:
10/23/2007 12:59PM

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

authors avatar
Re: custom plenum and fuel rail on Rover EFI manifold
Posted by: BlownMGB-V8
Date: August 19, 2012 10:35PM

Yep that can be a problem. You might want to put a couple spare ports on the side somewhere.

Jim


Scott68B
Scott Costanzo
Columbus, Ohio
(495 posts)

Registered:
10/25/2007 11:30AM

Main British Car:
1968 MGB GM 5.3 LS4 V8

authors avatar
Re: custom plenum and fuel rail on Rover EFI manifold
Posted by: Scott68B
Date: August 20, 2012 06:07PM

Wow, nice stuff! I don't have anything to add but I can't wait to see it in person. Looks like you're using a GM TPS and IAC on your throttle body. How big is the throttle body? Just curious.


AL WULF
Allen Wulf
Wheat Ridge, CO
(33 posts)

Registered:
01/18/2008 12:48AM

Main British Car:
'67 MGB-V8 '62 MGA MKII Deluxe Buick 215

Re: custom plenum and fuel rail on Rover EFI manifold
Posted by: AL WULF
Date: August 20, 2012 07:19PM

"A question for people who have installed Rover EFI manifolds on Buick engines: what did you do about the thermostat bypass hose? Rover flipped it from left-side of the thermostat to the right-side. (Third photo.) Did you cut and weld, so you could use a straight hose? Source an S-shaped hose?"

When I put the EFI manifold on my 215 I capped the by pass in the front cover. You can still used the 215 thermostat housing on the EFI manifold. (I am using a Buick 300 housing that point straight ahead) The openiing for the bypass on the thermostat is below the water opening and doesn't need to be capped. I am currently using a Buick front cover on a Rover 3.9 with the capped off by pass. Seems to work OK without the bypass. If I'm missing something please let me know.

"Consider splitting your fuel rail in the front." Why bother. You don't need to take it off that often in my opinion.

Al Wulf



Moderator
Curtis Jacobson
Portland Oregon
(4308 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: custom plenum and fuel rail on Rover EFI manifold
Posted by: Moderator
Date: August 20, 2012 10:55PM

Thanks guys! Excellent feedback. I really appreciate the encouraging words.

Quote:
Consider splitting your fuel rail in the front.

I thought long and hard about it, but decided adding flex hose or fittings to the middle of the steel rail looked like a lot more work. I think the rail is ready to be plated now.

Quote:
How big is the throttle body?

The Chevy throttle body bore measures 72mm in diameter, which seems generous compared to the Rover 3.9's bore of 65mm except that Chevy put a peculiar stamped steel extension on the back side of the butterfly to restrict airflow. Chevy evidently used various different restrictors to tailor the throttle body for different applications. I actually have two different junkyard butterflies, with two differently sized restrictors. Some tuners trim or remove the extensions.

Quote:
I am currently using a Buick front cover on a Rover 3.9 with the capped off by pass. Seems to work OK without the bypass.

Whew! It would be a real pain to modify the Rover manifold to match a Buick thermostat cover. I'll move that to the very bottom of the to-do-if-time-permits list.

With regard to vacuum ports, I think the best way to make straight NPT-to-hose-barb fittings work might be to weld a couple little blocks onto the bottom of the plate and achieve 90 degree turns by drilling perpendicular pairs of holes. That's a couple more widgets to have machined before I visit the TIG welder.


minorv8
Jukka Harkola

(120 posts)

Registered:
04/08/2009 06:50AM

Main British Car:
Morris Minor Rover V8

Re: custom plenum and fuel rail on Rover EFI manifold
Posted by: minorv8
Date: August 21, 2012 01:27AM

What about the trumpets, are you leaving them the same length ? Std manifolds have them mounted at different length to compensate the difference in port length ? Also, what will be the distance between the trumpet and the top of the plenum, looks like there is very little space.


Moderator
Curtis Jacobson
Portland Oregon
(4308 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: custom plenum and fuel rail on Rover EFI manifold
Posted by: Moderator
Date: August 21, 2012 02:10AM

Yes, I'm aware of the trumpet issues... as reported here:
Quote:
The inside diameter of each trumpet is 3.81cm. The cross-sections of the runners in the cylinder heads are significantly smaller, but in the intake manifold the runners quickly transition up to round cross-sections of about 3.8cm diameter each. The average total length of all eight runners measured from intake valve to open plenum is about 38.75cm. (Runners 1 and 8 are approximately 41cm long. Runners 2 and 7 are approximately 39cm long. Runners 3 thru 6 are approximately 37.5cm long.)

All eight trumpets will have to be trimmed, but how much they'll be trimmed hasn't been determined yet.

Equal length runners (from the port) aren't necessarily best, as McLaren demonstrated back in their Can Am days. McLaren had a lot of dyno time to play around in, and their conclusion was that deliberately varied runner length could widen the top of the torque curve. I wonder if there's a handy trick for individually optimizing them. Comparing exhaust gas temperature?

My machinist friend has suggested that we might roll out the tops of the trumpets to a larger radius and wider bell-mouth.


Moderator
Curtis Jacobson
Portland Oregon
(4308 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: custom plenum and fuel rail on Rover EFI manifold
Posted by: Moderator
Date: August 24, 2012 02:09PM

I've been reading a bit more about runners and trumpets. If anyone is interested, tmoss's posts here might be interesting. In one of them he links to this document about plenum size and runner length: Plenum Size and Runner Length Interestingly, that document includes some runner volume suggestions. If you extrapolate to get from 302 Ford numbers down to Buick/Rover numbers, it seems to be saying that a good target for total runner volume (valve to trumpet tip) for a 3.5L engine might be between 342cc and 420cc per runner. Based on a quick estimate, I think the stock Rover/GEMS system comes in around 442cc/runner on average. I'm almost curious enough to cc them accurately.



I'm about ready to start installing vacuum ports. I realize now that I'd forgotten about the MAP sensor, so I'll add one more 1/8 NPT threaded hole for that.

Question: How much condensation accumulates in an EFI plenum? Crankcase vapor? Fuel fumes? Moreover, how concerned should I be about those contaminants affecting or damaging my MAP sensor? I'm thinking an extension to put the MAP port above the floor of the plenum might be a good precaution.


tdecell
Trey Decell
MS
(31 posts)

Registered:
04/10/2010 12:13AM

Main British Car:
1974.5 MGB GT 3.9L Rover

authors avatar
Re: custom plenum and fuel rail on Rover EFI manifold
Posted by: tdecell
Date: August 24, 2012 07:57PM

Curtis, I'm sure you've seen these...
[www.actproducts.co.uk]


Moderator
Curtis Jacobson
Portland Oregon
(4308 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: custom plenum and fuel rail on Rover EFI manifold
Posted by: Moderator
Date: August 24, 2012 09:00PM

Yep... and I saw the price tag too! (197 pounds = 311 dollars) A wise guy once told me: "There's a time and a place for everything." but I'm skeptical about the inside of an EFI plenum being the right place for carbon fiber bling.


tdecell
Trey Decell
MS
(31 posts)

Registered:
04/10/2010 12:13AM

Main British Car:
1974.5 MGB GT 3.9L Rover

authors avatar
Re: custom plenum and fuel rail on Rover EFI manifold
Posted by: tdecell
Date: August 24, 2012 11:00PM

Whoa!! I overlooked the price.... was searching and ran across it one day. Hadn't really looked at it close. I think other options would be in order.


Moderator
Curtis Jacobson
Portland Oregon
(4308 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: custom plenum and fuel rail on Rover EFI manifold
Posted by: Moderator
Date: December 18, 2012 02:58PM

Making slow but steady progress!

TestFit-FuelRailEtc.jpg

Fuel rail is complete and has been electroless-nickel plated. New air cleaner housing is complete. (Intake air temp sensor will enter from cabin side, under the dashboard.) TIG welding on plenum and intake manifold is ~90% complete. Welding inevitably causes a little warpage, so I brought the plenum back out to my very good friend Scott McRoberts (at McRoberts Machine Shop) to have gasket surfaces (to Rover manifold and GM throttle body) fly-cut flat.

Next I'll take the plenum back to the expert welders at Peterson Fluid Systems and have them weld on bosses I've made for PCV, MAP, and vacuum advance connections. The sides of the plenum will then need to be cut down at least a half inch, and at the same time a ledge will be cut into the thick back wall. That will provide a sealing surface for the lid. Due to bonnet clearance issues, the lid can't be as tall in front as the throttle body is at the rear... Scott and I have a plan for a billet aluminum lid designed to match Buick-style valve covers. Trumpets will probably be tuned/trimmed/staggered/whatever... but I haven't decided on lengths yet.

Fuel injectors have been cleaned and flow tested, and should be back on Friday. Fuel tank with built-in high pressure pump is scheduled to arrive in January.

I guess it's time I start tracking down MegaSquirt parts.



rficalora
Rob Ficalora
Cypress, TX
(2370 posts)

Registered:
10/24/2007 02:46PM

Main British Car:
'76 MGB w/CB front, Sebring rear, early metal dash Ford 302

authors avatar
Re: custom plenum and fuel rail on Rover EFI manifold
Posted by: rficalora
Date: December 18, 2012 04:10PM

It's looking great Curtis. You planning to have it done in time for BV8 2013?


Moderator
Curtis Jacobson
Portland Oregon
(4308 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: custom plenum and fuel rail on Rover EFI manifold
Posted by: Moderator
Date: December 18, 2012 05:04PM

Thanks. Yep... Omaha or bust!


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5329 posts)

Registered:
10/23/2007 12:59PM

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

authors avatar
Re: custom plenum and fuel rail on Rover EFI manifold
Posted by: BlownMGB-V8
Date: December 18, 2012 07:59PM

Looking good Curtis. Just curious, what did you have to pay to get your injectors cleaned and tested?

Jim


Moderator
Curtis Jacobson
Portland Oregon
(4308 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: custom plenum and fuel rail on Rover EFI manifold
Posted by: Moderator
Date: December 19, 2012 01:58AM

$16 each. I chose this gentleman, and am very pleased with his responsiveness and excellent communication:

[www.mrinjector.us]

I realized you were building a test rig just hours after sending my injectors off!


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(5329 posts)

Registered:
10/23/2007 12:59PM

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

authors avatar
Re: custom plenum and fuel rail on Rover EFI manifold
Posted by: BlownMGB-V8
Date: December 19, 2012 11:35AM

That's OK Curtis, I'm not up and running with it yet. It looks like a good process he uses as far as I can tell and the ultrasonic cleaning is something I will add. How many data points did he give you on the testing? Was there a graph generated? What I've seen is that only testing for full flow is not enough, you need to know what it does at lower flow rates. After all, most of your driving is at part throttle.

Jim
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