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What did you do with your MGB today?

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jakdedert Avatar
jakdedert J Dedert
Nashville, Tennessee, USA   USA
In reply to # 3590317 by joelabs My HIF4 carbs on 73B have been acting up lately and I was hoping that someone with HIF4s has ran into a similar issue. Car not running properly; feels under powered at times like maybe running on 1 carb? I don't fully understand how these things work and I literally take my phone out to my garage and watch John Twist video on tuning these exact same carbs.

My rear has no change when raising the piston; I have turned the mixture screw to all the way lean (left) and all the way rich (right) but no change in the rear carb. I raise the piston a bit but it does not stumble or do anything...no change....idle does not go up or down. The front carb works as expected; raise the piston, idle stumbles a bit but goes up to normal...i tweak that mixture screw and get different results until I get it adjusted.

Any idea what this rear carb is doing? I have never taken them apart and not sure where to look; seems something is off here. I plan to take car to a local MG shop in my area for a fall/winter tuneup as we start to lose driving days here in Chicago, but I would like to enjoy drives for the next month or 2. Let me know if anyone has seen this. Thanks for the advise.

Joe
It kind of sounds like your rear carb isn't working at all, or perhaps very little. A quick check would be to take the air cleaners off and cover the front carb intake with the engine idling. It's how we used to balance them back when (I did, anyway).

Obviously if it's not working, the car will die. The trick is to figure out why, which I'll leave to the more experienced members of the group.

I would suggest you start a new thread with an appropriate header that will catch the attention of those most able to help.



jak

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joelabs Avatar
joelabs Joe L
Elgin, IL, USA   USA
1973 MG MGB
Jak, I agree on the rear carb; car actually died on me a few times when I adjusting the mixture on the front carb. I am going to remove the rear carb to have a look at why the mixture screw seems to have no affect and learn more about how these things work. Found another thread about similar issue. Carbs were rebuilt about 2 years ago so time for another look. Thanks

jl

oldredsel Avatar
oldredsel Silver Member Rick Crosby
South Dartmouth, Massachusetts, USA   USA
1959 Edsel Villager "OLD Red EDSEL"
1969 MG MGB GT "Emma"
2003 Chevrolet S10 "The S10"
2011 Subaru Forester "Mom's Princess Mobile"    & more
@300 miles of "shunpiking" on the blue highways to Stowe VT for a week with the BGT in the Green Mountains leading up to this weekend's British Invasion show! (Pics will have to wait until we return home.)

Cheers,

Rick



The journey is the destination.

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Donthuis Avatar
Donthuis Don van Riet
Rijswijk, ZH, Netherlands   NLD
Renewed both rear brakecylinders because I found braking effect lacking on one and feared rusty insides, like on 2014 MoT when the present ones were needed to replace two that rusted solid. Strangely enough these 2014 ones (investigated after the new ones were in) were not rusted at all, but had a lot of fluid leakage and the pistons just fell out of the bores, so light was the resistance eye popping smiley

I feel these 2014 ones, now replaced after only 2,5 years already had bad quality seals inside. I may refurbish one of them, having a set of spare seals or just put them in my garage. The new cylinders from Lockheed were so cheap, refurbishing is hardly worth the trouble. In any case the fluid in the rear brake circuit is now renewed as well, the front circuit fluid is rather recent with new calipers..

barrybarnes Avatar
barrybarnes Silver Member Barry Barnes
Reno, Nevada, USA   USA
1978 MG MGB "ZoooomB"
Sunday, I put four more coats on my 78 ZoooomB for a total of six base coats of Torch Red.

Tomorrow, we'll put on at least two coats of clearcoat, wait 48 Hours, hit it with 1500 grit wet and dry, wait another 48 hours, and then go for the last clear coat.

It's looking great and I'm very excited about the final effect.

In a few days, we'll also clear coat the bumpers and hardtop that were painted several months ago.


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Mrblowhard2U Avatar
Mrblowhard2U Glenn Wellington
Eugene, Oregon, USA   USA
1973 MG MGB "Irene"
Jak: The piston (damper) holds a stepped needle rod which rides in the jet allowing fuel to enter the intake. It's held in place with a small screw, perhaps this may have loosened and the needle does not move when the piston moves. Remove the damper cover and pull the piston out and check the needle. Glen

timb65 Tim Boyle
El Dorado Hills, CA, USA   USA
1965 MG MGB
If it's not the needle, it might be that they are really seriously out of balance. I managed to get my hs4s so out of whack on the idle adjustment that lifting the rear piston did nothing and the front piston always seemed lean.

The unysyn tool failed me completly. Found out by listening with a tube to the intake breath at idle, and then was able to sync both.

I then backed off the mixture and brought them up the same amount - still playing with timing/idle/mixture but by sound, seems to be balanced and not had that issue again.

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oldredsel Avatar
oldredsel Silver Member Rick Crosby
South Dartmouth, Massachusetts, USA   USA
1959 Edsel Villager "OLD Red EDSEL"
1969 MG MGB GT "Emma"
2003 Chevrolet S10 "The S10"
2011 Subaru Forester "Mom's Princess Mobile"    & more
Did a little over 100 miles around Vermont's Green Mountains in the BGT. Started with a stop at the Alchemist Brewery's welcome center and ended with a sunset drive up to Smugglers Notch. cool smiley

While in Stowe village, we had a few locals welcome us as the first arrival for this weekend's British Invasion, but by the end of the day we noticed that others had started to arrive, a TR3, a Jensen Healey, a dark red RB MGB roadster, a TR6, and a RB Midget! thumbs up

Cheers,

Rick



The journey is the destination.

Chinick Avatar
Chinick Humberto Hernan Herrera
Panama, Panama, Panama   PAN
Today applied the first coat of RustOleum Rust Reformer on the area behind the bumper. When finish this process then will install a new valance and front spoiler.

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joron Avatar
joron Silver Member Michel Joron
Roxboro, Quebec, Canada   CAN
1977 MG MGB "Victoria"
The front suspension is completely renewed, now. The last parts were the engine mounts; finally done, today.
Entire brushings, shocks, engine mounts (right bracket); the handling could not be better.


Rear suspension last year, front suspension this year; the only thing I have left is to renew the seat covers and foams a project I keep for this winter. I will buy the foams but the covers, there is a possibility to get it hand-made.

My tough jobs list is complete this year. Okay the rear engine seal leaks too much @ 3500 rpm but it is the only leak.

I have even real heat now; it takes 2 thermostats to finally get one which works.

Hopefully, I will be able to use my car in fall without freezing. I will test if the heat is enough on the 24th September since it is the last car show, for me this year.



1977 MGB Red 'Victoria'
All Classics:
Married, 2 children, 2 dogs, MG MGB May to December.



Edited 1 time(s). Last edit at 2017-09-12 09:25 PM by joron.

barrybarnes Avatar
barrybarnes Silver Member Barry Barnes
Reno, Nevada, USA   USA
1978 MG MGB "ZoooomB"
Joron, I'm with you on the suspension rework. I did mine this year and it's a lot of work as you well know. Never thought an old body could hurt so bad from laying on concrete. Even the padded creeper got painful at times. Since mine was a late model and thus had been raised off the ground by the factory quite a bit, I also lowered it a total of 2 inches while I was working on the suspension. The result of the lowering and new bushes and pads was worth it and the car rides and handle so much better with the Prothane bushes and pads. Good luck to you and enjoy.

PS: That's undercoat, not oil, on my differential. This is the most heavily undercoated car I've ever seen. It ranges from a quarter of an inch to as much as an half an inch in places. Looks kind of ugly from underneath but it sure has protected it from rust over the years.



Edited 1 time(s). Last edit at 2017-09-13 10:13 AM by barrybarnes.


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joelabs Avatar
joelabs Joe L
Elgin, IL, USA   USA
1973 MG MGB
Jack/Glenn, on my HIF4 rear carb, removed dashpot, piston...everything looked fine. Attached pic of jet...it was way lean. Front carb was just about flush and looked correct.

I set rear to be flush to match front then put piston, needle, etc back, refilled dashpots. If I cover the front carb, the car does not die, so that's a good sign.

When I raise the piston 1/4 turn to check mixture, the front carb raises and returns normal; rear carb raises very slightly...almost no change in exhaust note on rear. Balanced them with tube to eat and they have about same hiss now. Idling around 1k.

In am hoping to keep it stable until fall/winter where it will get full tuneup and service. Thanks for the advice.


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joron Avatar
joron Silver Member Michel Joron
Roxboro, Quebec, Canada   CAN
1977 MG MGB "Victoria"
Barry you have worked well. Mine is not too that clean; way cleaner and I salute you I imagine the amount of work to paint the different parts. If I find the courage and time I will post the photos of the result.



1977 MGB Red 'Victoria'
All Classics:
Married, 2 children, 2 dogs, MG MGB May to December.

oldredsel Avatar
oldredsel Silver Member Rick Crosby
South Dartmouth, Massachusetts, USA   USA
1959 Edsel Villager "OLD Red EDSEL"
1969 MG MGB GT "Emma"
2003 Chevrolet S10 "The S10"
2011 Subaru Forester "Mom's Princess Mobile"    & more
Put another 100+ Vermont "Green Mountain" miles on it. cool smiley Started the day heading north on VT-100, through Morristown, Hyde Park, Eden. . . towards the Canadian border. Didn't get that far, but didn't have my passport with me anyway.

After returning to Stowe, we then did a pass through Smugglers Notch to Jeffersonville. . . and then back again. thumbs up

A few other British Invasion participants have now rolled into town, with a lot more expected tomorrow and Friday. smiling bouncing smiley

Cheers

Rick



The journey is the destination.

Ex-Calif Avatar
Ex-Calif Gold Member Dan D
Cincinnati, Ohio, USA   USA
1968 MG MGB GT "Bart - Yellow And Naughty"
1977 MG MGB "Red Betty"
2012 Jeep Liberty "Tank"
2014 Hyundai Accent "Skate"
Drove the GT to the monthly British Car Club meeting in a light rain. This month we BBQ'd at the classic car restorations shop owned by one of our members and told stories. Club is pretty active. Still about 12 car show events on the schedule this year. Always cool to visit this shop and see all the cars under restoration.

According to our officers the club's doing great apparently. Started talking about volunteerism for next year's club car show.

Can't beleive we are already talking about the Christmas party arrangments as well. Where has this year gone...

About 50 folks showed up out of 135 paid up members.



The goal - Reliable summer driver interspersed with mechanical tinkering...
Motto - "Driving fifty in the twisties..."
On Mods - It's your damn car - Do what you want. Haters gonna hate...
On SUVs - Drive your B like a soccer mom is texting her friends about how she wants to kill you...
Red Betty - http://www.mgexp.com/registry/GHN5UH418165
Bart - http://www.mgexp.com/registry/GHD4U146898G

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