Dave Underhill Dave Underhill (19 posts) Registered: 09/05/2017 07:30AM Main British Car: 1972 MGB GT 2.8 Chevy |
Radiator
I have a 72 GT with a 2.8 5 speed out of a 83 Firebird.
Would a new MGB rad be enough to cool it properly? I have an older rad in there now and it doesn't seem to be enough. |
ex-tyke Graham Creswick Chatham, Ontario, Canada (1165 posts) Registered: 10/25/2007 11:17AM Main British Car: 1976 MGB Ford 302 |
Re: Radiator
The older MG rads up to '76 were tube and fin construction - not very good from a heat transfer perspective.
Later RB rads from 1977 had a more modern serpentine construction. I would recommend a later rad with a suitable shrouded puller type fan. Don't be afraid to move the rad about 6" forward to the RB location. |
Dave Underhill Dave Underhill (19 posts) Registered: 09/05/2017 07:30AM Main British Car: 1972 MGB GT 2.8 Chevy |
Re: Radiator
Thanks Graham, I'm just an hour or so up the road from you. In the Aylmer area south east of London.
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Dave Underhill Dave Underhill (19 posts) Registered: 09/05/2017 07:30AM Main British Car: 1972 MGB GT 2.8 Chevy |
Re: Radiator
Thanks Carl, I will give that a try.
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Re: Radiator
I have a both an aluminum V8 rad of Chinese origin and a V8 brass repop and both work fine. I also have an expensive English made aluminum repop which is superior to both of these (superbly made and welded) which works even better but at twice the cost. Both of the first two are available from me. PM with any interest.
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Dave Underhill Dave Underhill (19 posts) Registered: 09/05/2017 07:30AM Main British Car: 1972 MGB GT 2.8 Chevy |
Re: Radiator
Thanks Johan, I ordered and received a Chinese 3 row aluminum rad. Put it in yesterday and took it for a drive last night.
It runs noticeably cooler at road speed but still gets pretty warm in town. It's a crossflow rad. |
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rficalora Rob Ficalora Willis, TX (2764 posts) Registered: 10/24/2007 02:46PM Main British Car: '76 MGB w/CB front, Sebring rear, early metal dash Ford 302 |
Re: Radiator
If it's cooling sufficiently at road speeds but not in town or when idling, you probably have an air flow issue now. What fan are you running? Is the radiator shrouded?
Note, other issues can cause overheating too... * Air in the cooling system * Running lean * Retarded timing |
Dave Underhill Dave Underhill (19 posts) Registered: 09/05/2017 07:30AM Main British Car: 1972 MGB GT 2.8 Chevy |
Re: Radiator
I have a 10 inch pusher fan on the front of the rad. No room on the back for a fan and a shroud. Could go to a bigger fan.
Timing is advanced form what the manual calls for. It's not pinging so I might try and advance it more. Don't know how I can richen it, it was running lean but not as much since I made a cold air intake for it. |
rficalora Rob Ficalora Willis, TX (2764 posts) Registered: 10/24/2007 02:46PM Main British Car: '76 MGB w/CB front, Sebring rear, early metal dash Ford 302 |
Re: Radiator
Can't say for sure, but the fan is probably a bit small.
Lean/rich - I'm guessing you have a carburetor. Should be able to change jets in the carb. Google/read up on how to tune your carb or have it done. No room for puller fan/shrouding - you're effectively using the 10" diameter portion of the radiator for cooling when moving slow or stopped. Can you move the radiator forward? Or, post a picture of the engine bay so we can see what you're dealing with? |
BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6468 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: Radiator
Moving the radiator forward and using a puller fan would be a good first step. Volvo fans are quite good, readily available, have a very good relay, and are about the largest diameter you can fit. They also may come with a shroud that can be cut down to fit. Their dual temp sensor is available in the right ratings as well and does a good job. It's either a 16 or 18mm thread, taps that size are available for around $20 or so.
Jim |
Dave Underhill Dave Underhill (19 posts) Registered: 09/05/2017 07:30AM Main British Car: 1972 MGB GT 2.8 Chevy |
Re: Radiator
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ex-tyke Graham Creswick Chatham, Ontario, Canada (1165 posts) Registered: 10/25/2007 11:17AM Main British Car: 1976 MGB Ford 302 |
Re: Radiator
Quote:The difference in factory rad position between your '72 and a '77 - '80 'RB is about 6" forward. Are you sure that 2" is all you can get? Water pump mounted fan not an option? Temps rising when idling,as Rob has pointed out, are typically due to low airflow and/or no recirc protection. Your front mounted pusher is contributing to a grossly underperforming rad - your rad is capable- just need to maximize its potential. Feel free to stop by Chatham any time and we can go over a cooling diagnosis and strategy. |
Dave Underhill Dave Underhill (19 posts) Registered: 09/05/2017 07:30AM Main British Car: 1972 MGB GT 2.8 Chevy |
Re: Radiator
If I cut out anymore forward I will be cutting out a reincorcement piece. Might not matter though.
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Dave Underhill Dave Underhill (19 posts) Registered: 09/05/2017 07:30AM Main British Car: 1972 MGB GT 2.8 Chevy |
Re: Radiator
I might make a trip down Graham. Your about two hours from me.
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BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6468 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: Radiator
That piece you are referring to doesn't add much and is almost routinely removed. The stiffness of the front crossmember far outweighs it. On my car and the Roadmaster we not only removed that and the panel it is attached to, we cut off the frame stubs and welded in 2" x 1/16" wall square tubing that follows the taper to the outer edge of the grille opening, allowing us to install a 32" wide crossflow radiator, all with no ill effects. We modified the bumper brackets to match.
You don't have to worry about it. If you are concerned, a lower radiator guard can be built which adds back some at least of that stiffness plus protects the bottom of the radiator. I'm a big fan of those, but recommend you not build it heavier than it needs to be to protect the radiator. It can also be incorporated into the air dam (spoiler). With those changes the radiator can be moved all the way out to the grille and even tilted, giving you plenty of room for a puller type fan. Jim |
Dave Underhill Dave Underhill (19 posts) Registered: 09/05/2017 07:30AM Main British Car: 1972 MGB GT 2.8 Chevy |
Re: Radiator
Thanks Jim, I will have to decide how much work I want to go to.
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