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hardened valve seats - update

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larrym Avatar
larrym Silver Member Larry M
near Sacramento, CA, USA   USA
1963 MG MGB "Racer"
1968 Volkswagen 1600 "Manx"
corallary to an older thread
http://www.mgexp.com/phorum/read.php?1,3654919,3654919#msg-3654919

below - might suggest that running a tank of leaded race gas thru a fresh "stock" head w/o hard seats might gain the same result as installing hard seats?

http://dannysengineportal.com/how-to-install-and-grind-valve-seats/

"Many people think that lead was a lubricant and somehow prevented wear. In fact, the lead caused a chemical reaction with the cast iron of the cylinder head and the stainless steel valve, forming oxides and halides that locally hardened the wear surfaces. This local hardening is what actually helped to prevent seat recession.

During the changeover period, it was not uncommon for a vehicle that had been initially run on leaded fuel to be switched to unleaded.

The initial use of leaded fuel had created the local hardening required and the switch to unleaded created no problems.

However, if these same heads were then reconditioned, the machine shop would machine away the protective layers. As a result, seat recession would occur very rapidly, sometimes in as little as 3,000 miles.

The OEMs used an induction hardening technique to locally harden the valve seats areas. This process was supposed to produce a hardness depth of around .070″, but in many cases it was found to not be deep enough to allow for re-machining during head rebuilding.

(thus) These early unleaded fuel heads also needed to have exhaust seat inserts fitted to them when they were rebuilt."

ErnieY adds this "See post #12 here": http://www.mgexp.com/phorum/read.php?1,2457989,2458247#msg-2458247



Edited 2 time(s). Last edit at 2018-02-11 04:38 PM by larrym.

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ohlord Avatar
ohlord Gold Member Rob C
North of Seattle, N.W., USA   USA
1957 Land Rover Series I "EYEYIYI"
1971 MG MGB
1971 MG MGB "Bedouin 2"
Just do it...



"I'm a long way gone down this wild road I'm on
It's gonna take me where I'm bound
It's a long way around"



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RD2 Radar/ Electronic Warfare Technician
Vietnam 1969-1972

Basil Adams Avatar
About 12 miles from Sears Point, CA, USA   USA
Tetraethyllead works as a buffer against microwelds forming between the hot exhaust valves and their seats. Once these valves reopen, the microwelds pull apart and leave the valves with a rough surface that would abrade the seats, leading to valve recession. When lead began to be phased out of motor fuel, the automotive industry began specifying hardened valve seats and upgraded exhaust valve materials to prevent valve recession without lead.



Basil C. Adams
1956 MGA Coupe (Show Car)
1957 MGA Roadster (Driver)
1958 MGA Coupe (Racecar)
1959 MGA Coupe (unrestored)
1960 MGA Coupe (unrestored)
1960 MGA Roadster (Driver)
MKIII Elva Courier (E1056)
1967 427 Cobra
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A coupla late MGBs
1960 Austin Healy BN7
More Cars than Brains

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sandglowB Avatar
sandglowB Silver Member Al Blosser
Uniontown, OH, USA   USA
1977 MG MGB
Basil is right



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coffeemung9920 Avatar
coffeemung9920 Gold Member James C
Inman, SC, USA   USA
1971 MG MGB "Miss Take"
1972 MG MGB "Bee 44"
1999 Ford F-150 Pickup 4WD
2010 Mini Cooper    & more
So, if you don't know whether you have hardened seats or not, is it smart to put in a lead additive?



The problem with political jokes is that they too often get elected.

Perdido Avatar
Perdido Gold Member Rut Rutledge
Tuscaloosa, AL, USA   USA
In reply to # 3679103 by coffeemung9920 So, if you don't know whether you have hardened seats or not, is it smart to put in a lead additive?

James,
If there’s a rebuild in your future I would just do it then. If everything’s running well I wouldn’t bother with an additive and address it when and if it happens.
Rut



1960 Bugeye undergoing restoration, 1275
1970 MGB, Pale Primrose
1967 Triumph TR4a
1966 Triumph TR4a
When I went to school, they asked me what I wanted to be when I grew up. I wrote down 'happy'. They told me I didn't understand the assignment, and I told them they didn't understand life. John Lennon

Speedracer Avatar
Speedracer Platinum Member Hap Waldrop
Greenville, SC, USA   USA
1967 MG MGB Racecar "The Biscuit"
Running leaded fuel in a engine with head that has cast seats will not repair it, I know, I tested this extensively. We like many other racers thought, well since this head is now dedicated to racing and will only run on leaded rules there is no need to install hardened seat inserts. Well that thought process was incorrect, we would lose valve seal on the center exhaust valves to the tune of about 20-30% and the other two exhaust valves to about 10-20%, after one weekend at the track, mind you this was all tested before running and found to be in the 1-2% leakage range. We tried refacing/re-lapping the seats but it would just repeat itself. Only putting in hardened exhaust seat inserts let us maintain low leakage percentage. Sorry based on my own R&D, I have to cry BS on this.

Who knows if lead fuel additive helps or not, I don't guess it could hurt, but definitely not repair. Like so many oil/fuel additives, it is hard to see real evidence to back up their claims, but I can for sure tell you with complete confidence leaded fuel on freshly cut and hand lapped in cast iron seat with indeed begin to see excessive seat leakage in a very short time period.



Hap Waldrop
Acme Speed Shop
864-370-3000
Website: www.acmespeedshop.com
hapwaldrop@acmespeedshop.com



Edited 1 time(s). Last edit at 2018-02-11 10:02 AM by Speedracer.


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fast-MG.com Avatar
fast-MG.com Gold Member Dave Headley
Cortez, 4 corners, Colorado, USA   USA
To add to Hap's post, every head I build, whether race only or fast road use get exhaust seats. All race heads and many fast road heads also get intake seats, this to restore the chamber depth and improve short side radius into the valve seat.


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RAY 67 TOURER Avatar
RAY 67 TOURER Ray Marloff
Fort Bragg, CA, USA   USA
1967 MG MGB "My Girl"
Installing hardened seats also reduces the frequency that the valves need to be adjusted. Since putting together the '64 head, with hardened seats and stainless steel valves back in the early '90s on my '67 B, I've only had to adjust the valves a few times. Do it right the first time and forget it. Not installing hardened valve seats is false economy. RAY

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coffeemung9920 Avatar
coffeemung9920 Gold Member James C
Inman, SC, USA   USA
1971 MG MGB "Miss Take"
1972 MG MGB "Bee 44"
1999 Ford F-150 Pickup 4WD
2010 Mini Cooper    & more
Is it possible for the layman to look at a head and tell if it is hardened seats or not? I have a head I might want to use, good in all other respects.



The problem with political jokes is that they too often get elected.

Rod H. Avatar
Amity, OR, USA   USA
1964 MG MGB
1968 MG MGB GT
NAPA did the exhaust seats for the head I put on my GT for almost an absurdly low price. Was under $50 for parts and labor. Costs more now I'm sure, given it's been several years, but I can't see not doing it given all the advantages.



I can't understand why people are frightened of new ideas. I'm frightened of the old ones. John Cage

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ohlord Avatar
ohlord Gold Member Rob C
North of Seattle, N.W., USA   USA
1957 Land Rover Series I "EYEYIYI"
1971 MG MGB
1971 MG MGB "Bedouin 2"
Parts alone are about $40 now



"I'm a long way gone down this wild road I'm on
It's gonna take me where I'm bound
It's a long way around"



"These are the days that must happen to you"

RD2 Radar/ Electronic Warfare Technician
Vietnam 1969-1972

Rod H. Avatar
Amity, OR, USA   USA
1964 MG MGB
1968 MG MGB GT
In reply to # 3679326 by ohlord Parts alone are about $40 now

Maybe they screwed up on the billing. They charged me just under $10 for all four seats, but perhaps they were supposed to be that much each.



I can't understand why people are frightened of new ideas. I'm frightened of the old ones. John Cage

'63 MGB
'68 MGBGT
'80 VW Vanagon Kombi
'09 Mazda 3 with 5 speed manual

Speedracer Avatar
Speedracer Platinum Member Hap Waldrop
Greenville, SC, USA   USA
1967 MG MGB Racecar "The Biscuit"
In reply to # 3679319 by coffeemung9920 Is it possible for the layman to look at a head and tell if it is hardened seats or not? I have a head I might want to use, good in all other respects.

James, it is not easy on a used head that has been running because it covered up with carbon burn, on clean and de-carbonized head it doesn't get lot easier, because a stock head has both a ring around the stock seat, and some times even ledges inside the bowl that can easily fool someone. Then if you bead blast the head, all the metal becomes mono-tone, so seat insert can easily camouflage itself. In a perfect world, like you would pick up head from the machine shop with the valves out of it, you would simply see the difference in the look of the metal in the insert and that of the cast iron head. So James I guess the answer would be in most cases, no it is very difficult, even for a trained eye.



Hap Waldrop
Acme Speed Shop
864-370-3000
Website: www.acmespeedshop.com
hapwaldrop@acmespeedshop.com


Member Services:
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ohlord Avatar
ohlord Gold Member Rob C
North of Seattle, N.W., USA   USA
1957 Land Rover Series I "EYEYIYI"
1971 MG MGB
1971 MG MGB "Bedouin 2"
https://www.bpnorthwest.com/valve-seat-exhaust-mga-1622-mgb-63-to-80.html?gdffi=7c26fa82af054ed48c16509776f45115&gdfms=B964619F222E4E6AA7289C142474830E&gclid=CjwKCAiA8P_TBRA9EiwAJrpHMxmkKdTaa83Pd8hXiO1ufCMuO7rhRGj-wh4TO8zfsm0SliOoTOy79hoCYJsQAvD_BwE

You got a dealthumbs up



"I'm a long way gone down this wild road I'm on
It's gonna take me where I'm bound
It's a long way around"



"These are the days that must happen to you"

RD2 Radar/ Electronic Warfare Technician
Vietnam 1969-1972

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