billbob1936
Active Member
Hello. Calling in engine folks to help identify if these heads have 1.88 or 2.02 intake valves? Also, do these heads appear too far gone with the rust on them?
340 Heads intake valves
- Thread starter billbob1936
- Start date
floyd
Well-Known Member
- Joined
- Mar 18, 2012
- Messages
- 474
- Reaction score
- 324
Those appear to be the bigger valves IMO. Always tough to judge the severity of rust from photos but they look like they might be salvageable to me. Also look to have a set of 273 adjustable rockers. Good luck
floyd
Well-Known Member
- Joined
- Mar 18, 2012
- Messages
- 474
- Reaction score
- 324
Here’s a pic of a head with 1.88 intake valves. Note the space between intake and exhaust valve.
Chryco Psycho
Well-Known Member
I believe they will clean up ok , I would put in hardened seat on the exhaust side .
pschlosser
Well-Known Member
the valves where they mate with the seat, they are, more or less, protected from exposure to air and moisture, and may prove to be sound and usable. the rest can be cleaned up, so I see no evidence by those photos, there is damage beyond repair.
billbob1936
Active Member
Thanks for the input folks. I have to drive about 3 hours on friday to meet with the seller. Not sure if I'll be able to open the valves to see if the chambers have any degradation. Also, unfortunately, the rockers are not included in the sale, but what kind of offer would be fair for those kind of rockers?
pschlosser
Well-Known Member
i would not want those rockers. if you want to inspect all the seats, the only way I can think of is buying and bringing a compressor tool, so you can remove the valve springs on each of the 16 valves, dropping them for inspection. if the seller isn't doing this for you, make him wait while you do it, it may take an hour to do so. the heads are not that well cared for, so don't over pay for these SB "J" heads.
pschlosser
Well-Known Member
those DO look like 1.88 and 2.02 heads, as the valves are nearly touching. the more common 1.88 and 1.60 valves have a clear gap between the valves.
billbob1936
Active Member
Thanks. It's getter harder to find good 2.02 J heads. I'll make the request for spring removal before making that long drive. I'd hate to do it for nothing.
pschlosser
Well-Known Member
they look rough. I vote $300 with the rockers, $200 or less without.
moparlee
Well-Known Member
Was wondering why you would say no to those adjustable rockers?
Xcudame
Well-Known Member
They are 70 or 72 "U" heads used on 340s and have 2.02" intakes and 1.60" exhausts (double verified by @floyd picture). worst case they need a little surfacing, but that will compensate for the thicker Felpro composite gasket. Also long as the rocker tips that contact the valve steams are not worn, no reason you can't those rocker arms!
Definitely need the harden seats!
Definitely need the harden seats!
billbob1936
Active Member
What year did they start coming from the factory with hardened valve seats? And was this for both intake and exhaust?
pschlosser
Well-Known Member
I think 72 and later, the year they released "unleaded fuel"
Xcudame
Well-Known Member
The small block heads with harden seats were 3671587. All the "J", "U" and "O" heads didn't have harden seats.
billbob1936
Active Member
This is the worst area. The rest look much better.
-
-
-
-
Xcudame
Well-Known Member
Since you'll have harden exhaust seats put in, these will clean up nicely with a good valve job and a little surface milling. If you can get them for a good price, snag them! Like you mentioned, they are not as common as they once were.
Vaanth
Well-Known Member
Chrysler introduced induction hardening of exhaust seats on the 1972 slant six engines. The process was phased into production throughout the year to all engines as processes were adjusted and equipment added. For 1973, all engines received induction hardened exhaust seats in the heads and continued in following years. Only the exhaust seats are induction hardened.
The following images show the announcement and description of induction hardening from the 1972 and 1973 Chrysler Service Highlights:
1972 Service Highlights:
1973 Service Highlights:
To determine if a 1972 head has induction hardening, look for the faint hardening ring mark around the exhaust valve, which will be difficult to see, if it can be at all, on a used head that has been run. When beginning to cut the seats in head machining work, it will be apparent if hardening is present.
Last edited:
billbob1936
Active Member
Thanks Vaanth, Great research. Did the intake seats eventually get the upgrade as well?
-
-
Vaanth
Well-Known Member
The intake valve seats do not need hardening, or hardened seats installed. The intake valves do not run hot enough to cause excessive wear that an exhaust valve can experience.
The exhaust valves and seats run much hotter, so the "pounding" loads in operation can cause them to wear faster, or recede, which leads to the valve "sinking" in the seat. The lead deposits from leaded gasoline provided a cushioning and cooling effect for this "pounding" and reduced the wear on the seats, although that was not its original intent.
Tetraethyl lead was first added to gasoline in the 1920s as a relatively easy and cheaper method to raise the octane rating of the gasoline. A side effect was the cushioning of the exhaust valves. Lead deposits also posed a problem with too much lead deposited leading to fouled plugs, coated valves stems, etc. Octane could be raised with other methods, but cost more. Standard Oil / American Oil Company, later Amoco, sold an unleaded premium gasoline whose marketing point was to help clean the lead out of the engine for better tuning. It was common to run a tank of "Amoco white gas" periodically to help with keeping the lead down to prevent plug fouling and other lead deposits in the exhaust system. The tetraethyl lead added a red color to the gasoline.
Phased lead reduction was occurring prior to and was mandated in 1972. To prevent exhaust valve recession, the valve seat was hardened. By 1976 full lead removal was mandated for catalytic converter use. Lead "poisons" the platinum and other elements used in the converters, hampering or stopping their function by plugging them.
Even with lead cushioning of valves, heavy use such as in trucks, especially large trucks, can lead to exhaust valve recession. Exhaust valve rotators, sodium filled valves, added cooling passages, and other means have also been used to combat this exhaust seat wear in those applications.
Induction hardening was used to harden the seat already machined into the head metal. Hardened seats can be added to existing heads by machining out the original seat and inserting the hardened seats into the machined area. Induction hardening was cheaper and quicker to implement at car manufacturer production levels than machining and adding seats. Induction hardening is relatively shallow compared to an added seat though.
Similar threads
- Locked
