We don't need hardened seats!
09-13-2018, 07:10 AM
#41
Drifting
FWIW.... Rebuilt my 327 in 1990. One of the original heads was cracked (trash) so I bought a set of 461 double hump iron heads and had a reputable shop replace the1.94 valves with new 2.02s, new springs, screw in studs, etc.. but no hardened valve seats. I've driven the car a little less than 30K miles since the rebuild. The car has never run on real leaded gas since the rebuild but I do use "Lead Substitute". Block was bored 0.30 over and forged TRW pistons installed. Also installed a blueprinted Crane L79 hyd cam. Compression was measuread at 11.1:1 and I always run premium gas, usually Shell 93. I do not race the car but did race at a drag strip a few weekends one summer many years ago. I will also on occasion do some "solo drag runs" down the road when nobody is around, although I haven't done that in awhile. Everything is stock specs right down to the orig. points ignition. All seems well.
09-13-2018, 08:57 AM
#42
Safety Car
Thread Starter
You guys are saying I'm trying to convince or persuade, I'm trying to inform those that may be interested in what they should do and what can happen if you fail to do it. I worked in aircraft maintenance for the last 18 years of my working life. Presented with the evidence in these 2 pics the faa would issue an airworthiness directive that would state everyone, not only people who have experienced a problem, operating an aircraft with these heads will repair them in accordance to the following ----. Until you do this the aircraft is grounded. In these pics you can clearly see what occurs this is valve recession it's not too many valve jobs. As you can see the valve is receding straight down into the head. I've also included a pic of a valve operating in a normal engine to day with unleaded fuel. The ones in my cars and the ones in yours look like this. Now what do you suppose that rough valve is doing to soft cast iron every time it seats. Again this info is only form people looking for information those that have made up their minds are free to ignore this info completely.
Last edited by Robert61; 09-13-2018 at 09:01 AM.
09-13-2018, 05:34 PM
#43
Team Owner
Member Since: Nov 2005
Location: Beach & High Desert Southern California
Posts: 25,503
Received 2,346 Likes
on
891 Posts
You guys are saying I'm trying to convince or persuade, I'm trying to inform those that may be interested in what they should do and what can happen if you fail to do it. I worked in aircraft maintenance for the last 18 years of my working life. Presented with the evidence in these 2 pics the faa would issue an airworthiness directive that would state everyone, not only people who have experienced a problem, operating an aircraft with these heads will repair them in accordance to the following ----. Until you do this the aircraft is grounded. In these pics you can clearly see what occurs this is valve recession it's not too many valve jobs. As you can see the valve is receding straight down into the head. I've also included a pic of a valve operating in a normal engine to day with unleaded fuel. The ones in my cars and the ones in yours look like this. Now what do you suppose that rough valve is doing to soft cast iron every time it seats. Again this info is only form people looking for information those that have made up their minds are free to ignore this info completely.
Look the two exhaust seat in this photo:
The seat on the right is visibly sunk into the head.
The seat on the left is noticeably higher, and more like what is seen with normal wear.
If fuel were the problem both exhaust seats would see the same depression and metal loss (same head material, same fuel, same abuse).
These photos look like the seats were cut prior to the photos, and if excessive recession were evident on the right exhaust seat some heavy handed person ground it out by grinding too deep (or was simply heavy handed and negligent). I would not reuse the head due to the exhaust seat on the right (and other seats that look as unevenly ground as these two). The work to properly blend the seats and then trim the valve stems to achieve good rocker arm geometry is not worth the labor cost, compared to finding heads in a better condition (or new aluminum heads with hardened seats)
I agree with you. If the exhaust seats were in an aircraft engine, and were as strikingly different as these two seats, I would not run them on an aircraft. Regardless if the difference is the result of erosion or a heavy hand, whoever assembled the engine last would not be trusted to avoid mistakes elsewhere (and that is not what you want to find when flying).
09-14-2018, 07:47 AM
#44
Le Mans Master
Member Since: Nov 2015
Location: Really Central IL Illinois
Posts: 5,208
Received 1,534 Likes
on
1,036 Posts
R66 here, am I the one this is intended for??? R 66 is fightin' back on the outside against the rail!!!!!!!!!!!
I have a set of boat anchors (both leaked) with hardened seats installed by a reputable machinist back in the 80s. He insisted they needed the seats due to unleaded fuel. He refused to replace them after they leaked and said I should run block sealer in the new engine to repair them. NOT ME!!!
Bottom line is: IF you have an experienced machinist that is aware of the thickness of the cast seats and / or uses ultrasonic testing before cutting on the head, hardened seats can be successfully installed and provide good service. I am thinking those machinist are rare and do not work at the local machine shops.
I have ran double hump heads without hardened seats for 45 years without replacing one head due to seat recession. My wife and I both drag raced SBCs for 20 years and had no valve seat problems.
I will NEVER gamble on the hardened seat installation unless I have a rare head that needs it and then only for that worn seat (and only if I don't have another head). Why spend money for something that adds no value nor durability nor performance.
Someone that knows how should set up one of those voting polls on hardened seats and DOT 5 fluid.
( ) All heads should have hardened seats installed.
( ) No heads should have hardened seats installed.
( ) Already have boat anchors with hardened seats installed, won't do it again.
( ) Already have heads with hardened seats installed - No problem will do it again.
( ) Add hardened seats for aftermarket racing valve springs
Ron
Last edited by R66; 09-14-2018 at 07:50 AM. Reason: racing
09-14-2018, 08:29 AM
#45
Safety Car
Thread Starter
In my first post I mentioned any competent machinist can easily do this. A competent machinist knows exactly where you will hit water on various machining operations. Gary posted pics of seats he radiused. Manufacturers make these the problem is the cutter needs to be radiused as well so it's not cutting square corner. That along with the correct diameter and depth of seat. And again the pictured heads are NOT the result of a bad valve job all of the exhausts are starting to recede. You'll notice nothing even close on the intake seats. The erosion you see is from the valve picking up iron. I did cut through a couple of heads early on and it didn't take long to figure out how to stop that.
09-14-2018, 09:06 AM
#46
Team Owner
Member Since: Mar 2003
Location: Greenville, Indiana
Posts: 26,118
Received 1,843 Likes
on
1,398 Posts
09-14-2018, 10:35 AM
#47
Instructor
How many miles do we really expect to put on our old cars? I'm lucky if I put a few thousand miles annually on each of my collector cars.. At that rate these stock heads will probably Outlast me. And if I do burn up a set, 461 and 462 camel hump heads are readily available at all the swap meets around here, at less than $200 a pair. Many look to be in very good condition, as more and more owners are going to after market heads. Valve seat recession is probably Not very high on our list of things to worry about...
09-14-2018, 10:50 AM
#48
Team Owner
Member Since: Mar 2003
Location: Greenville, Indiana
Posts: 26,118
Received 1,843 Likes
on
1,398 Posts
Well, heavens to Betsy. In good condition and they have had a steady dose of unleaded gas run through them for the last how many decades?
09-14-2018, 02:33 PM
#49
In my first post I mentioned any competent machinist can easily do this. A competent machinist knows exactly where you will hit water on various machining operations. Gary posted pics of seats he radiused. Manufacturers make these the problem is the cutter needs to be radiused as well so it's not cutting square corner. That along with the correct diameter and depth of seat. And again the pictured heads are NOT the result of a bad valve job all of the exhausts are starting to recede. You'll notice nothing even close on the intake seats. The erosion you see is from the valve picking up iron. I did cut through a couple of heads early on and it didn't take long to figure out how to stop that.
One more item to mention here, we would automatically pressure test ANY head before installing any seats! Not mag them, but pressure test only! We would also do the pressure test AFTER the inserts are installed, before ANY other work gets underway. That's just how it is here!
Thanks, Gary in N.Y.
P.S. This particular operation is basically a "non-issue" for us here, we leave this option 100% totally up to each customer. We are neither "for" nor "against" the inserts, customers make the final call. If we do install (8) inserts we WILL stand behind the integrity of the casting 100%, we have absolutely no problem with replacing ANY casting we "ruin". I would also add this, occasionally the "poor" condition on many of the heads we receive, there is no other choice but to install the seats, rare, but it has happened her over the years. One procedure will will NOT do is try to install O/S (exhaust) valves AND the inserts. In other words if the heads began life with 1.500" valves we would not do inserts AND 1.600" valves together.
The following users liked this post:
Drothgeb (09-14-2018)
09-14-2018, 05:37 PM
#50
Safety Car
Thread Starter
Agreed 100% covered 1.600 valves in post 4.
09-15-2018, 02:10 PM
#51
Burning Brakes
Member Since: Aug 2013
Location: palm springs ca
Posts: 1,063
Likes: 0
Received 314 Likes
on
178 Posts
Vintage Corvette heads are gray iron, not ductile iron, and gray iron is a very hard and tough material, which is why seat inserts were never installed.
The thin coating of lead oxide on valve seats, which seems to provide protection from recession is established early in the engine's life and is very long lived, so if you're concerned about seat recession, use leaded fuel early in the life of the engine and add some leaded fuel every few thousand miles.
Duke
The thin coating of lead oxide on valve seats, which seems to provide protection from recession is established early in the engine's life and is very long lived, so if you're concerned about seat recession, use leaded fuel early in the life of the engine and add some leaded fuel every few thousand miles.
Duke
This is exactly what a friend of mine that owns a engine shop said. The use of lead in the break in will impregnate it in the metal. Where did he get this info, at a seminar when he was upgrading his equipment. He advises all his customers to use lead for a minimum of one tank.
Dom
The following users liked this post:
Critter1 (09-15-2018)
09-16-2018, 02:06 PM
#52
Duke,
This is exactly what a friend of mine that owns a engine shop said. The use of lead in the break in will impregnate it in the metal. Where did he get this info, at a seminar when he was upgrading his equipment. He advises all his customers to use lead for a minimum of one tank.
Dom
This is exactly what a friend of mine that owns a engine shop said. The use of lead in the break in will impregnate it in the metal. Where did he get this info, at a seminar when he was upgrading his equipment. He advises all his customers to use lead for a minimum of one tank.
Dom
Interesting articles about hardened seats
The following 2 users liked this post by Nalrops:
Critter1 (09-16-2018),
jim lockwood (09-16-2018)