|
By dennis22 - 8 Years Ago
|
Hi guys,
Almost too good to be true... but finally I may of found some ECZ-G heads(to fix my miss matching head problem) however looking at the photos I’m wondering if the heads have had too much shaved off them?
Can anyone throw in their opinion looking at the pics?
|
|
By NoShortcuts - 7 Years Ago
|
Happy New Year, Dennis.
In looking at your pictures, I understand what is causing you to raise the question. Much depends on whether the heads you have are posted or not.
Click on the link below for the information provided by Tim McMaster to determine whether your heads are posted or not . . .
http://yblockguy.com/techtips/postedheads.html
After determining whether your heads are posted or not, you need to use a micrometer or micrometer caliper to measure the thickness of the 'pads' located on the exhaust manifold side of the heads. The pads are located at the front and rear corners of each head and below where the exhaust ports exit the cylinder heads and adjacent to where the spark plug holes are located. The thickness dimension of the pads between their top exterior surface and the surface that mates with the engine block deck was 1.000 inches when they were originally manufactured in the 1957 or the 1958 vehicle production year. Subtract your thickness reading from the 1.000 dimension to determine how much your heads have been cut AND whether the two were cut equally.
Check to determine IF the pads measure the same thickness on the front and rear pads on each head. IF the pad thicknesses vary significantly from front to rear on each head, it will indicate how they were machined OR how they were set-up by a shop that resurfaced them. Too, IF the pad thickness is different between the two cylinder heads, you'll know that the machine shop that did the resurfacing did not cut them equally and was likely looking to simply clean them up enough to ensure that they would seal uniformly against head gaskets.
John Mummert recommends that un-posted y-block Ford heads be milled a maximum of .025 inch. This machining dimension is recommended to prevent the cylinder head deck surface from flexing in service and causing head gasket leakage.
On his web site, John Mummert reports that posted y-block Ford heads have been milled as much as .045 inch without problems when put into service.
In rebuilding an engine for Karol Miller, Ted Eaton reported that he re-installed a set of 5752-113 heads that Karol had been running that had been milled .080 inch.
Click the link below for Ted's report of the Karol Miller engine build . . .
http://www.eatonbalancing.com/2015/05/01/unported-iron-heads-can-still-make-over-a-hp-to-the-cubic-inch/
Click the link below to see JM's cylinder head info that I've referenced above . . .
http://www.ford-y-block.com/cylinderheadchart.htm
Hope this info. helps! Enjoy your summer! 
|
|
By 62bigwindow - 7 Years Ago
|
|
If they have been milled would that affect the mounting surface if the intake? Or are there head gaskets to make it back up?
|
|
By charliemccraney - 7 Years Ago
|
Milling the heads and / or block will affect the intake mounting surface. There are not gaskets made to correct that. However, modern composition gaskets are thicker than the original steel shim gaskets so assuming that you start with an engine that has not been touched since it left the factory, you can remove a total of about .030" from the heads and block without having to do anything to the intake surface, if composition gaskets are used.
If the intake will not fit with only one set of head gaskets in place, then you need to mill either the intake flange of the intake or the intake flange of the heads
|
|
By BamaBob - 7 Years Ago
|
|
I have a set of ECZ-G heads that are still on the engine and I'd like to know if they are posted or not. What specifically is the difference between the large and small letters to be able to tell which is which? Also, how do you read the date code on the heads to determine the manufacture date? Thanks for your help!
|
|
By NoShortcuts - 7 Years Ago
|
BamaBob. Click the link below for a picture of what large and small letter G head casting lettering looks like. Consider reading the entire thread to get additional head information. Unfortunately, I'm not able to help you on cylinder head date code info. Ted Eaton wrote on this in the last year, I believe.
CORRECTION: In the thread referenced below, Ted explained how to read the cylinder head date code and gave examples. Ted's info is on the 2nd page of the thread referenced.
http://forums.y-blocksforever.com/FindPost113735.aspx
Hope this helps.
|
|
By Joe-JDC - 7 Years Ago
|
|
Measure the pads on the sparkplug side of the head. From deck to top of pad. Scrape off any paint. They are ~1.010" from the factory, and if they are less, you will know just how much they have been milled. Joe-JDC
|
|
By dennis22 - 7 Years Ago
|
Thanks Charlie, and Happy new year to you too.
How about that... first bit of knowledge learnt for 2018. This forum always seems to deliver the good oil.😁
I’m just waiting to hear back from the seller now with the measurements- hopefully the heads are within the tolerated measurement. I’ll let you know how I go.
|
|
By MoonShadow - 7 Years Ago
|
|
As I recall the un-milled heads will have pads about 1" thick. Those look like a pretty heavy cut. You can see they milled into the port area quite a bit.
|
|
By dennis22 - 7 Years Ago
|
Just had a chat to the owner of the heads and he said they measure 0.955-0.960 inch. So that would equal roughly worst case 0.40. He also said they are not posted😩.
What do you guys think? Too risky, or would you think they might be ok for an engine that only gets used a dozen times a year? (Providing the surfaces are all even and square)
|
|
By Y block Billy - 7 Years Ago
|
|
I beleive the head milling John is talking about is for supercharged applications with higher combustion pressures, in a non supercharged application I think more can be removed. I think the intake pad area needs to be milled .54 or .64 of what the surface milling was cant remember exactly off top of my head (must have been milled too much)!
|
|
By NoShortcuts - 7 Years Ago
|
Billy's point is a good one about the static compression ratio that most of us are dealing with when rebuilding y-block today.
I attempted to find the thread in our Forum Archive that was done several years ago by a Forum member on how to post un-posted G heads. It was a step-by-step description with pictures of installing posts in the un-posted G heads to prevent deck flexing.
Our Forum moderators, Ted, Charlie, or John, may be able to re-issue that thread. It was well done and complete with the info. needed to effect the modification. In my Archive search titled 'posting heads' I was able to go back 50 web pages, but that was only two years of entries that were pulled-up using that search title.
While the head posting may not be necessary, it could certainly give Dennis the peace of mind that he deserves after all the work he's put-into his engine and truck.
|
|
By MoonShadow - 7 Years Ago
|
|
Not a difficult job. Involved drilling a hole in the top of the head. Threading it and screwing a piece of 1/2" (?) allthread in until it was up solid against the deck side of the head, not through. Then cutting off the top of the threaded rod flush with the bottom of the rocker arm area. I don't think its necessary unless you plan to add boost.
|
|
By OlWeldinrig - 7 Years Ago
|
I just took about .047 off a set of 55 ecg heads to take them to interceptor spec.I thought it was only to much if heads were going to see a lot of hard abuse or a supercharger?Mine are low mile heads so I wasn't concerned with corrosion in water jackets.I think if you are just going to use as a weekend driver its fine.My thoughts
Dave
|
|
By charliemccraney - 7 Years Ago
|
I know the thread but I haven't found it, yet.
Here are some describing the operation but not actually showing it being done.
http://forums.y-blocksforever.com/Topic47013.aspx
http://forums.y-blocksforever.com/Topic33877.aspx
|
|
By Ted - 7 Years Ago
|
Here is a past thread discussing adding posts to the ECZ-G heads.
http://forums.y-blocksforever.com/Topic47592.aspx
It’s really only the ECZ-G ‘unposted’ heads that requires any discussion about adding posts. All heads made after the ECZ-G heads have posts while the heads preceding the ECZ-G heads are cast in such a manner that the intake runners provides the needed additional deck support. The ‘G’ heads were the first of the big valve / big port heads which has a lot to do with why the castings changed.
With that being said, it’s only the ECZ-G ‘unposted’ heads that requires the addition of ‘posts where there are none. All small letter G heads are unposted while it’s the big letter G heads that come with and without the posts depending upon when and where they were cast. The Ford shop manual specifically limits milling of the 1957 heads to 0.010” but it’s generally accepted that you can get away with as much as 0.025”. I’ve had personal experience with as set of unposted G heads that were milled 0.060” and both heads had a continuous issue with both head gaskets failing repeatedly. The gaskets were failing on the two cylinders on each bank that had the posts added in the later cast heads. In this particular instance, the heads were switched out to a pair of milled ‘113” heads and the head gasket problem simply went away. This was an engine that had the compression ratio bumped to 10.5:1 so it was already at the octane limit of available pump gasoline in the best of circumstances. Hence the need for posted heads.
|
|
By dennis22 - 7 Years Ago
|
Thanks for all the helpful information guys! At this stage it seems like quite a gamble to purchase these heads, especially since they are not posted. Thanks Ted for your sharing your real world experience, it’s always good hearing first hand accounts.
I’ll keep you guys posted is anything develops from this.
Thanks again for the amazing wealth of knowledge!
|
|
By PF Arcand - 7 Years Ago
|
Dennis: First are ECZ-G heads very hard to find in Australia?. If so it might be worth a gamble if you can get them "cheap". As noted by Ted, the engine he was dealing with was high compression. Most likely had domed pistons & or the block had it's deck milled down. If your engine block is stock & with stock pistons, for normal street use it might be o.k. On the other hand, if the heads need a complete rebuild or the head surface needs further cleanup milling, probably should pass on them.. Good luck
|