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11-27-2014, 11:20 AM | #41 |
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Re: Results of milling iron heads.
I measured clearance to my stock-style pistons (I believe they are Sealed Power) and EAB heads using clay. I don't believe my heads have ever been cut. I'd have to cut quite a bit more than .010 - .030", see below. The valve clearances are after rotating the engine thru two revs.
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11-27-2014, 01:02 PM | #42 |
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Re: Results of milling iron heads.
I don't trust the clay method any more. I use the aluminum ball method. Lwss messy and more accurate. Take a small square od aluminum, roll it up into a dmall loose ball, place a dab of grease on the spot to check and you'll get a very accurate measurement. I couldnt read your numbers. looks like .125??. Sounds like Merc pistons in your engines
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11-27-2014, 01:10 PM | #43 |
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Re: Results of milling iron heads.
They're stock-type and for Ford. Yes, 0.090" on the passenger side and 0.125" on the driver's side with used gaskets torqued down. I'll try the aluminum foil next time it's out. I ended up not getting them cut because it appeared to need such a huge cut.
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11-27-2014, 02:07 PM | #44 |
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Re: Results of milling iron heads.
Mine were 0.095" I think from memory. I took 0.050" off them, no problem.
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11-27-2014, 02:12 PM | #45 | |
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Re: Results of milling iron heads.
Quote:
Do the rebuilt stockers get the heads cut for your 0.040"-0.050" clearance with OEM pistons? The reason for the questions, I recall that it's been said that egge pistons have a higher crown. Don't know wether this is still the case. When I've measured the clearance on a Flathead with OEM pistons and stock heads, I usually get somewhere near Ross's numbers, twix 0.090"-0.120" these are numbers averaged from a few different engines, all pre end of war blocks and a couple of Pilot blocks (essentially a 1937-38 21 stud). Never measured a post war one. What do you reckon? Many thanks, Martin. |
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11-27-2014, 09:46 PM | #46 |
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Re: Results of milling iron heads.
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01-14-2015, 01:14 PM | #47 |
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Re: Results of milling iron heads.
I just heard back from the maching shop in regards to having my NORS 21 stud heads milled. I had him cc the chambers prior to milling and he said they were about 81cc chambered heads. I told him I wanted to get down to about a 60-62cc chamber to get the compression about 8:1 He milled .08 off one head and .09 off the other to get me a 61cc chambered head. He told me he measured for thickness to make sure there was enough meat. He told me they had 300 thousandths thickness. Pretty thick castings
Fryguy Last edited by fryguy; 01-14-2015 at 01:19 PM. |
01-14-2015, 02:11 PM | #48 |
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Re: Results of milling iron heads.
I wouldn't mill anything until I checked piston and valve clearance in combustion chamber.
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01-14-2015, 02:13 PM | #49 |
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Re: Results of milling iron heads.
WOW!! I have a similar problem right now, serves me right for not checking both heads. The .123 still bothers me, but .070-.090 is quite common. Milling the heads to increas the CR is a poor choice, because you'll probably have to have the heads re domed. I thinl ALL heads should be milled to give at least /050" piston to head clearance just to increase combustion chamber turbulence. This will improve throttle response and economy. Especially if you have to remove that much material, it will increase the CR some what. As for Egge pistons, you're right. If you don't like them for some reason then use what ever you do like. I've been using them for over 20 years and have had only a few problems which I solved one way or anothe. I consider my self an engine builder not a person that just puts everyting together and ezpects it to work. Every engine has it's own problems and application and you may have to think about what you rae doing. Ross pistons are one of the best Racing pistons on the market, but after 50 or60K miles in a street engine are pushing oil. Due to their design they must be fit Lose in the cyl. I run .005 at least because flatheads run hot and you don't want to gall a piston. I run .002" on an Eggy and the new Metric rings do the rest. IMHOP
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01-14-2015, 09:46 PM | #50 | |
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Re: Results of milling iron heads.
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05-22-2019, 01:05 PM | #51 |
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Re: Results of milling iron heads.
I'm very curious wondering why about the methods used to measure the clearance between the cylinder head and crown of piston?? By methods balls of tin foil or clay being used. Back in the early 80's working at a John Deere dealership that sold John Deere snowmobiles I was presented the task of working on them and there were a host of problems with some of the models of Kawasaki engines used in the liquid cooled sleds and this applied to the 440 Liquid cooled used in the Liquifire sleds. Extremely temperamental starting usually when engine was warm, not cold or hot and of course bogging while trying to accelerate from idle. After having numerous blasts of $h!t from angry customers with defective toys I discovered milling the heads on a lathe was a very positive solution! I used very soft solder used for electrical soldering and bent to a 90 degree and snaked through the sparkplug hole, rotated and measured using a micrometer. Obviously if the Kamikaze 440CC survived using solder as a crush measurement a venerable Ford Flathead should survive as well? Compared to using foil or clay and then attempting to properly measure using a micrometer. Milling the Kamikaze 440 heads .010 inch did wonders and of course if another came around with possible compression problems due to mechanical failure or wear, I would recheck using solder to determine if the mod was done or not.
Now for compression results? Anybody do a compression test before and after to see what is accomplished after milling? As Ron mentioned it is not necessarily the compression but turbulence being changed as well. Compression tests will have a variance as well due to altitude with sea level being the highest but a before and after would be nice. |
05-22-2019, 01:24 PM | #52 | |
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Re: Results of milling iron heads.
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