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#1 |
Junior Member
Join Date: Dec 2024
Location: NH
Posts: 10
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I ran into a problem today on my 31 Model A 4 banger.
I found a that a piece of the head surface was chipped away between the head stud hole and one of the combustion chamber areas. The same area is shown on the head gasket. Additionally I found a small crack in the head between a head stud hole and a water passage. My plan for this engine was just a cosmetic upgrade including new gaskets, studs, and a cleanup. If I bolt it back together how much life can I expect out of it? Any fixes for this? Unfortunately this is the block that matches the title. |
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#2 |
Senior Member
Join Date: May 2010
Location: Longbranch, Washington
Posts: 631
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If you are familiar with Belzona epoxy, it would be a permanent repair BUT it's quite expensive & that small repair area wouldn't warrant the expense.
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#3 |
Senior Member
Join Date: Jan 2020
Location: SF Bay Area
Posts: 2,110
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A very experienced welder should be able to braze that, followed by decking the block. You will need to pull the engine and likely disassemble it so the block can be pre-heated. If it was mine I'd be tempted to either leave it or try high temp JB Weld, followed by careful flat filing. Use a graphite head gasket like the Best 509G with copper spray, I think it's more likely to conform to any microscopic surface irregularity than a solid copper gasket.
The head - that looks terminal to me, or at least not putting much in the way of resources into fixing. You could use this opportunity to put a high compression head on it. Lots of discussion of HC heads here on the Barn.
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JayJay San Francisco Bay Area ------------------------ 1930 Murray Town Sedan 1931 Briggs S/W Town Sedan It isn't a defect, it's a feature! |
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#4 |
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Join Date: Jan 2012
Location: Western North Carolina
Posts: 5,873
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Jay Jay and I were typing at the same time. We both have the same response.
The crack in the head is common and many run them without repair. But, as Jay Jay said, you will be miles ahead with a 5.5 head from Snyders. However the divot in the block must be repaired. The Belzona epoxy may be overkill. JB Weld may do the trick. I would put a stud in the hole that is smeared with a light coating of grease or soap so that the epoxy will not stick to it. Clean the divot thoroughly with a final wipe with acetone. Fill the divot with the JB Weld. Do not use the quick cure version of JB Weld. After it has cured for 24 hours or more, sand down the surface with wet and dry paper wrapped around a flat file or flat piece of metal. Use progressively finer grit ending with 220. Then remove he stud and clean up the threaded hole with an #11 X-acto knife. Brazing and welding are options but you will have to completely disassemble the engine. There are some modern welding rods that will do a good job of welding to cast iron. Locate a welder who had experience with this kind of repair. The bock will have to be decked after the repair. I agree with Jay Jay on the Best brand graphite gasket and copper spay gasket sealer. I have the original engine to my car in my basement shop and a Burtz block in the car. I stamped the Burtz block with the serial number of the car using original stamps. Depending on what your plans are for the car, the Burtz block may be a good option.
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A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. Last edited by nkaminar; 01-03-2025 at 01:22 PM. |
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#5 |
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Join Date: Jan 2012
Location: Western North Carolina
Posts: 5,873
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It looks like the threaded hole in the block may have a helical coil insert and that may be the source of the problem. If the insert is in poor condition, it need to be replaced.
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A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. |
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#6 |
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Join Date: Aug 2010
Location: SF Bay Area
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#7 |
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Join Date: Jan 2020
Location: SF Bay Area
Posts: 2,110
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Good catch, Eagle Eyes. I missed that insert.
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JayJay San Francisco Bay Area ------------------------ 1930 Murray Town Sedan 1931 Briggs S/W Town Sedan It isn't a defect, it's a feature! |
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#8 |
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Join Date: Sep 2020
Location: Yorktown Virginia
Posts: 246
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I had a similiar issue with an engine and whoever put the helicoil in did so improperly and the top of the block was chipped out like yours. The local machine shop put a helicoil repair in which is larger than the helicoil and after installation it looked good. To do the repair I had to drop the pan, oil pump and unbolt the rods then push pistons to TDC and reinstall rod caps but not on the crank. I am trying to find pics but so far only found the before.
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#9 | |
Senior Member
Join Date: Aug 2012
Location: Texas
Posts: 392
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Ed |
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#10 |
Junior Member
Join Date: Dec 2024
Location: NH
Posts: 10
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i’ll look at it again tomorrow, i didn’t notice a heli coil there today
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#11 |
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Join Date: Mar 2022
Location: Milton,Ontario,Canada
Posts: 160
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Looks like alot of corrosion on the tops of those cylinders too
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#12 |
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Join Date: Jan 2012
Location: Western North Carolina
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The best way to put inserts in the block, any kind of inserts, is to use an old head as a drill guide.
__________________
A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. |
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#13 |
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Join Date: May 2010
Location: VA
Posts: 1,808
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#14 |
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Join Date: Oct 2010
Location: 40 Mt.Vickery Rd. Southborough,MA 508-460-0733
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For the block repair..as others have said you could use an epoxy to fix that.
Cylinder head can be metal stitched and then resurfaced. There may be other cracks in the head so you'd have to check. Something that Every model A goes through. https://www.jandm-machine.com/crack_repair.html |
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#15 |
Senior Member
Join Date: May 2010
Location: Clinton,WA/Whidbey Island
Posts: 4,457
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Put it together an Drive It!
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www.whidbeymodelaclub.com |
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#16 |
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Join Date: Jan 2020
Location: SF Bay Area
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Yes, as long as it is a tight fit between the hole in the head and the drill bit you are using. I’ve found that head holes, being cast, vary a bit in diameter. So each time I’ve had to do this I’ve made up a drill guide from some round stock.
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JayJay San Francisco Bay Area ------------------------ 1930 Murray Town Sedan 1931 Briggs S/W Town Sedan It isn't a defect, it's a feature! |
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#17 |
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Join Date: Dec 2024
Location: NH
Posts: 10
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I looked at it again today. There is a heli coil in the damaged stud holes. I found 2 other heli coils as well.
Should I leave the heli coil in the hole and do the JB Weld repair? |
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#18 |
Senior Member
Join Date: Jan 2012
Location: Western North Carolina
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Insert a stud and then take a square and see if it stands straight up. If it does, then you can leave the Helicoil in the block if it is in good condition. If not then you should redrill and retap the hole for a larger insert using a drill guide (old head). See post #8 where Orgsgt talked about a Helicoil repair. There are a number of inserts available and I would go with one that is not much larger than the original Helicoil insert.
To remove the old Helicoil, grab it with a pair of needle nose pliers and wind it out.
__________________
A is for apple, green as the sky. Step on the gas, for tomorrow I die. Forget the brakes, they really don't work. The clutch always sticks, and starts with a jerk. My car grows red hair, and flies through the air. Driving's a blast, a blast from the past. |
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#19 | |
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Join Date: Jan 2020
Location: SF Bay Area
Posts: 2,110
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Timesert might be a good choice for a replacement insert, just be sure to countersink properly or file the insert to the surface of the block.
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JayJay San Francisco Bay Area ------------------------ 1930 Murray Town Sedan 1931 Briggs S/W Town Sedan It isn't a defect, it's a feature! |
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#20 |
Junior Member
Join Date: Dec 2024
Location: NH
Posts: 10
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Thanks guys great info!
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