 Casting Marks or Concerning cracks?, Casting Marks or Concerning cracks? Engine rebuild |
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| Tking327 |
 Nov 25 2025, 04:55 PM
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#1
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Newbie  Group: Members Posts: 24 Joined: 17-August 21 From: Denver,CO Member No.: 25,815 Region Association: Intermountain Region  |
Hello, i tore down my 1970 1.7L to rebuild it and on cleaning the grease off the top of my crankcase, i saw the attached which made me nervous.
 . These 'cracks' are located essentially all over the top of the crackcase but seem more pronounced right over the cylinder/piston entry points, and a bit more concentrated on the drivers side. Are these cause for concern or just casting marks? I can sand an area down to see how deep they go but figured i would ask first. (The engine had been running well but smoking and leaking hence the rebuild). |
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| Jack Standz |
Nov 25 2025, 05:50 PM
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#2
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Senior Member Group: Members Posts: 596 Joined: 15-November 19 From: Happy Place (& surrounding area) Member No.: 23,644 Region Association: None 
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Typical feature of the case casting process.
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| mepstein |
Nov 25 2025, 06:51 PM
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#3
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914-6 GT in waiting Group: Members Posts: 20,255 Joined: 19-September 09 From: Landenberg, PA/Wilmington, DE Member No.: 10,825 Region Association: MidAtlantic Region
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Many threads on pelican about casting marks on engines and transmissions masquerading as cracks. You are good.
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| Puebloswatcop |
Nov 25 2025, 06:58 PM
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#4
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Senior Member Group: Members Posts: 1,682 Joined: 27-December 14 From: Mineola, Texas Member No.: 18,258 Region Association: Southwest Region |
QUOTE(Tking327 @ Nov 25 2025, 04:55 PM)  Hello, i tore down my 1970 1.7L to rebuild it and on cleaning the grease off the top of my crankcase, i saw the attached which made me nervous. . These 'cracks' are located essentially all over the top of the crackcase but seem more pronounced right over the cylinder/piston entry points, and a bit more concentrated on the drivers side. Are these cause for concern or just casting marks? I can sand an area down to see how deep they go but figured i would ask first. (The engine had been running well but smoking and leaking hence the rebuild).all cases have thes casting marks. some are worse than others. You should be good unless you see them in the areas where the case is machined, such as the crankshaft or cam cradles. |
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| Ninja |
Nov 25 2025, 07:36 PM
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#5
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Newbie Group: Members Posts: 23 Joined: 25-September 25 From: Granbury Texas Member No.: 29,004 Region Association: Southwest Region |
Normal.
Now, that surface you exposed, where the base of the jugs sit, is one of the more common areas to have machined flat. That surface sags with age alone. Sir Raby states it's almost never flat. You have to pull the head studs and find a machine shop that is willing to machine it flat. As it is lower than the case casting around it some machine shops don't have the equipment or knowledge to correctly mill that. |
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