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> Casting Marks or Concerning cracks?, Casting Marks or Concerning cracks? Engine rebuild
Tking327
post Nov 25 2025, 04:55 PM
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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. Attached Image . 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
post Nov 25 2025, 05:50 PM
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Typical feature of the case casting process.
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mepstein
post Nov 25 2025, 06:51 PM
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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
post Nov 25 2025, 06:58 PM
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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. Attached Image . 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
post Nov 25 2025, 07:36 PM
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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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davep
post Nov 26 2025, 08:23 AM
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The easy test here is to determine if the marks are raised above the surface which indicates a casting mark. These are easy to clean with a little solvent. On the other hand, if after wiping, there is still a trace of dirt below the surface, then a crack may be suspected.
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Tking327
post Nov 29 2025, 09:48 AM
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Super helpful these replies make sense. Thanks for the comment about the sagging as well. The machinist has a lot of experience in type 4 rebuilds so will ask him to pay attention to that. I was able to remove all but one of the long head studs with a little warming, but that last one is really stuck!
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Chad911sc
post Nov 29 2025, 01:18 PM
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Raby also says in his case comparison video that the 1.7 case is the strongest case of all the 914 engines. He shows the internal casting of the case where the sag happens, and you can see that the material is twice as thick on the 1.7 as the 2.0. So if you’re going to build it bigger that stock, you have a great case to start with!
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davep
post Nov 29 2025, 09:51 PM
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That is wrong, only one casting was being produced at any one time, and were used for all engines in production at the time. Perhaps the early W series cases were stronger than later cases, but that is about the evolution of the case.
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Chad911sc
post Dec 1 2025, 09:56 AM
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I’m not sure how to link a video to this site, but I watched the Raby video several times and he showed the differences in the thickness of the 1.7 to the 2.0, and it was a considerable difference on the internal webbing below the deck. He even states in the video that the 1.7 is better for a performance build over the 2.0 even though the 2.0 is considered the best 914 engine by most. I was just passing on the info from the video. I’m definitely not an expert or historian on this car by any means. I’m a newbie to the 914 world, other than my best friend had one in high school that was a beater…lol. I used to kick his ass in my bug with a 2110 dual carb engine.
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Chad911sc
post Dec 1 2025, 10:04 AM
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@davep
You are absolutely correct!
After watching it again, it is a 1.7, but he states that it is in fact the earliest W series made (IMG:style_emoticons/default/first.gif)
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Chad911sc
post Dec 1 2025, 10:27 AM
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https://youtu.be/siPS_EBLxLY?si=UnHu1rJrBZiel1wi
This is the Raby video….
Hopefully it works this way.
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