Will Orum Posted March 9, 2022 Report Share Posted March 9, 2022 After getting the head off and assessing the damage, I was struck with something that confused me a fair bit.. *See attached images* I initially thought the gasket had blown straight from the coolant channel but on further inspection, I saw that said channel wasn't a channel at all, rather a bore about 10mm deep. I pondered it for a while, looked at the head to see if it had any answers, no kind of hole or channel inline with it though. I was just wondering if anyone actually knows what this hole is for? My best guess is just a bore to aide with the machining process. I figured the coolant leaked around the gasket ring and into the bore, then blew out the gasket when it got hot enough. Its a bit of a shame about the rusty piston and cylinder, though I don't think it would be too much trouble to fix as most of the engine is coming apart in the near future anyway! Link to comment Share on other sites More sharing options...
NonMember Posted March 9, 2022 Report Share Posted March 9, 2022 That hole has been discussed here before. It does seem to be a bit of a mystery, but they all have it. Link to comment Share on other sites More sharing options...
thescrapman Posted March 9, 2022 Report Share Posted March 9, 2022 It is feasible to fill it in. Link to comment Share on other sites More sharing options...
Nick Jones Posted March 10, 2022 Report Share Posted March 10, 2022 It is a remarkably stupid design feature - unless your aim is to increase HGF. Causes more problems on the recessed blocks. Quite a few have filled them with brass plugs so the gasket fire-rings are fully supported. Nick Link to comment Share on other sites More sharing options...
PeteH Posted March 11, 2022 Report Share Posted March 11, 2022 What Is/was an even bigger mystery, is the fact that the Gasket appears to have the holes punched as well, IF the hole serves no purpose then at least the gasket should not have been penetrated hence weakening said Gasket?. Pete Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 11, 2022 Report Share Posted March 11, 2022 it sure is far too close to the fire ring it makes a good weak point even with the recessed block support Pete Link to comment Share on other sites More sharing options...
daverclasper Posted March 11, 2022 Report Share Posted March 11, 2022 Is that just on Spit 1500 blocks, or more importantly to me, Not on 6 cylinder blocks!. Ta Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 11, 2022 Report Share Posted March 11, 2022 believe this "hole" is just recessed block 1500 others will have a better idea Pete Link to comment Share on other sites More sharing options...
Nick Jones Posted March 12, 2022 Report Share Posted March 12, 2022 Not on 6 pots thankfully. Think it’s on all 1300 and 1500 4 pots, though doesn’t seem to cause as many problems on flat blocks. Nick Link to comment Share on other sites More sharing options...
Ben Caswell Posted March 13, 2022 Report Share Posted March 13, 2022 We cleaned a 1500 Dolomite block off with a solvent prior to fitting a new gasket and must have left a residue of the solvent/thinners in the hole, as when the engine was run up to temperature the gasket blew at the edge of the mystery hole? Link to comment Share on other sites More sharing options...
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