Hex Head drain plugs in engine block - thread size?

[BartonStag]

Hi all,
Looking to clean out the threads for the two hex head drain plugs in the engine block as part of the overhaul. I presumed they were 1/4" BSP - tho clearly they aren't. Anyone able to tell me what the thread type and size is please as can't find any info on them.

Thanks in advance for any assistance
Cheers
Gord

[richardthestag]

Hi all,
Looking to clean out the threads for the two hex head drain plugs in the engine block as part of the overhaul. I presumed they were 1/4" BSP - tho clearly they aren't. Anyone able to tell me what the thread type and size is please as can't find any info on them.

Thanks in advance for any assistance
Cheers
Gord

I thought they were bsp too, sometimes it is easier just to get a small wire brush on a drill to clean the threads out on the hole than worry about chasing the threads out.

https://www.toolstation.com/abracs-decarb-wire-brush-set/p15615

Rover v8 I think are UNF, but again wire brush bit on a drill has always worked for me

[jbuckl]

1/2” unf.

[APS]

suppliers I checked seem to suggest they are 1/2 inch unf. They come with a fibre washer, £4 + vat from paddocks.
I took mine out quite naively last summer, had no problems with drainage and when putting them back, no leaks.
If I done again I would probably buy two new ones in advance as luck rarely strikes twice

[BartonStag]

That's great folks
many thanks for your assistance
Cheers
Gord

[jbuckl]

I took trouble to retro fit original drain taps.
Great idea? ….. maybe…. But found that the left side tap makes tool access to the starter bolts even more ‘special’
Doh !