perkins 4.236 tools

[michaelratinter]

Does anyone know offhand what size wrench fits the retaining nuts on a 4.236 two-stud lift pump?

[michaelratinter]

Does anyone know if the fasteners on an old perkins are metric or fractional?

[Muckle Flugga]

Originally Posted by michaelratinter

Does anyone know if the fasteners on an old perkins are metric or fractional?

Older perkins were imperial… but some later fittings even on older engines may in fact be metric. The best way to tell is to get a set of each in hand and find the best fit.

[michaelratinter]

Yep. The nuts are hard to reach and hidden. I think a 9/16 will fit. Thanks.

[NoTies]

I'm pretty sure it's 13mm. A half inch wrench will suffice as long as the heads aren't worn/corroded or the nuts over tightened. Go for a 6 point socket or wrench if possible when unsure of size, less likely to turn the hex into a circle.

[michaelratinter]

Thank you. I have both. I'll give them a try.

[a64pilot]

9/16 and 14 mm are almost identical, pretty much interchangeable.

1/2 and 13mm, not so much

[michaelratinter]

Thanks again, everyone. I am pretty sure the size is 9/16. 1/2 inch was too small.

[NoTies]

Originally Posted by a64pilot

9/16 and 14 mm are almost identical, pretty much interchangeable.

1/2 and 13mm, not so much

9/16 = 14.288mm
1/2 = 12.71mm
pedantry

[michaelratinter]

Thanks to all who responded. The mounting studs are 5/16-24 thread. The original nuts were 7/16" across the flats even though standard 5/16-24 nuts are 1/2 inch across the flats.

I replaced one stud by cutting off a 5/16-24 allen cap screw. Installed it with threadlocker. Replaced the nuts with new nuts and split lockwashers.

I used an inspection mirror, head lamp, and 1/2" combination wrench to tighten the nuts. It took a few minutes to get used to the mirror image. I also put a loop of cord, cow hitched to the wrench, around my neck to keep it from falling into the bilge.

I also replaced the fuel filter with a Racor 500FG. After venting the fuel system: bolt on top of paper fuel filter (7/16" wrench), bolt on side of highpresure fuel pump (5/16" wrench), bolt on side of speed governor (5/16" wrench), and high pressure nuts at injectors 3 and 4 (5/8" wrench), the engine started and ran beautifully.

Cheers,
Rick