Course thread bolts

PIN 37 · #1 05-04-2010, 04:46 AM

Can anybody tell me where I can get course thread bolts as used on Lycoming
engines. I cant find them in the spruce catalogue. I want to get some drilled head bolts to bolt my crank sensor on my engine. (not supplied with the Plasma III kit)

Geico266 · #2 05-04-2010, 04:50 AM

They are on their web site.

http://www.aircraftspruce.com/catalo...es/anbolts.php

http://www.aircraftspruce.com/menus/ha/bolts.html

Can't use them funny metric bolts mate.

PIN 37 · #3 05-04-2010, 06:59 AM

I might be a bit confused, but aren't those bolts UNF, not UNC thread?

Geico266 · #4 05-04-2010, 07:02 AM

Quote:

Originally Posted by PIN 37

I might be a bit confused, but aren't those bolts UNF, not UNC thread?

You are correct. Hmmmm.

What size do you need?

shuttle · #5 05-04-2010, 09:26 AM

Phil,
Don't know of a source, other than your local GA/Piper/Cessna parts supplier. I know that the Piper sales company close to me stocks all the Lycoming parts.

In case it helps, here are the Lycoming part numbers for all the types of bolts I spotted in my Lycoming IO-360-M1B Parts Catalog

Lyc P/No = Description

LW-25-0.50 = BOLT-1/4-20 X 1/2 Long Hex

LW-25-0.94 = BOLT-1/4 -20 X .94 Long Hex
LW-25-1.00 = BOLT-1/4 -20 X 1.00 Long Hex
LW-25-1.13 = BOLT-1/4-20 X 1-1/8 Long Hex

LW-25-1.25 = BOLT-1/4-20 X 1-1/4 Long Hex
LW-25-1.44 = BOLT-1/4 -20 X 1.44 Long Hex
LW-25S1.50 = BOLT-1/4-20 X 1-1/2 Long Drive End
LW-25-1.75 = BOLT-1/4-20 X 1-3/4 Long Hex

LW-31-0.94 = BOLT-5/16 -18 X 15/16 Long Hex
STD-2246 = Bolt-5/16-24 X 1.00 Long

LW-31H0.88 = BOLT-5/16-18 X 7/8 Long Hex Drive

shuttle · #6 05-04-2010, 09:33 AM

Phil,

I googled one of the above p/no's at random and came up with this website:

http://www.aircraft-specialties.com/...aisle=LYCOMING

corbinace · #7 05-04-2010, 10:11 AM

OK, now you have me thinking. I only used red Loctite. Is that maybe not enough? This considering I have a dual LS setup and everything rests on those bolts staying in place.

rocketbob · #8 05-04-2010, 10:15 AM

You can get good quality grade 8 bolts that are superior to grade 5's that Lycoming specs from Tractor Supply. Worth noting is that Continental uses AN bolts all over their engines so there's nothing wrong with going that route either. In any case the through bolts provide the critical strength of an engine so any other bolts like the case half bolts merely keep the thing from leaking oil.

az_gila · #9 05-04-2010, 10:43 AM

AERO has them listed....

$2.47 for the 1 inch bolt

http://www.aeroinstock.com/products/...ail/index.html

PIN 37 · #10 05-05-2010, 03:22 AM

Corbinace, I too have duel LS, and I think it would be somewhat disappointing to have the engine stop in flight due to the sensor bolts coming loose, hence why I want to safety wire the sensor mount.

These aircraft grade bolts are very difficult to get here in Australia. I still dont know if there is such a thing as a 1/4 x 1/2 UNC drilled head bolt.(aircraft grade), much less where to get them. The places suggested so far dont ship to Australia in any case. (Spruce does ofcourse)