Cosworth Mk 16 engine & Modern Counterpart

[Craven]

Hi,
Gallery plugs on Ford blocks are NTPF this is a taper plug and is self locking.
FWIW
Ron.

[SJ Lambert]

The plugs in the Laystall crank need to be quite large - 3/8 NPT -it feels like one's using saucers to fill the gap!!

[SJ Lambert]

I think I'll use this Pegasus Auto Racing guide as a "template" for fixing the plugs into place with Loctite 272.

https://www.pegasusautoracing.com/docum ... =TECH00097

[rgh0]

Personally I would have balanced the crank with the plugs in place to allow for any variation in hole and plug location. Given the large size of the crank oil passages you really need to balance it full of oil also but that is impractical to do so you have to live with any asymmetry due to this and hope its been drilled accurately to maintain balance full or empty.

I would normally use Loctite 565 on plugs like this which is a anerobic setting teflon paste sealant . This is what the Pegasis page also recommends. Loctite 272 will also seal adequately in most normal situations but it is not purposely designed to seal plugs like 565 is but to lock nuts or bolt threads.

cheers
Rohan

[Craven]

Hi,
You are using the Pegasus site information as de facto information! Yet they state ?NPT stands for National Pipe Tapered thread. It is also sometimes called National Pipe Thread, NPTF (F for Fuel), American Standard Taper, or simply "pipe".
This indicates to me they don?t fully understand how these thread types are use.
Ron.

[rgh0]

Hi,
You are using the Pegasus site information as de facto information! Yet they state ?NPT stands for National Pipe Tapered thread. It is also sometimes called National Pipe Thread, NPTF (F for Fuel), American Standard Taper, or simply "pipe".
This indicates to me they don?t fully understand how these thread types are use.
Ron.

My interpretation of that page is they are trying to give a summary of American colloquial non technical usages. The probably understand fully the technical differences between the various specifications for NPT tapered NPT straight and NPTF

cheers
Rohan

[Craven]

Hi,
?You are using the Pegasus site information as de facto information!?
Point being,
? I think I'll use this Pegasus Auto Racing guide as a "template" for fixing the plugs into place with Loctite 272.?
Ron.

[SJ Lambert]

I'm confident of an adequate seal, I am aiming to maximise their locked "in-edness" - the high temp stud lock looked more attractive than even high temp pipe sealant in this application to me.

[SJ Lambert]

I do have some high temp loctite 567 thread sealant on hand as it happens - am still leaning toward the 272 thread locker though - plugs are only going 3/4s of a turn past finger tight before nipping up pretty tight - don't wanna split the crank webbing!

[SJ Lambert]

New cam bearings for the Cossie cylinder head - was about time after 50 years!

[2cams70]

Speaking from experience those Loctite 262/272 grades make screws real b*****ds to remove if ever you need to do so in future. Why do you need the high temperature 272 grade? A Crankshaft doesn't get that hot. You won't be able to remove screws secured with either of these grades without applied heat to break it down.

By their nature a tapered plug has a high level of friction between the threads so you have a built in "Nyloc" self locking effect anyway.

Why not use Loctite 569 grade? It's specifically for hydraulic fittings and only requires low force to disassemble. See Loctite chart attached. 100% sealing is not all that critical in this application anyway. A drop or two leakage of oil from here compared to the oil thrown off from the rest of the crank is nothing so no sealant at all is perfectly OK.

As Rohan said the crankshaft should be rebalanced after the plugs are fitted.

[SJ Lambert]

Loctite 272 gives me peace of mind.

I'm using 272 'cause hindsight is a wonderful thing (But I don't want to be a Monday morning quarterback).

If (and I admit it's pretty unlikely) one came loose I'd be kicking myself for not using the goop that makes em a bastard to remove.

Some heat and a breaker bar is gonna make em let go without too much a yelp in any event.

[rgh0]

A properly torqued tapered plug is not going to move and Loctite 272 just adds to " it is not gong to move" factor but if that make you comfortable thats good and i would do it also if i needed it to feel good. You have to have absolute confidence in you race motor builds as you will push them to the limit and you need no hesitation in doing that when coming out of a corner and holding off on the change for a couple of hundred rpm until you get clear of the guy next to you..

The more critical factor is how good is the crank balance once the plug is fitted and that is what i would be worried about as the various plugs will go in different distances and affect the balance versus no plugs.

Once oil is in the crank that will also affect the balance if the oil passages not symmetrical but not much you can do about that and you rely on the crank manufacture to have done a good job.

cheers
Rohan

[2cams70]

That Loctite 272 has a temperature resistance of 232 degrees C. You are going to have to heat it up to a temperature somewhat higher than that to break the bond. I don't know about you but I would not feel too comfortable heating the crank in a localised area to that level. The plugs will need to be removed again for oil gallery cleaning at some point in the future.

[SJ Lambert]

Got a leak on the Oil pressure adjuster screw on a Titan pump at the chamfered seat here


I'm intending to test O-rings under a close fitting press washer for a better squeeze than a nut alone. Because there's a chamfer there I am gonna avoid a Stat-O-Ring washer.......