Cylinder Head Nuts; Blue Locktite or Graphite Grease?

[Paul Ahnell]

Thank you all for your comments as you confirmed my thinking. I put a little dab of graphite grease on the nuts and the face of the washers rather than the thread locker. I did use Harry's recommendation to apply the final round of torque 3X. I'm pretty organized but he was anal, which shows in "Secrets..." where he gives precise direction and guidance using only the written word - no pictures. Met the Gent once; kinda quirky guy but he could be quick with a smile.

[Dick Weiss]

After cleaning all hardware--including the headbolts, I never use any lubes to headbolts except their O-rings!
I torque both heads alternately w/7-ft. lb. increments to 28 w/2-final checks; This equalizes the case stress!

Dick

[Bruce Smith]

So what’s the current thinking about blue Loctite on rod nuts? I think this was common practice as long as nuts are torqued before the Loctite begins to set-up.

Glad to hear so many come to the defense of Harry Pellow, wish I had the chance to meet him. He made very clear his problems with ‘Turkey’ built motors. I don’t think anyone put more effort into wiping out that end of the spectrum. His contributions are huge, especially when used with other references.

[C J Murray]

Even when still wet, Loctite is not a lubricant. The torque will not be accurate. Carrillo provides a special moly lubricant with their rods to be used on the threads and clamping surface. That gives an accurate torque reading that is then confirmed correct by measuring the bolt stretch.

[Bruce Smith]

Thanks Cliff. This looks like the stuff:

https://www.fvd.net/us-en/FVD10397599/f ... -1-oz.html

[Vic Skirmants]

I've used Blue Loctite on stock rod nuts for decades. And the special lube on Carrillo rod bolts.

[C J Murray]

I've used Blue Loctite on stock rod nuts for decades.

Time to stop!

[Martin Benade]

So opposite ends of the spectrum are both fine, either non-lubricating thread-locker, or non-locking lubricant?

[Martin Benade]

On Loctite's website they claim the regular threadlocker is a lubricant. They have a product for large 7/8th" or bigger bolts that is said to be an even better lubricant. It sounds like they are thinking about that property.

[C J Murray]

There are some contradictions on the ARP site...
http://arp-bolts.com/p/FAQ.php

Carrillo Does not mention Loctite and strongly supports the use of the lube that they supply with their connecting rods. They stress the importance of measuring bolt stretch as an indication of proper clamping.

If you Google Loctite/rod bolts the general opinion is don't do it.

I am guessing that Porsche used oil or moly lube and not Loctite when they built the engines and established the specification for torquing. I doubt Loctite has the same lubrication exactly and we can't measure stretch in this case so I feel more comfortable using an actual lubricant on stock rods. I have done it that way on every engine of every type or brand for nearly 50 years without a failure but I bet Vic hasn't had any fail either.

The one thing I never ever use on connecting rods are locking plates. Those are the sheetmetal things that get bent to keep the fastener from turning on some engines. They are the kiss of death on any engine that is used hard since they get hammered thinner with use and relieve the fastener of its clamping stretch. Throw them in the trash.

[Vic Skirmants]

"The one thing I never ever use on connecting rods are locking plates. Those are the sheetmetal things that get bent to keep the fastener from turning on some engines. They are the kiss of death on any engine that is used hard since they get hammered thinner with use and relieve the fastener of its clamping stretch. Throw them in the trash."
+1

[Martin Benade]

I wouldn't be that concerned about the general internet opinion about Loctite on rod nuts, but I would trust Carillo to know actual up-to-date facts based on testing and measurements.

[Ron LaDow]

Carrillo Does not mention Loctite and strongly supports the use of the lube that they supply with their connecting rods. They stress the importance of measuring bolt stretch as an indication of proper clamping.

You've probably dealt with them as long as I have, when you picked up the phone and might well have gotten Fred on the other end. In discussions with the guys there, they were clear that the stretch was the only way for you (the consumer) to do the final QC on the fasteners. I always did so, but NEVER had a bolt stretch to other than spec at the suggested torque; those guys knew what they were doing and still do (AFAIK).
To add anecdotally, DFV parts from Cosworth when they were in Torrance (?) were never usable without 'fitting'. ALL parts. Carrillo rods came out of the package, got bearing shells and bolted in. Jon B? You too?

The one thing I never ever use on connecting rods are locking plates. Those are the sheetmetal things that get bent to keep the fastener from turning on some engines. They are the kiss of death on any engine that is used hard since they get hammered thinner with use and relieve the fastener of its clamping stretch. Throw them in the trash.

Folks with more experience can (and will, if need be) correct me here, but I don't think those things were used beyond the 'spaghetti' early rods, which were never designed for loads generated by > 5KRPMs.

[C J Murray]

Porsche stopped using lock plates very early on. Classic English cars often used them along with many others but they have long ago disappeared.

[Al Zim]

Lubricants are much better now than in the 1970's when Harry was preaching the rebuild. A drop of oil on the threads and the bottom of the head nut will give you proper torque reading al zim