I Don't Like Palnuts
 

A quick question for you guys about what I should use to lock the connecting rod cap nuts in place.
This is for my '52 F1 with a C1BA/8RT Canadian built engine. The engine came with what might be called tab washers (?). They fit into the con rod cap and the tabs are bent up after torqueing the nuts to lock them in place.
On the left is one of the tab washers that was originally installed in my engine. They have been used twice, during the original build and reused by the previous owner when he rebuilt the engine and can't be reused again.
I ordered new con rod nuts and what I hoped were new tab washers, they shipped Palnuts (as shown on the right in photo).
I got info from the manufacturer of the Palnuts about the suggested torque for these nuts. I only tried 4 of them and two of them failed before I got to the suggested torque of 60 in.lb. (that's only 5 ft.lb.!) I don't trust these Palnuts to stay on the con rods or to lock the con rod nuts.
My question... is it ok to place a jam nut on each con rod nut? (I can get jam nuts locally and are a low profile nut).
Thank, Terry

Re: I Don't Like Palnuts
 

Terry, Personally, on every engine I build, I just use loctite. I think adding extra lock nuts as you're proposing would, if nothing else, affect the balance.

Re: I Don't Like Palnuts
 

a good high strength thread locker every time

Re: I Don't Like Palnuts
 

Engine manufacturers haven't used a lock on rod nuts, since the 60's.

I would be very comfortable using new grade 8 nuts on the rods, torque to spec.

Re: I Don't Like Palnuts
 

I really like ARP rod nuts they sell for flatheads. I put a dab of blue locktite in the threads even though it’s not needed

Re: I Don't Like Palnuts
 

I use the same 3/8 locknuts as used on the small block Chevys. Readily available at your local parts house .

Re: I Don't Like Palnuts
 

Chevy is the answer no loc tite.


R

Re: I Don't Like Palnuts
 

As a "belt and suspenders" type of guy, I have to ask : Is the just because it's not needed, or is there a reason not to use it?

Re: I Don't Like Palnuts
 

Thanks everyone for putting their two cents in.
If my memory is right, the new nuts I got are the Chevy ones. So I'll not add any jam nuts.
But, as a '"Overkill" type of guy, I'll use blue loctite.
Thanks, Terry

Re: I Don't Like Palnuts
 

A fastener that is properly assembled and torqued to spec will NOT come loose.
FRICTION is what keeps it together.
There are NO Pal Nuts, Tablocks, cotter pins, jam nuts, Loctite or weld that will keep it together if it is not torqued to spec on assembly.
Torqueing is only half of it also. The thread needs to be clean and lubed with some kind of thread lube like ARP has. If you don't have ARP lube, rear end gear lube will get by. The face of the nut needs lube also.
LOCTITE WON'T WORK IN THE PRESENCE OF OIL. You need the lube more than the Loctite.

A lot of rod failures can be attributed to tightening with a torque wrench that was out of calibration.

The modern nuts that are refered to as "Chev", "Cat", etc. are called "MARSDEN" nuts.
They have slots on the back and look similar to a castellated nut but the slots are thinner.
The thing that makes them work is a relief on the inside of the face that causes the lands on the back to distort and exert clamping force when the nut is torqued.

For what it is worth, race engine rod bolts/nuts use NO locking method other than friction. Either plain nuts or plain thread 12 point bolts.

Re: I Don't Like Palnuts
 

I have been using pal nuts on automotive and aircraft for 60 years. I have yet to see one fail.

Re: I Don't Like Palnuts
 

Neither have I but then I don't torque them near that tight. It's just a jam nut.

The Robinson helicopters use a butt load of the things since the FAA required a double lock on all flight controls. The nuts used are a damn good lock nut and don't normally need a pal nut so it's just to meet the regs. I usually tighten them snug to the nut and then a bit more to even the flats out with each other. The standard torques for 3/8" fastener would be 29 to 60 in/lb so they are giving you the max torque of a pal nut. I would be closer to 29 in/lb myself.

Re: I Don't Like Palnuts
 

While this contradicts the fact that I have used loctite, I cannot agree more. Even ARP states it is not needed, and highly recomends their lube. I dont build many engines so my opinion should be of little concern

Re: I Don't Like Palnuts
 

Been using Chevy nuts for the past 50 years.

Re: I Don't Like Palnuts
 

Got a part # for those Chevy nuts? I’m putting one back together now and will try them.

Re: I Don't Like Palnuts
 

I think all SBCs use the same rod nuts, maybe the BBCs as well, but don't know about that one.

Re: I Don't Like Palnuts
 

The SBC, 5.7" long rods use 11/32 nuts. The SB 400, uses 3/8's nuts.

Re: I Don't Like Palnuts
 

A Chevy man! All my Chevy experience is pre-400. Actually mid-60s, ran a B/A with a SBC for one season and then switched to SBF. Sooo, limited up to date SBC knowledge, LOL. My dirt cars were Ford as well, I always liked to be different!

Re: I Don't Like Palnuts
 

The small journal Chevys...265,283,early 327...used the 11/32" bolts and nuts. When Chevy went to the larger journal cranks (starting with the later 327 and continuing through the 400) all the bolts/nuts are 3/8" regardless of rod length.


Terry

Re: I Don't Like Palnuts
 

Hi Terry, with one exception.

The '67 model year Camaro's with the SS/350" option got a large journal unit but still with the 11/32" rod bolts. This was the only time and I believe it was offered only in the Camaro's, it was also the earliest year for the 350"?

(Add) To answer the O.P's question, we use ARP 3/8" rod nuts with a 7/16" socket size, either 6-pt or 12-pt, these are the "AN" series nuts and are far superior to any others. We also have the conventional 3/8" ARP's, 9/16" 6-pt socket with a built-in washer for better seating.

Thanks, Gary in N.Y.

P.S. This little known fact caused much confusion in the aftermarket back then, everyone assumed when they saw the smaller rod bolts it was automatically a small journal unit, caught a bunch of us off-guard! These "only-year" rods were easily identified by a "dimple" under the rod eyes. Here's a shot of the rod, it's the one in the middle!

Re: I Don't Like Palnuts
 

I guess that tells 2 things about me.

1. I'm NOT a Chev guy

2. My last year as a auto mechanic was 1970 and in 1969, I replaced the block of my best friends 67 Camaro, 350 (split cyl wall) and that was probably, the last Chev engine that I tore down, although I do use rods from the SBC 400, to narrow and put in 302 Fords.

Re: I Don't Like Palnuts
 

Sorry Frank, guess that is somewhat like calling a Ford guy a dirty name. :)

Re: I Don't Like Palnuts
 

Sorry y'all, but I've never had a problem with calling myself a Chevy guy. You mean to tell me that Ford continued making motor vehicles after 1948? DD

Re: I Don't Like Palnuts
 

Check out the Engine Masters Series for the Ford Y block builds, then watch Ford vs Ferrari. :)

Re: I Don't Like Palnuts
 

Ya, I'm a 5.0 and 460 fan.

Re: I Don't Like Palnuts
 

See, Frank...I'm not a Chevy guy either! LOL :D Thanks, Gary, for the education. I didn't realize they did that-never ran into it in many years of running my own shop in the '70s through the '90's.

Just got back from a hundred mile drive in the '41 Merc and happy to say the rod nuts are still in place even without the pal nuts! :D:p:D


Terry

Re: I Don't Like Palnuts
 

No offense, Jerry :) But, I am a fan of them in the rear view mirror ;)

Flathead, don't forget this years EMC, a 390 FE was first and a 289 second. I'm sure a flathead could win it some day, too but, I think it would have to have Ardun heads on it.

Re: I Don't Like Palnuts
 

Ya don't totally scrap a yblock. http://yblockguy.com/

some yblock video fun. lots of torque for a heavy ass motor.

https://www.youtube.com/user/mctim64


mouse motors are great, no doubt


.

Re: I Don't Like Palnuts
 

I was never a fan of the 239/312 Y block. My dad bought a '54 Ranchwagon, in '57 and had to replace the engine within a year. He put a '55, 272 in it and we never had any trouble after that. But, when I was a mechanic, the ONLY cracked Ford block, I ever saw, was a 312, cracked from the main, to the cam bearing. They also had rocker arm oiling issues. I had to put external oiler's on several 292's in my 8 years as a mechanic.

As Ford's premier V8, they only lasted from '54 to '57, I'm not sure why Ford had such a short term engine. I think a short deck 317, would have been a better short run engine.

Re: I Don't Like Palnuts
 

The cam oiling issues started with the 215/223 and continued into the y-block era...when you rebuild them a tiny groove cut into the cam solves that issue...
312 with the larger main bore and same size maincaps wasn´t one of fords brightest idees...312 crank turned down to the smaller mainbearing size and put into a 292 block works better. Or new steel maincaps.

Re: I Don't Like Palnuts
 

Yes, i did one or two, 223's also.

On the 292's, the issue was that the oil passage would plug up, that went to the rocker arms (maybe the 223's too?). I think the main cause of that was detergent oil in engines that had run on non-detergent and the slug that the detergent oils freed up, clogged up that passage. Detergent oil, ruined many '50's engines, mostly by clogging the oil pump intake screen.

Re: I Don't Like Palnuts
 

Do the have Chevy stamped on them?? LOL

Re: I Don't Like Palnuts
 

As this has turned into a Y block discussion. Shortly after getting the motor running in my T-Bird (57 312) I had the rocker oiling issue on one side. All the passages were clear. The problem was the cam bearings. The oil passes around a groove in the cam. My bearings were worn to the depth of the groove, effectively stopping the oil from passing around the cam to the one side. I tore it down and replaced the cam bearings. All good ever since.
Mart.