Setting main caps on my Hemi.

When I tore my engine apart , two of the lock washers on the main cap bolts had cracked into two. So I installed two new hardened lock washers on those bolts. Well I got up to 70 lbs and the crank stopped spinning by hand.(WTF)? one of the old washer cracked and was stopping the crank from spinning as it was wedging between the bolt and the weight. I didnt notice it untill I started loosening the caps to find out which cap was the culprit.
Anyway, I checked my 4 Pontiac blocks and none of them had lock washers. I'm thinking that these are not needed and have removed them all and torqued them to 80-85 lbs. Is this OK skipping the lock washers? If they are torqued to 80 lbs I dont see the problem. The crank spins pretty freely but the rear seal is probably putting a bit of resistance on it. I can turn the crank easy with my hand around the snout.

 

I have never seen lock washers on main bolts.

Tommy

 

Thats what I figured!!!!! Thanks, I'm golden!!!

 

I'd pop them all off and check the crank and bearings again. Sometimes you might have to take some emery paper to polish the crank where it made marks during binding.

 

ARP studs or bolts use only a hardened flat washer to distribute the torque to the cap-I never ever saw any lock washer on a main cap. Someone screwed up.

 

Make sure your caps are in the right places and orientation too.

 

I have a virgin Red Ram [Dodge] sitting on the bench and there ARE lock washers on the main cap bolts...

I hope that you didn't throw them all away...

 

Lock washers! Thats a first for me, how do they account for torqueing i wonder? I'd replace the whole mess with studs, with 60yr old lock washers i'd always wonder if the main bolts got torqued to proper clamp or the lock washer bound up. I'm looking at one of those engines now for my truck but hadn't read that far in the hemi book.

 

Think about it. At 85 pounds torque, a lock-washer is just a flat washer.

Here's what NASA (rocket scientists) says:

The lockwasher serves as a spring while the bolt is being tightened. However, the washer is normally flat by the time the bolt is fully torqued. At this time, it is equivalent to a solid flat washer, and its locking ability is nonexistent. In summary, a lockwasher of this type is useless for locking.

Which is why people use flat washers for torqued bolts.

 

Since you have experienced a 'problem', I suggest removing all of the caps and inspecting inserts and journals just to be sure...
Studs are always a good idea on any engine and not terribly expensive. If you stay with bolts use a hardened flat washer, Mopar pkg of 20, about $6, Mopar Part Number 4120459


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Early Hemis used lockwashers. No one screwed up.

As has been said, tear it down, inspect the bearings and crank, find out why it is binding. Replace the lockwashers with good flat washers and have another go at it.

 

I also have an un-touched 276 DeSoto sitting here with Washers from the Factory.

Better re-check them bearing clearances !

 

Is this an "early" early Hemi thing? My untouched '55 331 and '57 392 do not have lock washers on the mains. Sounds silly in fact...

 

As was said but maybe unclear, it was the washer that came from under the bolt againt the weight of the crank. No binding on the bearings. I thought that was what it was until loosening the caps when I noticed the washer.
It spins fine now with exception of the new seal friction. I'm sure it would spin a few rotations if the seal wasn't installed. Also I think at 80 lbs and only 7-1 compression, these bolts really dont take a beating. I'm not too concerned about going to studs. I am also thinking that the lower end was never touched (Stock bearings and crank diameter) so the stretch cycles by torqueing are minimal. So I learned that the early Hemis did have lock washers. Hmm What were they thinking!! LOL!
Oh also all I could get for clearance on the thrust bearing was .004
I think that will be acceptable as oil can still squeeze by. Factory says .006-.012 .

 

They are all in the right order and they can only fit one way. I knew a guy that built his Pontiac block and installed all his bearings backwards and when he tried to turn it over it wouldnt budge. You wonder why he didnt spin the crank while tightening? He sold the fully rebuilt engine to a club member for like $200 and he took it apart and flipped the bearings around and its been running strong for 8 years.I got up to 70 lbs when the binding all of a sudden just happened. It was the washer coming out of the main cap and wedging against the weight.
Thanks anyway for the advise.

 

Not all Early Hemi's are the same - I don't recall ever seeing lockwashers on the mains of any 392's I ever took apart. Personally I wouldn't use them. YMMV

 

A lot of '40s and '50s engines had lock washers but they were done away with later because they are not necissary (same with pal nuts). You can go back together without them but make sure your bolts don't bottom out in the hole. As said before studs are a great way to go here.

 

I can see why they did away with them. 3 out of 8 cracked in half!!

 

I should have said it was an early-early-hemi thing. I've seen them on a few 51 331s but not on 54 331s.

As for what they were thinking... I don't know. Maybe some traditionalist designer thought they needed them. I recall seeing other types of retaining devices on earlier motors, cotter keys on model T engines I think. But, we've had 60 years since then to better understand bolt operation, and bolt stretch is adequate to maintain fastener force.

 

I had em on my '51 331 and tossed em out and bought the hardened flat washers that 73RR mentioned...I'm going with studs in the Poncho motor since that will see much more abuse than my 331 stock rebuild would have...

 

Oops,,,I was wrong.
Just went downstairs and looked at my Desoto 291 that I recently purchased. It does have lock washers and I pulled the number 3 main cap to take a peek.
Guess what,,,the lock washer is broken and a piece is missing.

I was gonna go through it good anyway,,,so I will do away with the locks and just use flats. Or studs altogether!

Thanks for bringing this thread up,,,it is important to check.

Tommy

 

Why even use flat washers . Just put a dab of oil under the head of the bolt and on the threads and torque them down. Most all engines dont use flat washers either. All my Pontiacs just use bolts and they take a beating as shown on the next post of my 2 bolt Pontiac. The second video is it in action.

 

How much HP are you going to use on your Poncho? I have about 430 and hit it with 150 shot of nitrous at the track. This engine 400 cid was built in 1991 and still looks brand new inside.
The heads are non ported and are running the stock 41 year old valves. The video of My Cameo shows what it does on Pump gas. Nothing wrong with just bolts up to a point.
This is basically the details of my Pontiac engine. No choke and it fires up just like the video after sitting for months.
http://www.youtube.com/watch?v=Xuq-3a0AHEU&feature=channel_page

This one shows my car in action!! You have to love Pontiacs.!!!!!!!!!!!!!!!!!!!!
And to think, I could have shoved a 455 into my Whippet with aluminum heads as I have them sitting on my garage floor.

Crank up the volume!!!

http://www.youtube.com/watch?v=6dTfMAH9UL8&feature=channel_page

 

Just make sure the bolts don't bottom out before the touching the cap.

 

No problems with bottoming out. Thanks for the concerns.

 

Washers are for load distribution...the head of a bolt is relatively small compared to the diameter of a washer...think of them as the snowshoes of the fastener world...

 

Good logic ^^^^^. The washers also prevent the bolt head from galling the cast cap which you will not see and you will not know that the torque reading is skewed.



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Why do 90 % of all engines not use lock washers or any washers on main bolts or connecting rod nuts?
I understand the galling but again most engines dont use any washers. The factory lock nuts would create more galling than just the bolt itself. Even my Pontiac blocks have no washers on the heads, main caps , or connecting rod nuts.. Wouldn't the torque ratings on these critical bolts be scewed? If the head bolt is the same diameter of the washer, then as far as speading the load, it wouldn't make a difference.

 

The lock washers that were factory on the early hemis are the same diameter as the bolt. Thats why when the lock washer split, it actually wedged into the weight of the crank while tightening.

 

The two most common purposes of a washer are: To distribute the pressure of the nut or bolt evenly over the part being secured and, to provide a smooth surface for the nut or bolt.

Most cap and head bolts are very high quality bolts, and the bolt has a machined surface on the bottom of the head.

Unlike many bolts you use to build a house with, as those are almost always unmachined and dig into the wood crudely, and thus a washer is required.

If you flip the bolt over, and note a machined smooth surface, then the washer is not going to provide much difference. It only provides more area to distribute the force, and is usually a softer metal that can absorb the vibration better. Cast iron is softer than the metal used in the bolt though, so my guess is that the main purpose of a washer is to provide more area.

You've probably seen rectangular washers to provide more area across a width. You wouldn't just throw these washers out, as they serve a purpose.