Rebuilt Nailhead Break In, Tips?

I am right at the end of a long three + year power train swap on my 54 Buick Special. Out came the 264 and the three speed, and in went a fresh and bored out 401 Nailhead with a TH400. The factory rear is out with a 56 Olds on Leafs in the back. It fires up and stays running. I havent broke it in yet however. I will hopefully be finishing the throttle linkage, kickdown, and pedal assembly tomorrow, and then she will be complete again. (minus a couple little things)

My first question/concern is: Does anyone have some tips and thoughts on how best to break in the engine and check for problems. Im a mechanical novice in the grand scheme of things and wanna be ahead of the game tomorrow when I finally get to pull it out of the shop.

The other concern is, I havent finished my exhaust, is it a bad idea to break in the motor without a good length of pipe offthe exhaust manifolds for back pressure or am I worrying for nothing.

Any other thoughts will be much appreciated. Im so glad I am almost back on the road. Just in time for wyoming weather to turn nice again.


Heres a pic 8 years ago when I drove it in high school.




Heres a photo of late when it got back on the ground with a new engine, trans and Rearend

 

exhaust length is not a big deal. run it at 2grand for 15min or so then set ideal a 1500 for a few minutes then you should be good to go. adding break in lube is a good idea as well.

 

anybody ever used the electric kickdown from lokar on those trannys, they seem very simple, but I was curious were they connected the key on wire from.

 

x2 on the brake in lube. Most oils today don't have the zinc in it to help the metal to metal thing and valve lifter break in. Most racing oils have it but a bottle of ZDDP will do.

 

I believre you can use oil for diesel engines still has the additives the feds made thenm take out of motor oil.

 

In your post you said "It fires up and stays running." How long have you run it already? Hopefully not long at all, because if you put a new cam and lifters in it, started it and just let it idle for an while, you are taking a risk of inadequate cam lube for break-in. At first startup, you should immediately set the timing, then bring the RPM up to 2 grand and let it run that way for 15 minutes to make sure the cam is flooded with oil while it does it's "get aquainted" dance with the lifters. And definitely use a break-in lube additive.
I'm keeping my fingers crossed that you've not started it too often.

 

X2
Ensure everything is ready before you attempt to start the engine. Fuel, Ignition, prime the oil system, carb, you can wipe out a flat tappet cam very easily. And like CapeCodBob said diesel oil works great for break in. Shell Rotella T is popular with any of the zinc additives added also. I would add a bottle of zinc at each oil change also.

 

Break in went good. Sounds mean. Once it got real hot it did start puking out coolant under the thermastat, above the water pump. I'm not sure, but I think its a seal or gasket that is not sealed correctly. Hopefully thats an easy fix. A good machine shop that does vintage engines put it together a while ago, and I didnt have a hand in it so I am not familiar with that peice of the puzzle. Any tid bits on that would be much appreciated. Ill dive into my manuals as well to see what I can find.

 

Theres an o-ring between the cross over tube and the front cover. I have seen them leak there because the o-ring slipped out of place during assembly........
Nice looking ride, by the way!

 

Thanks man, Ill be happy to have her back on the road. My brother (whom is more mechanically inclined then I am) mentioned the o-ring. Hopefully it can be fixed without much problem. Looks like I know what I am doing for memorial day.

 

I'll second or third the o-ring. They can be a PITA if there is any corrosion or pitting in there.

And as for the break one, the Nailheads have it a little easier than a lot of other engines as far as cam wear goes, they have relatively light spring pressure. I still do the whole ZDDP additive thing and good oil, but I'm not sure it's quite as urgent as some of the other engines.

 

I switched out the o-ring, and may have made it worse. :s
Everything else came together well.
Does any have any tips to sealing that area around the o-ring. Is there a sealant that can be used or should I try and get another one?

 

Sometimes finding the right o-ring can be a PITA, I usually get one that is close and use a little RTV to help it. Most of them at this point have some pitting which makes it difficult.

 

So would you put the RTV on top of the o-ring?

 

Is it smooth in there? It kind of depends on the amount of pitting. If it's pretty bad I'll use a little more and I kind of coat the o-ring and make sure it's dry in there. If it's smooth I use less. Does it feel like the o-ring is fitting pretty tight? It's all kind of a feel thing.

 

If seems like it is tight but there is definately pitting and corrusion. and alittle build up residue that I tryed to remove what I could

 

Clean it the best you can, I try to use as little sealant as I can get away with while getting the job done. As these things get older and older it gets harder and harder though. I wish new ones were available.

 

If a company made some cast ones, they could even get pretty flashy with them and add some details, they would prolly sell the shit out of them. I know I would buy one.

is there any other factors that could be contributing to it leaking so bad.

 

Just a thought, as I'm not familiar with nailheads, but remember, when you use rtv, just snug the part down at first and let the rtv "set up" for a while, then finish tightening. That way, you're not squeezing all the sealant out.

 

Shouldn't be an issue here as the part we're talking about doesn't get tightened down.



If you look at where the yellow arrow is pointing. There is a nipple that extends from the water crossover, it goes down into the timing cover and is supposedly sealed by an o-ring. Once the water crossover is pushed down in it's bolted to the block to hold it in place. I am of the opinion that you only use as much sealant as you need and not put to much on. Hopefully it'll only take a little.

 

The black valve covers look sweet by the way.

Im gunna try it later today, Ill let you know how it goes.