Re: H-I-J '76 Nova re-fit.
 

I feel your pain, as I've been through this with 2 different engines. Not saying these are your problems, but just wanted to share what caused the issues in my case. First was 2 different shortblocks that kept losing oil pressure at rpm. Blew the first one up at the stripe, then borrowed a short block and put my heads on it. First trip to the track it lost pressure coming out of the water box. After swapping the oil pump, it did the same thing. The only thing I could think of that I had changed from the prior year was the oil filter....I had switched from Wix to K&N. Well, I put a Wix back on and had no more problems. The K&N just was too much of a restriction at high flow rates.
Second fiasco was a brand-new build with a Dart block. Had good pressure through 6 dyno pulls, but each pull made less power than the last. Changed parts, inspected everything, and it just kept eating bearings. Eventually, we had another crank ground and that did the trick.
The original one had the end counterweights turned down in a lathe.....the second one did not and now has around 70 passes on it with no issues.
Like I said, I'm not trying to tell you what your problem is, just to keep an open mind and think about what's going on inside the engine at rpm.

Re: H-I-J '76 Nova re-fit.
 

Look and check everything. Is crank round and straight, correct radius that is tangent, mains on same C/L as seal surface and timing gear. Rods round and straight, no interference between bearing tang and groove in rod.

Re: H-I-J '76 Nova re-fit.
 

Thank you Paul, duly noted.

Re: H-I-J '76 Nova re-fit.
 

I am re-checking this also, thanks.

Re: H-I-J '76 Nova re-fit.
 

Sorry about the updates or lack thereof. Work has been nuts so time is limited. Weather is getting hot so my energy level is nonexistent, nevertheless I am working a little and we're pretty much ready to go back together AGAIN, hope to get some of that done this weekend. I haven't really done much to change anything and everything checks out so at this point, I have a positive outlook and low expectations. This is the last time I'm doing this.

Re: H-I-J '76 Nova re-fit.
 

Don't get discouraged Todd...

Drag Racing can be a real difficult challenge but eventually if you keep trying you'll succeed......

Been there, done that as they say and for me its been many times....

I hope you get better results when you get it back together....

Re: H-I-J '76 Nova re-fit.
 

Todd and Autumn,


Knowing this engine experience has been painful and expensive for you folks. Stout hearts and you can overcome this.


You made commented that everything checked out as OK and I assume within specs. Since the oil filter flow capacity has been addressed, how about this little detail to consider. What are the bearing clearances vs the SAE wt of the oil you have been using? Some folks swear by the water type viscosity oils, but if the clearance is large, they can't maintain an adequate hydrodynamic wedge and will skin the bearings up every time.



Hope it proves to be something simple like described above and that you can solve it and get to dyno time and racing soon.;)



Best of Luck to you both.


Regards,
HB2:)
Dissident

Re: H-I-J '76 Nova re-fit.
 

At this point Rich it seems I might be too dumb to figure this out hahahaha. If this doesn't work I'm throwing the whole short block in the scrap bin.

Re: H-I-J '76 Nova re-fit.
 

I am going to a higher weight oil this time around.

Re: H-I-J '76 Nova re-fit.
 

FINALLY! I had a day I could get away from work so we finally saw some forward progress. Checking clearances, got the adjustable guide plates welded (I'll get a pic tomorrow) and made a puck to install cam bearings. I should be able to work all weekend so I'll be back with updates.
https://i.imgur.com/QsZlu8s.jpg
https://i.imgur.com/k0IykhN.jpg
https://i.imgur.com/5W4atW8.jpg
https://i.imgur.com/Ui5nf2i.jpg
https://i.imgur.com/oSqwYOT.jpg

Re: H-I-J '76 Nova re-fit.
 

As promised welded guide plate pics. Spent the day frustrated, all we had to do was check the mains and start assembly. #3 main seemed weird in that the cap didn't snap in the block, I could push it in real easy, wasn't like that before, and the bearing was .0005-.0007 tighter than the rest. Pulled the bearing, re-torqued and the bore read .0005 tighter than when it was align honed. I replaced all the new bearings with the old set of King's I kept and although they seemed to check more consistent betwen all of them, #3 was still screwed and for some reason everytime I torqued the mains it comes back with a different measurement. Engine pic is of it being checked with the King bearings. The camels back... it's broken!
https://i.imgur.com/A9cahvdh.jpg
https://i.imgur.com/TJEr9aUh.jpg

Re: H-I-J '76 Nova re-fit.
 

Todd,
I'm so sorry to read of all the issues this engine is producing, you are a trooper. Where does one go as of now? :confused:

Wishing you all the best,
Glenn

Re: H-I-J '76 Nova re-fit.
 

I think I found 2 good blocks local to me, I'll pick them up Monday and order a new crank to get started.

Re: H-I-J '76 Nova re-fit.
 

Todd if your going to stick with a stock block I would look for a 4 bolt with nodular caps.

That's probably not going to be easy to find nor does it insure its a real good block cylinder wall thickness-wise.....and it still needs a lot of prep work

I know its expensive but a Bowtie or an aftermarket, legal block is a far better choice....

Re: H-I-J '76 Nova re-fit.
 

Check out the Dart shp block.

Re: H-I-J '76 Nova re-fit.
 

Check the new blocks before you send them off. The main bearing housing bore might surprise you. "If it ain't broke don't fix it"

Re: H-I-J '76 Nova re-fit.
 

I like the Dart block I bought for my Chevelle.It's quite thick, rather heavy, but nothing I could do to it would hurt it,barring a broken rod or something. You've had the crank checked and done so many times it probably isn't the problem, check and use i again if it's a steel crank. The production GM 350 blocks tended to be thin,sometimes you go through a lot of them before you find one with no core shift or thin places where it needs to be thick.It sounds like something is structurally weak in the block you have been using, something obviously moves when you torque it down if the results keep changing. Einstein said that the definition of insanity is when you try the same thing over and over expecting different results. This block sounds like you constantly try the right thing the same way each time, and different results keep popping up. Something is moving around and giving you different results each time. It could be a hidden crack, a soon to be crack, or some type of metallurgical flaw.It could result in disaster. Also, 4 speed cars are harder on a lot of things, the Dart block might be what's required to keep the cylinders round, the decks flat,and the main bearing line bores straight. The NHRA approved parts list has the correct part number for that block, and Summit ships them right to your porch.

Re: H-I-J '76 Nova re-fit.
 

The two blocks I have access to are NOT nodular caps, just grey iron. Since were looking at less than 400hp I'm not worried. I want two engines so I need a cheap one to run then I'll buy a good block and internals for a nice one.

Re: H-I-J '76 Nova re-fit.
 

The NHRA legal replacement part number for a 4 inch bore SBC with a 2 piece rear main seal is 31161111. Summit shows it in their catalog for $1718.26 on page 124. That's the March-April catalog.

Re: H-I-J '76 Nova re-fit.
 

Everything is absolutely correct, especially this.

Re: H-I-J '76 Nova re-fit.
 

That will for sure be my next one.

Re: H-I-J '76 Nova re-fit.
 

Today we pulled the redneck A/C from the rafters for what will surely be another hot summer. Started pulling Racepak bits out of the boxes and found a spot for the logger just for something to do. I'll update on the block situation tomorrow, if I can pick one up local I'll have a plan in place pretty quick.
https://i.imgur.com/nGfGyPrh.jpg

Re: H-I-J '76 Nova re-fit.
 

So was the #3 main cap broke?

Re: H-I-J '76 Nova re-fit.
 

If something is in fact wrong with the block, I cannot see it. Something is definitely wrong, but as usual I can't find a smoking gun.

Re: H-I-J '76 Nova re-fit.
 

Definitely frustrating to say the least.

Great thread and good luck getting it back on the track!

Re: H-I-J '76 Nova re-fit.
 

Not trying to go off topic however since so many knowledgeable / helpful people have responded to this thread, how does one identify a production 4 bolt block w/ nodular caps ?

Re: H-I-J '76 Nova re-fit.
 

The caps with 2482 cast into them are nodular as I'm told.

Re: H-I-J '76 Nova re-fit.
 

Picked up a block today, .030 over newly machined with new freeze plugs and cam bearings installed, but looks as if it's been sitting in a shop for some time. Here's the plan, about an hour away there's a guy that I know of that has a strip tank for car bodies, it TOTALLY strips paint and rust from steel so I've pulled all plugs and cam bearings out of this thing and I'll drop it to him tomorrow to see how it works removing rust from blocks. Hopefully cleaning the water jackets so it's ready for hardblok on the inside and super clean everywhere else. some probably think I'm crazy for using a stock block, but I promise I have a plan. This will be a backup engine (if it ever runs) to a real nice one later. Nothing special here, certainly no worse than the 2-bolt we had.
https://i.imgur.com/TDoPI3mh.jpg

Re: H-I-J '76 Nova re-fit.
 

Yes Todd is correct. Three center 4 bolt caps have 2482 cast into them and usually N also. Nodular iron is still cast but better than plain grey iron.
Some caps are really pretty weak.

I’ve taken engines apart with a broken center main cap and the engine was still running !

Re: H-I-J '76 Nova re-fit.
 

Ok, and the caps with the #3412 cast on them are the regular,less desirable type.

Re: H-I-J '76 Nova re-fit.
 

Those are the standard "grey iron" cap.

Re: H-I-J '76 Nova re-fit.
 

Todd check yet PM Dick

Re: H-I-J '76 Nova re-fit.
 

I saw that about the desiccant plugs? My PMs are wacky sometimes and I cannot respond but I did see this Thanks.

Re: H-I-J '76 Nova re-fit.
 

Dropped the block off today, it'll most likely be a week before I get it back to start machine work.

Re: H-I-J '76 Nova re-fit.
 

Seems to me that aftermarket steel main caps are available someplace for 4 bolt main 350's,must be better than the originals.Just trying to remember where I saw them.

Re: H-I-J '76 Nova re-fit.
 

They're everywhere, lots of aftermarket ones for sale.

Re: H-I-J '76 Nova re-fit.
 

Why put money into a questionable foundation.Cleaning block, Filling block, installing main caps etc.

Re: H-I-J '76 Nova re-fit.
 

30 years ago we sonic tested and Brinell hardness tested all small blocks.

The range from soft to hard was pretty significant.....and a hard block would easily make more power.

Ideal was hard and decently thick cylinder walls.....

.060 over was a lot.....

Cylinder walls were just about always not consistant

Core shift could be ridiculous

You can usually see the cam being off center by the flat machined surface at the face of the cam hole...not concentric

I had one engine I built at home that was so far off center it was silly

The crank and cam centerline were way off center.

So bad I had to get different rods. It was a 383 and I could not get clearance on one side for the rods to block even after grinding and the other side went right by with plenty of clearance.....

Aftermarket and even Bowtie blocks are far better....

Just sayin!!!

Re: H-I-J '76 Nova re-fit.
 

Put the money you will spend on main caps and the labor to fit them towards a Bow-Tie or Dart block.

Re: H-I-J '76 Nova re-fit.
 

I honestly don't see this as being questionable. How is a 400hp stock block an issue?