Projects rebuilding after the crash

Some really nice looking welding,,,,,,it will turn out fine .

oh well,,,,,,it’s the price you pay for Nitro !
It could have been much worse .
Imagine if these components had not been designed to be run on Nitro ?

And even then,,,,,,the Mighty Hemi can take damage,,,,and still live to run another day .

Tommy

 

First pass .002 still has a few low spots.

 

What do you use to machine the welds? I mean the tooling. I assume you do it on a Mill, is it a CNC program or ?
Damned interesting!

 

Its done on a surfacer. A big wheel with cutters spins cutting off material. Nothing special is used on the welds. This machine will cut it.

 

Thanks for posting these repairs Brian. I have only seen this kind of repair work done ounce in my life, years ago.

 

The cutting wheel has a hole in it. A indicator is dropped through the hole at all four corners . The supporting blocks under the head are screwed up or down. This is how the head is set parallel to the wheel.

 

Very cool. Please post pic of it and the process please.

 

.008 later its flat.

 

Time for lunch. The blocks sleeve register is just about ready to be cut.

 

Brian
For years I saw plenty of magazine articles and photos of aluminum head and block repairs and always thought the guys that repaired/replaced whole sides of blocks were close to being magicians.
I had an opportunity years back to witness it first hand while visiting Rodeck prior to buying my block. I was given a shop tour not long after a big NHRA event and walked by a pile of windowed aluminum Fuel blocks waiting to be repaired.
While that was quite an eye opener, I was introduced to well known 50's/60's Indy builder Quinn Epperly who was putting a fairly large chunk of aluminum back into an old Offenhauser block, this kind of work is obviously not for the average backyard builder.

 

Its for sure hard core. Very challenging to say the least.

 

Thanks for taking your time Brian to share this with us, really appreciate it.

 

Are you going to re-profile the chamber with a CNC or just by hand? Also does this stuff get Zyglo'd or dye checked for cracks in critical areas?

 

The chambers get cut with special tools. Nothing is cnc. The depth of the cutter is set based on a undamaged combustion chamber. A stop is set then the table is moved to the damaged chamber. Some hand blending is usually required. New seats and o ring grooves along with a light touch up on all the other seats and its done.
The sleeve bores and registers were cut tonight. This is a very time consuming job. It has to be perfect. There are no second chances. First thing in the morning the sleeve bores will be honed to size. Its only 18 degrees outside so i put the sleeves on the back deck to cool and shrink overnight. The block will be heated with the big propane torch so the sleeves drive in easier. When the block temp normalizes it will be decked. Then cam bearings go in. I have the cam with me to check the fit.
When i get home the block will go to my local speed shop to check the align bore and hone the new sleeves to size. The sleeves are so hard regular stones will wear out. Diamond stones are needed for this job. Last thing is to re install the deck pins.

 

On a normal fuel car the sleeves sit above the deck a few thousandths for the most bite on the head gasket. The seal on the cumbustion chamber is the only issue. This wont work with a street engine trying to hold water. There is too much gap between block and head. We have found the best results in decking the sleeves flat with the deck. A slight coating of clear silicone is all thats needed to keep the water where it needs to be. Setting the o-ring at .008 above deck instead of .015 really helps keep the water from leaking out. These were all things learned by trial and error. There are no you tube videos out there to show me how to do this. Sure its alot of work but its also fun and rewarding to make something work when most said it couldnt be done.

 

And your not just working on the run of the mill small block.

 

No but you fix them the same way.

 

First, nice work on the repair of the block!
I do have a question, is the valve spring rate / RPM causing the valve stretch?
I would assume the nitro is not the cause since it would be pushing the face of the valve into the valve seat when firing. Nitro engine science is new to me

 

I dont have a answer for that. I do know whenever a valve pulls through a retainer we check for stretch. If its over .050 its junk.
The spring rate on my set up is 340 lbs at 1.950 when a spring goes below 300 lbs its replaced. This is normal blown hemi alchohol or nitro specs. There is alot of pressure pushing on the back side of a big intake valve trying to keep it off the seat

 

A ridgid hone cleaned up the sleeve bore. A torch heated the block. Wd-40 on the sleeve helps it go in. After lining up the index marks it was driven in. It was then pushed outside to cool. When it returned to a normal temp the sleeves were hit again. If its too hot the other sleeves can move up. Now they are set. Its time to surface the block. Here a few pics of the tools of the trade.

 

Going through the process. .002 coming off. The new sleeve was brought down to deck level first. Then a pass was made over the whole deck.

 

How much can you keep taking off the deck & heads before compression changes or different pistons are needed? Thanks for taking the time to share all this.

 

That’s why there are so many different thickness head gaskets .
A lot of tuning in a fuel engine is with the gaskets .
And also,,,they are only milling a few thousandths off,,,,,that can be done many times .

Tommy

 

Its only .005 total. Its not enough to make a difference. Once you get over .010 then thicker head gaskets can be used. The compression is only 6.5 so the pistons wont be a issue.
Lowering the head that little bit wont effect the pushrods. There will be enough adjustment.
O-rings seal the intake to the head so they can take up difference. The manifold bolt holes are slotted for many different combinatiins of deck heights.
The parts used in these engines are designed to come apart and go back together easily. They also allow for tuning changes regarding deck height changes. Its not uncommon to run different thickness gaskers side to side. A thicker gasket will reduce heat on that side if the whole side is picking on the pistons.
If one cylinder is getting picked on that hole can get a piston thats lower in compression. These measures are only taken if larger nozzles in that hole arent achieving the desired results.
To run these nitro engines sometimes you do unconventional things that seem wrong yet they work. They are done by teams everyday.

 

Controlling cumbustion chamber heat is everything. Everyone has seen picks of firey explosions. This can happen when a piston gets a hole burned in it allowing oil to hit the chsmber. Other damage can occure to. Porcelain can burn off the plug. The trash gets under the valve or on the seat causing a big leak. The pistons can have their rings pinched again causing a leaking cylinder. Torched out head gaskets can occur to. Careful examination of the plugs can direct the tuner to make the right changes to make the engine live.

 

Years back when Nitro was starting out, what was the repair and daily operations like. Was it really different compared to todays work? I would suspect the materials and quality of parts have made life a little better.

 

The iron stuff was thrown away because it was hard or impossible to fix. Thats the beauty of a aluminum block. Repairs can be made.

 

Heres that nasty combustion chamber now. New o ring receiver grooves have been cut. Its a very delicate procedure to get them in correctly.
The seats in the repaired chamber need to be replaced. They wont clean up unless the valve gets sunk. Overall lookin good.

 

Beautiful work! Prettier than a new paint job. Thanks for the great thread. I'm learning so much here.

 

Very nice milestone, thanks for bringing us along.