Welding BBC Block

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I am building a Twin Turbo 427 for my boat. The heads I bought have provisions for additional head studs to prevent blown head gaskets but unfortunately the block does not. I machined four blocks out of 1018  mild steel and need to weld them in the lifter valley. This modification has been successfully performed by many engine builders for many years. I am unable to locate a local shop capable of the modification and the only one I did find charges $500.  I have several questions as how to do this modification and any help would be greatly appreciated.I plan to pre-heat but do not know what temperature would be the best.I was planning on using NiRod99, Super Missile, or Stainless rod. Which of these would be better for my application? I read an article saying to use aluminum bronze rod and set my TIG machine to AC. Has anybody tried this method?Article:http://ezinearticles.com/?How-to-Tig...red&id=2532882Is this a possibility I should consider?Thank You,Earle
Reply:The alum bronze rod sounds more like brazing with tig than welding. Brazing has always been an acceptable method of cast iron repair.There are a few here who specialize in cast work, I'm curious to hear their approach to this..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Originally Posted by DSWThe alum bronze rod sounds more like brazing with tig than welding. Brazing has always been an acceptable method of cast iron repair.There are a few here who specialize in cast work, I'm curious to hear their approach to this.
Reply:Yes, the 1018 blocks are 1" x1" x1.5" with a .450 hole. they are welded into the valley and provide additional fastening of the head. On a big block Chevy there are two cylinders on each bank that lack a bolt/stud top center of the cylinder. BBC engines are notorious for blowing head gaskets in this location with high compression and boosted engines. Old racers preform this modification before blocks were built with provisions for the extra bolt. New aftermarket blocks are cast with them already in place.I was hoping to get some advice on TIG welding the 1018 to the cast iron block. I just came from the welding shop after posting and they suggested NiRod99 and pre-heat to 500-600 degrees. Welder at my work says he has successfully welded mild steel to cast with Supermissile and Stainless Steel rod. I am trying to find the best and strongest way possible to attach these blocks and would like to know if anyone here has any tips or advice to this procedure.I could re machine new blocks out of a different material if it is recommended.Thank You,EarleLast edited by Earlesurfs; 08-31-2009 at 03:46 PM.
Reply:I have worked on the old and new style blocks, havn't seen any old ones moded for extra bolts though. Welding mild steel on cast is a non issue-no probs. The length of the pad? Or how long will the welds be? Maybe make pads outa weld, would reduce pad length. Older blocks are lower in nickel and softer than newer blocks. I have welded castings with arc before but when the weld is critical I use OA torch......If I was given pads to weld onto block I would want them long enough to withstand stud/bolt torque. If looks arn't an issue I would braze the pads on or build pads out of bronze. Block is probably 40,000 tensile max, most common bronze rods are 60,000. I would use nickel silver brazing rod, its 80,000 tensile and the procedure is the same.Heat block to 700 degrees and keep it there while welding. If using oven check while oven is open, when you loose 200 degrees stop welding and reheat ( you usually have about 5 mins). After final weld reheat to 700 and hold for 20 to 30 mins. I usually bring down oven temp 100 degrees every 30 mins untill it gets to 400 then turn off oven and let it cool in closed oven. If you use a brick oven you can usually turn off oven after postheat. The brick when heat soaked cools slow enough.Peter
Reply:First have you tried O-ringing the block first? I remember a mod from long ago where the extra 2 head bolts were added with out welding. As I remember it the extra head bolt was a socket head capscrew. The bolt was installed in the intake ports.  A hole was drill in the top of a port that would later be filled with a 3/4" socket head pipe plug. Though this hole the real work took place. A hole would be made in the floor of the port and counter bored for the cap screw. Directly below this a hole would be drilled and tapped in the block. The pipe plugs in the roof of the port had to hand finished. After all the head bolts were installed the pipe plugs were installed with sealer.This memory is over 25 years old so I would check with some racer that done this more recently.Tough as nails and damn near as smart
Reply:Thank You for the great advice. The oven we have here at work that is big enough for my block only goes to 425. could I possibly heat to 425 then heat whole lifter valley with a torch and use a laser thermometer till 700 and keep heating while welding. Then slowly reduce heat with torch and stick back in oven? It is a later (78-90) block and from I have read has a higher nickle content than the older blocks. O-Ringing the block was a good way to seal block to heads but they did not always seal right away and sometimes never sealed completely. They now have multi layered (Cometic)head gaskets that are not cheap but work really well. If I start stuffing 30psi+ into this thing with aluminum heads, multi layer and copper/O-ring block/heads are not necessarily going to hold up. The head lifting ever so slightly will cause pressure to escape and blow the gasket at the least. Worst case could melt through cylinder wall and head and trash the engine. The bosses and bolts just have to be strong enough to keep head from lifting. 7/16" bolt torqued to 35 foot pounds. It is kinda preventative not 100% necessary. Nothing worse than blowing your boat up and being towed back the first day at the river!Picture of what I am trying to accomplish:http://www.usaperform.com/images/CenterStud_BigM.jpgThank You Again,Earle
Reply:Im with Castweld on this.  Avoid the Arc. Brazing done right will exceed the strength requirements, and with no cracking issues. I know the mod you are talking of, and have done similiar work....at work. 2bar boost isnt out of line, our production engines run up there. Have fun!-Aaron
Reply:Originally Posted by EarlesurfsThank You for the great advice. The oven we have here at work that is big enough for my block only goes to 425. could I possibly heat to 425 then heat whole lifter valley with a torch and use a laser thermometer till 700 and keep heating while welding. Then slowly reduce heat with torch and stick back in oven? It is a later (78-90) block and from I have read has a higher nickle content than the older blocks. I wouldn't go that route. If you talk to ten "weldors" about this most will swear they can tig, stick, or even mig it with a little heat or even no heat. Use a oven capable of 700, use your ir to "look" inside water jackets and at thick areas around line bore to be sure you have heat soak. Can you get it done as you said- possibly- but do you want to chance cracking it?O-Ringing the block was a good way to seal block to heads but they did not always seal right away and sometimes never sealed completely.O ring with copper gasket and receiver groove is best...Period. Go in the pits and look at a top fuel engine set up. They now have multi layered (Cometic)head gaskets that are not cheap but work really well.Yes I agree 2nd best set up. If I start stuffing 30psi+ into this thing with aluminum heads, multi layer and copper/O-ring block/heads are not necessarily going to hold up. The head lifting ever so slightly will cause pressure to escape and blow the gasket at the least.Yes that is cause, bolts stretch and- oops- blown gasket Worst case could melt through cylinder wall and head and trash the engine. Not trash- I weld flame outs often The bosses and bolts just have to be strong enough to keep head from lifting. 7/16" bolt torqued to 35 foot pounds.Looked at your pic, thought push rod would be close. Build pad from bronze and tap it. Instead of some weld around perimeter of the "blocks", pad would part of casting - would take full torque. Check your deck older blocks are usually only .400 thick and bolts go into water jacket.In all cases of lifted heads I have been around, the cause has been detonation. Some won't agree. Lean,timing, cross fire, ect. Each One! Spend a few dollars and go to a dyno w/8 egt's &8 o2's and iron out your probs. For a boat I would knock off a few degrees and fatten it up a tad over max hp tune up.  Then gaskets will live. But bad news- the "next weak link" is rods, crank, and main webs,thin cyl walls, and....dizzy: It is kinda preventative not 100% necessary. Nothing worse than blowing your boat up and being towed back the first day at the river!Not fun or cheap.Picture of what I am trying to accomplish:http://www.usaperform.com/images/CenterStud_BigM.jpgThank You Again,Earle
Reply:If you use Everdure, you may not be able to grind with anything but a stone. It gets so hard, that you cannot file or use rotary files with much success. You will be stuck to stone grinding. But it does stone grind nicely. I have welded my everyday beat on vice with Everdure, and it has not broken again, since the original break. I welded a broken oil hardened steel cutting die once. And filled in the edge where I could not find the pieces of the die. The Everdure was so hard it actually was able to cut a couple hundred pieces of steel. And kept a decent edge. I was able to finish the job.        Sincerely,             William McCormick
Reply:Originally Posted by castweldGood LuckPeter Oh, and check after welding, the deck will be off around welds.
Reply:So... I have been super busy with work and have not had time to work on this project.This weekend is looking good and I tried to purchase some Nickle Silver Brazing Rod. I was thrown off because I was asked what percentage of silver I would like. I assume more Nickle and less Silver would be stronger but would like some advice on what rod to purchase. Thank You,Earle
Reply:take a look at the cometic or felpro muti-layer head gaskets. I have built a few supercharged engines and these head gaskets work great. you need a very smooth surface finish to run them . I have not o-ringed and receiver grooved a block in years since these gaskets came out. to be honest the amount of money you have in the top end of the engine , I would just look into purchasing a aftermarket block. they are lite years away from a  stock factory block, in terms of strength and design. they do weigh a little more than a stock block. but in the long run you will be better . use a  set of head studs also for better clamping force.
Reply:The best easiest rod to use for cast is Cronacast made by Cronatron. I have used Super missile, nickle, Nirod, and a lot of others, but Cronatron is the best by far. Do a web search on Cronatron.Ps. I am not a salesperson, I am a weldor6"XX P5P8 6G