Posted From: 18.104.22.168
|Posted on Wednesday, 21 April, 2004 - 12:07 am: |
I have a serious problem, and any advice would be greatly appreciated.
My 4 1/4 six cylinder postwar engine has a crack in the block. I have received expert specific advice on how to effect a repair using overlapping setscrews all along the crack, which method I think is sometimes called "stitch weld." Probably that is what I will attempt, but before doing so I want to make sure there is "no stone unturned," and that I have full knowledge of all methods that offer hope.
The crack is horizontal, lengthwise, on the right side, at the very bottom of the water jacket, and it extends almost the full length of the block. The crack is old, and was previously repaired with some kind of filler on the outside, but that has failed.
I am advised against welding because the material is very thin. I don't weld well enough to try that anyway.
I am aware that a method used to successfully repair P-III blocks that have suffered severe corrosion at the bottom of the water jacket is to pour in some epoxy resin to seal the bottom, after damming up where the cylinder barrel is inserted. I understand this works well for those engines. Perhaps that method may have application to my situation.
A 1-inch deep pool of epoxy at the bottom of my water jacket would completely cover the crack, and if the epoxy were to stick, this could effect a permanent repair. Problems with this approach are of course how to make sure the epoxy will stick, and also how to create a dam around the water drain so the future function of the water drain will not be impaired.
I do not think reducing the depth of the water jacket 1 inch would significantly affect cooling. The water jacket is much deeper than the piston stroke, and the area that would be filled is well below the bottom of where the inside of the cylinder is exposed to combustion gasses.
I need to carefully consider exactly how I might accomplish this because I will have only one shot at it. If I fill in with something that does not work, I may be unable to do anything else afterwards.
I might clean out the bottom of the water jacket with acid and then flush with my pressure washer. What acid should I use? What other considerations are there to making sure the epoxy will stick?
Is there some flexible tubing I could stick through the water drain and route it above the anticipated level of the epoxy to form a path for water to escape in the future?
What is the best material to use? I think epoxy because I believe that is what the P-III people use to fix their problems, but maybe there is some other material that is better. It would be perfectly OK I think if the repair material did not become rock-hard, so that some flexing would be possible with heating and cooling of the block.
It is possible some approach exists that I have not considered. What's that?
Please, all thoughts very welcome here. Help, help!
Post Number: 154
|Posted on Wednesday, 21 April, 2004 - 12:37 am: |
Could I post this on the RREC members' site for you ? I know a few subscribers in the UK who would jump to help you. I do know of several special repair methods, but the UK people may offer some really positive up-to-date advice on this disaster.
Post Number: 244
|Posted on Wednesday, 21 April, 2004 - 09:58 am: |
When I was employed in the steel industry, we often patched non-critical defects [blowholes, porosity, shrinkage cavities] in castings with a two part metal filled epoxy - I still use a product made by Devcon which is available in a range of metal fillings from industrial suppliers.
I would be wary of using this in load-bearing areas or areas subject to cyclic stressing without detailed discussion with the manufacturers.
Posted From: 22.214.171.124
|Posted on Wednesday, 21 April, 2004 - 12:55 pm: |
Of course you can repost anywhere you think any sincere help might come forth.
Extra words for minimum
Posted From: 126.96.36.199
|Posted on Wednesday, 21 April, 2004 - 04:49 pm: |
Bill not to familiar with this model of car but have many similar problems and have over come them with successful welding.
First question is whether the engine is still in the car.
Second,not a great one with words but i assume the damage is frost and not where the block has run dry of water and refilled with cold water.
If it is frost are the face's of the crack equal or is one side raised.
Post Number: 155
|Posted on Wednesday, 21 April, 2004 - 06:29 pm: |
Dear Bill V,
David's suggestion of using a Devcon repair is what I had in mind too. Devcon products have been around for decades, and I have seen some absolutely amazing results using this well-proven stuff on severely cracked blocks (frozen and broken conrod holes alike), but there may be even better products nowadays.
I have posted your message on the RREC board, so let's see what comes up there.
You will find a proper repair method soon, so take it easy !!!
What is your location in case a local expert crops up ?
Post Number: 157
|Posted on Wednesday, 21 April, 2004 - 08:57 pm: |
A response from Ashley James in the UK already ! I am sure that if you contact Technilock in the UK, they would advise a suitable repairer in your local area and country.
Mike Jones may have a spare block +44 (0)1789 400011
Malcolm Hobbs has a late 4.25L MKVI block bored to 4.5L which he may sell: email@example.com
Alternatively you should take it to Technilock in Derby, they advertise in most of the Classic magazines and work to the standards of Lloyds insurers of marine engines. It will need to be stitched or welded by an accredited expert if the repair is going to be reliable.
Make sure it is converted to a full flow oil filter as well, assuming it has not already been done.
Thanks, Ashley, I'll pass it on: this information isexactly what is needed. Yes, this car has a full-flow... spin-off (hooray) oil filter. It is the one with the adaptor plate, not the Flexolite.
Posted From: 188.8.131.52
|Posted on Thursday, 22 April, 2004 - 04:12 am: |
Actually I have a spare block, but I don't know for sure it is good. I will need to clean it up and magnaflux it all over the areas where problems can occur.
If it comes to changing the block, that is a project for next winter. It is spring now where I am, and I want to be driving. I am trying to keep the car on the road this summer, and I am going to make as good a repair as I can do myself with the engine in the car. Then if it holds, good. If not, new block next winter.
Posted From: 184.108.40.206
|Posted on Friday, 23 April, 2004 - 05:18 am: |
Bill as you would like to proceed with the car through the summer months and make the best repair apart from two types of welding which are 100% successful.
I can recommend LEP Chemical LTD.The product can be applied along the crack and will start to cure in about 2/3mins.
As i am not familiar with this engine i do not know if the damage can easily be delt with or if the manifold etc is in the way with regard to grinding and cleaning the crack.
The product Will stand temp of up to 300f.
compression strength 18,000psi
Tensile strength 6,000psi.
modulus of elasticity 6x10'5.
It has a shear strength of 700psi.
David G is correct with regard to the cyclic stressing as it has a long crack and temp variations etc,this is the best product i know of apart from the two welding procedures that i carry out being 100% long term successful.
Hope this may help as the car is a must for the enthusiasts in the summer.
Posted From: 220.127.116.11
|Posted on Saturday, 24 April, 2004 - 05:36 am: |
One surprisingly effective way people used to repair blocks was to soft solder them, welding is usually disasterous unless the whole block is heated in a well insulated furnace to dull cherry red, the weld done and then as long as possible allowed for it to cool. And even then they can distort.
However a good propane torch, Baker's fluid (vicious flux) and plumber's solder does not require enough heat to cause worries and I've known repairs to last for years.
Posted From: 18.104.22.168
|Posted on Saturday, 24 April, 2004 - 12:03 pm: |
I'm into it. I am stiching the crack with 1/4 BSF screws set in JB weld, and patching a couple of holes with steel plates sandwiched around the block wall with a bolt through them to clamp it tight around the hole. The hole itself is filled with titanium putty.
Posted From: 22.214.171.124
|Posted on Saturday, 24 April, 2004 - 07:07 pm: |
i don't agree with Ashley regarding the his statement about welding,i have MIG welded blocks and other cast iron items with very good results.as long as the cast is of good quality it works ,why i don't know, maybe David Gore does with his background.i think Ashley is referring to stick welding but you can get rods for welding cast that are cold welding but i have never used these so i do not know if these are any good or not.soft soldering cast is a new one to me but maybe it works OK,i will try it sometime just out of curiosity, it may be very good.
Posted From: 126.96.36.199
|Posted on Saturday, 24 April, 2004 - 08:24 pm: |
Ted well done you have taken one of my two practises of welding cast iron blocks in place.
I do not no why it works 100%,but only if I carry out a procedure the same every time.
Of course ark welding is the next best in my experience with a high nickle rod content.
Hope bill has good results with his stitching a practice i have seen but one that i have never carried out on a block.
Have repaired a side valve alloy head many years ago with that method ok.
Brazing is another way but to much heat probes in my mind.
Ashleys way is very interesting but on a long crack with the different heat causing expansion contracting i feel the solder may weep a little,
But as i have not tried it i cannot comment.
Ted keep us informed.
Posted From: 188.8.131.52
|Posted on Sunday, 25 April, 2004 - 02:24 am: |
I recommended Technilock in Derby UK not realising that the block in question was the other side of the World! However I had good reasons.
Technilock are Lloyds approved for the repair of marine engines where there are no replacement parts available, they used to repair B60 blocks for the MOD; overheating cracks were very common on military B60s and finally, they specialise in the repair of the most appallingly damaged and irreplaceable old cast iron castings.
Stitching is very effective, even on very thin water jacket walls. They do precisely what Bill is doing but every inch or so, a tie piece is hammered in accross the crack to draw the sides together and reduce the chance of the crack creeping onwards. It might be worth talking to them for guidance.
Lots of people arc weld cast iron and get away with it, however it is not good practice nor is it safe to risk with old or irreplaceable castings, hairline cracks inevitably develop in all directions because of differential expansion rates in an extremely brittle material.
If you own something cast iron and irreplaceable that has cracks in it, it is best to at least talk to someone like Technilock before you decide what to do and if you are in the UK, I recommend a visit, it is quite staggering to see what they can repair.
Posted From: 184.108.40.206
|Posted on Tuesday, 27 April, 2004 - 06:30 am: |
Have today carried out some testing with plumber's solder it does work but for how long with engine heat variation i can't say.
like wise with testing to-day silver solder more heat but less than brazing far stronger joint but cannot say if the long term result is as good as the MIG set up.
Post Number: 36
|Posted on Wednesday, 28 July, 2010 - 08:32 pm: |
how did you get on with this repair ? Ihave the same problem with my block