Filling a cast iron cylinder head

[cardiffrob]

Can I pick your collective brains?

I have lots of old low-compression heads for old sidevalve engines and have one decent high-comp one. The difference is merely an area of the chamber that is either removed or left in. What could be sensibly done to weld the chamber back to the high-comp profile? Bronze/Braze etc? Lots of pre-heat and then a skim, obviously. What TIG rods might be suitable? 25-35hp 1000cc sidevalve, so not likely to be glowing red during use.

Ta.

Rob

 

[Tinbasherdan]

last cast repair i did, i found i had more success using MMA with NiFe rods, its still going now so im going to assume it worked!!

 

[cardiffrob]

Here are the 2 designs.

 

[frank horton]

be a bit scared of all the warping..........perhaps keep looking for another.....what they off.......Frank

 

[cardiffrob]

Derrington Sidevalve head for the Morris engine.

 

[gavcarter]

Is there enough valve clearance for a heavy skim of the head / block?
Skimming enough off would have the same effect as filling in the combustion chambers.
Just depends if there is enough room between piston and valves.....

 

[cardiffrob]

Not really. The valves run very close to the head and the alloy one has the pockets cut into the roof to offset the skim that it has had to help the comp ratio. Looks like welding a steel head or CNC cutting from a bare block of Ali are the only solutions.

 

[gavcarter]

Cylinder heads get repaired on big agricultural stuff, tractors diggers marine engines etc. Big diesels, pistons like bollards and compressions ratios around 20:1.

If these can be ground and welded along cracks, to be repaired, i dont see how there isn't a way to fill in a bit of the chamber.

No idea how but cast steel and cast iron is weldable.
How much hassle it is is another matter though

Alloy heads are weldable too, with the right kit. I'd ask around engine rebuilders etc.
Espcecially people who do classics where another head just isn't an option.

 

[gavcarter]

 

[cardiffrob]

Yeah, I watched that one this morning. I've just gone through the welding of another Ali head but cast iron is a different animal, innit.

Presumably an iron head can be brazed if the braze melts at a temp higher than Ali since the Ali doesn't burn up in normal use. I know the heat disipates through Ali quicker but this is a rather basic, low-powered engine.

Ali-Bronze seemed to be a possible candidate.

 

[gavcarter]

Try it on a scrap head?

 

[8ob]

I would have thought it would be easier to build up/reshape the top of the piston than mess with the head.

bob

 

[gavcarter]

Would probably want a crank rebalance then though....

 

[cardiffrob]

You can't change the shape of the pistons in the sidevalve engine. You can see where they go in the picture of the iron head in post number 3.

 

[8ob]

You can't change the shape of the pistons in the sidevalve engine. You can see where they go in the picture of the iron head in post number 3.

They do with the flat head fords, they flycut the heads and fit raised top pistons. Standard on the left in pic below and some other modified ones.

 

[Bill Edwards]

Tig braze would possibly be an option (not my area of knowledge) but welding it cold with MMA using the correct rods for cast iron certainly works.

 

[fizzy]

I once had a block skimmed only to reveal a pit/bubble in the casting. I was told that is was now only fit for scrap. I mixed up some Araldite 24hr with iron filings. Filled the hole and pared it off with a razor blade. The engine did another 100,000 miles no problems!

 

[zeppelin builder]

View attachment 128460

Here are the 2 designs.

I did a pair of blind ones for my v twin enfield with pure nickle and an air hammer to peen them
Brought them up to harry ricardo spec
Might be easier cheaper to o/a braze think tig would boil out years of carbon/ fuel deposits and end up in a total mess
Must try experiment with
Mig brazing i think that wouldnt boil up the parent metal

 

[graffian]

I knew someone who used to braze chunks of steel into V6 heads to seperate ports.

 

[zeppelin builder]

I knew someone who used to b3raze chunks of steel into V6 heads to seperate ports.

Ford essex ? Swaaymar boat anchor?