In need of a crank welder/grinder

how deep are your pockets? Last I heard is there are no forged 4.2 cranks only billet and they are ~$3k.

As for a grinder/welder your actually looking for a Tool and Die man.
 
bowez said:
how deep are your pockets? Last I heard is there are no forged 4.2 cranks only billet and they are ~$3k.

As for a grinder/welder your actually looking for a Tool and Die man.
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no Im looking for a welder machinist
a/ weld rod areas

b/ offset grind crank to change stroke using weld materiel for the offset the re-grind will need
(read: old school technique)
 
Frankly, there are several issues with your idea.

1) It's been done, and the results were not effective (read, it broke).

2) By the time you are done with all the operations necessary to hopefully make the crank hold up (weld, grind, heat treat, nitride, etc.) you'll be a lot closer to the cost of a billet than you think.

3) To exceed the power handling capabilities of the cast steel 4.2L crank you will have to invest money on a scale that makes a $2500 crank a minor detail.

4) The performance difference between a 3.8L and 4.2L are minimal in comparison to the investment necessary to make it work. Power is determined primarily by the cylinder heads and blower. Suggest spending money where it will make the most difference.

:)
 
I was concerned with crank breakage at the number one main bearing with the cast crank. But a crankshaft support (external) made for the engine may fix that . I have seen one made for a 5.0 motor

So just drop in a truck crank ,forged pistons and rods, and full port job right?

since you seem to know a great deal, are the 4.2 valves larger than stock S/C?
Are the valve stems the same size? (if not, Brodix will make guides for me if the valves are larger)
 
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4.2L heads are split port so you won't be using them on an SC type engine. If you need parts for cylinder heads, I have all the programs worked out as far as what fits what and reasonable prices for the parts to get the job done. For example the guides on most SC heads are pretty whipped out by now anyway so you'll want to put bronze in regardless.
 
Definitely trust Dave on this. I've seen his setup and have his workmanship in my motor. Good stuff all around.
 
the valves I run in my 4.2 are larger than stock 3.8 take up all the room in my 1984 chambers, and use Brodix custom guides .

These I can put in your hands. How are they not the larger 4.2 valves? ( the machine shop led me to believe they were when they did my heads.

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I do not have a pic of the valve faces
 
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plstktnkr2 said:
the valves I run in my 4.2 are larger than stock 3.8 take up all the room in my 1984 chambers, and use Brodix custom guides .

These I can put in your hands. How are they not the larger 4.2 valves? ( the machine shop led me to believe they were when they did my heads.

42front.jpg


I do not have a pic of the valve faces
Click to expand...

I meant you will not be using 4.2L heads on your SC motor. You can use the valves if you want to. The 4.2l intake valves are bigger, exhaust are the same size. Since all split port heads are NA, they target a higher intake to exhaust flow ratio. On an SC we focus a little more on the exhaust. Most people opt for stainless steel aftermarket valves instead. The biggest valves that will fit the stock seats properly are 1.840/1.570. If you want to go bigger you can, but you'd need to install larger seats to get the benefit of it.
 
I think there were a couple years of single-port F-150 4.2L's, so those heads could in fact work. But it's not that important - 3.8 singleport heads are the same as those. And splitport heads won't work, as Dave said.
 
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