Dohc 4 valve 6.8 v10 head build

Early 2000's Ford Explorers has 8.8 IRS rear ends as well. Very cheap. Very plentiful. I used one in my RX7.

3_8scbug said:

anyone have any ideas on how to build the cams?

What are the odds that you could make a set of V10 cams out of 2 sets of V8 cams?  Gun drill, slice and dice, install a rod through the center to make them straight, spend way too much time aligning everything, and then tig them back together…?

This is probably a terrible idea but it’s all I’ve got.

therieldeal said:

3_8scbug said:

anyone have any ideas on how to build the cams?

What are the odds that you could make a set of V10 cams out of 2 sets of V8 cams?  Gun drill, slice and dice, install a rod through the center to make them straight, spend way too much time aligning everything, and then tig them back together…?

This is probably a terrible idea but it’s all I’ve got.

thats my thoughts on it as well. in my mind it works. i was thinking a degree wheel and spin the lobes to mimic lobe seperation of the 2 valve heads so the firing order is correct, .once they are in the correct position tig weld them together.

In reply to 3_8scbug :

I’d get a scrap V8 head to bolt the cams into while welding, too… easily keep them clamped straight, and pull heat away quickly but evenly.

therieldeal said:

In reply to 3_8scbug :

I’d get a scrap V8 head to bolt the cams into while welding, too… easily keep them clamped straight, and pull heat away quickly but evenly.

yeah, when we get the heads cut and welded together that would be best i think.

You'll have to cut and weld the heads, then deck, trim and line-bore the cam tunnels before you try using it as an alignment fixture. 

Then you can simply dowel an existing cam to the add-on piece, but getting those lobes dialed in closely will take a lot of patience and precision. Simply tacking the tube can cause it to pull far enough out of alignment to watch the needle on your dial gauge walk several thousands. You wanna shoot for less than .003" total indicated runout (TIR) if your engine will have any chance of surviving a test run.

Gingerbeardman said:

You'll have to cut and weld the heads, then deck, trim and line-bore the cam tunnels before you try using it as an alignment fixture. 

Then you can simply dowel an existing cam to the add-on piece, but getting those lobes dialed in closely will take a lot of patience and precision. Simply tacking the tube can cause it to pull far enough out of alignment to watch the needle on your dial gauge walk several thousands. You wanna shoot for less than .003" total indicated runout (TIR) if your engine will have any chance of surviving a test run.

Honestly I think it will be easier than it appears at face value

3_8scbug said:

Honestly I think it will be easier than it appears at face value

Not sure if serious...

Gingerbeardman said:

3_8scbug said:

Honestly I think it will be easier than it appears at face value

Not sure if serious...

Extremely serious. Not sure you understand what I am capable of

3_8scbug said:

Extremely serious. Not sure you understand what I am capable of

I try not to make assumptions about people's skillsets, but I've watched plenty of competent folks make a dog's dinner out of a project because it was outside their wheelhouse. Don't underestimate just how closely those lobes need to be located, just how straight and stiff your fixture needs to be, or just how much distortion can be induced with welding heat on those thin-wall tubular cams.

It's your project, I'm not trying to discourage you, I've just found over the past 2 decades that preparation made all the difference between success or failure on projects. I worked on some doozies, professionally and personally.

3_8scbug said:

Gingerbeardman said:

You'll have to cut and weld the heads, then deck, trim and line-bore the cam tunnels before you try using it as an alignment fixture. 

Then you can simply dowel an existing cam to the add-on piece, but getting those lobes dialed in closely will take a lot of patience and precision. Simply tacking the tube can cause it to pull far enough out of alignment to watch the needle on your dial gauge walk several thousands. You wanna shoot for less than .003" total indicated runout (TIR) if your engine will have any chance of surviving a test run.

Honestly I think it will be easier than it appears at face value

Expect it to be warped in new and interesting ways after you cut it all up and weld it together from five separate pieces.

Since it's all one-off stuff anyway, I wonder if you can just do an end-run around the problem and make the cam journals in the heads smaller, and just have the cam journals reground to the new smaller size.

Still seems easier and more likely to succeed to find someone with experience with making cams out of steel billet and see what they'd charge.

If I fail I will turn to someone else

3_8scbug said:

If I fail I will try a different way before i turn to someone else

and i'll be reading along... :-)

Currently looking for 2 sets of heads

Getting the nova close to putting the engine in so I will be looking into custom tunes and unlocking the Pats (passive anti theft system)

3_8scbug said:

Getting the nova close to putting the engine in so I will be looking into iTunes and unlocking the Pats system

Those are all words?

In reply to Knurled. :

Edited

Ok update on the dohc build. After lots of painstaking measurements I have a solution. The heads are simple. The camshafts were going to be the hardest part to figure out. So ford made a 3 valve v10. The 3rd valve which is the exhaust valve has its lobe of the cam in the exact place where the cam caps would go on a dohc cobra or other 4 valve ford modular engine. All specs of both style cams (3 valve and 4 valve) say that if I machine the 3rd lobe down to the spec needed I can bolt the cams to the newly created v10 dohc. I will work on things like setting the overlap and other things after.

I am watching with interest, splicing and dicing heads always seems like a fun project that I have yet to take on.

3_8scbug said:

Ok update on the dohc build. After lots of painstaking measurements I have a solution. The heads are simple. The camshafts were going to be the hardest part to figure out. So ford made a 3 valve v10. The 3rd valve which is the exhaust valve has its lobe of the cam in the exact place where the cam caps would go on a dohc cobra or other 4 valve ford modular engine. All specs of both style cams (3 valve and 4 valve) say that if I machine the 3rd lobe down to the spec needed I can bolt the cams to the newly created v10 dohc. I will work on things like setting the overlap and other things after.

Let me get this straight. 

• The 3V SOHC cam has three lobes for each cyl.  Inlet - Exhaust - Inlet correct?
• For the intake cam you use a stock three lobe cam, using the two intake lobes and machine down the exhaust lobe correct?
• For the exhaust cam you will again use a stock cam with the two intake lobes being re-profiled as exhaust lobes and again machine down the exhaust lobe correct?

I think this is what you're saying. 

In reply to Adrian_Thompson :

That's how I read it, and that is great news!

That sounds like a pretty slick way to get around chopping, aligning and welding camshafts.

Adrian_Thompson said:

3_8scbug said:

Ok update on the dohc build. After lots of painstaking measurements I have a solution. The heads are simple. The camshafts were going to be the hardest part to figure out. So ford made a 3 valve v10. The 3rd valve which is the exhaust valve has its lobe of the cam in the exact place where the cam caps would go on a dohc cobra or other 4 valve ford modular engine. All specs of both style cams (3 valve and 4 valve) say that if I machine the 3rd lobe down to the spec needed I can bolt the cams to the newly created v10 dohc. I will work on things like setting the overlap and other things after.

Let me get this straight. 

• The 3V SOHC cam has three lobes for each cyl.  Inlet - Exhaust - Inlet correct?
• For the intake cam you use a stock three lobe cam, using the two intake lobes and machine down the exhaust lobe correct?
• For the exhaust cam you will again use a stock cam with the two intake lobes being re-profiled as exhaust lobes and again machine down the exhaust lobe correct?

I think this is what you're saying. 

Correct, then the cam caps will bolt in place of where the lobes once were. Also the 3 valve has much greater lift than say a 2003 cobra camshaft

Hey how would I move this topic or have it moved to the builds forum?

In reply to 3_8scbug :

Ask the Mods in the Canoe/Mod support Thread