I have to agree with everyone in here that you are doing a great job. I only wish that I had the skill and the time to do a project like this.

Great Job!!! Thanks for the constant posts.

 

As suggested, I checked my rod clearance over the weekend.

The specification for the rod clarance is .001-.002. First I pulled #7 and #8 rod caps, then check the clearance with plasti-gauge. It appears I'm about .0015. The plaasti-gauge wasn't as wide as the .001 scale, but it was definately wider than the .002 scale. The scale that I'm holding, the firstgreen block on top is the .001 scale and the second green block below it is the .002 scale.

Earlier I mentioned I had a heck of a time finding the torque specs for the rod caps. I searched my CD manual over and over and couldn't find anything. So I torqued the bolts to 40ft lbs.According to other service manuals I've used, rod torque specs ranged from 30-45ft lbs. So I figured 40ft lbs was a adequate number.



For all those who have ever said "how can I get more power from my engine" I'll post my thoughts and opinion on this tomorrow.

Later

 

Wow what a great job you're doing! Hopefully one day I'll have the time to do this.......

 

Just wanted to mention that you should change the front main seal before you button her back up. It looked like it was leaking there before.

 

It's on the to-do list

 

Just curious, why did you edit your original post. I read your original post in my email notification and itlooked like good relevant info.

 

Since I have the heads and intake manifold off, I started to think "how would these heads and manifold benifit from an old fashion port and polish"

With that in mind, I started to investigate. I'm not going to go into the benifits of porting and polishing. I'm sure you'll get tons of info if you Google that subject.

The following steps have been around for decades, I just applied it to a my Disco engine.

First I took a Sharpie and painted the intake ports on the head, temporarily attach the intake manifold gasket, then scribe the outline of the gasket.








What you see above is how much material can be removed from the ports to increaseair flow.Also called gasket match.

Even the water jacket ports below can benifit with port matching.



Then do the same for the exhaust ports on the head.





After completing theintake and exhaust ports on the head, then you need to do the same for the ports on the intake and exhaust manifolds.FYI, I did not mock-up my exhaust manifolds (they are still attach to the y-pipe in the truck) but the steps would be the same.
Paint, attach gasket then scribe.









Once again in the following pic below, even the intake manifold water jacket portcan benefit for port enlarging.



That's pretty much it when it comes to port matching, but I'll be dead wrong if I say that's all there is to it. Ideally you want to increase air flow without decreasing velocity.Don't forget to Googlethis topic for more indepthinfo.

The following pics below shows what's involve in polishing the port.The idea behind polishing is to remove the flaws that's part of the casting process.

This is a pic of a intake port on the head. Besides the casting flaw that I'm poiting to the intake ports in the head were relatively in good shape with little flaws


The exhaust ports on the other hand need work





What you're trying to achieve is a mirror like finish in all the exhaust ports and a smooth texture finish in the intake ports.

The following pics in my opinion can also yield some benifits if done properly. Increase the ports where the plenum and intake manifold attaches to each other.



The mating surface between these two items is amachined surface. There's no gasket or o-rings between these two mating surface (which i was surprise to see)



I would suggest taking these two pieces to a machinist to see if they can enlargethe ports equally. Imeasured the openings with my caliper and they roughly measure 1.5 inch. Without the aid of a flow bench machine, figuring out how much to enlarge them towould be anyone guess. Increase air flow without decreasing velocity.




If you have never seen the combustion chamber on a 4.0, here you go. I don't know if the 3.9 is the same. The combustion chamber is also another area where you would want to polish to a mirror like finish. This will decrease carbon build-up and detination.



Appearantly these heads must have been used in other application because of this boss that was cast in the head.



I've readhow Disco I owners can use the 4.6 short block during a engine rebuild.I don't have the numbers or hands on experience to back up what I'm about to say, but with a 4.6 short block and anice port and polish, you should be able to see a noticeable HP gain.

Here's a link to Standard Abrasive website for a DIY porting.

http://www.sa-motorsports.com/diyport.aspx

 

I will probably bee getting my heads re-worked this summer. I was totally considering this. I look forward to seeing how it turns out.

BTW, you are correct on the 4.6 swap. http://home.twcny.rr.com/eeibooks/rover/engine.htm This is where someone with a D1 swapped to a 4.6. He used the long block, but the heads are the same for a 4.0 and 4.6

 

It'll be interesting to see how it performs in the real world. Hopefully you'll get a lot more power (and gas mileage) out of it.I am pretty active in the Corvette circles, but my person focus is on paint and bodywork. My understanding was there was merit to leaving the casting imperfections as they help create desirable turbulance. Also I just read an interesting article about the debate offlow vs. velocity (smaller D-shaped ports).

You're doing good work, keep us in the know.

 

Thanks for the link, I remember seeing (hearing)that You-Tubelink before.You helped my with two things

1) I've always thoughtthat DI's could only use the 4.6 short block. Now I know both 4.0 and 4.6 long blocks are the same. Not includingaccessories.
2) With the link,I finally know what this is. I was wondering what sensor wasbolted to the back of the block with a reluctor ring mounted on the flywheel. Now I now it's the crank angle sensor