Head work

[jory]

I'm working on my 3.0 build again after a while of not being able to afford parts. I just ordered new rings for the 10:1 Diamante pistons, since the Chrysler 8.9:1 rings didn't fit. So what can I do to my heads to get more performance? I'm open to any suggestions but I don't know the first place to start on this. The heads only have 30k on them and they still have the valves and springs in place. What's proven to give more flow/power?

[Ondonti]

Basically Ed is proven to be able to work on the heads well.

I think the only easy "gain" that a random person (like myself) can do is from using larger valves and if you dont know how to port the head right your gains might be elusive still.

I had great results on the intake port with a +2 valve but larger valve on the exhaust port ONLY gained flow above .200" lift with a +1mm valve. I think that is partly due to the porting I did on the exhaust.

There are gains though. Since I have big cams my exhaust ports are able to have more time @ the higher lifts where my port does flow decently but if I had stock cams then gains would be less pronounced.

My Duster is making more power @ 4400 feet of elevation
Then my Spirit did @ Sea level.

The duster has 1.9 points less compression too! 7:1 compared to 8.9:1
So heads combined with cams can make nice power n/a or turbo/supercharger/nitrous

[c2xejk]

Yup, without a flow bench you are shooting blind...

Currently I have the intake port w/stock valve at ~230 CFM. I can get it to 235, but the head would likely be only suitable for a high RPM setup... My goal has been to get the measured velocity to ~250 feet/sec (fps) at .35" lift and ~300 fps at ~.40"+

On the exhaust side what the flow bench can tell you is much more limited. Basically you focus less on the CFM and more trying to get the port exit velocity to 300 fps. Right now with an insert I have it to about 284-294 fps at the .35"-.45" lift. On the heads I am working on now, I plan trying one additional step that kills the flowbench CFM, but is supposed to do wonders for a running engine...

Right now the biggest obsticle to a good exhaust port is casting. I have been toying with going to a +2 or +3mm valve, but for the moment there are some things I want to try with the stock valve...

As for gaining only over .2" lift on the exhaust port, that seems to be pretty much true as soon as you do _anything_ to the SSR. Some rounding of the SSR is "necessary" to get the high-lift flow up enough to get the velocity in the right ball park... Too much rounding can kill the low-lift forward flow _and_ increases the low-lift reverse flow. (ie. increase reversion which kills low-rpm power...) It is a balancing act...

One final note, on the intake port, increasing low-lift flow kills low-rpm power. Sometimes it helps power above peak torque, but only sometimes... Yeah, I know most publications say the exact opposite...

[jory]

I'm lost when it comes to head porting. If I send it to the machine shop and get the valves backcut or a 3-angle valve job would I see any gains? Secondly are there any obvious restrictions in the ports that I could remove?

[lookin]

Ed would you please check your PMs?

Thank you.

[mopar2ya]

Good thing I have a flow bench....

[lookin]

Ed's heads really do make power. I watched his minivan take off this weekend, and that sure made a believer out of me.

Wish I could afford them.

[jory]

I will definitely send my spare heads out to him some time in the future. For now I'm putting my stock 30,000 miles heads on it and running it for a while.
My piston rings came in the mail this week and this time they are the right ones. I'm going to start putting it together tomorrow. I'll do the rings, pistons and rod bearings, then the oil pump and front/rear main seals and the bottom end is basically done. Then I need to order an aluminum flywheel and new clutch, pull the engine/trans and swap it all out. I also have a new alternator, P/S pump and firm-feel steering rack that are going in.

[Ondonti]

what bore are your pistons?
honed the block right?

[jory]

The first thing I did was have the block honed and hot tanked. The engine I tore apart was in excellent shape since it only had 30k on it, so all the block needed was a honing. I'm using stock bore 10:1 Diamante pistons and my rings are STD size as well.

[mopar3.0]

ive yet to see a 3.0 that needed to be boared . one had 360 ooo km

[jory]

Well I measured the rings and installed the pistons and rod bearings. Now I can't find my new oil pump that I had sitting in a box in the cellar for months or the rear main seal housing. But I'm making progress on it. I'll post a pic later on.

[jory]

Here's a picture. Rods are all bolted up, rear head is torqued down and that's as far as I got today.

[jory]

I pulled the motor from my Spirit Saturday night and put some more parts on the engine.





check out this clutch disc. It was a stock T2 IIRC...