Porting and Polishing Heads

What about diesel porting, specifically the TD5?

I've seen lots of conflicting info about whether polishing should be done, ALL agree not to polish the inlets, but many say to polish the exhaust side and others say do not.

I saw in Lara's 2.8 stroker rebuild thread that he also put a radius to the head face to valve seat area for all the ports, does anyone have any technical information about this, the post suggests that it helps with low down pickup (googled in vain).

I've got a dead stock 10p head here that I can practice on before going at the AMC head on the motor - really don't want to spend the 1200 GBP that places like Turners & Doncaster Race Engines charge over here...

Vehicle has a hybrid turbo, big map, allisport IC, allisport cast exhaust manifold... Engine was fully rebuilt about a year ago with new pistons/rings/chains/guides/bearings/etc.

I know not doing too much polishing is the go on a pre chamber injected or carby petrol because the turbulence helps to mix the petrol but I doubt this will be the case with a direct injected motor such as a diesel.

Interested to know.

Happy Days.

Here's a link to the post showing the work done to radius the head face to valve seats... http://forums.lr4x4.com/index.php'sh...=3#entry486634

The manufacturer has spent many hours and many dollars designing the inlet port to give swirl for better combustion. Like someone said they tested a TDi head and the swirl was great. If you port it it will give better power at high revs but less torque at lower revs. The exhaust is not as critical and porting and polishing will probably be helpful in getting the gasses out. I asked Turner how their heads affect torque but got no reply. If you want to get more power and torque out of a TD5 probably to two main things are bigger intercooler and an ECU chip but these cost dollars, still better than wasting money on inlet ports.

regards ackie

Quote:

---

Originally Posted by ackie

The manufacturer has spent many hours and many dollars designing the inlet port to give swirl for better combustion. Like someone said they tested a TDi head and the swirl was great. If you port it it will give better power at high revs but less torque at lower revs. The exhaust is not as critical and porting and polishing will probably be helpful in getting the gasses out. I asked Turner how their heads affect torque but got no reply. If you want to get more power and torque out of a TD5 probably to two main things are bigger intercooler and an ECU chip but these cost dollars, still better than wasting money on inlet ports.

regards ackie

---

Most performance engine builders will disagree, rover v8 head casting is atrocious so any work is a benefit.

Sent from my GT-I9300 using AULRO mobile app

Quote:

---

Originally Posted by ackie

The manufacturer has spent many hours and many dollars designing the inlet port to give swirl for better combustion. Like someone said they tested a TDi head and the swirl was great. If you port it it will give better power at high revs but less torque at lower revs. The exhaust is not as critical and porting and polishing will probably be helpful in getting the gasses out. I asked Turner how their heads affect torque but got no reply. If you want to get more power and torque out of a TD5 probably to two main things are bigger intercooler and an ECU chip but these cost dollars, still better than wasting money on inlet ports.

regards ackie

---

I thought swirl was to enhance fuel mix PRE combustion chamber, so wouldn't really make any difference on a direct injected engine? Would probably nadger things up on a tdi though?

Quote:

---

Originally Posted by ackie

The manufacturer has spent many hours and many dollars designing the inlet port to give swirl for better combustion. Like someone said they tested a TDi head and the swirl was great. If you port it it will give better power at high revs but less torque at lower revs. The exhaust is not as critical and porting and polishing will probably be helpful in getting the gasses out. I asked Turner how their heads affect torque but got no reply. If you want to get more power and torque out of a TD5 probably to two main things are bigger intercooler and an ECU chip but these cost dollars, still better than wasting money on inlet ports.

regards ackie

---

Go back and re-read my post/s. ;)

You can greatly enhance torque below the torque peak with intelligent porting.

Quote:

---

Originally Posted by BennehBoy

I thought swirl was to enhance fuel mix PRE combustion chamber, so wouldn't really make any difference on a direct injected engine? Would probably nadger things up on a tdi though?

---

Check out Tdi inlet ports if you get a chance, initially you'd think they are all wrong.

They have a huge turn and a definite shelf or ridge to induce a huge amount of swirl.
All I can think is that the swirl and turbulence continues in the chamber/bowl, enhancing combustion as the fuel is injected.

It's to enhance cylinder fill,think of emptying a bottle by swirling it but in reverse.Sir Stanley Hooker made great use of swirl when he re-designed the inlet on the Merlin 45 and really got the thing pumping,not only power but throttle response.Mass production needs compromises,the engine designers will balance production costs,ease of manufacturing and performance,they can't have people polishing ports on the production line and they don't need to,we don't need to look for the last 10th of a second on a road car. Pat

Quote:

---

Originally Posted by PAT303

we don't need to look for the last 10th of a second on a road car. Pat

---

Some of us are perfectionist when we can be though. Sometimes we cant afford the time or the money but we still want to be.

Happy Days.