-
MK1 V6 Conversion - Project Mini-Me
*Finally* getting round to starting this, albeit with a bit of brief intro and crappy pics...
As some of you may recall, in September we picked up this;
Then not long after I did a run and picked up a 3VZ-fe engine along with a Mk2 Rev 3 box and shafts. 
They were sitting around for a while, but last weekend work commenced!! :icon_biggrin::icon_biggrin:
First things first were to get the heads sorted. Planning on getting them skimmed either 0.5mm or 1.0mm and also wanted to port and polish them. I decided to get the porting done first before skimming just in case I have any accidents with the grinder.
So heads stripped down;
Got myself setup on the bench and make shift lighting rig.
Ports to start with;
After a bit of ginding, ended up with this. It still needs a smoothing out a little more but the main things I've done is removed the boss from the valve guides, narrowed the split and also removed the lip as the port drops into the valve opening which you can't easily see.
It is a lot more time consuming than I thought, but going slowly to be safe. The back of the port I also managed to do by going in through the valve opening, which felt like open heart surgery for fear of grinding a valve seat away. But, a steady hand and many coffees got me through it.
One head has been done, but still the other head to do. Once I've finished porting the heads, they will be going away for a skim and then I'll start porting the v-bank and the plenum as much as I can reach into.
Will remember the camera next time to get some tidy pics. 
-
Are you re grinding the valve seats while you're at it? Probably a good idea. Your engine really benefitted from just that IMHO.
If you need more shims when you reassemble grab them from the scrap heads when you're up.
In fact take the heads!
:)
-
Gonna ask the engineering place if they can do it, but may just end up lapping them in tbh.
After much reading, getting rid of the lip where the port drops to the valve and the boss of the valve guide makes the most difference. Not looking for any silly expectations though if I get an extra 5 horses then if be happy.
Getting a list of bits to pinch from you, will see how I get on and whether I need the extra heads. :-)
-
I'll be honest, I've not heard of the guide being ground out before. It is possible to replace those by the way, they're generally a softer metal such as brass, and drift into the head.
Oh and I've got a shitload of stem seals if you want them.
Bring the Cammy up, we can fill the boot.
:)
C.
-
I wouldn't grind the guide down, you do need some interference of the air to create swirl there was a huge topic on inlet port shaping on here years ago and it was found you could get negative results if too much was done.
From memory I think cleaning up the profile and a bit of port matching got the best gains, I think they used to call it a stage 1 head years ago, which was like a fast road head stages 2 and 3 were more street racer and full on competition turbo head, I think Patrick you should be aiming for a 1 1/2 version.
Personally I would go with a 0.5 head skim or half again on the block and the other half on the block if it needs it, it will be interesting data any way you do it even at a 1mm skim and I can't wait to see the results.
-
Noted.
I don't mean I've got rid of the valve guide I mean the big hump just before them that is left during construction. :-)
-
I think Pat is aiming for Stage #1, although probably without realising it! Smooth the ports and remove any steps etc.
:)
c.
-
Just be careful not to take too much material off, there isn't a massive ammount you can remove from there. I think 4V6 did a comprehensive thread on 3VZ head work if they're still available on here.
-
-
Yeah Ive read a load of docs before starting and one thing they pretty much all said was resist the urge to go grinder happy. Lol.
The ports get smaller and smaller as they enter the chamber which is to increase the air speed as it goes in and that the biggest gains are seen from removing the lip as it drops into the valve inlet and also the hump just before the valve guide. I did consider removing the guides but decided against it but may try on the next one. I have bullet tipped the guides though but only a little.
As Tiggs says removing the guides completely isn't advised. It would help air flow but the guides are that length for a couple of reasons a) to support the guides and b) heat transfer. By removing them completely its likely to cause issues within a couple of thousand miles if not less...
Was very tempting to just go silly with the grinder though, even though I was cringing at first looking at all the Alu filings coming off it kinda gets addictive. Lol.
It's my first attempt though so I'm not expecting perfection but just a little improvement and I'll be a happy man. :-)
Posting Permissions
- You may not post new threads
- You may not post replies
- You may not post attachments
- You may not edit your posts
-
Forum Rules
Reply With Quote
