Jump to content


8 Port 998Cc Cnc Machined Billet Head And Collectors

  • Please log in to reply
85 replies to this topic

#76 Elmtech


    Passed Test

  • Traders
  • PipPip
  • 30 posts

Posted 09 August 2013 - 03:50 PM

any more news on this guys?


Yeah it's been a while since our last update.

Anyway, we eventually got the 1.3:1 rockers and installed them. We did some runs with them on the street and based on the logged data lost a bit of power compared to the 1.5:1 rockers, even after we adjusted the timing.

While we were doing some more testing with them we had some nasty engine problems too. We pulled one valve through the aluminium retainers and almost pulled another one too, the valve that was pulled through actually dropped completely into the cylinder. Thankfully it didn't do that much damage and the only parts needing replacement were the valve and valve guide. We put it back together with titanium retainers now though so we won't have that problem again :shades: . While we had the head off we also noticed that the steel plate dividing the 2 and 3 exhausts had vanished, apparently it had gotten soft enough to get blown out the exhaust. We replaced it with a thicker plate now.

We also built a much larger plenum to hopefully get the intake working better, but it didn't seem to help that much and it was so thin/welded poorly that it cracked open. We're going to get rid of the plenum now and are designing some rolling barrel throttle bodies that should be done next week. That's also something that could potentially be built into the head as an option.

#77 brum,brum,mike


    Super Mini Mad

  • Just Joined
  • PipPipPipPipPipPip
  • 554 posts
  • Location: Gloucestershire

Posted 16 December 2013 - 09:24 PM

any updates? ;D

#78 giacomo


    Super Mini Mad

  • Members
  • PipPipPipPipPipPip
  • 684 posts
  • Location: Southend/west cliff

Posted 07 January 2014 - 02:51 PM

any updates? ;D

What he said :D this would be nice in my race car ;)

#79 megamini_jb


    Crazy About Mini's

  • Members
  • PipPipPipPipPipPipPipPipPipPip
  • 5,491 posts
  • Name: Jamie
  • Location: -

Posted 25 March 2014 - 07:43 AM


#80 Elmtech


    Passed Test

  • Traders
  • PipPip
  • 30 posts

Posted 31 March 2014 - 06:11 PM

So, the Mini is running again. We finished our cnc-machined barrel throttle bodies a while ago and got them installed..so far they seem to be working nicely.

We also fried the autronic ecu we were using. Instead of simply buying another ecu we decided to make our own fully customizable ecu, X-EMS. It's working already and is capable of running the engine as can be seen in the video. There's still a lot of tweaking to do on it, but the idle is already much smoother than on the old commercial ecu.

Link to the ecu info page



The intake manifold is just modified from an old one we were using, so it's a "bit" too long at the moment. It's easy for us to shorten it now in steps to see if it makes a difference.



A closer look at the barrel throttle bodies.



#81 Domneon


    One Carb Or Two?

  • Members
  • PipPipPipPipPipPipPip
  • 720 posts
  • Location: Redditch

Posted 31 March 2014 - 06:49 PM

Wow that is amazing!

#82 Elmtech


    Passed Test

  • Traders
  • PipPip
  • 30 posts

Posted 17 May 2014 - 05:01 PM

A small update again:

We did a bit of mapping with the loong intake and then decided to 3d-print some shorter velocity stacks to hopefully make the intake less restrictive at high rpms. They turned out pretty smooth which was a nice surprise. Below is a picture of one of them without a filter.




And another pic of both of the velocity stacks installed with filters, they're still too long to fit inside the engine compartment, but for testing purposes that doesn't matter.




After we added some timestamps to the datalogging and did a bit of mapping we could compare the data to what we had with the older intakes. Despite still running the 1.3:1 rockers the data clearly suggests we are making more power than ever before at above 7000rpm. We also did a compression test as we've been suspecting the valve seats aren't really sealing that well, and it gave everything between 10-16bar depending on the cylinder. We'll take the head off next and have the seats properly machined at a machine shop. Hopefully that will give us some more hp. After that we'll reinstall the 1.5:1 rockers and probably have it dynoed again.


Our x-ems ecu is also working nicely and it has no problems idling around 1000rpm despite the 320degree camshaft. It should also get even better after we get the valve seats fixed.


Here's a recent video of us doing some road testing:

Edited by Elmtech, 17 May 2014 - 05:09 PM.

#83 Elmtech


    Passed Test

  • Traders
  • PipPip
  • 30 posts

Posted 31 May 2014 - 12:41 PM

Time for another update :shades:


We were going to have the valve seats machined to finally get them to seal properly. As we removed the valves we could easily see that most of the valves had been leaking slightly and particularly one exhaust valve had been leaking a lot where the valve seat surrounding had originally been "damaged" during the machining process. We'd have to have the valve seat removed and then weld the head around the seat to get it fixed. Instead of doing that we decided to machine a new head :lol: .




New head and old head next to each other. Valves seats+guides and all freeze plugs installed. They are close to identical with only some minor changes here and there. Of the ports only the center exhaust ports were reshaped a bit and made larger by moving the pushrod holes to give more room.




On the old head the (thicker) splitter plate was still in place but was slightly deformed. We made the groove for the plate deeper now to allow the plate to thermally expand as it gets quite hot. We also cnc machined all of the valve guides as can be seen in the pic above so that they precisely match the ports and don't hinder the flow as much.




Combustion chamber with valve seats machined in place. We were hoping we'd get them leak-free by doing some precise probing and a few other tweaks, but it seems the guides are just too short to stay straight when they're pressed in...as a result they're not good yet so we'll have them machined on Monday, this time we won't be doing any hand lapping ourselves.




On the old head you can see that weird adapter piece for the water temp sensor. This was fixed in the new head by directly milling some m18x1.5 threads into the head






New center exhaust adapter to fit the new port shapes/sizes.


Hopefully we'll at least have some data logging results next week, should be interesting.

#84 yeti21586


    He's A Lumberjack And He's OK

  • TMF+ Member
  • PipPipPipPipPipPipPipPipPip
  • 3,714 posts
  • Name: Chris
  • Location: Hampshire
  • Local Club: None

Posted 31 May 2014 - 02:40 PM

but this is still only a 7port as on the head youve got 4 inlet and 3 exhaust, having said that im very impressed by it and would love one!!!!





#85 Dusky


    Crazy About Mini's

  • Members
  • PipPipPipPipPipPipPipPipPipPip
  • 5,322 posts
  • Location: Belgium

Posted 08 November 2014 - 04:36 PM

Any news? :)

#86 ministar


    you ate the whole wheel of cheese?

  • Members
  • PipPipPipPipPipPipPip
  • 835 posts
  • Location: Derby

Posted 14 January 2022 - 12:19 PM

I know this is a massive thread revival, but check out what these guys are up to now….


Youtube Elmer Racing



1 user(s) are reading this topic

0 members, 1 guests, 0 anonymous users