XU10 2.0T inlet valves in 1.9 8v head

[DamirGTI 340]

Building another 1.9 8v engine for my daily 205 , and thinking about fitting XU10 2.0T inlet valves as i have two sets collecting dust !

 

Anyone tried and if so is it worth going larger than stock inlet valves ? (head will be ported , multi angle seats etc.)

 

D

[welshpug 1,644]

Are they not shorter than standard xu9ja valves?   More like low comp xu9 where the chamber is taller?

 

I cannot say for definite, but I doubt they will make much difference on their own in the 83mm bore as you are putting the valves closer to the side of the chamber, in effect actually shrouding them more not less.

[petert 577]

I’ve just fitted a set into that rare Grp A head I’ve been building. No big deal, other than you need to use XU10 collets & retainers. Obviously need to check seat pressure etc.

 

They’d definitely flow more on an 86mm bore but I’m sure Mattsav has posted flow figures in the past for this mod.

Edited July 10 by petert

[DamirGTI 340]

On 7/10/2024 at 1:50 PM, welshpug said:

Are they not shorter than standard xu9ja valves?   More like low comp xu9 where the chamber is taller?

 

No , they're the same length wise as 1.9 valves ! as Peter said only twin groove on the stem for the collets .

 

D

[DamirGTI 340]

23 hours ago, petert said:

I’ve just fitted a set into that rare Grp A head I’ve been building. No big deal, other than you need to use XU10 collets & retainers. Obviously need to check seat pressure etc.

 

They’d definitely flow more on an 86mm bore but I’m sure Mattsav has posted flow figures in the past for this mod.

 

Hmm , so what do you recon Peter ? worthwhile venture/endeavor or better keeping stock size 1.9 valves ? 

 

I can see shrouding potentially problematic and not much "meat" to work with for unshrouding , very little on the edge of the chambers to open up but liner dia. does seem problematic .

 

I remember , late mr. Guy Croft also experimented with variety of valve sizes and found flow bench tested stock size to be best but "penny on a stick" shaped , i believe PTS sport/race valves or something like so .

 

D

[petert 577]

I’ll take some pics next week for you. Sorry, can’t do until late next week. I found the flow charts. I suspect Matt sent them directly to me. Theydidn’t have XU10 valves in XU9 head. They were comparisons of stock & ported heads. 
 

Really important are the XU10J2 retainers. Collet position is very different.

Edited July 12 by petert

[petert 577]

I found some pics:

1. Seats cut in Grp A head for XU10 valves

2. Differences in collet positions between Catcam, XU9 and XU10 retainers. You can see the difference in collet position.

 

[DamirGTI 340]

See i really haven't spotted that difference in collets depth , thanks for a heads up !

 

Fancy sharing some pictures of that Grp A head , aka port shapes ? really curious what's been done to that head with regards to the ports .

 

Thanks !

D

[petert 577]

On 7/15/2024 at 9:00 PM, DamirGTI said:

Fancy sharing some pictures of that Grp A head , aka port shapes ? really curious what's been done to that head with regards to the ports .

Sorry, it's a bit hard to show port shapes with the valves in. Here is one of the chamber with the XU10J2 valves. They are very close, but you can see where the chamber has been unshrouded a little on both inlet and exhaust.

[DamirGTI 340]

Kind of what i had in mind too , there's very little space till the HG fire rings but still there is "some" for unmasking the valves on the sides .

 

Understood !

 

Anyhow without the flowbench , i can't venture too deep into porting aka making some serious reshaping .

Will stick to what was good till now on the heads i've done so far .

 

One more curiosity i remember , adding material in the inlet port might be interesting to try out on these XU heads .. GC did some testing by putting deflector on the inlet port floor entry (bare port no valve)  and found/measured that the inlet flow increased and quite a bit % wise , but some of that flow gain % was reduced with the valve fitted .

 

D

[petert 577]

Adding material (epoxy) to the port floor is popular with older American V8 heads. I'm told it increases velocity but lowers port volume and rarely stays in place. Speier Racing Heads do it a lot. Plenty of pics on FB.

Edited July 30 by petert

[DamirGTI 340]

Yeah , i did that once on a BMW M54 head .

 

It was necessity after porting/reshaping bowls as the OE bowl shape on that head is horrendous (both inlet and exhaust) !! and a lot of work was needed after which the wall thickness to the coolant galleries became pretty thin on certain areas potentially prone to cracking , so had to fill with epoxy and reshape again leaving just an small skim of epoxy . Clear coating the epoxy on the end . 

 

So far i know that engine/head still works to this day ! .. but i agree , i'd rather fill with weld or something more "stable" though there's very good epoxy like Belzona but costs quite a bit $$ and usually packed in larger containers for industrial use . 

 

The stuff with which GC was experimenting was more like "swirl flap" on modern engines , basically an piece of plastic or aluminum cut with the chamfered edges and placed on the inlet port entry where the gasket goes , just a little bit higher from the port floor aimed to shift the air up towards the bowl area .

Will see if i can find some pictures (unsure as it was long time ago ..)

 

D