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18E head on X20XEV

2K views 19 replies 4 participants last post by  Astrona 
#1 ·
Oh, my X20XEV toothed belt broke down, and the worst happened - it didn't start after replacing the belt. Hopefully pistons are ok.

I don't have recources to repair the head nor buy a new one.
I have spare 18E head with manifold and injection system for my other car.
I have a plan to use this head on XEV.
I haven't found anything about this conversion yet.
I have an intrest for this project :)
For the budget (i will sell simtec 56.5 injection parts, manifolds, camshafts)

A bit crazy, but is it?

What would be the biggest restriction on my way?

I've thought through almost all parts.

The xev would have
* 18E head
* 18E manifolds
* LE2-Jetronic
* 18E alternator
* 18E ignition sys

The biggest problem would be compression ratio. Can you calculate/predict it for me? I have 2 cyl-heads 1mm skimmed and 2mm skimmed (10.4:1 & 12:1 on 1.8L). 10.4 head would have 11.6:1 if the 2.0L block has the same piston top etc. But i've heard, that 20XE-pistons raise CR compared to 20NE up to 1:1. Therefore CR would be 12.5:1.
What to do? Enlarge 18E combustion chamber? skim pistons :mad:? 2 gaskets?


18E + X20XEV = 20YEP :p

Thank you.
 
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#4 ·
Rob@RSC said:
comp too high
see tomstickland as to how much he had machined off his 16v pistons, he used the 20se head
Actually the only information about these pistons & CR is already from his site.

But what about XEV (not XE) pistons. XEV's CR = 10.8:1 not 10.5:1. Is this additional pressure aslo related to pistons crown?
 
#6 · (Edited)
Dav1d said:
If the valves are bent, I dont think the pistons wont be too healthy either.
The x20xev has outputs for the inlet manifold switchover+ other stuff. You'll need to find a way rounnd that too, unless you're not using the x20xev ecu ?
I know a guy who had almost the same accident. The Only broken things were 2 exchaust valves & 2 valve guides (not pistons).

I won't be using this "8-runner-manifold".

Manifold, TB, fuelrails, fuel-pressure-regulator, ECU, injectors & all sensors would be from 18E Jetronic.
I think these yellow injectors are ok, if i raise the pressure. They produced 133bhp on my tuned 18E @2.5bar.

This conversion is more like XEV-block to 18E engine :) but with A/C, powersteering,transmisson and stuff.
 
#7 ·
Rob@RSC said:
yeah probably a little
OK.

I can machine this comb.chambers up to 6cc biger (each one) - which is more than 10% decrease in CR.

If i accomplish CR 11.3:1 with some mods for example, is it ok? I ask because i wont be using ignition system with knock sensor anymore :(, but mechanically adjustable distributor.
 
#9 ·
Rob@RSC said:
not ok no
unless you run methanol... lmao
But i raised my 18E engines CR without a problem from 9.5 to 10.4:1.
I know a Corsa wich has c20xe witrh CR 14:1, but it wont run without toluen or similar additives. He only runs dragstirps (ET <14sec). But i will drive this car every day.

11 is the magic number?

Actually methanol is not the case. I wan't to run relatively cheap.
although technicalSpirit (ethanol) is here only 1pound per half a litre :D
 
#10 ·
eats hoses tho
i ran 10.summat:1 on an 18e, had to run high fuel pressure and additives to stop pinking
14.1 would see the pistons clear through the head...that been calculated correctly? 12:1 is about the highest you can ever go and thats not a pump fuel engine imo
 
#11 ·
Rob@RSC said:
eats hoses tho
i ran 10.summat:1 on an 18e, had to run high fuel pressure and additives to stop pinking
14.1 would see the pistons clear through the head...that been calculated correctly? 12:1 is about the highest you can ever go and thats not a pump fuel engine imo
Couldn't you get rid of pinking by adjusting the ignition?
It's funny, because i've heard pinking only once, and that were, when dizzy's spring got loose.

I don't know about that Corsa much. Sry.
Isnt the height of the comb.chamb. ca. 8-9mm so you can raise CR a lot more :D
 
#14 ·
It can't be that bad.
If it runs ok with std 10.8:1 it must withstand some higher CR too.
I know this hi CR was possible also thanks to the XEV c.chamber but....

Isn't 10.8:1 @ -30C like 11.9:1 @ +20C? Because if power made in these conditions is equal, then peak pressure etc must be alike also.
hmm
 
#15 ·
j1400 said:
I know the 20XEV pistons aren't as dished as the 20XE items, so you'd probably be looking at a even higher C:R,
Now i see why this isn't so popular conversion :D

Do i have to measure some how the chamber sizes to be sure? combustion chamber is the only thing i'm going to change, when watch from cylinder.
i replaced the head gasket a year ago, but can't remember how small that chamber was.

if 20NE head + c20xe block = 11.5:1
then 20NE head + x20xev <= 11.5 + (10.8-10.5) = 11.8:1

18E + X20XEV = 11.8/1.8x2.0 = 13.1:1 actually it's wrong.
Do you know the CR of 18E head on 20NE block? Then we can calculate.
 
#16 ·
OK the CR will be the problem. So what to do?
Enlarge 18E combustion chamber? (-10%)
how absurd is "2 gaskets" "idea"? (-13%)

If the CR would be 13.1:1 i could lower it with these 2 steps to 10.3:1 already, so the problem would be solved.
 
#17 ·
comb chamber is quite big already, i concentrated on port and throat with mine, didnt manage to do much with the valve area tbh
2 gaskets, always better with 1 custom thick one, but yeah of course
or rebore and fit 20ne pistons? standard ne cr is 9.5:1 iirc, summat like that anyway
 
#18 ·
Rob@RSC said:
comb chamber is quite big already, i concentrated on port and throat with mine, didnt manage to do much with the valve area tbh
2 gaskets, always better with 1 custom thick one, but yeah of course
or rebore and fit 20ne pistons? standard ne cr is 9.5:1 iirc, summat like that anyway
I've tried my first and olny porting also on that head.
http://web.starman.ee/slyy/1968/2004Sept/comb_camb2.jpg
It needed a bit smoothing of corners and valvethroats.
It isn't round. So why not make it round.

I've heard about custom gaskets, but i think it will be also pretty expensive.
Wasn't NE 9.2:1 :)

I think reboring & replacing the piston is a bit overkill at the moment.
Maybe skimming the piston is a bit realistic.

Does 18E block fit between Astras F's X20XEV engine mounts?
 
#20 ·
Rob@RSC said:
well, use a 20ne block?
all big blocks have same fittings on them
nice work by the way, looks good
gaskets probably 80-100 quid, but reusable
I think 20NE & 18E has the same fittings.
But my year 1997 xev has "new block" or smtg. It curved walls, A/C and powersteering fittings on block, which 18E doesn't have. Also dipstick has different place. 20NE wont help.

I've fitted FWD 18E inplace of RWD Kadett B 1.1L using Rekord 18S mountings transmission, dizzy and stuff - but this Astra actuallly isnt my big project, althogh i've got 100km/h in 8.1sec - pretty good for family Caravan. but its also my everyday ride - so i want to keep it cheap and simple.
So the block must stay.
My headwork looks nice (80 roller grit @2800RPM does it), but i havent tried it yet. I think it needs new seat angles to be got, because of rough handling of drill :p. I also skimmed it maybe too much (2mm).


80 quid is too expensive - but it may be a lot cheaper here in Estonia.

One option is to use C20XE head is out of budget, althogh it's cheaper than repairing or buying the ECO head.
My friend bought a good used 2.5V6 engine 320£, i'm not willing to pay even third of that. :p to get mine runnnnning.
 
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