Vauxhall 8v seh/ne engine knowledge needed...

[rust4life]

Hi All,
I've just landed myself a 2.0 8v Vauxhall engine out of the 'bay which I'm guessing came out of a Frontera judging by the amount of mud it's caked in!
It's going in my Chevette which already has Manta 1.8 donor parts - engine, sump, 'box and rear axle etc.
I was just wondering if anyone knows much about these SEH/NE 8v engines?
Are the 1.8 and 2.0 engines basically the same except bore size or are there differences in the head - port sizes, valve sizes, cams etc?

I'm thinking 1.8 head on the 2.0 block might work? Will eventually run on twin 40s to keep it old school but any tuning/rebuilding tips for these engines would be much appreciated. The 2.0 only cost me a tenner so I cant really complain that the cam is a little worn and the valves look like charcoal briquettes can I?

[DavidB]

Is it an SEH or an NE? I'm pretty sure the heads will swap - the only problem is the oilways in the head/block being different, but I think you'll be OK. The NE and the XE (16v) share the same block, so you can use the XE head on an NE block. Do you want power or cheapness - have you thought about using a Saab B204R turbo out of a 900/9-3? You can get them for £150 and have 250bhp for an extra £50. I'd honestly stick to the 8v, they're under-rated and go on forever.
You've already made a good start having all the bits to convert it to RWD though.

[Mantasport]

The 1.8 and 2.0 are physically the same size/fit, but there are a several differences.
The inlet manifold flange is different for the injection and carb heads, because they actually changed the head and moved the inlet ports in the up to get a better flow for improved torque and better flow.
Internally they have larger valves, a completely different profile cam suited for injection, the cam carrier is different as it has the dizzy at the rear, there are different pistons that change the compression ratio, and a crank sensor through the side of the block to a crank that has a sensor ring on it.
Your current exhaust manifold will fit though as they didn't change the exhaust side of the head.

You can mix the heads around to a degree apparently but i have not done the 1.8 onto 2.0 setup myself.
If you use the 1.8 dizzy mount at the front of the cam you need to block the oil way and dizzy at the rear of the head, or just use the 1.8 cam carrier and a cam without the dizzy drive in it.

The SEH (130bhp) compared to the NE (115bhp) has different pistons to raise compression, a different cam and different ECU
Both pistons have bowls in them the SEH just has a smaller one giving a 10-1 ratio rather than 9.2-1 (or something like that) on the NE.
To get more power you can also fit the pistons from the later X20XEV ecotec engine which are flat topped (with 4 small valve cut outs) to increase the compression further, and if you retain the injection the later XEV injectors fit and give a better spray pattern.

If you go to carbs you really need a non injection camshaft to get them to work well, injection cams normally have less lift but a longer duration than carbs need. So if you can find one a good aftermarket cam for the 1.8/2.0 designed for carbs would be ideal for 40's. You can run them on the manta cam but its a very mild thing.

Depending on what your £10 engine needs to rebuild it you could get to a fare amount of cash. A new oil pump last time i got one was around £100, shells weren't bad nor piston rings but add a gasket set, head bolts and other assorted bits and you're getting quite a larger parts bill. Depending on how far you go
If you also factor in a set of 40's and manifold you're looking at quite a bit of money for a reasonable power output, at a guess a 2.0 SEH with 40's should be around 135bhp with a good cam and maybe a hike in compression it could make around 145-150bhp (ish) but will be a little lumpy to drive.

The other option and the one i would go for all day long is just buy an C20XE instead, £300 on a good engine and £150 on an exhaust manifold and you'll have 150bhp with a very driveable engine that runs smooth and has more than enough go for anything you want to do.
It also bolts directly in with the parts you already have, just get a late Dispack version without a dizzy. 6 wires to connect and run the standard injection.

I've run a standard SEH, a SEH with a piper cam, a SEH with XEV pistons and injectors, and XE's in mantas and would have the XE engined cars all day long.
Far nicer to drive around, better torque and power delivery reliable running and plenty of performance

[rust4life]

Now that's the kind of in depth knowledge I would expect on this fine forum - thank you gentlemen!

So to recap...
The 2.0 has larger valves than the 1.8 and different inlet port positions?

My 2.0 ebay special is an NE whereas the Manta 1.8 is an SEH so I will have a look at the inlet manifold I already have for the twin carbs and see which head it fits, as that will decide things to a certain extent.
Sounds daft but I really want to keep it old school as I've never had a car with twin 40s and I just think they'll look sweet in the Chevette's engine bay!
That said, I'm not going to shell out vast amounts of cash I don't have on the 20ne when I know the Manta engine is healthy (ignoring the kippered GM Varajet carb) so next step will be to drop the bottom end out and have a look at the crank etc.

Am I right in thinking that I can swap the cam and carrier from the SEH onto the NE, giving me a carb friendly cam and front mounted dizzy setup?
*starts scouring ebay for performance cams...*

[`state]

Its all getting abit confusing so..
The 20ne and 20seh blocks and heads are the same,identical. The seh has different pistons,cam and ecu. The manta engine is an 18s. The 18s has bigger inlet valves and different port spacing as mantasport says.
I don't think id change the 1.8 to a 2.0 unless its knackered. The 1.8 is a shorter stroke so revs alittle quicker and ive never found much difference between them. But you`ll probably get best results using the ne bottom end with the 1.8 head with the carbs bolted on.Sort of best of both worlds.
Ive always put either ecotec or 20xe pistons in my 8v engines and it makes a big difference with the higher cr and asset of pistons can be had for around 40 quid.

[Mantasport]

Your current manta engine isn't a SEH that designation is only for the higher compression 2.0 injection engine with 130bhp
The manta engine has a 9.2-1 compression ratio (same as the 20NE) and in standard original fettle gives 90bhp, well when it was new it did.

As you already have an inlet manifold check which head it lines up to and go from there.
It really depends if you're just after the look, or if you also want loads of power from it.
For looks run as much of the 1.8 engine as you can with whichever head the manifold fits, and the 1.8 cam and carrier and dizzy. For twin 40's you'll need to fit an electric fuel pump as the mechanical one on the engine won't keep up.

For more power use the 2.0 bottom end with XE or Ecotec pistons to raise the compression, whichever head fits the manifold, a performance cam (for carbs) the 1.8 cam carrier and dizzy and your 40's. You may also need the dizzy modifying to remove the vac advance, and will need a session on a rolling road to get it setup right.

Of course if you're manifold fits the 1.8 then just fit 40's and an electric fuel pump and you never have to actually take the engine apart.
If it fits the 2.0 head you could always sell it and buy one for the 1.8

Oh and just to throw another idea at you, rather than 40's how about bike carbs, now they are old school

[Deleted]

if its from a frontera its likly to be either a 2.0ne or a c2.0se the 2.0seh wasnt fitted to frontera's

[rust4life]

Decisions, decisions...
The inlet manifold has the answer - well one answer anyway...

TO THE WORKSHOP!!!

[sal]

Sorry to drag up an old thread but some if the above is relevant to what I'm doing at the moment.

I have an 18e fitted in my mk2 cavalier that is causing me a real headache with electrical faults in the injection system. I also have a spare16sh with carb from another mk2 cavalier that I broke and the engine runs great as i done head gasket etc whilst still in car.

So I was intending fitting carb onto the 18e in place of injection. I checked mechanical fuel pump would operate from 18e cam and it appears to do so but from the above will this injection cam cause running issues? Would I be better with the 1.6 cam transferred or just fit the 1.6 engine as it should bolt straight in?

Apologies again if I should have started new thread but thought info already here was relevant.

Thanks

[usedabused]

I don't know a great deal about these engines put I do have a complete cam kit for one brand new still in the box......

[roscocav]

i ran 1.8 bottom end with 1.8 head 1.6 cam carrier, fuel pump and cam in my mk2 cav. All on the varajet carb, went bloody well. What issues are you having with the 1.8?

[sal]

Thanks rosco so you used the cam box and cam from the 1600 engine along with the varajet? I hadn't actually thought of doing that. I was going to keep the 1800 cam and box and just bolt pump and manifold on until I read this.

It's been blowing fuel pump relays. 3 have gone after 10 mins running in workshop. Guys on mk2 cav have pointed me to check looms injectors ecu etc which I have checked and can't find fault. Also been suggested it could be something going low resistance when warmed up but Cant get it to run that long lol.

I don't want to change anything that I can't undo later but need the car running for ease of working on it.

[sal]

Dec 20, 2013 22:27:53 GMT usedabused said:

I don't know a great deal about these engines put I do have a complete cam kit for one brand new still in the box......

I'll let you know if I need this but I hopefully have all the parts I require at hand.

Thanks

[roscocav]

i think i might have some wiring diagrams that will assist you in a bit of fault finding. 1.8 on injection is much better then either 16sh or 1.8 running carb

EDIT: sorry not got them any more, will have a think

[roscocav]

Have you checked the wire from the relay to the pump? if this shorts that will blow the relay, also check you've got the right fuse in the fuse box as this can also blow it.

[sal]

I've checked the wiring that's visible and all appears good. I need to weld sills on so when I strip the interior for this I'll check the loom that runs along the inner sill for any problems.

[`state]

Have you changed the actual pump? I had a mk3 astra with the 20se engine in that kept blowing fuses and then the relay. After much head scratching a mate suggested the pump and low and behold it was that. It was on its last legs so got really hot after acouple of minutes then seized up so tried to draw more power hence blowing the fuse and relay. Once cooled it would work ok again for afew minutes.

[Mantasport]

Do you know what part of the fuel pump relay is blowing? It has a couple of functions.

If its the fuel pump output that's going then most likely is a faulty fuel pump or wiring, rather than anything in the engine/loom
Easy way to check, pull the power wire off the fuel pump (and wrap it for safety) run a new wire with a fuse from the battery to the pump and start the car
If the fuse blows your issue is at the pump, if it doesn't and the relay is also ok then its most likely the wiring from relay to pump

So if its the fuse it could be the pump or the earth wire to the shell, so check/change the earth and try again. If it still blows the fuse get a replacement pump

If the pump doesn't blow the fuse but the relay still dies you need to dig into the loom and look for breaks, or change the loom.

[steveg]

It sounds like you have a similar selection of junk to me ! I fitted a 1.6 seh engine in my Astra. I have various bits off a 1.8 Astra engine kicking about still as well.
I was going to fit the 1.6 inlet manifold and Weber carb onto the 1.8 engine but when I stripped it down I found it was full of bits of broken cam cover and not very happy.
I've still got the head, ECU and a few other bits and some of the engine loom I think. If any of it is of use let me know.
Hopefully you can sort the electrical problem out as fitting a carb ends up getting a bit involved as you have to sort out the fuel pressure and ignition to get it running.

[sal]

Thanks for all the advice it's greatly appreciated

Long term I'll get the injection sorted but carb was a means of getting it mobile whilst I work on it. It needs a fair bit of welding and full respray so it isn't going to be a quick turnaround. Having read the replies here I think I'll leave the idea of carbing the 1.8 engine. There's probably easier ways if I really need to move the car.

Steve. Yes I do have a few bits lying around lol. Thanks for offer I'll be in touch if I need anything after I get a chance to dig a bit deeper if that's ok?