My C20LET conversion thread

[Mieran]

Update post #38






Instead of making lots of separate threads I thought it would be better to keep all questions in one place.

I will update as I progress.

1- What fuel pump? My car had a XE and an external GM pump, no idea what its capable of.

I was thinking Walbro 255 (http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=160328270282&ssPageName=STRK:MEWAX:IT)?

2- The engine is running 291 BHP (apparently), is this intercooler good enough? LINK (http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=250666981582&ssPageName=STRK:MEWAX:IT)

3- I'm using F28 with flat type flywheel, I done some research and people are saying I need F28 clutch plate and F20 pressure plate. So I'm going to to buy a new F28 clutch kit and a second hand pressure plate, is this a good idea?

One more thing, what clutch do you recommend?

4- I might get a LSD for the box, is there anything recommend to change other than the oil? And what oil should I be using?

[blue_peg_16v]

Instead of making lots of separate threads I thought it would be better to keep all questions in one place.

I will update as I progress.

1- What fuel pump? My car had a XE and an external GM pump, no idea what its capable of.

I was thinking Walbro 255 (http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=160328270282&ssPageName=STRK:MEWAX:IT)?

2- The engine is running 291 BHP (apparently), is this intercooler good enough? LINK (http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=250666981582&ssPageName=STRK:MEWAX:IT)

3- I'm using F28 with flat type flywheel, I done some research and people are saying I need F28 clutch plate and F20 pressure plate. So I'm going to to buy a new F28 clutch kit and a second hand pressure plate, is this a good idea?

One more thing, what clutch do you recommend?

4- I might get a LSD for the box, is there anything recommend to change other than the oil? And what oil should I be using?
1. good pump its what i run and im around the same figures
2. yup that will be biggenough as long as your not upping the power much more
3. cant use the flat fly with f28, f20 plate will not fit f28 box you need a pot fly wheel and full turbo clutch or an aftermerket lightened version of the pot fly wheel
4. sprip the box fully when fitting to check the syncros there still available and you will be peedoff if you get it all in and it crunches so you have to remove it again, and obviously you will need new diff bearings and id fit new drive shaft seals too

hope that helps

[Mieran]

Thanks for the answers.

But I'm sure people have fitted a flat fly to a F28 before

[blue_peg_16v]

the flat fly is when fitting an let with f20 if the engine is standard you can just get away with an uprated clutch, the imput shaft on a 28 is bigger than a 20 so the f20 plate wont fit,

the odball combo of f28 clutch plate and f20 preasure plate is used with a pot fly when you fit an f20, the f28 clutch plate will not fit a flat fly wheel either, just like late and early xes are not interchangable all lets had a pot fly wheel so the combo you listed will not work trust me

i have the same combo on mine potfly 28 clutch plate and f20 preasure plate with f20 box, got the full 28 clutch with the engine and its way to big for the 20 input so the 28 input is to big for a 20 clutch

the only way you can run a flat is with a silly speck paddle clutch so benefits are out weighed by cost imo

[Mieran]

Hows using a f28 clutch plate on a f20 box possible? Aren't the splines different? :confused:

You might have a clutch kit made for a pot fly to suit a f20, all late coilpack XEs came with pot fly.

[blue_peg_16v]

iv got it the wrong way then i have f28 bit that bolts to fly and f20 clut that goes on the splines

but as i said all lets had pots so the outer f28 bit wont fit a flat like with an xe you cant interchange early and late

i also tryed the flat fly with f20 full clutch and it was useless with phase 3 was fine on standard boost but on full boost car was slower than standard boost due to the amount of slip lol

i sould of gone with my words f20 friction plate f28 cover lol

and an xe cover wont give enough clamping on a flat as i am still using the same f20 bit just now have the 28 cover and pot fly

[blue_peg_16v]

i realy shouldnt drink then try to articulate lol

[Mieran]

Quick question.

What bolts can I use on the crank pulley?

I will be using a single pulley.

[Graeme]

M8x25 cap head x 6 bzp not stainless

[Benn]

I can supply them. In allen key head.

[Mieran]

Cool, cheers.

Benn I will give you a PM if I don't find any locally tomorrow.

Any reason why not SS?

[Benn]

Ss isn't as strong. The ones i have are +8.8 and comer in a finish that's nice and silver.

[Mieran]

I'm having difficulty taking the sump off :confused:

Undone all the bolts but the sump feels like its stuck to the engine, any ideas?

[craig green]

It is stuck, find a scraper & ease it in, do not lever it off with a screwdriver. Risk of bending the sump edge or even cracking it.

Just perservere.

[Mieran]

Couple of questions:

1- anyone got a diagram of turbo coolant pipes and does anyone sell these or have to make your own?

2- what turbo to afm pipe can you use if you don't want to cut and bend the slam panel?

[Benn]

1, yes. Roose make them in Nova fitment.
I was told the front on (pointing at the rad) goes to the small out let on the rad.
The one front the rear/side of the turbo goes to the header tank.


2, if you dont wanna cut the slam panel then you'll need to cut and weld the turbo inlet..

[Mieran]

cheers Benn

£106 for 2 pipes is a bit pricey imo, any other alternative?

[Benn]

That want 50 for the front one i've just ordered.. No where else i've seen do them. Cheaper is to make your own.

[Mieran]

might end up using the standard cav/cali ones and extend them if need be

[Mieran]

Two small issues.

1. In the digram below is says there should be a pipe going from the turbo to rocker cover which also linked to top of amal valve. (pink line)

The 2 breather holes are 15mm diameter and the amal valve is 4mm and I can't find a T-piece with 2 15mm ends and 1 4mm end

So whats the trick there?

http://img.photobucket.com/albums/v321/bennh/Crap/letmotronic.jpg

2. The turbo oil feed is clamped down by a nut but I didn't get that when I bought the engine :mad: and Vauxhall don't sell them no more.

Where can I get one?

[Gareth_C]

Instead of making lots of separate threads I thought it would be better to keep all questions in one place.

I will update as I progress

3- I'm using F28 with flat type flywheel, I done some research and people are saying I need F28 clutch plate and F20 pressure plate. So I'm going to to buy a new F28 clutch kit and a second hand pressure plate, is this a good idea

more questions post #20

I dont think it would make much difference but im running a f28 box on my c20xe. I use a flat billet flywheel, with a helix 4 paddle friction plate and a early c20xe helix pressure plate and i have no problems hope it helps. :thumb:

[Lee H]

F20 pressure plate is not as strong as an F28 one so you may have clutch slipping problems if you are planning on more than standard power.

[lomas]

leave the pipe off that goes from amal to rocker cover or get a straight piece off 15mm pipe and weld a 4mm pipe to the side n drill it

take the thread out of turbo and get a one piece banjo bolt with same thread, go to revolution/ xo/ nut n bolt place in blaydon,

[Mieran]

Cheers :thumb:

Should I leave the top hole on the amal open or blank it off if I don't connect it to the 15mm breather pipe?

[lomas]

leave it open

[Mieran]

Anyone has a diagram for c20let cooling in a Nova?

I found this but its for a XE plus my rear water pipe has 2 exists not just 1

http://img.photobucket.com/albums/v14/lashednova/20plumbingguide.jpg

[Iain]

The solid pipe that goes round the back of the block/head? XEs have two as well, as does the diagram above.

[Mieran]

My engine has one of these on

http://www.txautosport.co.uk/ekmps/shops/jbimotorsport/images/cavalier-calibra-turbo-4x4-stainless-steel-water-bar-%5B2%5D-49-p.jpg

On the diagram it shows one exit

[Lee H]

Diagram shows 2 exits. One to heater matrix and one to header tank.

[Iain]

Diagram is for the different type of solid pipe, which has one outlet on the back and one outlet on the side, as Lee said it is going to the header tank.

[Mieran]

This pipe (circled red) comes from the back of the inlet manifold, whats it for and where does it go?

http://i55.tinypic.com/dlmh5d.jpg

[Mieran]

Been searching and I think I have an idea where everything goes now but correct me if I'm wrong. :thumb:

- Return from rad goes to turbo
- Return from turbo goes to top of header tank
- Rad exit above fan switch goes to thermostat housing
- Pipe that goes behind the engine goes to bottom of rad
- Exit on side of the head goes to bottom of header tank
- That pipe circled above coming from inlet manifold goes to top of header tank (I'm going to t-piece it with return from turbo)
- 2 exits on rear pipe have been joined together because I don't have a matrix

[Mieran]

Can anyone confirm if thats the right order above? ^^^



Also, according to this diagram below it says tank vent valve should be connected to throttle body and active carbon canister.

On my engine the tank vent valve is connected to throttle body but I don't have an active carbon canister so do I leave one end of it open or block it?

http://www.max-boost.co.uk/max-boost/resources/diagrams/LET_motronic.gif

[nova_stee]

Been searching and I think I have an idea where everything goes now but correct me if I'm wrong. :thumb:

- Return from rad goes to turbo
- Return from turbo goes to top of header tank
- Rad exit above fan switch goes to thermostat housing
- Pipe that goes behind the engine goes to bottom of rad
- Exit on side of the head goes to bottom of header tank NO IT GOES TO ONE ONE THE PLASTIC PIPE AT THE REAR
- That pipe circled above coming from inlet manifold goes to top of header tank (I'm going to t-piece it with return from turbo)
- 2 exits on rear pipe have been joined together because I don't have a matrix JOIN ONE OF THEM ON TO THE SIDE OF THE HEAD

[Mieran]

Ok so one of them goes to side of head and other to bottom of header tank?

[Benn]

http://img.photobucket.com/albums/v321/bennh/Crap/letmotronic.jpg

Plug the vent valve in, but dont pipe it up.

[Mieran]

.

[Mieran]

Am I correct in saying, number 1 links to rad and number 2 goes to header tank?

http://oi55.tinypic.com/2zg7uja.jpg

[nova_stee]

yeah the abova is correct.
pipe from side of head goes to matrix other matrix pipe to a outlet on the blck plastic pipe on back of head then last outlet on black plastic pipe to header tank