Engine tune-up? Where to start? So many questions... (long)

Post by **bigginger** » Thu Aug 24, 2006 5:43 pm

There was me thinking that I was the only person who was annoyed by this...

Post by **Packedup** » Thu Aug 24, 2006 6:31 pm

Stig28 wrote:The first ebay one isn't an MG Metro one, it's an aftermarket manifold. As far as I know, the MG Metro manifold only takes HIF carbs, not HS carbs. It's definitely got four studs in a square. An aftermarket one may well take either so worth asking the seller to measure stud spacing for you. FYI the HIF is an eighties carb whereas the HF is of sixties vintage.

The diagonals are the same, so you can fit an HS4, HIF 38, HIF 44 (don't know about 2" carbs, never wanted to go that big!). There might be a problem of the upper unsed stud fouling something if I recall, but it's not exactly tricky to wind it out

The aftermarket one could well be based on the MG Metro one, I have a feeling quite a few are. Which isn't to say it's a bad one at all, though if you've got a servo (which I couldn't quite tell from the pic I remember) then it's not a lot of use unless you then want to mess around drilling and tapping a hole in it...

The turbo one is hateful for a NA engine as far as I know. It's very "log" like, so poor for flow. Of course, a turbo engine doesn't need to worry about making sure the path is as free as possible for normal atmospheric pressure to fill the cylinders!

You can leave the water pipes unconnected, mine are plumbed into the heater return. Water heating improves economy but might reduce power slightly though nothing like as much as using direct exhaust heat.

Indeed. It'll help prevent fuel condensing on the walls, and improve warm up times a little, but for ultimate power it's slightly better to leave it unplumbed. I personally think the minor advantage economy wise isn't worth the effort of plumbing it all in, just as others may think the untidyness of leaving it unplumbed is worse than the miniscule power hit connecting it up

Post by **Kevin** » Fri Aug 25, 2006 8:36 am

I guess I have to make sure I get one that the HS4 carb will fit on? There are some that have four studs in a square, whereas my carb has two bolts diagonally opposite eachother.

They will both fit the diagonal fitting is across the square what you need to do it get the right size for the carb its no good fitting an 1 3/4" onto an 1 1/2" manifold as the throat will have to be opened out, but as mentioned before the MG Metro one is a good all rounder and is designed for an 1 3/4" but a 1 1/2" will fit.
http://cgi.ebay.co.uk/MG-Metro-Inlet-Ma ... dZViewItem

Post by **dunketh** » Fri Aug 25, 2006 1:29 pm

Has anyone tried the trick in the club manual of (carefully) hacksawing a small gap between the inlet and exhaust parts of the manifold- thus making the induction gasses slightly cooler and therefore denser, therefore more power? Does this actually work??

This seams a bit pointless and very hard to do.
Might as well hack it right off and fit another inlet from something else.

If anyone wants a pre-hacked minor manifold I have one with the inlet chopped off you can have for postage.
Unfortunately its for an HS2 not 4.

Post by **bmcecosse** » Fri Aug 25, 2006 2:24 pm

Yes - avoid the turbo manifold - it's useless for a normally aspirated engine. The aftermarket MG copies are all much of a muchness - if the price is right go for it. If fitting a 2 diagonal bolt carb on the 4 bolt flange - you may need to make a little blanking plate to make sure air doesn't leak in at the unbolted corners.

Post by **pskipper** » Thu Aug 31, 2006 10:14 am

This seams a bit pointless and very hard to do.
Might as well hack it right off and fit another inlet from something else.

If anyone wants a pre-hacked minor manifold I have one with the inlet chopped off you can have for postage.
Unfortunately its for an HS2 not 4.

Hi Dunketh,

Is it the exhaust part? I've tried pm'ing you about this but the messages are just sitting in my outbox

If it is then I'm interested (don't want to loose the farty exhaust note

).

Philip

Post by **dunketh** » Thu Aug 31, 2006 1:53 pm

PM'd you back.
I can only get on here at luncthime, at work.

Don't have a computer at home besides a dusty un-used Xbox that someone gave me.

I've now fitted a mini manifold with HS4 carby and standard mog exhaust - and it still farts. Just a little deeper and not as sweetly.

(I've just re-read my original posting... how can an exhaust manifold be carb specific? Doh.. must have been an off day...

)