29 replies to this topic

[leepol83]

Hi
Ive got a thread running which is getting massive so starting a fresh one so hopefully will get some more help with it 👍🏻
Currently trying to seal up my exhaust manifold on the inlet part, I’ve a 1998 mpi with an LCB manifold which I think is the issue as it was fine before I fitted that, I’ve tried a number of gaskets from genuine rover mpi ones to cheap £3.00 ones from eBay with not a lot of change, don’t get me wrong getting a little better each time, I’m looking for advice on tried and tested methods to seal it up and believe me before anyone says it I’ve searched 😂😉 this has to be a common issue as I’ve found loads of people struggling with it, but the answer is always just put a gasket on 🤷‍♂️
Would really appreciate any helpful advice and greatly appreciate all the help in my other thread aswell so thank you for that
Cheers chaps look forward to some ideas 👌🏻👍🏻
Ow and I’ve checked the depth of the flanges and the exhaust flange is a tiny bit thinner and I mean like 0.5mm if that so not a million miles off
Thanks again in advance

[Midas Mk1]

Have you checked the flanges for squareness? I kept blowing manifold gaskets (all high end, swiftune, med), my lcb flanges were warped.

Decent genuine maniflow lcb and the difference was night and day

[leepol83]

Have you checked the flanges for squareness? I kept blowing manifold gaskets (all high end, swiftune, med), my lcb flanges were warped.

Decent genuine maniflow lcb and the difference was night and day

Checked they look good it’s from Minispares (Maniflow) so should be good, the exhaust out isn’t leaking, it’s leaking on the inlet side, sprayed around with brake cleaner and revs up when sprayed on the inlet
Thank you

Edited by leepol83, 03 January 2021 - 07:29 PM.

[leepol83]

Anyone used these days there 1mm thick ?
https://www.ebay.co....tm/283647635349

[Tones61]

You will prob need a big port gasket,
I had an issue on mine where the original mpi gasket in not wide/depth enough to reach the lcb flange

[leepol83]

You will prob need a big port gasket,
I had an issue on mine where the original mpi gasket in not wide/depth enough to reach the lcb flange

R right ok which gasket did you use ?
Thank you

Edited by leepol83, 04 January 2021 - 08:57 PM.

[Tones61]

Any big port one,I used the thick grey soft type as appossed to the foil/silver dotted one

[MiniMadRacer]

Are the Flanges for the Inlet Manifold and Exhaust Manifold the same thickness? I am thinking the clamping force is not sufficent across both manifolds if they are different thicknesses

[GraemeC]

You will prob need a big port gasket,
I had an issue on mine where the original mpi gasket in not wide/depth enough to reach the lcb flange

 

Not likely the issue if it is the inlet side leaking.  I have had a head ported so much a standard inlet manifold didn't actually cover the inlet ports though!

 

 

In fact from what's described I doubt it is the gasket at all and the thicker one linked to is unlikely to improve things.

 

If the exhaust manifold flanges are slightly thinner than the inlet manifold then I'd expect the inlet to seal up.  Is there anything that is prevent the inlet manifold seating properly - such as the bottom of the injection unit fouling on something that is holding it up?  Do you have port rings in place that aren't seating properly?

[leepol83]

You will prob need a big port gasket,
I had an issue on mine where the original mpi gasket in not wide/depth enough to reach the lcb flange

Not likely the issue if it is the inlet side leaking. I have had a head ported so much a standard inlet manifold didn't actually cover the inlet ports though!


In fact from what's described I doubt it is the gasket at all and the thicker one linked to is unlikely to improve things.

If the exhaust manifold flanges are slightly thinner than the inlet manifold then I'd expect the inlet to seal up. Is there anything that is prevent the inlet manifold seating properly - such as the bottom of the injection unit fouling on something that is holding it up? Do you have port rings in place that aren't seating properly?

Exactly my thought it looks like it’s pulling up nicely all even and square, I’ve got the rings in place and sealed up properly, just makes no sense

[leepol83]

Can I do a smoke test on it ?
How do you do it ?
Thanks

[GraemeC]

Are the rings allowing the manifold to tighten against the head face though - if they are too proud they'll hold it off slightly (this is where a thicker manifold might help).

 

I don't think a smoke test would be east to do.  I would be tempted to remove all the carb/injection stuff from the manifold and bolt it up on its own to see if I could see the issue.

But I would really check that nothing from the inlet side is sitting hard on the centre branch of the exhaust manifold.

[leepol83]

Are the rings allowing the manifold to tighten against the head face though - if they are too proud they'll hold it off slightly (this is where a thicker manifold might help).

I don't think a smoke test would be east to do. I would be tempted to remove all the carb/injection stuff from the manifold and bolt it up on its own to see if I could see the issue.
But I would really check that nothing from the inlet side is sitting hard on the centre branch of the exhaust manifold.

I did check the rings and they go in far enough, I did grind the rings down abit just incase but still the same, only thing I’ve noticed is on the inlet manifold faces if I put a stair edge across them it’s not flat on both of them it’s almost dished down to the hole, but does seem exactly the same in both ports and looks factory? 🤷‍♂️

[Tones61]

I also had to file mine flat at they were bent on the faces on inlet manifold flanges ,
Easy to do,just plug all holes with cloth

[leepol83]

I also had to file mine flat at they were bent on the faces on inlet manifold flanges ,
Easy to do,just plug all holes with cloth

Ok that makes sense bassi assuming they should be flat then ?
How did you file it what did you use ?
Thank you 🙏


On another note if I was to use a little weaker in it just to be sure would this be ok ?
https://www.ebay.co....tm/392984516181
I’ve also ordered a updated turbo gasket not cheap but hopefully good 👌🏻

Edited by leepol83, 07 January 2021 - 10:34 PM.