Fitting Effing manifold......

[malc4d]

Any secrets on how to do it.......

[wilf]

Am in the same boat just now. My manifold came off easily, no sign of tightness or binding. The heads have not been moved.

But it won't go back!


I have:

Helicoiled all threads in the head, taking care to get the drill in at the correct angle.

Drilled the holes in the manifold for the short bolts to 9.5mm

Drilled the holes in the manifold for the long bolts to 10mm.

Trial fitted the manifold without gaskets and checked that all 12 bolts will pull up. They do.

Checked the gap with feeler guages between the mating faces with the bolts in position - was 10 to 12 thou, pretty even all around. So the 60 thou thick "payen" gaskets were simply making the manifold sit high, out of position.

Ordered some "thin" gaskets from Paddocks.

Will apply the thin smear of Tiger Seal around the waterways as per the Rimmers video https://youtu.be/0OId08cslg4 and cross my fingers!

[DMT]

I had the same issue refitting the manifold after removing the water pump rotor. I wasted the cost of payen gaskets too but JUST managed to get a thinner gasket to work.

I read recently this problem is due to the heads being fitted incorrectly. I would assume this means the sequence of fitting the heads and the manifold is critical.

[flying farmer]

The problem is that the gaskets compress as the manifold is tightened down.

The old ones that fitted ok are the thickness the new ones need to be when you start to fit the manifold in order to get the bolts to fit. This is why the thinner ones are often the only way to get the manifold to fit.

Drilling the holes bigger often helps but its still a PITA.

My prefered solution was always to take a few thou off the manifold face using a flat surface and some coarse emery cloth. Time consuming, but it ensured the manifold faces were flat and the angle of the manifold faces could be matched to the angle of the head faces and that meant the coolant stayed inside the engine.

The factory method was to tighten down one head then loosely fit the second head with the manifold loosely fitted between the two. Tightening down the second head ensured the head and manifold faces were aligned and of course all the bolts were already in place.

This doesn't help if both heads are already fitted, and removing one head and fitting a new head gasket just to fit a manifold is further than most want to go.

Neil

[jbuckl]

I had the same issue refitting the manifold after removing the water pump rotor. I wasted the cost of payen gaskets too but JUST managed to get a thinner gasket to work.

I read recently this problem is due to the heads being fitted incorrectly. I would assume this means the sequence of fitting the heads and the manifold is critical.

Yes , they have no traditional alignment.
both heads have to be loose fitted; best at finger tight with wellseal. then the manifold (dry) to pull the heads towards the manifold.
if the heads have been skimmed not parallel to original face now is the time to check gaps / correct.
Then, ideally a sprocket alignment check / shim.
then the heads can be torqued down.
then remove manifold, add pu sealer to manifold gaskets & refit & tighten.
if you haven’t got spare manifold gaskets, it’s a recipe for Murphys law!

[gbb483]

I've not tried this - perhaps the pros could comment - but how about fitting just one gasket (dry) and tighten everything down. Then repeat with just the other gasket. Would this pre-compress the gaskets such that you could then fit them both? Or would it wreck the gaskets?

[jbuckl]

I've not tried this - perhaps the pros could comment - but how about fitting just one gasket (dry) and tighten everything down. Then repeat with just the other gasket. Would this pre-compress the gaskets such that you could then fit them both? Or would it wreck the gaskets?

If you are referring to the head gaskets, thats why I use the wellseal on them.
If you are referring to the manifold gaskets, use the £8 set first, then the pukka ones aka payen. So long as it seals who gives a stuff about the cost of manifold gaskets? As posted in another thread, I keep manifold gaskets in stock … as a guarantee against Murphy’s law!
Anyway if the heads and manifold are all drawn up together before a final tighten , it pays dividends.
Ive worked on rebuilt stag engines (last done by a couple of ‘big name pros’) that have bad head alignment.
We all make mistakes, but that one is tricky to fix afterwards. But pu sealer is your friend

[gbb483]

I'm referring to the manifold gaskets. The problem here is that the heads haven't been moved, so their gaskets aren't a problem.

[jbuckl]

I'm referring to the manifold gaskets. The problem here is that the heads haven't been moved, so their gaskets aren't a problem.

No, but the (incorrectly? Clamped) head position could be.
Making adjustment after the event can be tricky…. That’s why pu sealer can be your friend in that case, along with new bolts, good threads, std, thin or thick manifold gaskets & maybe enlarged manifold bolt holes.
Alternative is an in-depth investigation / operation to achieve better alignment.

[singapore stag]

Thank goodness, I have done this job 3 times and each time it was a ' piece of cake ', and thats on different cars, the one thing I excelled in was the fitting of the manifold. Bet now I will find it a nightmare....sods law.

[alan_thomas]

We all make mistakes, but that one is tricky to fix afterwards. But pu sealer is your friend

Sorry pardon my ignorance but ‘PU seal’ is what?
tried many different sealants over the years, never found one I like and a very slight weep means I’m going to do this loathsome job again - Alan

[Goldstar]

Polyurethane I think Alan

[MandM]

I blued out my manifold as Neil has said. then stuck the Payen gaskets to the manifold with Stag well seal and left over night, put it in position and push the manifold into the V, compressing the gasket and making the holes line up , this way you are not trying to bend the Manifold flanges into the heads.



IMG_20190907_150217_HDR.jpg we see if i have anymore photos

[Wheelz]

I use a file to carefully elongate the bolt holes in the manifold. Then if it still doesnt align a crowbar to lever downwards on the manifold usually does the trick.

[wilf]

The thin gaskets worked for me, see my "obstinate water pump" thread. And I didn't have to resort to trying to lift the garage roof like MandM! (phew)