Re-fitting manifolds

[TRevver]

Does anyone have any tips for re-fitting the inlet and exhaust manifolds for a 2L mk1 Vitesse?

To say that the fit between the flanges of the 2 manifolds at the engine block surface is a tight fit would be an understatement!

I’m wary of adopting the “hit it with a big hammer” approach - especially on the cast iron exhaust manifold which has a hairline crack already.

 

Thanks in advance for any tips / suggestions.

[68vitesse]

I have taken file to the inlet manifold before now to get an easier fit between the exhaust flanges, from memory only had to ease a couple of contact points slightly.

Regards

Paul

[Pete Lewis]

yes add some relief  there's no good reason for them to be under stress ,  its probably years of hot/cold has made the exhaust shrink with the continuous normalising 

being a tight fit will only induce air leaks as you fight to clamp them to the head , its worth running a die nut down the bolts so you know no crud is holding the tightening 

of the bolts 

Pete

[NonMember]

Yep, as they said. I had to relieve a couple of places on mine to make it fit nicely and not keep blowing gaskets.

[TRevver]

Thanks - all sorted and it sounds like a good idea for the die nut too👍

 

[TRevver]

Looks like I spoke too soon! The exhaust manifold HAS shrunk! Everything else fits perfectly but the manifold now doesn’t fit over the 2 brass studs at either end.

Im guessing one solution might be to rebore the holes at either end of the exhaust manifold??

It came off absolutely no problem about 6 weeks ago, although the engine had been run to loosen the studs a bit. Maybe that heat was enough to cause enough expansion to remove it easily?

Another option, warm manifold with heat gun before re-installation?

Time for a beer! 

[JohnD]

Pop it in the oven, 400C, wait half an hour!

[TRevver]

Brilliant! I’ll wait until my wife’s gone to get some toilet roll!

[68vitesse]

Not sure if it is a good idea but I have retorqued the manifolds bolts and nuts after the first hot cool cycle.

Regards

Paul

[dave.vitesse]

1 hour ago, 68vitesse said:

Not sure if it is a good idea but I have retorqued the manifolds bolts and nuts after the first hot cool cycle.

Regards

Paul

Yes, re-torque/check after things cool down otherwise you can end up with leaks. Standard workshop process.

Dave

[johny]

I re tighten my manifold bolts a couple of times a year as the heating/cooling seems to slacken them and then I get leaks (MK1)

[dave.vitesse]

45 minutes ago, johny said:

I re tighten my manifold bolts a couple of times a year as the heating/cooling seems to slacken them and then I get leaks (MK1)

Sound like the gasket was on it's way out.

Dave

[johny]

I've had it a couple of times with new gaskets but this last time with a tightening routine no further problems. As I say each time I redo them they have loosened....

[Pete Lewis]

its important on MK1 type heads the bolts /holes are clear it only has a 20-22 lbft on the  double clamps and 24-26 on the end studs  which is quite low for a 3/8unf thread 

overtightening can spread the clamps 

pete