manifold distorsion, tips?

[NicBowman]

Hi, fitting my exhaust manifolds, boy what a shitt@r of a job! Did the near side one 4 times before it was all okay, on off on off, it was like the okey cokey.

The off side has a problem where the four flanges are not well aligned with the head, so put two bolts in and two more won't line up. Manifold is very stiff to flex around to get inline, any tips? Apart from dump the manifold!

Nic

[Johno]

You may already be doing this, but only turn the bolts a couple of turn into the head, and do all of them and then tighten down once all in. Taking it down progressively working across all of the bolts. Has worked for me historically . . .

However, I have also heard of people having to open the flange bolt holes to get them to line up as well . . .

[GreenV8S]

Has it been welded? Can't think why else it would have distorted. I'd want to check that the ports lined up well enough and that the mating surfaces were nice and flat if it's distorted that badly. If everything else is OK then you could just open up the holes, but my guess is that there'll be more wrong than that.

[2Munkys]

Bizarre isn't it Nic. Are your manifolds the OE items? The originals (I think they're Magnex) I've had off and on more than once and alignment has been fine. I've had two sets of aftermarket manifolds (one mild steel with ceramic coating and one set of stainless) and despite everything aligning perfectly when initially fitted, should you remove and refit them for whatever reason, it's a chuffin' nightmare. I've checked them with a 'straight edge', even put them on a 'flat plate' and all has been well, BUT, there's always been ONE 'kin hole out of alignment. Gotta be some kinda 'spooky syndrome' goin' on me thinks!

[NicBowman]

Mine are not original, I am going to waist the bolts to allow fitment.
Other tips have been to stick a screwdriver in the other hole to help, tricky though.

Ta


Nic

[GreenV8S]

NicBowman said:

Mine are not original, I am going to waist the bolts to allow fitment.
Other tips have been to stick a screwdriver in the other hole to help, tricky though.

Um, both of those sound like highly dubious ideas tbh. If the problem is simply finding the hole, fit all the bolts loosely and hold the manifold away from the head to help you engage any troublesome bolts. From what you were saying I thought that the bolt holes in the head didn't line up with the bolt holes in the flange. Although you *could* waist the bolts to give you more scope to wobble them around and allow them to be pulled down the the holes out of alignment, I think it would be a very bad idea. It'll weaken the bolts and make them more vulnerable to breaking off in the head, which can really spoil your day. If the holes don't line up then the proper solution is to straighten the manifold or as a bodge open out the awkward holes slightly.

Edited by GreenV8S on Wednesday 5th September 19:43

[SI 4.3]

Should be interesting I have J.P s steel ones on mine,the manifold gasket has gone on the right hand side and they have not been off since fitting them new 2yrs ago.
Simon.

[Pasco]

SI 4.3 said:

Should be interesting I have J.P s steel ones on mine,the manifold gasket has gone on the right hand side and they have not been off since fitting them new 2yrs ago.
Simon.

Hello Simon old buddy

So long as the chap who fitted them used plenty of copper slip you will be fine mate

[Ballistic Banana]

I have some JP mild steel ones Ceramic covered. The offside one took some lining up on mine to the fact i had to elongate the two holes at one end (near no 2 ). I had tried the all in a couple of turns but still they would go in. Just taken it off this week Been on about a year and the then new Gasket had been leaking ...bloody things

BB

[Tank Boy]

I had this problem as well .
Check that the exhaust flange is flat with the heat it will bow making the bolts harder to get in and not pulling up straight causing a leaky gasket.

I got round this by getting the flange skimmed flat at a machine shop went on first time and has been on and off since with no probs.