Changing Exhaust manifold gaskets.

[scooby_doo_do]

This is driving me nuts. I took off the exhaust so i could get to the rocket cover bolt's, and looking at the state of the manifold gasket i would say its possibly been leaking on the underside, so decided to get some new ones and replace them.

So here's where the fun begins.... 5.7 v8 small block..

1, starting from back of car to front, i get all but the last two bolts in.. which don't line up...
2, tried then from front of car to back, can only get 4 of them in now...
3, tried brute force to try and line up the exhaust - no joy, bolts won't go in, and no place to use leaverage with a screwdriver..
4, covered in fibre glass stuff from exhaust wrap,
5, back to step 1
6, given up..

I'm hopeing someone's going to tell me a nice and simple way to do it.. Or do i need the assitance of a freind to pull the exhaust into position whilst i put the bolts in?

Many thanks

Craig.

[MattYorke]

Ratchet strap?

[738 driver]

Craig, tubular headers can be a nightmare to re-fit but should not be too far off the mark. Did you apply the same rules as your water pump job?.......start all the bolts/studs by a couple of finger turns before applying any tools and keep the tightening sequence opposing/even!

[V8 DOM]

scooby_doo_do said:

This is driving me nuts. I took off the exhaust so i could get to the rocket cover bolt's, and looking at the state of the manifold gasket i would say its possibly been leaking on the underside, so decided to get some new ones and replace them.

So here's where the fun begins.... 5.7 v8 small block..

1, starting from back of car to front, i get all but the last two bolts in.. which don't line up...
2, tried then from front of car to back, can only get 4 of them in now...
3, tried brute force to try and line up the exhaust - no joy, bolts won't go in, and no place to use leaverage with a screwdriver..
4, covered in fibre glass stuff from exhaust wrap,
5, back to step 1
6, given up..

I'm hopeing someone's going to tell me a nice and simple way to do it.. Or do i need the assitance of a freind to pull the exhaust into position whilst i put the bolts in?

Many thanks

Craig.

most tubular manifolds ive made, ive mounted on a solid plate accross manifold, however if your headers have become stressed and out of shape after welding then u have a nightmare.

Have far out are they?

Can they be bent back into shape?

Have you looked at making the holes slightly bigger if they are only just out??

As answered already couple of turnns on each bolt, do not tighten untill all in, also dont only turn in 2 threds otherwise forcing other parts of exhaust on will rip out the boly and its thred

Where are you?? anyone local ill come and help out

Good luck

dom

[scooby_doo_do]

Thanks guys.

They aren't too far out, say 3mm for the last 2 bolts, so will try again tommorrow night when i've got more time/patience... lol.

i thought it was just me - but if they can be a pain, then i shall pursue..

Not fitted the pump yet - turned up today :-) looks very nice, so can't wait to try and fit that (comes complete with all new bolts and gaskets).

Thanks

Craig.

[GreenV8S]

scooby_doo_do said:

They aren't too far out, say 3mm for the last 2 bolts

That's a massive amount for them to be out. Is there any scope for the manifold to spring, or is the port spacing fixed by the exhaust flange?

[738 driver]

Its probably that the heat band-aid stuff has caused some minor hotspots/distortion, might not be as much as 3mm when its all sitting square!

[Steve_D]

Because there is not a common flange the pipes can 'spring' after being through the heat cycles. Mine were a pig to fit when the engine was on a stand but not too bad when in the car.
As someone else said, Start by fitting bolts at the front of the engine and you want them engaged by at least a bolt diameter. As you get towards the back pull the manifold using a ratchet strap secured back to the chassis.

Steve

[60mph]

I have a common flange . Is that something new or old ? Already had them off for some engine work but they went straight back on . Remember you are screwing into aluminium ; mine are stainless steel bolts and don't pick up on aluminium . If you do get a picked up bolt take everything off and insert the bolt all the way with a smear of engine oil to save the thread.

Frank

[Steve_D]

60mph said:

.....mine are stainless steel bolts and don't pick up on aluminium ......Frank

Stainless and ali do not like each other and will pick up. To be safe use a barrier such as Duralac or if not available use copper grease.

Steve

[V8OWNER]

Steve_D said:

60mph said:

.....mine are stainless steel bolts and don't pick up on aluminium ......Frank

Stainless and ali do not like each other and will pick up. To be safe use a barrier such as Duralac or if not available use copper grease.

Steve

Steve.. I thought copper-ease was a bad idea between dissimilar metals, as it accelerated the electrolytic corrosion?

[738 driver]

Not every SBC has light-alloy heads..... its hard to tell from the photos but I thought they maybe cast iron!
Hopefully all will be resolved soon.

[Steve_D]

V8OWNER said:

Steve_D said:

60mph said:

.....mine are stainless steel bolts and don't pick up on aluminium ......Frank

Stainless and ali do not like each other and will pick up. To be safe use a barrier such as Duralac or if not available use copper grease.

Steve

Steve.. I thought copper-ease was a bad idea between dissimilar metals, as it accelerated the electrolytic corrosion?

Don't know, you may be right and I stand to be corrected.
However, working with stainless and ali on naval weapon systems it is mandatory to use Duralac on the joints and fixings.
My gut feeling is that copper grease would be better than nothing.

Steve

[ROWDYRENAULT]

Guys I have seen these problems on my Renault R5 Turbo headers see a bunch of heat with 17lbs of booast and move around some. The best answer is use studs. now your not going to run the risk of cross thearding the alloy head which could turn into a major mess. ARP builds a stud that is made of stainless has a allen head receptor on the end. The studs go in FINGER TIGHT with the correct lube supplied by ARP then you torque the supplied 12 point nut to spec while holding the stud with the allen so that you do not bottom the stud in the hole. Problem solved. nOTICE THAT IF THE HEADERS ARE OFF A BIT YOU CAN CONVINCE THWM TO MOVE OVER TO THE STUD BECAUSE YOU ARE NOT TRYING TO MOVE THE HEADER AND START THE BOLT AT THE SAME TIME. lEE

[Boosted LS1]

Agreed, studs are the proper way to go if you have space.

If you have to use bolts then try to get them all in loosly and work from there, nipping each one up a bit at a time. In the past, when I had a crap exhaust I used to use a posidrive screwdriver through the exhaust bolt hole and into the head to lever it into a position. Far enough to get other bolts screwed into place. Tubuler headers can be utter crap, especially some of the stainless ones.

[ezakimak]

the studs wil also allow for more thread engagement in the head as well,
more thread engagement will potentially avoiding stripping of said thread as well.

[Steve_D]

The only problem with studs and the Ultima header is space.
There is very little clearance around each fixing so getting a ring spanner over the bolt head/nut is impossible for many of the bolts which is why many use bolts with a 12 point head.

If you go the ARP stud route then you will also need their 12 point nuts.

Steve

[Boosted LS1]

^ Could you sleeve the block down and use a smaller diameter stud? It's still be strong enough.

[V8OWNER]

To get round the binding on an old rover v8 I fitted helicoils, steel on steel then.. no probs..

[V8 DOM]

please dont get smaller studs or bolts as it increases the possibility of stripping the thred...

Agreed studs are the way to go, but if space is a problem you could drill the holes in the headers slightly bigger to allow for easier install, however if the headers are blueprinted to the ports they will be offset, but normal headers are 1mm or so out anyway...

If you want to cure that you will never worry about again, get a solid 5/16 piece of metal, match it to your head ports, then cut the flanges off the headers and weld headers to solid piece of metal. The advantage of this is when making metal flange you can match to the heads and then match inside of exhaust...A perfect match.....

example below is 23 degree or get from USA for approx $10 each side



Dom

dom

Edited by V8 DOM on Friday 30th January 13:26