Cutting exhaust manifold/ lower bolts

[chris1972]

I think I have a leak from my manifold gasket, so was going to replace them when I do the plenum and valley gasket. However, I've heard of owners cutting a slot beneath the lower manifold bolt holes to allow it to be removed and replaced much easier.

I was thinking of doing the same, but wondered what tool/ cutting disc would be best? I was thinking of using a 6mm die grinder, but not sure which discs (or how many) are needed.

Any suggestions?

[Discopotatoes]

I have mine done, and it does make it easier to remove, I didn't cut them but i would use a 4" angle grinder with metal cutting disks

[chris1972]

Thanks. Would you use anything with the disc to aide cutting? Also, I read the RV8 guide to getting the bolts on and off. Just wondered if anybody has used one of the ratchet spanners to speed the process up and if they fitted?

[QBee]

You may be luckier than me - six of mine were so totally stuck that, after having the heads off and trying everything he knew on the workbench, my TVR expert had to cut the bolts off and start afresh with new ones. Its the problem of steel bolts in an alloy head I guess, and them maybe never having been removed in 13 years three months and six days.

[Discopotatoes]

chris1972 said:

Thanks. Would you use anything with the disc to aide cutting? Also, I read the RV8 guide to getting the bolts on and off. Just wondered if anybody has used one of the ratchet spanners to speed the process up and if they fitted?

No just use the disk on its own, replace the bolts with ARP 3/8 head bolts and nord lock washers

[Colin RedGriff]

The ratchet spinners help on the bolts you can get them on! I bought some half moon ones which were a bit thinner around the head than my stubby ones. However the number that you can actually get them on is limited.

I used those, open ended spanners and sockets (thinwall) with a combination of extensions and ratchets. Well worth giving the bolts a good soaking of plus gas or penetrating fluid a day or two before you want to start.

[spend]

You need to be very careful cutting the slots as the manifold will not drop straight down (human frailty) typically you hook the rear on and swing the manifold down in an arc pivoted on the rear IYSWIM. An Angle grinder will cut the slots pretty quickly with a cutting disc(not grinding), bigger the better as you just take a couple of slices out about 8mm deep.

The best arrangement for the lower fixings IMO are studs with serrated flange nuts (so no washers getting in the way), wasted studs being the ultimate as they give you more room to locate the manifold as you drop it down as well as being fitted with smaller head nuts (typically UNF so no loss in strength).

The studs & bolts that I use allow ratchet ring spanners to be used on 6/7 of the 8 fixings. Removing & refitting manifolds has become a pleasant experience

[Sardonicus]

Removing & refitting manifolds has become a pleasant experience
[/quote] Clucking Bell Dave I never thought I could hear those words spoken about that job

[chris1972]

Excellent, thanks for the responses. I'll get some penetrating oil on the manifold bolts a couple of days in advance and hope they come without too much of a fight!

[Sardonicus]

chris1972 said:

Excellent, thanks for the responses. I'll get some penetrating oil on the manifold bolts a couple of days in advance and hope they come without too much of a fight!

I think the people who have trouble with these have been very unlucky or the car has lived up North or near the Coast for to long IMO has I have done a number of these cars now and never had any problems removing these bolts and even if I did I would resort to using the Air Hammer or Gas Bottles route way before I decided to shear the heads off and go down the head removal road

Edited by Sardonicus on Thursday 4th April 13:43

[spend]

Sardonicus said:

...even if I did I would resort to using the Air Hammer or Gas Bottles route way before I decided to shear the heads off and go down the head removal road

Wouldn't that mean having to cut the body in half so that you could get either air tool or torch anywhere near the bolts?