ACT manifolds keep undoing bolts & blowing gaskets

[Dominic TVRetto]

The previous owner put ACT manifolds on, and ever since I bought the car I have had problems with it blowing gaskets on both sides - each gasket lasts 1 year to a max of 1.5 years before it happens again. I use the car daily, and have probably had to get this sorted about 10 times in my 6 years of ownership

The bolts come loose - I'm guess because of heat expansion in the stainless steel and the familiar chuffing starts to happen...

Can any other ACT manifold owners tell me if this happens to them? Surely I can't be the only person it happens to...?

The garage has wired the bolts the last time, and it's happened again even so.

Can anyone suggest a remedy that will stop this happening - I am at my wits end now to try and get this permanently sorted.


Thanks in advance...


Dom

[mk1fan]

A set of ARP bolts and Nordlock washers seem to be the normal solution for TVR manifolds.

Although, with stainless bolts (on V6 S), and split washers I found they needed a nip every few months. Do you check the nuts are still tight at all?

[N7GTX]

I've just posted in another thread about this very problem. I've had my car 2.5 years and today just fitted the 4th set of gaskets. First set were with original manifolds and lasted about 3 months (low mileage) when the manifolds failed so bought ACT ones. Standard gaskets were fitted by the dealer. They failed after just 6 months - some bolts were loose, some gaskets blown - so asked for stronger ones. They supplied some uprated gaskets designed for supercharged and turbo engines and fitted them using new bolts and Nordlock washers. They have lasted around 15 months although there was blowing some time ago.
So today I have fitted another set of the 'uprated' gaskets (£45) complete with new 'black' bolts which I assume are high tensile ones. Again I have fitted Nordlock washers to prevent loosening.
Examining the gaskets it appears that despite the 'uprated' name, the one nearest the driver had blown through as the bolts were still very tight.

On Rover SD1s the manifolds are cast units so not the exact same shape but they are fitted using tabwashers. Perhaps they could be slightly modified to fit?

http://www.ebay.co.uk/itm/ROVER-SD1-3500-V8-ONLY-E...

[QBee]

I have a standard TVR cat y piece available if anyone wants to give up completely....

[bobfather]

mk1fan said:

A set of ARP bolts and Nordlock washers seem to be the normal solution for TVR manifolds.

Although, with stainless bolts (on V6 S), and split washers I found they needed a nip every few months. Do you check the nuts are still tight at all?

I have ACT manifolds with ARP bolts and Nordlock washers. I can assure you this doesn't solve the problem. Nordlock washers need to be harder than both the bolt flange and the manifold plate so that the Nordlock teeth can bite into the surface to prevent rotation. The ARP's are too hard so they just slip on the Nordlock washers. I used a punch to pop mark my ARP's so that they would lock onto the Nordlocks. This appears to have worked. I had to retighten a couple of times but they've remained tight for the past 18 months

[andy43]

I've got the act gaskets, small headed bolts, nordlocks and manifolds and agree they still need a nipping up after a while. I've marked them with marker pen so I can see fairly easily if they have moved. Centrepunch is an excellent idea. Access isn't 'ideal' for a couple of the lower bolts...

[s p a c e m a n]

I can't see how they'd still come loose if they used proper wire lock bolts, they'd only be able to undo half a turn at most? Are the bolts coming loose or is it the gasket failing first making the bolts seem loose?

[Boosted LS1]

The cosworth v6 engines I work on have copper aero nuts and they never go slack. Maybe it's something to do with them adjusting to the studs expansion rates. They're clearly not the cheapest nut that could have been used to bolt on a manifold so must have been chosen for a reason. You can buy aero nuts from stockists but expect to pay a bit more for the copper items.

[bobfather]

This was my effort with pictures of the ARPs pop marked

https://www.pistonheads.com/gassing/topic.asp?t=14...

[QBee]

QBee said:

I have a standard TVR cat y piece available if anyone wants to give up completely....

I am the Morris Marina in your Top Gear TVR improvement world.......

[Sardonicus]

The composite manifold gaskets compress over a period inc heat cycles etc big bore MLS gaskets would get my vote if they was available so far so good early days however

[RobXjcoupe]

I nip the bolts up regularly but wondered if it's the weight of the manifold that causes the issue in conjunction with the heat cycles?

[ChimpOnGas]

ChimpOnGas said:

I've got ARP bolts with Nordlocks on the original TVR manifolds, mine still need nipping up every year or so.

I feel the Nordlocks are better than spring washers but they're certainly not the definitive solution.

The ARP bolts on the other hand are a no-brainer as they have a smaller 3/8” head rather than the 9/16” of the original bolts, this makes the little bujers so much easier to access & tighten.

These look tempting though....

https://www.youtube.com/watch?v=Ua9LdFs5Bn8

Or better still these, assuming there's space for the locking tabs?

https://www.youtube.com/watch?v=-m29dYvTT0E

[Boosted LS1]

Why are tvr's having these issues in the first place? It must be something basic?

[RobXjcoupe]

Boosted LS1 said:

Why are tvr's having these issues in the first place? It must be something basic?

Just my opinion but I think the design and weight just puts strain on the securing bolts. The standard Range Rover manifolds go straight downwards to a pick up y piece and then to the main exhaust pipe where as the tvr version shoots forwards, down then back under the engine and doesn't allow much for engine movement so the manifold bolts take the strain and are constantly being levered away from the block as the engine twists under torque and which eventually blows a manifold gasket if worked loose. It's a wonder the manifold bolts don't eventually sheer under stress or just pull out of the Ali block.
I reckon larger diameter bolts would rip out the block so best just nip up the standard ones as part of a tvr service quirk

[N7GTX]

Sardonicus said:

The composite manifold gaskets compress over a period inc heat cycles etc

Even with the Nordlocks and bolts still very tight, the gasket for 6/8 was blown through. Examining it and the layers had completely disintegrated so its thickness was around half of a new one. Yet around the bolt holes it was still relatively intact.
As everyone has tried various methods to stop this problem, I'm inclined to think its a better gasket we need

[bobfather]

If people are suffering from repeated gasket failure I would ask whether the failures are always in the same place, if so you should consider whether there is damage to the mating surfaces or warping of the manifold plate

[Dominic TVRetto]

bobfather said:

This was my effort with pictures of the ARPs pop marked

https://www.pistonheads.com/gassing/topic.asp?t=14...

Read this thread with much interest, especially about the Proform Self-Locking Wedge Header Bolts...

The thread kind of petered out, what was the concensus on these in the end? In theory they look like they would stop the bolts undoing in circumstances where nordlocks might fail (ie. hard SS bolt surface not allowing them to bite and lock...)

Thanks,


Dom

[bobfather]

Dominic TVRetto said:

Read this thread with much interest, especially about the Proform Self-Locking Wedge Header Bolts...

The thread kind of petered out, what was the concensus on these in the end? In theory they look like they would stop the bolts undoing in circumstances where nordlocks might fail (ie. hard SS bolt surface not allowing them to bite and lock...)

Thanks,


Dom

Those bolts are perfect in every respect except one, they are too short. If like me, you find that some of the outer thread on the heads is weak or missing due to corrosion of the original mild steel bolts then you need every bit of the length of the ARPs. When you take the depth of the Nordlock, the manifold plate and the gasket off the bolt length the remaining insertion length is already worryingly small especially if the threads on head are compromised

[Boosted LS1]

Just for interest here's a picture of an aero locking nut. You just use a thick flat washer underneath.