3.2 Intake Manifold - Uh oh!...This doesn't look good!

[Anil]

Whilst investigating a potential vacuum leak, I decided to check the tightness of the intake manifold nuts with my brand new Sealey torque wrench.

Unfortunately, during the process, I have managed to snap the right hand side intake manifold mounting point off !

I'm still not sure what happened here. The torque wrench was set correctly at 15lb/ft (~24Nm) and I managed to tighten the first three nuts with no issue. The nuts turned less than 1/4 turn and the wrench clicked as expected.

On the 4th nut, the wrench turned maybe 1/2 a turn before I felt it loosen slightly. Took a closer look and noted the nut had cracked the mount. The corresponding plastic bakelite spacer had also cracked at the same spot. See pics below.

Anyone else have this happen before and is the intake now scrap or can it be saved?

Looking at the positives, two of three lower gaskets had split...

[Chris T]

Anil, I have 2 spare 3.2 inlets if you need..... PM me. Chris.

[osc911]

Do keep those as spares, I'd say it's weldable. 

[Anil]

1 hour ago, Chris T said:

Anil, I have 2 spare 3.2 inlets if you need..... PM me. Chris.

Thanks for the offer, Chris.

I may actually have a spare intake somewhere, but will need to check which side it is.

 

However, I'm still unclear as to what caused the original failure.

Do I have a a dodgy torque wrench or had the spacer collapsed causing the torque wrench to tighten down further than expected?

Anyway I'll be replacing all gaskets and spacers so hopefully won't encounter any further issues with the replacement intake.

 

[Nige]

Defo weldable but used replacement probably easier/cheaper in the long run. 

[Northy]

ITBs… you know you want to. 

[Anil]

23 hours ago, Northy said:

ITBs… you know you want to. 

He he ... That's exactly what Shirish said to me! Maybe one day.

 

A spare unbroken intake manifold has been found and is ready to fit.

Both intakes have a layer of baked on oil deposits within each tube. Anyone had them vapour blasted to clean them up?

I also read about the "triangle of doom" but it looks bone dry around that area.

However, the breather hoses were cracked and will need replacing.

Anything else worth checking/replacing whilst everything is apart and accessible?

 

[Nige]

Fuel lines check

[Northy]

Bushes on throttle linkage?  Defo fuel lines. Dr Rocks incident springs to mind.  Replace the oil pressure switch? 

[Beaky]

On 02/10/2022 at 21:13, Anil said:

However, I'm still unclear as to what caused the original failure.

Could it have been an underlying issue (metal fatigue) that only came to light when you tighten it again. 

[SurlySurdi]

9 hours ago, Beaky said:

Could it have been an underlying issue (metal fatigue) that only came to light when you tighten it again. 

I've had so many things I've tried to fix or improve only to break stuff. On the plus side you've revealed a weakness which was waiting to be discovered and have ended up dealing with it.

[Anil]

I've been (very) slowly putting things back together over the past two weeks and today got round to finally firing it up.

Amazingly it started up straight away. It was only a quick start-up test but I will plan to take it out for a lengthy spin tomorrow.

Just a few notes :

1) I'm a complete beginner when it comes to working on the engine so whilst it may have been a straightforward job for most, I had to take my time and recheck everything multiple times. The youtube videos linked below were really useful when it came to dismantling the intake and putting it all back together :

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

 

 

2) I used genuine Porsche gaskets and insulators. Not sure how they differ from the OEM gaskets but they were good quality items.

3) Good call on re-checking the fuel lines. My main fuel lines had been previously replaced, but the small J-hose under the left side fuel damper still appeared to be original. I think I replaced it just in time as the hose was showing signs of cracking when flexed at the elbow bend (see pic below). As with the other fuel lines, I decided to use a genuine Porsche part for this hose. The new J-hose is made of a different reinforced rubber so should hopefully be good for a number of years. If not documented in the service history, I highly recommend everyone checks this hose as it is usually forgotten.

4) I had to replace the right side intake but no matter how much I cleaned the replacement I couldn't get the colour to match the original left side! The best option was to get both intakes vapour blasted locally. I think they came out really nice with a smooth peened surface. I just applied some ceramic wax over the top to try and offer some additional protection.

5) With the intakes removed it was also an ideal time to replace the original sound pad, which was crumbling away at the edges.

6) Gratuitous pic below of the finished job. Ignore the acne on the fan! The fan/surround had both been powder coated by my local "The Wheel Specialist" over 12 years ago. Whilst the surround is fine, the fan has started to bubble in few places in the last couple of years. I think it may be time to re-do it with a cerakote finish.

[Ian Comerford]

Great work Anil, looking forward to seeing you out in it soon

[Northy]

Well done mate 👏