[Kurt Vitin]

Forgive me if I missed it, but I would suggest that you get an Abarth Shop Manual. It might help with where things go and getting your torque values correct. If that head is not properly torqued you can bet you will be blowing bubbles in the radiator (aka a blown head gasket). Please keep us updated on your progress.

I was looking into one that I found on eBay but they for some reason blackmailed my account after buying an mid-pipe for my other car. But When I went to the dealership I asked them about my issue and they printed me out a few pages from the manual to remove and install the multi-air. If I end up needing to take off the head (last resort) Ill find a manual to buy.

 

[PaulDay]

Today I spent the whole day trying to make a tool to make the multi-air install a bit simpler. I might have failed quite miserably at making the first iteration, the prongs I made to compress the springs didn't have enough leverage and would bend rather than compressing.

The compression tool is not needed. You'll need another person with you when you reinstall the MAU.

I didn't have the compression tool and I wasn't going to spend several hundred for a one-time use.

Basically, once you have the MAU set in place, insert all the bolts, without screwing them in at all. Using some force (One person on each end of the MAU.), align the MAU into the position over the two guides. Starting at the center, hand tighten the bolts while forcefully holding the MAU in position.

Once you've reached the limit of turning the bolts by hand, starting at the center and working outward, alternating sides, turn each bolt a 1/4" of a turn while continuing to forcefully hold the MAU in place. The MAU will eventually set down over the guides and won't need to be held any longer. Continue tightening 1/4" at a time until you can see that the MAU is fully touching the head all the way around.

Tighten to factory specs.

If you're lucky, the cam will be at a position where only one lobe is fully compressing on the MAU roller.

I'm gonna take apart the multi-air to see if I could possibly clean out the plungers

I also did that, had them moving like greased lighting. They were all covered and stuck with carbon. After some extensive reading, I decided to just bite the bullet and buy a new MAU. I did not find one rebuild sucess story. There was a place in the UK that was rebuilding the MAUs, but quit after difficulty obtaining the internal pistons that the cam rollers compress, which seems to be the main point of failure from what I've read.

Good luck.

Have a good day.

 

[Kurt Vitin]

I also did that, had them moving like greased lighting. They were all covered and stuck with carbon. After some extensive reading, I decided to just bite the bullet and buy a new MAU. I did not find one rebuild sucess story. There was a place in the UK that was rebuilding the MAUs, but quit after difficulty obtaining the internal pistons that the cam rollers compress, which seems to be the main point of failure from what I've read.

Good luck.

Have a good day.

Thank you for your insight, and mostly I want to take apart the MAU to diagnose the problem if it is a multi air problem

thanks again will keep you guys posted

 

[Bennysc1]

I was wondering if the MAU (brick) is replaced, will that create and restore the compression back to the cylinder that is low? Given that there is no damage to the piston or ring.

 

[PaulDay]

I was wondering if the MAU (brick) is replaced, will that create and restore the compression back to the cylinder that is low? Given that there is no damage to the piston or ring.

From what I've been able to deduce is that when one of the hydraulic/electrical lifters goes bad, it leaves a valve partially open, leading to no compression on that cylinder. The hydraulic/electrical lifters in the MAU allow the engine's CPU the ability to control the lift and duration of the intake valves, regardless of the cam lobe specs during rotation for maximum torque at said RPM if required. This is what gives the MAV engine it's low-end torque, but it leaves those MAUs susceptible to carbon build-up failure.

After replacing, it seems that it takes a while for a partially stuck open valve to work again. It's not stuck fully open, just enough that the return springs can't overcome the seized valve in the guide until it heats up and releases. For me, I was afraid to run it after the replacement and still having a dead cylinder. Finally, I said what the ****, run it until it blows up. If it's a bent valve, I'll have to pull and possible replace the engine anyway. Once I let the engine run and heat up properly, the valve popped closed, and the cylinder started firing normally with full power.

The main reason is carbon buildup in the oil. With a turbo, this happens much quicker than a normally aspirated engine. The car had been setting for the two last years, with short local trips, usually once every several months. Oil was changed on milage, not time, which was a mistake. MAU failed after the car was suddenly put back on the road daily for about a month without the oil being changed. The oil changed was solid black. Everything I remove from the MAU was coated with carbon.

I read that when the MAU fails, you'll get air puffing out the intake air duct off the throttle body. That's where I was at after a full tune-up. If the issue is a bent valve, from a bad timing belt jumping teeth, it could be either an intake or exhaust valve. If you're getting puffing out of the exhaust pipe, than you have a bent exhaust valve, which will be caused by the jumped timing belt.

If the timing belt has not jumped any teeth, then the open intake valve is caused by a MAU failure.

With all that being said, I believe for MAU longevity, the engine oil needs to be changed on a strict schedule, especially if running a turbo, to prevent carbon buildup in the oil and causing MAU issues. Fiat also recommends a special oil for the MAV engines that's supposed to prevent carbon buildup. It probably just boils down to using a high quality oil and faithfully changing the oil following Fiat's recommend oil change schedule.

There are several articles that go in depth on the workings of the MAU and the advantages of infinite positioning of the intake valves obtained by use of the hydraulic/electrical solenoids.

Have a good day.

 

[J.B.]

From what I've been able to deduce is that when one of the hydraulic/electrical lifters goes bad, it leaves a valve partially open, leading to no compression on that cylinder. The hydraulic/electrical lifters in the MAU allow the engine's CPU the ability to control the lift and duration of the intake valves, regardless of the cam lobe specs during rotation for maximum torque at said RPM if required. This is what gives the MAV engine it's low-end torque, but it leaves those MAUs susceptible to carbon build-up failure.

After replacing, it seems that it takes a while for a partially stuck open valve to work again. It's not stuck fully open, just enough that the return springs can't overcome the seized valve in the guide until it heats up and releases. For me, I was afraid to run it after the replacement and still having a dead cylinder. Finally, I said what the ****, run it until it blows up. If it's a bent valve, I'll have to pull and possible replace the engine anyway. Once I let the engine run and heat up properly, the valve popped closed, and the cylinder started firing normally with full power.

The main reason is carbon buildup in the oil. With a turbo, this happens much quicker than a normally aspirated engine. The car had been setting for the two last years, with short local trips, usually once every several months. Oil was changed on milage, not time, which was a mistake. MAU failed after the car was suddenly put back on the road daily for about a month without the oil being changed. The oil changed was solid black. Everything I remove from the MAU was coated with carbon.

I read that when the MAU fails, you'll get air puffing out the intake air duct off the throttle body. That's where I was at after a full tune-up. If the issue is a bent valve, from a bad timing belt jumping teeth, it could be either an intake or exhaust valve. If you're getting puffing out of the exhaust pipe, than you have a bent exhaust valve, which will be caused by the jumped timing belt.

If the timing belt has not jumped any teeth, then the open intake valve is caused by a MAU failure.

With all that being said, I believe for MAU longevity, the engine oil needs to be changed on a strict schedule, especially if running a turbo, to prevent carbon buildup in the oil and causing MAU issues. Fiat also recommends a special oil for the MAV engines that's supposed to prevent carbon buildup. It probably just boils down to using a high quality oil and faithfully changing the oil following Fiat's recommend oil change schedule.

There are several articles that go in depth on the workings of the MAU and the advantages of infinite positioning of the intake valves obtained by use of the hydraulic/electrical solenoids.

Have a good day.

That is very nicely articulated!

 

[Kurt Vitin]

Thanks again Paul, everything for me is leading to the same conclusion, after pulling the MAU again after running it (probably wasn’t my greatest idea to run it). Cylinder one seemingly is clogged and will not let any of the oil that’s in it from escaping leading to no compression, cylinder two it seems was on its way out too. The one plunger that blew the side of the housing (the one I lost the clip on) is stuck open and the other for the same cylinder has the same feeling as cylinder 1, so by my observations cylinder 2 should have had no compression but the 1 plunger was missing letting the valve stay closed possibly running the cylinder off of the one intake valve. Now that you mentioned it, when I pulled the plugs cylinder 1 had excessive carbon build up on the end, I’ll take apart the multi air now so I can get a better understanding of it.

while I had the valve cover off I painted it red because red means fast
That’s about the progress I’ve had so far will keep you guys up to date
Thanks again for all the responses!!

 

[Kurt Vitin]

After another compression test and a few broken t50 bits I took the head off…. And I don’t think there’s ever been a man so happy to discover burnt valves before. Cylinder 1 is missing half a valve and it looks like cylinder 2 was on its way as well
I’m gonna look to find a complete engine tomorrow and see if I can pick it up soon

 

[Kurt Vitin]

Question…..
Would a 2013 abarth 500 engine be compatible with a 2012 abarth?
I know it’s the same engine and all but I just want to be sure….. thank you

 

[J.B.]

Yeah, they are the same.
Thanks for following up this. I'm curious to learn if it was bad mutiair brick that caused the valve to burn. And here's a question for you - at this stage, would you rather not do the valve job? Just curious having done a couple of heads on Ducatis recently.

 

[Fabio13]

Wow. At least you now have a definitive answer to your problem.

 

[Kurt Vitin]

Just picked up the engine today, picked it up from Massachusetts so it was a 4 hour drive round trip, I put it in the back of my outback and sent it on its way. I had to rearrange the garage with the help of my dad and a friend so we put the abarth on the lift so I can easily take out the engine.
Answering your question JB, I’ve done both an engine swap and head work before and I rather do an engine swap because in this case, I would’ve needed to buy a new head and a MAU unit and all the gaskets that follow, it comes out to be cheaper for me to just buy an engine and swap it in.
I just bought all the fluids I need to complete the job now it’s a matter of doing it (hopefully running and driving by next week)
will keep you guys up to date!

 

[Kurt Vitin]

In terms of removing the transmission, it doesn’t appear that the slave cylinder can just be bolted off as it looks like it’s behind a black gasket, I’ve heard some people have to bleed the system, is that true? And the linkage in the back, is there a bracket that holds on the lines and then do I just pop it off from there with a screwdriver?
thanks again for any clarification