Fiat Twin Cam Head Gasket (NLC)

[111Robin]

I'm re-fitting the head to a Multipla after the cam belt broke and bent all of the exhaust valves. Problem is I'm only able to do a couple of hours each weekend so it's taking forever plus it's easy to forget things over such a prolonged re-build. On fitting the new head gasket, I tried it boths ways it would fit over the two dowels and opted for what I thought was the correct way with the waterways etc. lined up. Problem is, there is a tab on the gasket, that sticks out on the left hand side of the block (1st pic) that is preventing the timing belt idler pulley from fitting. I am assuming therefore that this tab should be on the right hand side of the block towards the back (2nd pic) (the only other orientation the gasket will fit over the two dowels. Can anyone please confirm this before I strip the head off again to replace the gasket (again). (I think I know the head needs to come off again but I'm so sure I checked both orientations and chose the only one that lined up correctly). (photo's are of the old gasket btw)

[111Robin]

or if anyone happens to have a 1.6 twin cam with the head off can you take a pic of the block to see the positions of the waterways/oil feed

[111Robin]

Damn it. Found a photo of the cylinder head on the web, proving gasket on wrong way around. I feel a Rab-C moment coming on....... Did something similar re-building a Mini gearbox years ago, left a detent pin/spring out resulting in fully stripping the box and starting again, ah well, some you win.......

[robin]

Bad luck, I just hate it when you discover you have made this type of mistake On the plus side, you've discovered the fault before it led to something worse than wasted time

Good luck getting it back together, again ...

Cheers,
Robin

[111Robin]

Head off again, gasket confirmed wrong way around, new gasket tomorrow, crack on with building it up. If I hadn't already removed the belt idler pulley it would have been obvious as the gasket can't be fitted incorrectly as the tab hits the pulley. Unfortunately I removed it as there is a new one in the belt kit and I was going to fit it once the head was on. I guess that's how you learn, pity it's probably the only Fiat twin cam I'll ever work on... (car was "given" to me, hard to refuse)

[111Robin]

Got a new head gasket at the factors today, Payen, nothing like any head gasket I've used before. It's basically two thin steel plates (joined along both sides but open at each end). The bottom face is completely flat, no raised seals or rings around the bores, completely flat. Top surface has the seals (waterways/bores) pressed into the plate to give a slightly raised effect. How on earth does this seal on the block side if it's completely flat ?. Paranoid now, it's torqued down and the belt back on. Anyone used this type before ?

[steve_weegie]

Sounds like an MLS gasket - I just rebuilt my K with one

On the K, the top layer is completely flat too, where it mates with the head - its covered in some kind of "special goo" to make it stick when it heats up the first time. On the K, you loose some of the clamping force between the fire ring and liner, and this is why you need your liner heights spot on if you're going to use one. Not sure about the construction of the fiat engine though....

Cheers,

Steve

[robin]

You should be clamping down on the fire rings with either type of gasket, so I don't understand where the "loss of clamping force" comes from?

Anyway, yes, this will be an MLS gasket and it will seal if used properly.

Cheers,
Robin

[steve_weegie]

I believe that as you're effectively clamping the steel water and oil seals, as well as the fire rings with the MLS, the force transferred onto the fire rings is less than the elastomer gasket.

Cant say for sure as my MLS came with the top shim already attached and I didnt get a chance to measure if the oil and water seals were flush with the fire rings...

Cheers,

Steve

[mac]

I've been using Payne gaskets for years on everything from my old Talbot Alpine, my even older Spitfire, a TR7, Audi 80 oil burner and the elise.

Never had an issue with them and it has and is my gasket of choice.



2p



Mac

[111Robin]

Not happy. Head back on, cam shafts on, timing belt on, cam shaft and flywheel locking tools off and..............can't turn the engine, locked solid. Cam shafts/belt back off, still locked solid. Head back off, turning freely. So, it appears that with the wafer thin MLS gasket, the pistons are contacting the head, (timing set with 1 & 4 at TDC). Pistons are proud of the block at TDC but with the old fibre gasket the pistons are below the fire rings. With the MLS gasket that is (estimated) less than half the thickness of the fibre gasket, the pistons are proud of the gasket. So I will now re-fit the old fibre gasket and torque the head down just to prove the point. This MLS gasket is listed as correct for the engine so how can it possibly work given the thickness compared with the fibre gasket ?

[robin]

I assume it didn't come with a shim to fit on top of the gasket itself?

Are you confident of the timing? Reason being that if you had the timing wrong, the piston may lock at or near TDC if it's touching a valve.

Finally, if the engine is like the K, turning it over whilst the liners aren't locked can cause the liners to lift and break the seal between liner and block which means you need to remove them completely and refit. I don't know anything about the FIAT engine - it may be off the solid block type and so that's not relevant. If the head bolts are short chances are you're OK - if the head bolts are really long, you may have made matters worse.

Cheers,
Robin

[robin]

Ignore the second part of that - just reread your post and noticed you tried with camshaft off so the valves will all be closed (am assuming your bent valves were replaced and sit flush into the head with the camshaft off).

Cheers,
Robin

[111Robin]

Yep it's not the cam timing as it's still locked with the camshafts removed (each cam is locked with a keyed plate to set the valves correctly with No.1 at TDC so can't really go wrong if that was the issue). Cams removed (each camshaft is in a seperate housing that bolts to the top of the head), all valves obviously fully closed so nothing to do with piston/valve interference, can only be piston to head clash. No liners in the block. No shim with the gasket, just the double layered gasket in the sealed packet. To be honest, the gasket looks more like a shim as it is very thin but I've checked the Payen part no. on their site and it is correct for this application. What surprised me was the price of the gasket, £14, whereas the fibre gasket the factor has listed is around £50!!? (I didn't buy on price BTW, the factor just ordered what showed up in their parts system, I had no idea it was a multi-layer gasket). So, tomorrow I'll put the head back on with the fibre gasket I originally fitted the wrong way around and see if the crank turns. Hacked off as I thought I would have it running before new year, sick of the sight of it now. Worst is my brother has claimed the car (but he's conveniently never around to work on it) so I really just want it running and out of my sight.

[robin]

Chin up matey! If I were in Scotland I would come round and give you a hand.

As you just want shot of it, build it up with the other gasket fitted correct orientation, get it running, put it on the street, job done

Cheers,
Robin