five alarm emergency for Lil B
 

OK B, this is a non Porsche emergency but the Fiat blogs suck for tech assitance so here we go.

Fiat 124 1608 cc Twin Overhead Camshaft, I removed the old timing belt and tensioner without first aligning the top timing marks. However, the engine was in pefect valve timing when the belt was removed and the cams and the crank have remained in the proper relationship since beginning the repair.

Is there any reason to think the timing won't be perfect when the belt is simply replaced?

Factory manual states to recheck timing, I plan on using turning the engine by moving the car forward in gear (engine off). If for some reason the timing is off I'm hoping any valve impingment will occur gently. I don't expect the timing to have changed but with an interfearance engine I'm now a bit afraid. Fiat states that the cams and crank should never be moved independantly while the belt is off and so they have not been.

ANY and all help is genuinely appreciated the car belongs to my dad, today is his birthday, I'm hoping his Sunday present is a running convertable.

I would find a service manual, and follow the recommendation for lining up the timing marks. Based on an Integra & Toyota I've done, the cams can easily move, even if the crankshaft hasn't moved. Once you remove the belt, valve spring pressure can turn the cam. Even following proceedure, lining up the marks, I've had to re-adjust the belt because I didn't tension enough slack out of the belt. You can check this by turning the engine over a few revolutions with a wrench on the crank pulley bolt, and rechecking your marks.

Don't rush the job for a deadline, better to get it right!

Steve

day um! Comon 24 looks and not a peep? Nobody has any ideas? on this forum? Ut oh looks like I'll be flying blind Sunday...

Stephen, thanks man, I considered the valve spring tension and potential for the cams to move, I did not observe so much as a milimeter of movement, I'm hoping the timing is sound. I guess the key will be turning the engine slowly to make double sure the relationship is correct, the factory manual states clearly DO NOT turn the cams with the belt off under any circumstances. Hopefully, moving the engine manually, with the belt reinstalled will not cause damage if I go slow and make double sure no valves get bent.

I had a friend who was NUTS for all type of italian cars. He had a Fiat Dino, Ferrari Daytona Coupe, , a '63 250GT and the most pristine 124 Spyder I've ever seen - http://usera.ImageCave.com/Lilbastar... Fiat 124a.jpg He passed away from cancer a year ago and the family sold all his cars. I was hoping to pick-up the 124, but it was the only car the family kept.

IIRC, the Fiat Twin Cam is an interference engine, not because of the valves, but because possibility of the crank hitting the aux. shaft which is arguably worse because it causes a full engine teardown to correct instead of usually just a top-end with a valve interference engine.

Instead of pushing the car in gear (you'll literally have a ton of momentum built-up to damage anything if the timing has shifted), I'd take a socket and breaker bar to the crank pulley instead.

But, I have to caution you, if you think the timing may have slipped, even a possibility, the best thing to do would be to pull the timing cover and re-check the timing marks on the cam sprockets - that's the safest thing to do anyway.

:cheers:

Cam cover is off, auxillary shaft was moved for sure, I have the Fiat crank tool made specially for turning the engine. What damage can the auxillary shaft do? I have not yet determined what it does, I was thinking oil pump. This car is a 1971 has 50,200 on it, no winters, I am now seriously concerned about the engine and I'm really not sure how to put this thing back together B, any other ideas?

The manual only says to recheck the timing after belt replacement, not how to correct any errors, or how to carefully do this. The bearing was rusted and ready to go, I'll be upset of I cause the demise of said engine trying to prevent the demise...

PS I think the pic you posted is a Eurospec, spiders didn't have round marker lights, they are rectangles in US form. assuming I don't wreck it, here's one of the best examples in the entire country.. I need to know the relationship of the crank pulley to the auxillary shaft timing mark, then I could just realign them, right?

http://i232.photobucket.com/albums/ee32/firesphotons2/fiat001.jpg

I don't know if this will help you, but I did the very same thing about 20 years ago on an old nissan pickup.

I was pretty sure the cam didn't move, but was very sure the crank had. I could find the cam timing marks, but not the crank marker - So I inserted a long pencil (eraser side down) into the #1 piston spark plug hole, and gently rotated the crank until the piston pushed the pencil to it's highest point (tdc). Be careful, you have to keep a hand on the pencil, and keep it straight, if you put it in sidewides, it'll snap, and you'll have half a pencil in your cylinder - and make sure to break the lead tip off before you start.

another word of caution - don't rotate the crank "all the way around" to find tdc, rotate it back and forth, gently - make sure your spark plugs are all removed, or you'll feel pressure (at least you should be feeling lots of pressure with the plugs in) and think you're hitting something.

good luck, keep us posted

You may well be right about it being a euro-spec, IIRC it's a '78. Owen was in Int'l. commodities and frequently went to europe and brought back cars - he had an elise from germany which he brought back and did a Sun conversion to (Honda VTEC motor).

Which manual are you using? The Brooklands is OK and gives a step-by-step pictoral on swapping the T-belt and aligning it. Also, there are factory manuals available - Fiat Factory Manuals

Again, IIRC, each camshaft sprocket has a timing mark on the back and a corresponding timing mark on the camshaft housing. Each of those camshaft sprockets should align with the marks on the camshaft housings and the crankshaft timing mark should be at top dead center when # 4 piston is ready to fire. the auxiliary shaft has two marks that should point at approximately 1 o'clock, or towards the tensioner bolt. Here is a link to the factory manual diagram for T-belt replacement - It's for the 2.0L motor, but essentially the same: Fiat 2000 Timing Belt

The cam marks and crank pulley will also line up at #4 cylinder exhaust stroke as well - 4-stroke motor. Be certain not to misalign these settings as you risk poor performance and possibly valve damage. Crank the engine over at least two full strokes to assure that nothing is binding.

If you're real nice, there's a guy in MI who has all sort of instructions for timing on the spider named Mike Bouse. If you email him and introduce yourself, he may be able to better assist you than I because he has waay more experience with Fiats than I do - he's a member of FLU (Fiat Lancia Unlimited). Reach him at: mbouse@chartermi.net

:cheers:

Thanks Fred, I'm reluctant to move the crank or cams independantly of each other as the valve timing should be right, I did not observe and spring movement of the camshafts and I know the crank didn't move. I just spoke to a local mechanic who told me the auxillary shaft drives the oil pump anf the distributor but cannot strike the crank, it's only the valves that are in danger. apparently the aux shaft alignment has more to do with the iginition timing than anything else.

My current plan? (which he said sounded good)

1) replace belt and tensioner as is.

2) remove plugs, hand turn crank slowly, observe timing marks, hope for smooth operation.

3) assuming the timing is correct, align marks for cams and crank, pull belt off of tensioner, turn aux pump to it's mark, reassemble, pray like hell...

I have a Fiat factory manual to work from, not as good as I wish it was..

this is a good plan, but a suggestion. Mark the crank pulley with a dab of white out (if it doesn't have a clear marking on it) and count how many turns you rotated the crank.

If you're timing is off, you car "rewind" the crank to the original position...it'll help you start over...

..I've done a few different belts on different models, and I don't think I've ever done one without at some point being completely worried I messed up - a little fear here is a good thing, considering the consequences of a mistake. I bet you've nailed it...keep us posted

On an interference engine you do NOT want to rotate the crank if the timing is off. That forces the pistons up into the open valves! If you have that issue for more than a few degrees, you need to remove the head, set the crank to TDC (different for many motors - the FIAT uses the #4 cylinder, NOT the #1), then rotate the cams (off the block) to their approximate positions before reinstalling the head.

:cheers:

yes, of course.

but if you're rotating the crank, and you're off by 1degree, it's possible to rotate the crank several times before the valves met the piston and feel any kind of resistance...so knowing how many times you turned the crank will allow you to return to the starting point.

OK... we mostly agree. I just would not personally tell anyone who suspects a timing problem to rotate the crank, esp. on the net where I'm not able to see for myself how far off it may or may not be.

Another thing occurs to me though. If installing a belt, has the lister checked valve for adjustment? If not, and the car uses the old inverted bucket-type tappets (lots of Brit cars, SAABs etc. use this), it's necessary to pull the head to rotate the cams to check the valve clearances, then mic the shims to determine which have to be swapped and by how much. It's an ugly job which basically needs to be done twice to be sure everything's correct. If this is the case, your manual will give you an OK range for the valve clearances. If such, you want to set the valves to the most generous setting within the OK range because as the mileage piles up, the valves get pushed deeper and deeper into their seats closing the gap between the tappet and the cam lobe. Setting the clearances to the maximum allowable spec prolongs the time that the valves will remain in spec before needing to do the procedure again. I'm not certain the FIAT Twin uses this method, but if so, it's worth doing this work before installing the T-belt.

:cheers:

we 100% agree - but at some point you have to hand rotate the crank - it's just part of the job, and being able to return to the point where you might have been closest to TDC is of tremendous value.

How could it possibly be off that much is shut down, not moved and previously in synch? I'm going to email your pal, work net was down all afternoon.

It may not be all that much off, but turning the crank is not the way to find that out. Think of the motor like a symphony of parts, when everything hits their mark, there's beautiful music, but when they are out of sync, the music (read performance) is awful and sometimes injurious to the parts.

We're on the internet here... you don't know me and I don't know you, your skill level or the actual positions of any of the various timing marks - only what you tell me. I'm not going to tell you anything which could injure your car. Would I turn my crank a degree of two - sure, but slowly with a socket and breaker bar trying to feel (as a safecracker would) what the internals are doing. At the slightest resistance, I'd stop. That's one reason I recommended you turn the crank rather than push the car in gear... you have no feel for what's going on until it's waay too late.

BTW, I'm not a friend of Mike Bouse, I've never met him. But, my late friend knew him or of him, and told me that he lived in MI and he would respond to emails sent to him on Fiat questions, plus I've seen his name mentioned - in some reverence - on some of the FIAT boards where he's offered to send procedures to those emailing him. I put it up here figuring it was worth a shot for you. I assume you probably already know this, but my friend also gave me the link to what he said was the best FIAT parts source in the country - C. Obert & Co. out in Cali - C. Obert & Co.

I don't have this stuff right at my fingertips, but in response to you, I went and reviewed a bunch of past correspondence and emails my late friend and I had exchanged through the years. It was kinda nice to be able to go back and re-read them and remember what good times we've had and what a truly good friend Owen was to me... R.I.P.

:cheers:

It is much, but better to find out rotating the crank by hand and finding out before you button up the engine. When you rotate by hand, you'll feel the slight resistance.

If you think the you did the job correctly, but you're missed by a little, finding out by rotating the crank by hand will prevent you from doing any major damage to the engine.

It's a "just in case I messed up" measure, it's something do after every timing belt job. :cheers:

OK Progress report and important question, many thanks for all responses, it's good to get all opinions and research done before holding wrenches. Mike did get back to me, seems like a very nice and knowledgeable man. Regarding the crank turner, I have the luxury of the factory Fiat tool.

The bottom line question is this:

Will hand turning the crank with belts on as slowly as humanly possible and stopping at the least bit of resistance hurt anything?

The auxillary cam as it turns out has a fuel pump cam on the end of it, the instructions state the cam can be returned to the 1 o'clock position irrespective of the valves and crank, boy is that a "hole tightening" sentence to accept. It was rather ambiguous as it then says it has to be close to the other marks, what? Lil' B has me so jumped up I'll be turning the crank like my EOD cousin takes on an assignment!!

oh the pressure!

BTW B, I'm a decent wrench, (smart enough to do homework) but dumb enough not to have found all this before starting the project. My father, still an AFST member mechanic, turned 82 today, he just doesn't remember anymore. He's counting on me!

PS Steel plugs, Aluminum head, will a break free soak do the job?

Thank you all.

Glad the email worked out for you. IMHO, you need to be like an EOD tech when spinning the crank... you'd be surprised how little resistance is required to bend stuff on some engines. But, as you describe it, I'm comfortable that you're safe to proceed.

BTW, I wasn't impuning your abilities at all, it's just that when someone here gets on and says stuff like "I know it's a little off", or "it may have moved", the last recommendation I'm gonna make long-distance is to spin the crank.

I've done a lot of mechanical timing in my day, in fact just a month ago I completed a valve adjustment and timing chain replacement on a 48 valve jaguar V12 with shimmed bucket tappets from a '94 XJS Cab. That was arguably the worst automotive experience of my life - checking clearances, micing shims, moving shims around where possible and figuring out what shims needed to be ordered for what cylinders. I finally had to write an Excel program just to keep it all straight - like crawling on the edge of a straight razor!

But, as involved as that was, I once did a FIAT/OSCA few-off 1200 race engine which had no reference marks whatever. You had to mount a degree wheel on the crank and a dial indicator on the cam lobe, then run a straight edge from the degree wheel to the cams - the whole thing depended upon your seat-of-the-pants accuracy... and you think you're experiencing performance anxiety?

A long time ago, I made a tool to make sure everything stayed as set when I had a Jenson-Healey w/ Lotus 910 engine. I took a piece of bar stock and spot welded some welder's spring clamps to it to hold the cam sprockets in place, the other end on the crank pulley. I then made a reference mark on the block w/ a paint pen. When it came time to add the belt, I could check the reference mark and be certain nothing had moved.

Realize that the first time is scary. But, once you've done it, the next will be a piece of cake. IIRC, the FIAT motor needs a new belt every 30k mi. So, if you keep the car long enough, you'll get to visit this again. From the sound of your experience, and your anxiety, I believe you'll be fine. You can only test the water so far... eventually you just have to jump into the pool.

:cheers:

momentum is your enemy - and your ears are your friend. If you're off by a little, it will take several turns before you feel and hear it.

It's very easy to bend a valve by rotating the crank with a wrench, but by hand, it's much much harder. You also have the advantage of knowing your firing sequence - so as each cylinder approaches it's tdc, watch the positioning of your valves.

And remember to keep track of how many times you turned the crank, if (and from the sounds of things, this isn't going to be a problem) you're off, and you feel like you're fighting to turn the engine, rewind the crank to where you started.

Looking forward to hearing a great success story tomorrow!