five alarm emergency for Lil B

[eightsandaces]

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.

[stephen wilson]

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

[eightsandaces]

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...

[eightsandaces]

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.

[Lil bastard]

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 - 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.

[eightsandaces]

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

Originally Posted by eightsandaces

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

[eightsandaces]

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

Originally Posted by eightsandaces

My current plan? (which he said sounded good)

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


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

[Lil bastard]

Originally Posted by eightsandaces

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

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