Timing Keeps Slipping

[ng_randolph]

Recently, the 1986 X1/9 starting to sputter and white smoke after a five minute idol.
I checked the timing the timing was way off, + by a lot. I reset the timing back to +10. I drove the X and it drove fine for a few miles and again it started acting up, sputtering, no power and smoking.
Could this be because of bad gas? Or, the timing belt (which was changed out prior to me owning the X)???
Don’t know what to do and at the end of my rope right now.
This did all start after I filled up with 89 octane non-ethanol gas.
Any suggestions would be greatly appropriated.
Thanks,
Mike

After this first happened, you were able to correct it by resetting the ignition timing. This would seem to indicate that the valve timing was and is correct, and that the problem is not related to cam, crank or their respective sprockets. As others have mentioned, a distributor that is not properly clamped in place could cause this, and in this case you would be able to see (but may perhaps not notice) that the distributor had moved. I am wondering if perhaps the aux sprocket is not properly registered to the aux shaft (sheared dowel / Woodruff key; don't know what is used here). There is a bit of power transmitted to the aux shaft, as it drives the oil pump, so the sprocket could easily be slipping on the shaft if it is not properly secured.

 

[Tavalin]

Sounds good. Be sure to double check the stud, clamp and nut that anchors the distributor. From what you described it seems it wasn't fully holding the distributor in place. Try spinning the nut all the way down the stud without the clamp in place, to see if the threads are good the full length.

Dr. That is the first thing I did. I reset the timing and checked that everything was tight with no slippage. The distributor is good to go. Everything inside still looks new as well.
One thing off the check list. Now on to no. 2 or 12003...
Mike

 

[Tavalin]

After this first happened, you were able to correct it by resetting the ignition timing. This would seem to indicate that the valve timing was and is correct, and that the problem is not related to cam, crank or their respective sprockets. As others have mentioned, a distributor that is not properly clamped in place could cause this, and in this case you would be able to see (but may perhaps not notice) that the distributor had moved. I am wondering if perhaps the aux sprocket is not properly registered to the aux shaft (sheared dowel / Woodruff key; don't know what is used here). There is a bit of power transmitted to the aux shaft, as it drives the oil pump, so the sprocket could easily be slipping on the shaft if it is not properly secured.

So, to check that is to pull the distributor completely out? Everything seems to be tight and correct but that doesn’t mean anything.

When I originally pitched the X1/9 I had to pull the distributor to set everything back to TDC no. 4 piston from TDC no. 1. It was 180 degrees out of time when I purchased the X (Matt noticed that from a pic I sent him about something else) and was that way for over 18 years according to the PO.
So I hope that is not the issue. I replaced the dizzy, cap and cleaned everything inside prior to even noticing the engine being completely out of time. Doesn’t mean that cant be the issue.
Oh well, I have until September 28 to get her running and reliable again for a major car show I am already invested in.
All this happens when I finally have the compression back where it is supposed to be and running correct.
The trials and tribulations of owning a Fiat/Bertone.
Mike

 

[Brad Garska]

I'm not sure if it has been mentioned (didn't read entire thread) check the distributor advance to ensure it is not sticking. This will cause erratic ignition timing.

 

[Dr.Jeff]

then 10mm bolts with 12mm upper shank

I believe these (the third ones in the factory parts image) are the TTY ("stretch") bolts? They are 10mm bolts that actually reduce in shank diameter then enlarge again back to 10mm (not 12mm) at the upper shank?

EDIT: I just looked at the image again. Perhaps the ones I am describing here are the fourth ones (M10, TTY), not the third ones (also M10, but not TTY)?

Here is why I ask that. I have two sets of M10 (1.25) head bolts that have different shanks. The dimensions I'll refer to are actual measurements. In this first picture you can see them side by side; the black arrows are 10mm, the yellow arrows are 9mm. The top bolt is a M10 thread but the shank is actually 9mm all the way up until it reaches near the top, where it becomes 10mm. The bottom bolt is also a M10 thread but has a 10mm shank all the way to the head. You can see the difference immediately where the threads stop and the shank begins, and again near the heads. I assume the top bolt is a TTY ("stretch") type, and the lower one is not?

This second picture is the same two from a little different angle. Here you see a couple of other differences between the two types. The top bolt (TTY?) is longer overall (red arrows), and has a longer section of threads (blue arrows).

If the top bolt is a TTY, it is not like others that I have encountered on other (non Fiat) engines. Usually the shank would begin at the the threads as 10mm, then reduce to 9mm, then enlarge again to 10mm before the head. Something of a Dolly Parton / Mae West "hourglass" shape. The top bolt in my pictures does not start as a 10mm shank from the threads, but is already 9mm. Compare the two bolts right where the threads stop (blue arrows in second picture).

 

[Dr.Jeff]

Mike, there could be two possibilities related to slipping drive gears. The one referred to earlier was the toothed belt pulley on the end of the aux shaft (driven by the timing belt). If that pully was slipping then the aix shaft could change position and therefore the distributor as well. The second one is on the end of the distributor shaft. It is part of the distributor assembly. There is a drive gear that the aux shaft connects to to rotate the distributor. If the pin that secures that gear to the distributor shaft has failed, then the gear will slip relative to the shaft and change the timing. It would be unusual for either of these to happen, but they are things to check.

 

[Jeff Stich]

I believe these (the third ones in the factory parts image) are the TTY ("stretch") bolts? They are 10mm bolts that actually reduce in shank diameter then enlarge again back to 10mm (not 12mm) at the upper shank?

EDIT: I just looked at the image again. Perhaps the ones I am describing here are the fourth ones (M10, TTY), not the third ones (also M10, but not TTY)?

My comment was made solely in direct reference to the factory parts diagram that Dan posted, which details the various bolt diameters & bolt lengths. For clarification, diameters "Ø" are underlined in green, lengths "L" are underlined in red:



All of my SOHC engines use the old 12mm full-shank bolts or studs & bolts, so I have no comment on TTY or your apparent (mix of) odd-sized bolts, sorry.

 

[Dr.Jeff]

Thanks Jeff, I was asking because I'm not sure. Like I said these look different from the TTY one's I've seen. But like you, most of my experiences have been with regular bolts, not TTY. So honesty I'm not sure if they are TTY or not.
That factory image is the first time I've seen a list of the different ones.

 

[Tavalin]

Going to dig in when I get home. Going to try and find the issue(s) prior today ordering parts. I am going to change out the tensioner and timing belt anyway to there is one order. Just need to find the root cause and go from there.
Thanks,
Mike

 

[Dr.Jeff]

Never hurts to change the T-belt and tensioner regardless.

I'm always surprised at how bad the tensioner bearing is despite a brand new belt on all of the engines I work on.

 

[ng_randolph]

So, to check that is to pull the distributor completely out? Everything seems to be tight and correct but that doesn’t mean anything.

I am suggesting you remove the aux sprocket and check if the dowel is present and intact. JimD posted a photo of his engine with the aux sprocket removed here, and you can see there is a dowel to register the sprocket to the shaft. There isn't much room around the aux sprocket with the engine in the car, so I don't know how easy it is to remove the sprocket.

 

[Tavalin]

I am suggesting you remove the aux sprocket and check if the dowel is present and intact. JimD posted a photo of his engine with the aux sprocket removed here, and you can see there is a dowel to register the sprocket to the shaft. There isn't much room around the aux sprocket with the engine in the car, so I don't know how easy it is to remove the sprocket.

That looks very difficult to do with the engine still in. I will look at it tomorrow and see what all is going to be involved.

Got caught up in family stuff when I got home from work today so I wasn’t able to even look at the X1/9.
Mike

 

[Dr.Jeff]

On the engine I recently took apart, the nut that holds the pulley onto the aux shaft was very difficult to remove. I had the engine out and on a stand, and was using a impact gun. But it still took a lot of hammering with the gun before it eventually broke loose. Not that they are all that way, but if it's not been off in a long time then it can get corroded and very frozen. I don't recall if the hole for the drive pin penetrates all the way through the pulley and if the end of the pin itself can be seen. But that might help if it can. Although the pin could still be sheared, if you can see it then at least you know it is there. Eliminates one possibility without removing the pulley.

Here is another thought. Since you are going to replace the timing belt anyway. While the belt is off, remove the distributor cap and turn the aux shaft pulley with one hand while holding the rotor with the other hand. See if the two feel really well connected, or if there might be a possibility of one turning without the other. This may help determine if there is any problem with either the pulley drive pin or the distributor drive gear.

 

[Tavalin]

On the engine I recently took apart, the nut that holds the pulley onto the aux shaft was very difficult to remove. I had the engine out and on a stand, and was using a impact gun. But it still took a lot of hammering with the gun before it eventually broke loose. Not that they are all that way, but if it's not been off in a long time then it can get corroded and very frozen. I don't recall if the hole for the drive pin penetrates all the way through the pulley and if the end of the pin itself can be seen. But that might help if it can. Although the pin could still be sheared, if you can see it then at least you know it is there. Eliminates one possibility without removing the pulley.

Here is another thought. Since you are going to replace the timing belt anyway. While the belt is off, remove the distributor cap and turn the aux shaft pulley with one hand while holding the rotor with the other hand. See if the two feel really well connected, or if there might be a possibility of one turning without the other. This may help determine if there is any problem with either the pulley drive pin or the distributor drive gear.

Dr. Jeff,
Great advise. I am going to have to print this off and perform the troubleshooting per your words.
Still haven’t had the time to start the project. Plus, it storming outside and too humid in the garage to even think about working on it.
Maybe this weekend but I really need to get moving on it.
Thanks...
Mike

 

[Dr.Jeff]

I happened to have the aux shaft pulley off and took a couple of pics.
The red arrows are the pin on the shaft, and the hole in the pulley where the pin fits. Due to the large size of the bolt head/washer, you may not be able to see the pin very well with the pulley still on.

The yellow arrows are interesting cracks in this pulley. They start at a large steel bushing in the center of the pulley and radiate outward. I don't know how common this is or what exactly caused them.

 

[Jeff Stich]

View attachment 23995

The yellow arrows are interesting cracks in this pulley. They start at a large steel bushing in the center of the pulley and radiate outward. I don't know how common this is or what exactly caused them.

It's fairly common for these old-style plastic/phenolic pulleys (on both camshaft & auxiliary shaft) to fatigue from age/use. Sometimes they'll get cracks like yours, sometimes the metal center hub gets loose where it meets the plastic pulley, so the pulley may wobble or quickly slip back & forth on the hub (makes a rhythmic clacking sound similar to an exhaust manifold leak). This can also be a source of wandering ignition timing.

Do yourself a favor & get/install one of the metal aux. shaft pulleys (couple different styles to choose from), & toss the plastic one in the trash. Same goes for the cam pulley if that's what you have.

 

[Dr.Jeff]

couple different styles to choose from

Interesting JeffS, I had not paid attention to the various materials used on the aux pulleys. For the cam pulleys I have three types; one is a stamped(?) steel, another a cast steel (iron?), and then a aftermarket adjustable aluminum.

On the metal aux pulleys, when you say a couple different styles to choose from, do you mean stamped vs cast or otherwise?

This can also be a source of wandering ignition timing.

Mike, something else to look for...if you have a plastic pulley (difficult to tell by looking at them). The outer portion of the pulley can spin on the inner portion of it. Look at my last picture (earlier post) how there are two parts to the plastic pulley. A center section (toward the red arrow) and the rest of it (toward the yellow arrows). I suppose there really isn't any easy way to know if it has spun. But read the description JeffS gave on how that would sound. And look for cracks like on mine. However I think this would be a unlikely cause of the timing changes, but I suppose it is possible.

 

[Tavalin]

Okay,
Ordered a head gasket, tensioner and belt. I now need to know what bolts to use. I have reread the posts and am very confused concerning the 10 bolts for the head. From what I think I understand is that I can’t reuse the stretch bolts. So, I need to purchase a new set. I saw where there might be another alternative to the stretch bolts. Can’t remember what the type is called or even the specs but they are supposed to be as good or better.
I don’t know.
What is recommended?

Also, I keep telling myself that I am going to start the troubleshooting effort but keep getting pulled away. Time is ticking down until the car show September 28th. I need to just buckle down and start doing it.
But, family first. I have a friend that wants to come over. He wants to help. Very technical guy. Amazing custom built (by him) a one owner 1996 Toyota MR2. I will share a pic of his car someday. The engine is just a work of art. Hard to get him to commit because he is also very busy.
That is life but again I say, family comes first.
Mike

 

[Dan Sarandrea (Phila)]

Okay,
Ordered a head gasket, tensioner and belt. I now need to know what bolts to use. I have reread the posts and am very confused concerning the 10 bolts for the head. From what I think I understand is that I can’t reuse the stretch bolts. So, I need to purchase a new set. I saw where there might be another alternative to the stretch bolts. Can’t remember what the type is called or even the specs but they are supposed to be as good or better.
I don’t know.
What is recommended?

Also, I keep telling myself that I am going to start the troubleshooting effort but keep getting pulled away. Time is ticking down until the car show September 28th. I need to just buckle down and start doing it.
But, family first. I have a friend that wants to come over. He wants to help. Very technical guy. Amazing custom built (by him) a one owner 1996 Toyota MR2. I will share a pic of his car someday. The engine is just a work of art. Hard to get him to commit because he is also very busy.
That is life but again I say, family comes first.
Mike

Hopefully you purchased an Astadur or equivalent no-retorque head gasket, because that type of head gasket works together with the stretch bolts to eliminate the cumbersome retorquing requirement.

If our regular vendors don't have any stretch bolts, here is what you need from Eursport in the UK. Small stuff like these gets here pretty fast. https://www.eurosport-uk.net/shop/i...id=296&zenid=157ef3edad486cbc6e8d1006541ef82f

 

[EricH]

I saw where there might be another alternative to the stretch bolts.

You don’t have to use the stretch bolts. The only downside is that you if don’t use the stretch bolts you’ll need to retorque them once after a few hundred miles. (This means taking the cam box off if you don’t have the magic Fiat wrenches).

You’ll want grade 10.9 M10x1.25 bolts, five 100mm and five 80mm. Belmetric or any of the other suspects will have them, or you can buy a set from Midwest.