New engine issues

[digitech]

Okay, so finally was able to get the new engine started late today. Took a while for it to start - couldn't seem to get fuel up from the tank and then had to jack the timing around a little. But the real issue is it looks as if the timing belt wants to walk off, to the rear of the sprockets. What would cause this - I know it wasn't this way before I rebuilt the engine? And is there any definitive way to tell which sprocket belongs on the intake and which goes on the exhaust cam?

Also, I have constant clatter while the engine is running and while I rev it as well. I assume it's valve clatter but I thought I have adjusted the valves fairly well on the bench.

Anyways, if anyone has some insight into these issues, I'd appreciate it.

[So Cal Mark]

with the camshaft dowel straight up, the timing mark on the pulleys should line up with the boss on the cam housing. Shouldn't be any clatter on a new engine

[digitech]

Yep, that checks out. I also verified proper sprocket placement via some orginal photos after I bought the car 7 years ago - I'm usually pretty good with the bagging/tagging so I DIDN'T THINK they were wrong but you never know.

Any ideas as to what's causing my timing belt to walk towards the rear?

I will begin the valve clearance recheck tomorrow - did I tell you how much I hate doing THAT on the car???????????????

[So Cal Mark]

is the aux shaft timed properly? Are your cam pulleys plastic?

[pastaroni34]

Double check that your aux and cam pulleys are torqued down to 83ft-lbs. This can cause both your belt walking issue and the clicking you hear.

[digitech]

Timed the aux shaft properly @ 1:30 and the pulleys are metal. However, they are not torqued to 83ft.lbs. - I'm sure the Fiat manual said something on the order of 35ft.lbs???

[So Cal Mark]

the aux shaft should be at 1 o'clock or lined up with the pivot bolt on the tensioner. 130 would be at the bottom as would any :30 oclock

[digitech]

Okay, then it's at 1:00 - just a difference in how we read positions I guess - it's right in line with the bolt as shown in the manual. Speaking of which, don't know where I got my torque spec from but the manual clearly states 87 ft. lbs for the cam/aux sprocket bolts as Jason said so I will re-torque them properly.

Am checking valve clearances today.

[baltobernie]

... But the real issue is it looks as if the timing belt wants to walk off, to the rear of the sprockets. ... And is there any definitive way to tell which sprocket belongs on the intake and which goes on the exhaust cam?

The timing belt is approximately 3/4" wide, and the pulleys are about 1", so there is plenty of room for the belt to walk back and forth. That's why there are lips on the pulleys; on the front of one, and the rear of the other to keep the belt from escaping.

With the pulleys on a workbench (concave side down), or on the car (looking from the front), the intake is usually marked with an "A", the exhaust with an "S". If the pulleys aren't marked - with the alignment pin at 12 o'clock, the intake will have a hole at 11:30, the exhaust at 12:30.

With the provenance of these cars murky at best, new owners are always encouraged to perform this simple check. We've seen cars with both pulleys identical, and, more frequently, pulleys swapped. The engines run poorly with the wrong alignment.

[digitech]

Valve clearances checked and there were no loose valves, there were however 2 way-too-tight intake valves so those will get re-shimmed. And both camboxes have leaks! Re-checked the torque of all cambox bolts and all were fine so I'll have to pull them and try some sealer with new gaskets; I was thinking I've heard of people using double gaskets - does this work?

The thing about the timing belt is it walked to the rear and has stayed there, slam up against the lip on the intake pulley; I've never seen this before and it would seem to indicate to me that one of the surfaces that it rides on is out of alignment slightly. I have not run it since tightening the pulley nuts though and perhaps that has fixed it - we'll see. Thanks for the help and suggestions, I need all I can get! I will try to get some pics tomorrow to illustrate the belt issue.

[ventura ace]

[quote="digitech"]Valve clearances checked and there were no loose valves, there were however 2 way-too-tight intake valves so those will get re-shimmed. And both camboxes have leaks! Re-checked the torque of all cambox bolts and all were fine so I'll have to pull them and try some sealer with new gaskets; I was thinking I've heard of people using double gaskets - does this work?
[quote]

It works to make twice the space between the head and the cam tower, which is why many people do this, due to a problem with the shim thickness needed being too thin (valve stems protrude to far. If you are asking if it helps for sealing, I can say that it adds another flow path for a leak. The leak is likely due to one or both of the sufaces not being flat or scratches in the surfaces. You can either have the surfaces machined flat, or use a sealer as you suggested. Hope it works for you!

Alvon

[fiatfactory]

.

[digitech]

Thanks for the advice! I was suspecting the sealing surfaces as well, I will give them a good going over, dress if needed, and double up on the sealer - I use Permetex Aviation gasket sealer, the sticky brown stuff. I knew the double gaskets would affect the valve clearances but was willing to risk it if it would fix the leaks. This is a MOST frustrating area to have leaks in as the oil runs onto the exhaust manifold and to fix them requires taking off the timing belt and pulling the box. In my case, not too bad considering I needed to re-check all of my timing sprockets anyway.

This is a COMPLETELY rebuilt engine with new everything. The initial machine shop work was performed by Paeco and when they were finally done, I had my doubts about some of it but that is another story. I can say I would never go back or buy another part from them! I then took the whole engine to another, local shop and had them go through it again, fixing what they found and re-balancing. You'd think it would be perfect after all of that time and money, hence my concern over the noise when I got it running. Hopefully, I'll have good news after getting it back together this weekend.

I think I will be looking for a new wife if that engine has to come back out!

[fiatfactory]

.

[pastaroni34]

Here's another thing to check that has happened to me once.. had some terrible clacking on a new engine I purchased. It was so bad I thought I had rod bearing issue. Turned out the builder didn't torque the flywheel bolts down. The clicking was the flywheel wobbling around. Luckily it didn't come off..