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Timing Degree T-Jet

How to Degree a Cam

Relevant Module: Camshaft Fundamentals > Adjusting Camshaft Timing

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Discussion and questions related to the course How to Degree a Cam

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Hello, i have One question.

1.4 liter Turbo manufacutered by fiat group has got timing belt with 1 big pulley on the exhaust cam (which can be changed with a variable pulley) , and in the opposite site both the cams has got a Gear wheel that make them turning, both runned by a chain (like the 1.8T vag BAM) i don't know if i'm explained well. I would like to ask and understand how to Degree the intake cam because you won't find variable Gear in the market for this engine , but only variable big pulley for exhaust camshaft

This Is timing belt side, the belt only makes the exhaust rotating

Attached Files

This Is gearbox side

Attached Files

You explained it well - the crankshaft turns the exhaust camshaft with the timing belt, and the intake is turned by a chain from the exhaust.

I don't know what is used to align the pulleys to the camshafts, there will usually be either a hole in the pully and a pin in the camshaft (or vice versa), or a keyway and key.

There are two "old school" methods, from before verniers were made, where an offset bushing is used in an oversized hole, or an offset (AKA stepped) woodruff key is used.

Like these - https://iskycams.com/shop/index.php?main_page=index&cPath=155

and like these - https://minisport.com.au/products/mini-moke-camshaft-woodruff-key-2-degree-offset

In either case, the problem may be finding what fits your engine - but a competent machine shop should be able to make a set of each, in differing values.

Hopefully that gives you something to think about.

Guys, i have a problem. My t-jet has got a "semi-head". I have cylinder head with valves and valve sprint, and i have another piece that goes on the cylinder head. I attach photo so you can see . It's completely enclosed, i have only 1 side that can be open to change the cams. I Need to Degree It, someone has got the same problem?

Another issue, this car has got hydraulic lifters. I buy 2 brand new hydraulic lifters to lock them at maximum extension a for degreeing purposes , but i don't know how to modify to block them at maximum extension.

PHOTO 1: Cylinder head with valves and valve spring (file 004944.jpg)

PHOTO 2: upper part of the semi-head (file 005054.jpg)

PHOTO 3: lower part of the semi head (you can see hydraulic lifters) file 005110.jpg

In the middle of the semi-head i have got the cams

Attached Files

Ah, so the camshaft housing is in one, single, piece with the camshafts fitted from one end? That end has the chain drive under the cover? Then, if that wasn't bad enough, you have no way to access the valves with the assembly in place?

The good news is that it's going to be, relatively, simple to time the intake to the exhaust - you may not actually need the solid lifters, as the DTI should be able to pick up on the underside of the lifter, or you can have someone machine up a couple of aluminium slugs that will slip into the lifter bores that the lobes can operate against. Again, depending on the indexing method of the chain' sprockets, this may be fairly easily done on a bench which allows easy access.

The bad news is that it's going to be very tricky to time the exhaust, because you don't have access to the valve train, to see what they're doing.

I don't know if this will work, and theres'a lot of faffing (messing) around involved. After setting the intakes to the exhaust, I would look to fabricate an adjustable pointer that would bolt to the front of the head, preferably a fairly strong 2-piece design, and I would find the exhuast, or inlet but that adds an uncertainty, valve's maximum lift point and adjust the pointer to a mark on the pulley - a light centre punch should do if there isn't a convenient one already there. Then I would fit it to the engine with a lightly bolted down hgasket of the thickness I would be using, and bring the crankshaft to the corresponding position for the fully open valve, as previously marked. Then, if required I would adjust it with whatever option is suitable, as mentioned before (really bad news would be if it was one of the engines that didn't use any alignment method, just torqued down really tightly). Then I'd repeat the max'lift check using the same method for the inlets.

I don't know if that makes a lot of sense, and I hope someone can further comment, but in the meantime, I'd suggest you continue your earch of the FIAT forums to see what others have done.

Ok, thank you for your time! i'll try

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