3.4L Motor Swap Underway!

[chaudanova]

^^ Brilliant! Love the innovation...

[Cloudsurfer]

Very ingenious indeed. Unfortunately, you are going to need more than just a tool to turn the cam to get it back into time. You really need the timing tools, and the auxiliary tensioners.

[insite]

Originally Posted by Cloudsurfer

Very ingenious indeed. Unfortunately, you are going to need more than just a tool to turn the cam to get it back into time. You really need the timing tools, and the auxiliary tensioners.

what makes you think that? i understand the process fairly well, but i've never timed one of these.

[Cloudsurfer]

Originally Posted by insite

what makes you think that? i understand the process fairly well, but i've never timed one of these.

Well, the first thing I would do is visually check if the chain did slip a tooth or not. If you put the engine at TDC, and the slot on the cam is parallel to the line of the head/ valve cover joint, you can be fairly certain it's in time (in your picture, it is not parallel, so if the crank pulley is at TDC you are likely off one tooth). If you pull off the oil extraction pump (take note of its orientation, as they use the same part for both banks, but in different orientation) in the head, you'll see a chainwheel, which is bolted to the exhaust cam by 4 10mm bolts. The chainwheel has slots to allow for adjustment. The intake cam (as I'm sure you know) is driven off the exhaust cam via a separate chain and this contains the VarioCam tensioner. So, if the timing is off on the exhaust, it is also off on the intake. The timing mark, which the timing tool fits into, is on the intake cam. The tool merely holds the cam stationary while bolted to the head.

Hypothetically, if the chain slipped one tooth, you could be able to remove the tensioner and move the chain over one tooth the other way and be done (you'd need the valve cover off for this) but I've never tried doing this. However, to actually time the engine, you must loosen those 4 10mm fasteners, and do the procedure. I would roll the engine over and check both sides if you get stuck doing this. The tool only fits into the cam one way, so if it won't fit on bank 1-3, it would fit into bank 4-6, so if you are timing bank 1-3, you'd have to roll the engine over a turn. When timing the whole engine, you time one bank, then roll the engine 360, then time the other. I then roll the engine several times and double check things. For a 5 chain motor, you do need the auxiliary tensioners, which place a precise amount of tension on the chains. Supposedly you can time a newer, 3 chain motor without these, but you do need the tensioners on a 5 chain motor.

The 10mm bolts holding the chainwheel to the exhaust cam should be in the middle of their adjustment range, so you should have plenty of range to move either way during the timing process. The easiest way of re-timing your one bank would be to move the crank until you can fit the timing tool into that side's cam, lock the tool down, loosen the adjustment bolts on the cam, then roll the engine backward and then forward (to take any potential slack out of the chain) until you hit TDC (you only want to move forward when coming up to TDC), lock the crank with the fixing pin, and then tighten the 4 10mm fasteners (10 pound torque if I remember). Then, roll the engine 2 full revolutions, and re-check.

Like I said, if you get stuck doing this, I would check both banks while you have the engine out of the car and it's pretty easy to do.

Personally, I find the way you time these to be very imprecise, as there is potential variation in way too many places (where the TDC mark is on the pulley, variation in machining those slots into the non driven side of the cam during manufacturing, variation in tolerances in the tool, etc) but short of figuring out "true" TDC with a dial gauge on piston 1 or 4, and knowing the overlap numbers, it is what it is.

[Gilles]

Originally Posted by insite

what makes you think that? i understand the process fairly well, but i've never timed one of these.

Ok, after reading several times Cloudsurfer's excellent and detailed description, the $85/hr and the cardbox on the back of the SUV makes sense to me

[insite]

i talked to jake; he thinks the auxiliary tensioners are total bs and completely unnecessary.

i will be timing the motor with no special tools & will post the procedure w/ pics when i do so. if i don't get to it wednesday, it will be awhile; probably won't get to work on it again until the 16th.

[clickman]

Originally Posted by insite

probably won't get to work on it again until the 16th.

Jeez, I don't know if I can wait that long. Talk about living vicariously through someone else!

[insite]

ok, timed the car yesterday. very straightforward & easy; no need for any funky tools.

to do this right, you'll need a couple of spare parts:

(3) green camshaft plugs (996.104.215.54)
(8) microencapsulated bolts (900.385.275.01)
(2) o-rings (996.107.221.51)
(1) tube of green loctite

first, we need to explain some things. top dead center (TDC) occurs when a piston is at its uppermost position within the cylinder. it's the point at which the piston stops travelling up and begins travelling down. the tricky part is that TDC occurs TWICE during an engine's 4 cycles. the first time is on the compression stroke & the second time is on the exhaust stroke.

per the factory shop manual, we want to be at TDC compression when we time bank 1 (cylinders 1-3) and TDC exhaust when we time bank 2 (cylinders 4-6).

first things first. in the picture below, we're looking at the front of the engine. if the engine were in the car, we'd be looking back through the firewall toward the rear of the vehicle. bank 1 is on the left and bank 2 is on the right.




now we need to remove three of the little green camshaft plugs from the motor. there are six total cam plugs in the motor. in the photo above, you would normally see three. there would be three on the other side as well. they're already removed in this photo.

on the left side would be two plugs. remove the bottom one. on the other side of the motor on the other head, remove the bottom one. on the flywheel side of bank 1, there is only one plug. remove it.

what we've done is to remove the cover for the timing side of the exhaust cams and the index side of the intake cams. more on this in a minute.

now, put a 24mm wrench on the crank pulley and rotate the engine CLOCKWISE until you get close to TDC.






TDC is indicated by a notch on the pully matching a mark on the crankcase as shown in the photo below:






you can 'lock' TDC at the crank by inserting an 8mm bolt through the hole on the pulley marked OT. it will slide into a recepticle on the crankcase as shown in this photo:


.

[Gilles]

Originally Posted by insite

probably won't get to work on it again until the 16th.

A friendly reminder, today is the 15th....!
so, get back to work and Please share your notes..ha!

.

[Overdrive]

insite, any updates here for us dedicated readers? :dance:

[Gilles]

Originally Posted by Cloudsurfer

Very ingenious indeed. Unfortunately, you are going to need more than just a tool to turn the cam to get it back into time. You really need the timing tools, and the auxiliary tensioners.

Ok it seems that the cam on the picture has jumped one teeth, and the cam obviously is still connected to the timing chain.

Question, if you 'loose' the chain tension as much as possible, would this allow you to rotate the cam (jumping teeth on purpose, one at the time) until you get back to the timing mark?

The cam phasing I have done in the past has always been on 'belted' engines, never with a chain which must be much harder, is this doable at all?

Or do you have to remove the valve cover to remove the chain from the cam sprocket, re-align the cam and then re-install the chain?

My questions here are pure curiosity and personal learning purposes, no criticism intended to anyone else comments.
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