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Discussion Starter #1
Today I checked the timing on my Busso 3.0. The results looked pretty bad - interested to know what others think.

It's in a recently-acquired GTV that has not run for several years; the guy I bought it from was in the trade and mentioned his mechanic had changed the cambelt at some point. The belt itself looks to be in good condition, and has evidently not been "wandering" on the sprockets.

When I removed the cambelt cover I discovered red paint blobs on the cover and on one of the cam sprockets - that didn't exactly fill me with confidence that cam locks had been used previously.

From the pics below you can see that the inlet cam on the rear bank is timed about right; but the other three are out, with both cams on the front bank out by some margin.

So a couple of questions:

1) How badly would this have affected the engine's running?

2) I need some longer bolts for the cam locks. Can anyone confirm what size they are - they look like M8 standard pitch?

(I've tried the bolts I have for my Twin Spark cam locks but obviously they are a different size... )

Pics below show paint blobs on the inlet cam, rear bank; then the locks on both cams on the rear bank; then the inlet cam on the front bank; and finally the exhaust cam on the front bank.
 

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Those cam locks wont hold them in the correct position....longer bolts or not. The lobe shape is different to the cut out on the locks so the cams will have play even when bolted down.
 

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Discussion Starter #3
Those cam locks wont hold them in the correct position....longer bolts or not. The lobe shape is different to the cut out on the locks so the cams will have play even when bolted down.
These are the LaserTools cam locks for the Busso V6 - which quotes the correct engine code for my car...?

If you look at the first pic, the cam lock fits the lobe on the rear inlet cam spot on. What makes you say the lobe shape is different (not a criticism - just curious)?
 

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just a quick question. when i do the3.2 the locks all sit on different lobes not all on the front lobes .. so maybe they also need to be on different lobes too

if i recall i changed the supplied bolts m8 x 1.25 pitch.. for either 40mm or if they were 40mm for 45mm .. also bolts wont hold cams still just for location need a pin wrench to hold pulley still while torquing up

https://www.totallyalfa.com/shop/tools/v6-camblock-fixings/ bolts

https://www.totallyalfa.com/shop/tools/alfa-romeo-v6-busso-24v-12v-and-twinspark-exhaust-cam-pulley-tool/

and a dial gauge for checking tdc too cheapest on ebay

https://www.totallyalfa.com/shop/tools/tdc-gauge-holder/

https://www.totallyalfa.com/shop/tools/v6-crankshaft-nut-socket/

https://www.totallyalfa.com/shop/tools/v6-busso-engine-cam-belt-tensioner-adjustment-tool/
 

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just a quick question. when i do the3.2 the locks all sit on different lobes not all on the front lobes .. so maybe they also need to be on different lobes too

if i recall i changed the supplied bolts m8 x 1.25 pitch.. for either 40mm or if they were 40mm for 45mm .. also bolts wont hold cams still just for location need a pin wrench to hold pulley still while torquing up

https://www.totallyalfa.com/shop/tools/v6-camblock-fixings/ bolts

https://www.totallyalfa.com/shop/tools/alfa-romeo-v6-busso-24v-12v-and-twinspark-exhaust-cam-pulley-tool/

and a dial gauge for checking tdc too cheapest on ebay

https://www.totallyalfa.com/shop/tools/tdc-gauge-holder/

https://www.totallyalfa.com/shop/tools/v6-crankshaft-nut-socket/

https://www.totallyalfa.com/shop/tools/v6-busso-engine-cam-belt-tensioner-adjustment-tool/
Back two cam locks sit on the lobes closest to the belt. Front bank inlet cam - lobe closest to gearbox, front bank exhaust cam - lobe closest to timing belt. Its just the front bank inlet which is the odd one out.

You can crack off the sprocket bolts and turn the cams one by one until they are all correctly positioned, at this point I'd just doublecheck the tension is OK, re-tension if necessary and then tighten the sprocket bolts again. The hardest bit will be freeing the sprockets from the tapers if the belt is going to be left on.

It's going to run a million times better with the cams timed properly, whoever did it before was clearly a bit of a nugget. I'm not sure how much faith I'd have in the belt, tensioner, idlers for the long term but if you're justing wanting to see if it can run better then there's no harm in retiming it with the belt left on for now.
 

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Today I checked the timing on my Busso 3.0. The results looked pretty bad - interested to know what others think.

It's in a recently-acquired GTV that has not run for several years; the guy I bought it from was in the trade and mentioned his mechanic had changed the cambelt at some point. The belt itself looks to be in good condition, and has evidently not been "wandering" on the sprockets.

When I removed the cambelt cover I discovered red paint blobs on the cover and on one of the cam sprockets - that didn't exactly fill me with confidence that cam locks had been used previously.

From the pics below you can see that the inlet cam on the rear bank is timed about right; but the other three are out, with both cams on the front bank out by some margin.

So a couple of questions:

1) How badly would this have affected the engine's running?

2) I need some longer bolts for the cam locks. Can anyone confirm what size they are - they look like M8 standard pitch?

(I've tried the bolts I have for my Twin Spark cam locks but obviously they are a different size... )

Pics below show paint blobs on the inlet cam, rear bank; then the locks on both cams on the rear bank; then the inlet cam on the front bank; and finally the exhaust cam on the front bank.
Did you use a TDC gauge?
Even slightly off timing makes V6 run terribly bad.
3.2 uses different camlocks than 2.5/3.0 locks.
 

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You can give that a lot of help without much effort. I suspect the poor lobe fit is because of the camera angle, but they must fit snugly. If they don’t, then send the locks back.

Here’s what I’d do:

1) Make damn sure I had TDC. I assume you’ve taken the dial gauge out in one of the pics? You definitely need a dial gauge.
2) Loosen the sprockets on the front two cams - 25mm spanner on the flats, 19 on the sprocket bolt. Loosen them one turn max.
3) With a (preferably brass) drift, tap the sprockets off the taper though the window in the cam cover.
4) Using the locks, get the timing spot on for the front two, lock up the pulleys again.
5) Rotate the engine a few times and check timing.
6) At this point, the only one that should be out is the inlet of the rear bank.
7) You may be able to fix the rear one with the same loosening approach - a suitable small pry bar behind the sprocket can spring it free.

You don’t need the long bolts right now - get the cam in precisely the right place using the flats on the shaft (so that the lock is dropped on fully) and nip up the pulley with your other hand.

Agree that it will run a shed load better - the idle on that must have been catastrophically bad.
 

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Discussion Starter #9
Thanks all for your comments - very helpful.

The belt is still in place and tensioned; my plan was to release the cam sprockets and nudge each cam into place as per Pud237 (Dan?) and rxe's advice above.

I've successfully loosened all of the sprocket retaining screws; but so far the sprockets are refusing to budge. I've applied WD-40 and will try again tomorrow.

Question: are the sprockets more likely to come free with the belt de-tensioned?

In the long run, if the motor is serviceable I will absolutely be replacing the belt, idlers and tensioner, but right now I'm trying to assess its condition without throwing too much money at it. The belt itself looks good so I'm happy for it to stay put at this stage.

Couple of other updates:

- Don't worry, I'm using a dial gauge to identify TDC on cylinder 1; I'd removed it at the time I took the pics.
- Bolts for the cam locks are M8 std thread; I bought some 50mm bolts from my local tool shop which are probably a whisker long - therefore, 45mm is a good shout.
 

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You do not have to take off the belt to loosen the sprockets. The front two will come off easily with a tap through the window. The back two will come off with a sharp tap with a pry bar underneath them. The rear one is very hard to get off with the belt still in place, you really need the rear bank intake off unless you have made a custom pry bar....

Edit - they’re not like the 12v sprockets with a key way. They’re a taper fit, WD-40 not needed, just a sharp tap.
 

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Thanks all for your comments - very helpful.

The belt is still in place and tensioned; my plan was to release the cam sprockets and nudge each cam into place as per Pud237 (Dan?) and rxe's advice above.

I've successfully loosened all of the sprocket retaining screws; but so far the sprockets are refusing to budge. I've applied WD-40 and will try again tomorrow.

Question: are the sprockets more likely to come free with the belt de-tensioned?

In the long run, if the motor is serviceable I will absolutely be replacing the belt, idlers and tensioner, but right now I'm trying to assess its condition without throwing too much money at it. The belt itself looks good so I'm happy for it to stay put at this stage.

Couple of other updates:

- Don't worry, I'm using a dial gauge to identify TDC on cylinder 1; I'd removed it at the time I took the pics.
- Bolts for the cam locks are M8 std thread; I bought some 50mm bolts from my local tool shop which are probably a whisker long - therefore, 45mm is a good shout.
I hope that I am allowed to post youtube links here. It will make life much easier if you referred to this video:
. It is a great tutorial on the 24v cambelts, timing, tension and sprocket removal. Hope it helps! Good luck!
 

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Thanks all for your comments - very helpful.

The belt is still in place and tensioned; my plan was to release the cam sprockets and nudge each cam into place as per Pud237 (Dan?) and rxe's advice above.

I've successfully loosened all of the sprocket retaining screws; but so far the sprockets are refusing to budge. I've applied WD-40 and will try again tomorrow.

Question: are the sprockets more likely to come free with the belt de-tensioned?

In the long run, if the motor is serviceable I will absolutely be replacing the belt, idlers and tensioner, but right now I'm trying to assess its condition without throwing too much money at it. The belt itself looks good so I'm happy for it to stay put at this stage.

Couple of other updates:

- Don't worry, I'm using a dial gauge to identify TDC on cylinder 1; I'd removed it at the time I took the pics.
- Bolts for the cam locks are M8 std thread; I bought some 50mm bolts from my local tool shop which are probably a whisker long - therefore, 45mm is a good shout.
Just out of interest, how's the project going? Engine fine?
 

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Discussion Starter #13 (Edited)
Just out of interest, how's the project going? Engine fine?
Not got to that point yet - managed to free the cam sprockets and have therefore been able to re-time the cams on the front bank.

I've re-torqued the sprocket bolts and re-fitted the cam caps, cam covers, plugs and coil packs - over the weekend I'll refit all the intake gubbins and then try starting it. I'm not confident it'll work though, as I think I've still got some valves sticking open... we'll see.

Neil from Italia Auto's cambelt change video is very useful - particularly as it clearly shows the whereabouts of all those fixings on the front of the engine that you can't even see with the engine in the car... there's really not much space to work in there, is there?
 

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Discussion Starter #15
OK, still not starting (having fixed the timing). I’m pretty sure I have sticking valves, resulting in zero compression on 4 cylinders.

Now, I’m sure the best way to fix this would be to remove and overhaul the heads - but before I take this step, is there any way to un-stick the valves without removing the heads?

For example - if I remove the camshafts and cam followers, will I get enough access to the valves stems to work them free?

Or is that wishful thinking?
 

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OK, still not starting (having fixed the timing). I’m pretty sure I have sticking valves, resulting in zero compression on 4 cylinders.

Now, I’m sure the best way to fix this would be to remove and overhaul the heads - but before I take this step, is there any way to un-stick the valves without removing the heads?

For example - if I remove the camshafts and cam followers, will I get enough access to the valves stems to work them free?

Or is that wishful thinking?
can you not do a cylinder leakage test to confirm before going further ... you could try freeing valves with penetrating oils etc but if they have been stuck open the seats could be damaged or the valves bent if it snapped and someone fitted a belt in hope..
compression test would do but cylinder leakage better and diagnosing leaks.. or a small camera to look inside cylinder cheap on ebay
,,
 

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If a valve is sticking, it should be really obvious - look for cam buckets that are clear of the cam when the lobe is pointing away. If you have any material clearance, then the valve is stuck. With the lobe pointing away from the bucket, it should be free to spin. The buckets themselves might be corroded (??? unlikely) but then stuck valves are pretty unlikely.

If all the buckets are free, and there is no clearance, you probably have bent valves. Those cams were miles out in the earlier picture. I suspect that was why it was laid up?
 

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I can't recall ever seeing stuck valves on a Busso V6.. I'd try compression testing it, or do a leak down test if you have access to the kit. Compression testers are cheap as chips.
 

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I can't recall ever seeing stuck valves on a Busso V6.. I'd try compression testing it, or do a leak down test if you have access to the kit. Compression testers are cheap as chips.
He already reported that it has 0 compression on 4 cyllinder I believe. Busted bottom end would not show 0 compression only if it is a hole in the piston which I doubt. I am pretty positive that the engine had broken or slipped on the time belt and bent the valves. I would suggest to get a set of second hand heads in good condition. These go in my country for 200 to 400 euros if it is a 2.5 or 3.0. However, to confirm, do a leakdown test or remove the heads.
 

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Discussion Starter #20
So, a quick summary:

- Last month, having received the car (GTV 3.0, not run for several years), I pulled the cam covers, visually checked the cams and applied some oil to the cams & cam followers; checked the condition of the cam belt, and ran a compression test on all cylinders. I had zero compression on cylinders 1 and 6, and healthy compression on the other four

- I then attempted to start the engine; it did start, but ran roughly and wouldn't idle. Aside from misfiring, it didn't make any strange noises - I did not hear any clattering or metal-to-metal contact. I shut down after a couple of minutes max. (We now know the valve timing was out; and with decent compression on only four cylinders it's no surprise it ran like a dog.)

- Today I ran another compression test. I now only have decent compression on cylinder 3, with zero on the other five cylinders!

- I borrowed an endoscopic camera and looked at the piston crowns - there's no obvious sign of damage to the pistons; I could see the depressions in the piston crowns for the valves, and some letters stamped into the centre of each piston crown. However - it was a cheapo camera and the screen resolution was not great, so I might have missed signs of contact between pistons and valves

- Whilst running the compression tests, I attempted to rotate the cam followers on any cam lobes that were not under load. They all rotated freely. However I noticed at least one (inlet on cylinder 6) where the two neighbouring buckets on the same cylinder were sitting at different levels, presumably meaning one of the two valves is not closing properly. Given cylinder 6 has never had any compression, this would make sense.

- Although I don't have the kit to perform a leakdown test, it seems clear that I have several valves not closing correctly. My questions are:

1) Why - are they more likely to be bent due to contact with pistons; or are they somehow just sticking due to lack of use over several years?

2) Why are more cylinders now showing no compression - and does that push us more in the direction of bent or sticking valves?

Either way - it seems further dismantling is going to be needed to get to the bottom of this...

(Sorry - that turned into a bit of an essay. If you've read this far, thanks for doing so - and if you can offer further advice on those two questions, even better!)
 
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