Performance 2L reBuild Giulia-Help Appreciated! - Page 14 - Alfa Romeo Bulletin Board & Forums

  #196 (permalink)  
Old 11-28-2011, 01:14 PM
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I have the timing chain in place now, and it seems to be timed. I say "seems" because when the cams are lined up to the marks, my crank TDC is just a teeny bit off of the pointer (I know my pointer is dead nuts by the way). I assume this is due to timing chain "slack". My next question will be about proper chain tensioner adjustment.
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Last edited by vespam5; 11-28-2011 at 01:17 PM.
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  #197 (permalink)  
Old 11-28-2011, 02:14 PM
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What soort of cams are you running? As I don't see you have created additional space at the valve buckets.

Given the high specs of the parts used, I would expect 12mm cams (or more) with fast opening times, but these won't clear the standard head.
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  #198 (permalink)  
Old 11-28-2011, 02:22 PM
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My cams are 10.6mm! I know these sound mild but I was convinced by a very experienced Alfa guy these work great on the street with a heavy sedan........If I want more later I will get more aggressive with the cams, etc since cams are not too expensive like my other cars (BMW etc).

Oh and my valves are adjusted, my engine machine shop did it for me since they had the assortment of shims handy.
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  #199 (permalink)  
Old 11-28-2011, 06:07 PM
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If you go to the tech section at IAP, you can find the original Shankle cam timing gauge - a printable cutout. Cut these out at the right size and you can mark your front cam caps with the cam angle.

Robert

PS _ AHA! Found em. Here:
Attached Images
  

Last edited by 60sRacer; 11-28-2011 at 06:18 PM.
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  #200 (permalink)  
Old 11-28-2011, 06:40 PM
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Quote:
Given the high specs of the parts used, I would expect 12mm cams (or more) with fast opening times, but these won't clear the standard head.
[/QUOTE]

Definitely. Modern cams for 105 Alfas, most seem to be 12mm, are a dramatic improvement over older deigns. Wes Ingram built an engine for the 2010 Carrera that made over 200hp and idled at 700rpm: 12mm intake and 11mm exhaust.
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  #201 (permalink)  
Old 11-28-2011, 07:03 PM
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The only interference is at the edges of the cam follower bore. easy to grind out enough clearance with a dremel. Be careful to de-burr the edges. No real problems with cam lifts over 12 mm. Sometimes takes some care with the cam clearance shims.

Robert
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  #202 (permalink)  
Old 11-28-2011, 10:31 PM
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I know I know I really would have gone for much more aggressive cams had I started with a stock head but the way I got my Sperry head was by sheer luck and it came with these cams. The previous owner said he was really happy with the performance and additional torque they gave compared to the euro cams he had on the head previously.

Perhaps (meaning I for sure will haha) I will go with a much lumpier cam a few months after getting this car moving on its own power!
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  #203 (permalink)  
Old 11-28-2011, 10:32 PM
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Quote:
Originally Posted by 60sRacer View Post
If you go to the tech section at IAP, you can find the original Shankle cam timing gauge - a printable cutout. Cut these out at the right size and you can mark your front cam caps with the cam angle.

Robert

PS _ AHA! Found em. Here:
Thanks Robert! But how do I use these exactly?
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  #204 (permalink)  
Old 11-29-2011, 05:42 AM
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If you print them out in the right size - the rulers in the pics should be real-size, then cut them out (I printed mine on card stock, but you could just use paper and glue them on). The gauges fit inside the two front cam caps (I & E) and you mark the cam timing angles just like the factory mark. Most alfa cams do well at 108, but your specific cam should have its specs and recommendations with it.

Note that anytime you change the timing chain ( or as it wears and stretches thru its life) you need to loosen the cam nut and remove the index bolt in the cam's sprocket. Turn the engine to TDC in its normal rotation with the chain tensioned loosened to take up all the slack; then rotate the cam - Alfa and others made a tool for this - to put the cam mark at the chosen position (from the marking gauge). The sprocket will stay still as the cam rotates; find the hole that aligns the cam and the sprocket, and reinstall the bolt and its cotter key. Tighten the cam nut and its lock plate.

Robert
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  #205 (permalink)  
Old 11-29-2011, 06:15 AM
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vespam,
You being a details guy, I'm a tad surprised you don't have a degree wheel set up and already used ?
It's a plastic disc with 360 degrees marked out. If you have the motor out and are timing the cams, you tape it to your flywheel, set up a pointer for it (I used heavy mechanics' wire bent into a 4-toe "foot" for stability, taped to the back of the block), then get a dial end gauge set against a tappet.
Rotate the motor and record the open and close events against the degree wheel reading, work out the lobe center, then adjust as you wish. This removes the lower chain slack from the timing setup, and also lets you judge it so you can compensate for it when you're checking cam timing without the degree wheel (in the car).
I know that I have about 2 degrees of crank rotation "slop" before the cams start to get pulled, because of the lower chain.
FWIW...
/Neil
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  #206 (permalink)  
Old 11-29-2011, 06:36 AM
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A degree wheel is old-school, and accurate. But the Alfa engine is so well made that you can do without it. The pulley TDC mark is very accurately located by the keyway on the crankshaft; the cam marks accurately indicate the lobe center. All you need to do is take the slack out of the chain system (stretch of the upper chain over its life will cause more shift in timing than the lower chain), and use the cam cap marks to accurately set the cams. Using valve lift O and C will give you the lobe center too, but with modern high-lift, fast ramp cams, its really hard to turn the cams to the same lift on the open and closed side, which will then give you a few degrees error.

Robert
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  #207 (permalink)  
Old 11-29-2011, 07:22 AM
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vespam,
In a different direction - if you want to go for a higher lift cam later, it may be worth the while to check how much lift your current spring retainers can go to without touching the valve stem seals, unless you already checked that or have info from the previous owner about it. The point is that the valve spring upper seat (the "hat" thingie) and the split wedges can be filed or sanded down to give a bit more lift without them banging the seals. This depends very much on what dimension the guides are, how far down they were installed, what style stem seal you have, etc...
I went through this the last time I had the head off, and prepped it for at least 12mm lift on both intake and exhaust, although I was using 10.9 cams at the time. I later went to 12mm on the intake, and it was "plug and play" apart from the shims, because I knew I had the space above the seal, and the bucket bores were relieved for it. And I know that I can't go above 12.3mm or so without removing the head and going through the rigamarole again...

I know you've already put the head on, though, so you'll have to decide what to do. In principle, you could remove a valve spring with the head installed, using one of the factory style tools, and do the check. You need to have the valve spring out to feel contact, or to allow the valve plus hat and wedges to rest on the stem seal. By factory style tools, I'm thinking of something I've seen pictured but not in real life, a lever that pushes down on the spring "hat" from above only (as opposed to a C-clamp sort of tool), while a separate curved rod goes through the spark plug hole to hold the valve closed. This can be used with the head in place. Or perhaps the old rope trick would also work similarly, I don't know. I'm not sure if I'm being at all clear here, sorry if not...

Sorry if I just seem to be raising complications.
Neil
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  #208 (permalink)  
Old 11-29-2011, 09:33 AM
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Quote:
Originally Posted by 60sRacer View Post
If you print them out in the right size - the rulers in the pics should be real-size, then cut them out (I printed mine on card stock, but you could just use paper and glue them on). The gauges fit inside the two front cam caps (I & E) and you mark the cam timing angles just like the factory mark. Most alfa cams do well at 108, but your specific cam should have its specs and recommendations with it.

Note that anytime you change the timing chain ( or as it wears and stretches thru its life) you need to loosen the cam nut and remove the index bolt in the cam's sprocket. Turn the engine to TDC in its normal rotation with the chain tensioned loosened to take up all the slack; then rotate the cam - Alfa and others made a tool for this - to put the cam mark at the chosen position (from the marking gauge). The sprocket will stay still as the cam rotates; find the hole that aligns the cam and the sprocket, and reinstall the bolt and its cotter key. Tighten the cam nut and its lock plate.

Robert
I couldn't find them on IAP, did you mean Centerline maybe? I will definitely use this chart tonight when I get home.
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  #209 (permalink)  
Old 11-29-2011, 09:36 AM
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Originally Posted by eedneco View Post
vespam,
You being a details guy, I'm a tad surprised you don't have a degree wheel set up and already used ?
It's a plastic disc with 360 degrees marked out. If you have the motor out and are timing the cams, you tape it to your flywheel, set up a pointer for it (I used heavy mechanics' wire bent into a 4-toe "foot" for stability, taped to the back of the block), then get a dial end gauge set against a tappet.
Rotate the motor and record the open and close events against the degree wheel reading, work out the lobe center, then adjust as you wish. This removes the lower chain slack from the timing setup, and also lets you judge it so you can compensate for it when you're checking cam timing without the degree wheel (in the car).
I know that I have about 2 degrees of crank rotation "slop" before the cams start to get pulled, because of the lower chain.
FWIW...
/Neil
Neil,

As 60s racer replied, I was told that the stock pulley TDC mark was enough to get all my cam timing perfect though I have very little experience in this department. I also have a aluminum fully degreed crank pulley which I will be using. I decided to have my Aluminum crank pulley sleeved with a SS sleeve around the front seal area and I have not done it yet so in the meantime my standard Steel pulley will be used.
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  #210 (permalink)  
Old 11-29-2011, 09:50 AM
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Quote:
Originally Posted by eedneco View Post
vespam,
In a different direction - if you want to go for a higher lift cam later, it may be worth the while to check how much lift your current spring retainers can go to without touching the valve stem seals, unless you already checked that or have info from the previous owner about it. The point is that the valve spring upper seat (the "hat" thingie) and the split wedges can be filed or sanded down to give a bit more lift without them banging the seals. This depends very much on what dimension the guides are, how far down they were installed, what style stem seal you have, etc...
I went through this the last time I had the head off, and prepped it for at least 12mm lift on both intake and exhaust, although I was using 10.9 cams at the time. I later went to 12mm on the intake, and it was "plug and play" apart from the shims, because I knew I had the space above the seal, and the bucket bores were relieved for it. And I know that I can't go above 12.3mm or so without removing the head and going through the rigamarole again...

I know you've already put the head on, though, so you'll have to decide what to do. In principle, you could remove a valve spring with the head installed, using one of the factory style tools, and do the check. You need to have the valve spring out to feel contact, or to allow the valve plus hat and wedges to rest on the stem seal. By factory style tools, I'm thinking of something I've seen pictured but not in real life, a lever that pushes down on the spring "hat" from above only (as opposed to a C-clamp sort of tool), while a separate curved rod goes through the spark plug hole to hold the valve closed. This can be used with the head in place. Or perhaps the old rope trick would also work similarly, I don't know. I'm not sure if I'm being at all clear here, sorry if not...

Sorry if I just seem to be raising complications.
Neil
Neil,

I really wanted a very radical cam, but I saw no harm in running what came with the head when I bought it. Pulling the head off in a few months and modifying it for 12mm cams almost seems like no big deal now that I have pretty much gone through everything on this car. If I am not happy with the power output I will be back to Alfa BB asking for cam recommendations haha! My head has some nice porting and valve work already so it can surely make more power from a higher lift cam. Let me just play with this "mild" setup for a while. I'm sure my engine machinist will happily have me back for some cam pocketing and other work associated with bigger cams. As it is now my lobes just barely clear the head.
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