Alfa Romeo Forums banner

1 - 20 of 34 Posts

·
Registered
Joined
·
423 Posts
Discussion Starter #1
My engine was recently redone (Poland) but does not runs very well. High idle, runs rough etc...
I have tried everything tuning the SPICA inj but need to go back to basics and make sure the cams are timed right (I have timed ignition.. just havent done cams out of lack of knowledge and know-how).

Here is the information I have.

- The cams are not stock. The last PO put Megacycle cams in this 2L engine (PO had the whole engine redone by Hasselgreen Race Engines in SF).
- I had Megacycle send me the info on the cams.
- Picture of Timing marks on cams and journals.

How should I time my cams ?

The specs show degrees but the engine is in the car and cant put any degree scale on transmission shaft etc..
Are the knotches in the cams meant to line up with the knotch on the journal (cams are not stock) ?
Why on the admission side are there 2 knotches on the journal ? I assume one has been added (Hasselgren race engine prepared the car in 1995 for PO).
My mechanic in France isn't sure how to set the timing on these.. any help will be greatly appreciated !!
Thanks

Roland
 

Attachments

·
Premium Member
Joined
·
13,476 Posts
The timing marks on the camshaft caps are to set the lobe centers. They are intended to line up with the marks on the cams - I'm sure that you know that. You need to know what year engine you have and if it is Euro or US spec. The marks were different from year to year in the 70's.

There is a template for making new timing marks. It is on the ABB somewhere. It came from a Shankle catalog so you might search on Shankle and template.
Ed Prytherch
 

·
Registered
Joined
·
3,585 Posts
Try this thread:
http://www.alfabb.com/bb/forums/engine-rebuilding/47980-cam-timing-mixup.html

Somewhere I have a template for marking the cams journals, but no way to get it on to the web, maybe it has been posted or someone can post it. Basically Intakes are ATDC = degrees after top dead center (102 for yours according to the chart) and exhaust are BTDC = degrees before top dead center (106 for yours according to the chart). So after marking the cam journals by use of the template or other means set the pistons with #1 at top dead center with the chain tight and the cams approximately as shown in your photos, then remove the venier bolts from the cam sprockets and loosen the cam nuts without disturbing anything! Now the cams will rotate without the chain or engine moving, rotate the cams individually so the mark on the cams line up the mark on the journals that correspond to the degree number from the template. Reninstall the venier bolts/nuts and tighten the cam nuts.
 

·
Registered
Joined
·
561 Posts
High, rough idle... I would say the injection is not set up quite right, bigger camshafts aside. Has the injection been set up according to AR specs? I would not be too sure of your Polish mechanics knowledge on Alfas and Spica (especially since he does not know which way the camshaft cap nuts go on....).

My advice: Ensure the injection really is set up properly! There is some awesome bed-time reading in the fuel section.
 

·
1966-2013
Joined
·
13,741 Posts
I might be out on a limb here, but it looks like someone re-marked at least the intake cam #1 journal for a different cam set.

The 'aftermarket' mark looks a lot like it's near the same position as what it is for the aftermarket cams I have in mine: 102 degrees.

Definitely do the template thing to confirm though, as I wouldn't take me at my word on that observation.
 

Attachments

·
Registered
Joined
·
374 Posts
Hallo Roland

I just did it last year, and it is very easy to verify the correct timing as well. I did it with shankle, but you might download the sme templates from centerline.

They give you the lobe center for Intake and exhaust.
So just print the templates and glue them on some harder paper and cut them out,( I did use a surgical knife ) and they will fit exactly into the front camcap for you to verify the correct lobe center. There was a special tool from Alfa Romeo as well

Greetings from Germany

Bernhard
 

Attachments

·
Richard Jemison
Joined
·
7,188 Posts
Cam Timing

Basically Intakes are ATDC = degrees after top dead center (102 for yours according to the chart) and exhaust are BTDC = degrees before top dead center (106 for yours according to the chart).
ROGERSPEED:
Why do you post when you don`t have a clue? Your information is exactly backwards. :confused:

The cam timing card from Megacycle tells you nothing. Is the duration at
.040? .050 (the norm?) what. A full profile of the cams would be what you need. However without degreeing in the cam it seems you don`t have an idea of when events are occuring.

The head is likely a USA head so factory marks could be anywhere. You need at least to start with a template from Centerline`s website.
I would suggest that you initially set up the cams at 104 int. and 104 exhaust. This should improve drivability by reducing overlap...
If you are only using the car for track events, then after doing above, advance the intake to 102. If all is well, the last tweek, would be to move the exhaust to 102 degrees lobe center. But when doing this be sure you have a minimum of .080 clearance between the valve and piston during the valve closing phase. You can use a plastic wire tie to check this, by running it through the spark plug hole and between the valve & piston while turning it over by hand. Of course the wire tie needs to be .075-080 thick.
 

·
Registered
Joined
·
3,585 Posts
ROGERSPEED:
Why do you post when you don`t have a clue? Your information is exactly backwards. :confused:

The cam timing card from Megacycle tells you nothing. Is the duration at
.040? .050 (the norm?) what. A full profile of the cams would be what you need. However without degreeing in the cam it seems you don`t have an idea of when events are occuring.

The head is likely a USA head so factory marks could be anywhere. You need at least to start with a template from Centerline`s website.
I would suggest that you initially set up the cams at 104 int. and 104 exhaust. This should improve drivability by reducing overlap...
If you are only using the car for track events, then after doing above, advance the intake to 102. If all is well, the last tweek, would be to move the exhaust to 102 degrees lobe center. But when doing this be sure you have a minimum of .080 clearance between the valve and piston during the valve closing phase. You can use a plastic wire tie to check this, by running it through the spark plug hole and between the valve & piston while turning it over by hand. Of course the wire tie needs to be .075-080 thick.
Thank you, either I don't have a clue or I got it backwards. sheesh. Every cam timing chart I've ever seen and used for Alfa lists the lob centers: Intake =ATDC and Exhaust = BTDC and as I suggested and you confirmed to use the Shankle or similar template to mark the cam journal and then set the cam mark to match, the chart Roland provided listed lob centers 102 intake, 106 exhaust, maybe you missed that, I've alway thought using the makers recommendations was the place to start, what's the problem?
 

·
1966-2013
Joined
·
13,741 Posts
The cam timing card from Megacycle tells you nothing. Is the duration at
.040? .050 (the norm?) what.

Hmmm, using the above timing card and reading all the words, (TIMING CHECKED WITH ZERO CLEARANCE, and TIMING AT .040" LIFT AT VALVE above the chart and ** although this timing is quoted at .040" with Zero checking clearance as found at the right) the timing #'s are derived when valve has lifted .040" off it's seat with the the lash set at zero.

For duration, well, that's listed right on the card: 258 degrees for both cams, again when the respective valve unseats by .040" and using zero clearance. (there's that ** although this timing is quoted at .040" with Zero checking clearance again....)

The numbers in the chart portion are derived using the method described above the chart (ZERO clearance and .040" lift). The alternate methods for checking using recommended lash is listed to the lower right after the reminder about ** although this timing is quoted at .040" with Zero checking clearance.

.008" lash on intake w/.0032" lift at valve will arrive at the specified chart numbers if matched against the open/close numbers resulting in correct duration and timing.
.010" lash on exhaust w/.0030" lift at valve will arrive at the specified chart numbers if matched against the open/close numbers resulting in correct duration and timing.

Followed by one more reminder at the bottom of the right side text: your opening and closing numbers will be the same as they would at .040" (lift at valve) with ZERO (lash)

Lobe centers will fall into place as a result of using either method above (zero lash or with lash) being employed to set things up. Conversely, if you use the DL-able index/degree mark guide thingies as suggested, the other numbers should fall into place if the cam marks are lined up with the new ticks on the journal you put there yourself using said DL-able index/degree cards.

Seems pretty complete to me, mabe it's just you who's confused :shrug:
 

·
Richard Jemison
Joined
·
7,188 Posts
Cam timing

Seems pretty complete to me, mabe it's just you who's confused :shrug:
Probably not.:rolleyes:
You both might gain a bit of cam design information from my website. Cam lobe centers given by a grinder is only a point to start. They have no idea of the intake & exhaust efficiency of the engines, only what is ordered by some customer... Megacycle offers no "Alfa" cams. They will grind what is ordered, and give a timing cards based on average parameters.
What is on that timing card or any grinders card tells you nothing but a single point on that cam as to profile. Look at the cams on my website that have nearly the same durations at .050, are the late ramp & nose the same? Then look at the different ramp rates (do you know the formula to compare ramp rates?).
Ramp rates for FI motors are different from carbed Alfa engines. That is why a knowledgable engine builder requires more information than given on that timing card.


ROLAND:
I hope my information helps you. On the cams butt or etched on the shaft will be numbers to identify the grinds. Intake and exhaust should not be the same.
If you PM me those #s I`ll see what I can find about them. (or you can email Barbara at Megacycle, and try to get the profiles) ;)

I guess as an option you can ask Tifiosi or Rogerspeed!:p
 

·
Registered
Joined
·
1,085 Posts
Checking cam timing

Let us not make this too difficult: Things to consider.

First is to verify that the cam cap is marked at 102*. Use the download template from Centerline to check.

Secondly, most all cams are NOT ground to match the Alfa timing notches on the cam. After the welding is done, the machining process locates the percieved best way to get the desired profile during the grinding, disregarding the index mark on the cam blank.

These cams MUST be degreed-in using a degree wheel and dial indicators, otherwise you can be 1 to 6 degrees off one way or the other. (sorry about that).

In my experience Megacycle Cams lobe centerlines match the notches, so if you degree their cams in at 102 degrees, then the notches will line up with the caps.

Thirdly, Megacycle always shows timing specs at .040" lift so guys like me buy their cams instead of finding out what their specs are at .050" lift and getting cams that are close, bypassing their efforts to design and market a product. If you degree in their cams using a degree wheel you will have the correct lobe center angle regardless if you use .040" lift; .050"; or .072" lift. The lobe center angle still will come out the same.

Hasselgren runs a dyno testing facility in Berkeley California, (across the Bay from San Fran) and is used by all of the "Big Boys", including setting up all of the Toyota Atlantic engines to match horsepower and reliability for that series engines.

Dan Marvin and Jon Norman have come up with the settings for these Megacycle cam grinds for the Alfa engines, (and many are not aware of the settings for these cams that work on the dyno, You have let the secret out). If you have the rest of the engine tuned correctly then the engine will run fine at intake at 102* lobe centerline; and exhaust at 106* lobe centerline. Most all other cams work best at 102* intake and exhaust. Changing these settings are for the guys that have EVERYTHING else correct in the tuning from air cleaner to tailpipe.

If these cams are at 102/106* LCL, then there are other things to check: ignition total timing and initial timing would be my first test; you need 9 to 12 degrees initial with these cams and a total of 33-35 degrees total at full advance. If you have these distributor settings, the valve lash is correct, the valves aren't leaking (compression readings within 10% between cylinders with the intake blocked open), and still can't get 1000 RPM idle, then work on the Spica adjustments (a whole nother week of emails). Also look for vacumn leaks

Hope this helps.
 

·
1966-2013
Joined
·
13,741 Posts
You both might gain a bit of cam design information from my website.
Only if I actually bother to visit it, but then I can think of several other sites to go to find references rather than to someplace where the site owners first response is to tell someone else they don't have a clue.

They have no idea of the intake & exhaust efficiency of the engines, only what is ordered by some customer
They don't have to know the efficiency, thier business to properly grind cams using specific numbers provided by someone who does know the about the specific engine (in this case, it would likely have been Hasselgreen Race Engines providing the specs) then give a reference point to line things up to ensure that when that reference point is aligned properly the profile meets the given specs for lift, duration and overlap.

Megacycle offers no "Alfa" cams
But apparently they can grind a set and keep record of it if they are provided with a proper set of specs.

They will grind what is ordered, and give a timing cards based on average parameters
Exactly.

What is on that timing card or any grinders card tells you nothing but a single point on that cam as to profile
Correct, a reference point to ensure that it's installed/aligned correctly to allow it to function as intended by the person or persons who supplied the specs to begin with. (it's worked for Crane, Offy, Edlebrock and any number of other manufacturers including 'Alfa specialist' suppliers for many decades now, what should Megacycle need to be any different?)


Look at the cams on my website
No.

Ramp rates for FI motors are different from carbed Alfa engines
Gee, thanks for the clue. Never would have known that if I hadn't seen, read, and generally already been aware of it for many years now. Hey, here's one for you, other marques engines need different ramps for thier carburetted engines than what thier injected engines call for too. (wow, who'da thunk it......)

I guess that's why when they sell cams, they are listed as better suited for for injected or carburetted and even use words like lobe shape/profile to decribe it a bit more deeply for the folks who may not neccisarily know why there's a difference, huh.

I guess as an option you can ask Tifiosi or Rogerspeed!:p
Or if not, and as there are so many other sources out there, at least try to find someone who isn't so friggin' full of himself.
 

·
Richard Jemison
Joined
·
7,188 Posts
Whatever...

Quote:
Look at the cams on my website

No.
Tifiosi

Slacker:
No problem for me. Most are looking for more knowledge and information. All your long post did was rant. Where did it prove me wrong?
Roland was asking for help I offered some insite. We also gained a bit of insite on others.:)
 

·
Registered
Joined
·
423 Posts
Discussion Starter #16 (Edited)
Cams

Thanks for all the responses...

I must admit I was a bit overwhelmed and lost with all the specs 040" lift; .050"; or .072" lift. discussion... I dont quite understand that yet.

What I did understand (and correct me if I'm wrong) is that I need to:

- Put engine at TDC (take out spark #1 and put a chop stick or something and get it to its highest point - I prefer that than using the P mark on front of engine in case it is off).

- Take camshaft cap off (one with markings) and put Centerline Int/Exh lobe template in it to check and mark the 102/106* LCL positions.

- Put cap back on and torque it to 14-16 ft/lbs

- Take off little nut on end of camshaft and untighten large nut on end of cam to free cam.

- Turn cam to match the 102/106* LCL position.
My only worry: the different angle markings are physically so close - 96 to 114 degrees - on the CENTERLINE template !! i am not sure how precisely I can match up the cam lobe mark with the markings and actually make a difference.

- Tighten big nut and put back small bolt in matching hole on end of camshaft (Worry#2: how do I get to the camshaft bolt hole if is located deep towards the bottom of plate -> hard to access ? Need to make sure i dont lose nut in engine casing !!)..

- Once I do that I will time the Ignition again (at 4000-5000 rpm on "M" mark which is about 30 degrees advance I assume).

I will do a compression reading is I can at the same time to find out if everything is OK there ...

Does this sound right ?

If engine still does not run well then it is the SPICA injection that is off (I have set it several times following Wes's guide). people locally are pushing me to go to carbs but it is another huge expense. I'd like to stay with SPICA and manage to keep the expense to a minimal (I probably need to consider an Ingram refurb) and have it last !


Roland
 

·
Registered
Joined
·
1,085 Posts
Additional Set up info.

Firstly: Tifosi: whay don't you tell us how you really feel :):)

Secondly: It was late when I wrote #12, "so here is the rest of the story".

Roland: check the Spica pump timing. It can be 180 degrees out and the engine will still run, but run poorly. Here's how to do it:

Mark the front pulley P and I marks so the marks are easy to see. Pull all the spark plugs, turn the engine over clockwise with a socket on the front pulley nut, untill both intake and exhaust valves are open at TDC (the P mark). Rotate the engine counter clockwise to the I mark. The pump timing marks should be aligned. (The mark on the pulley may be covered by the belt and hard to see, move the belt towards the front of the pulley). The timing mark on the pump is a verticle machined line on the front case of the pump. If the pump marks so not line up, the belt can be removed and reinstalled by spraying the pulley with WD40 to make it slide easily.

If it is timed ok, then make sure that the butterflies are set to close together: I turn the screw on the manifold untill the butterflies are slightly open then find a feeler gauge thickness that will give a slight drag when the burrerflies are opened and closed on the gauge. Adjust the balance screw so that the butterflies are equal. Then put the screw back to where it was. The short rod should be adjusted so that the butterflies are closed at idle and open exactly when the bellcrank is rotated.

This is the short list of what to do. If you do not have Wes Ingrams book on setting up the Spica linkage GET IT!!! It is only $30 or so, and it will save you hours of time. [email protected] The Spica system can be overwhelming, but if the basics are done as Wes outlines, it becomes very simple. Always start at the beginning when checking adjustments. No shortcuts. And I always check the timing first when diagnosing Spica problems.

An Alfa engine will idle OK with Spica (or carbs) and almost any cam profile if you follow the basics of setting things up. 99% of the time problems are due to not following the basics, not due to parts and pieces.

One customer tried for almost a year to find out why the engine I supplied the head, cams, ignition and receipe for ran so poorly. It wouldn't idle, was low on power, backfired and snorted:eek:. We emailed and talked alot long distance to come up with the soultion: He had not tightened all the carb mounts on the manifold, and they would leak vacumn: sometimes, sometimes not. It was back to the basics to fix the problem.

Hope this helps. George
 

·
Registered
Joined
·
3,585 Posts
Thanks for all the responses...

I must admit I was a bit overwhelmed and lost with all the specs 040" lift; .050"; or .072" lift. discussion... I dont quite understand that yet.

What I did understand (and correct me if I'm wrong) is that I need to:

- Put engine at TDC (take out spark #1 and put a chop stick or something and get it to its highest point - I prefer that than using the P mark on front of engine in case it is off).

- Take camshaft cap off (one with markings) and put Centerline Int/Exh lobe template in it to check and mark the 102/106* LCL positions.

- Put cap back on and torque it to 14-16 ft/lbs

- Take off little nut on end of camshaft and untighten large nut on end of cam to free cam.

- Turn cam to match the 102/106* LCL position.
My only worry: the different angle markings are physically so close - 96 to 114 degrees - on the CENTERLINE template !! i am not sure how precisely I can match up the cam lobe mark with the markings and actually make a difference.

- Tighten big nut and put back small bolt in matching hole on end of camshaft (Worry#2: how do I get to the camshaft bolt hole if is located deep towards the bottom of plate -> hard to access ? Need to make sure i dont lose nut in engine casing !!)..

- Once I do that I will time the Ignition again (at 4000-5000 rpm on "M" mark which is about 30 degrees advance I assume).

I will do a compression reading is I can at the same time to find out if everything is OK there ...

Does this sound right ?

If engine still does not run well then it is the SPICA injection that is off (I have set it several times following Wes's guide). people locally are pushing me to go to carbs but it is another huge expense. I'd like to stay with SPICA and manage to keep the expense to a minimal (I probably need to consider an Ingram refurb) and have it last !


Roland
Roland, I agree with George's advice on both the SPICA pump timing and the cam settings. The SPICA pump being set right, not 180 out is most important and then setting the cams, even though only what appears to be a slight difference does make a great deal of difference in operation.

Your description of setting the cam timing seems to be good. Of course you are setting both the intake and the exhaust cams, concensus is the intake is 102 and the exhaust 106."P" is correct for TDC, chopstick, dialguage and/or other tools are helpful. The small vernier bolt and nut between the cam sprocket (toothed pulley) and the cam itself is designed so as the cam is rotated a different pair of holes will line line up, it is a little tricky but not impossible.

When it comes to setting the ignition timing after having first set the TDC as part of the cam timing with the checks discussed an having made sure the pointer is at "P" for TDC, now for the advance timing you can use the "M" mark, make sure the engine is fully warmed up and maximum ignition advance should happen by 3000 rpm, the workshop manual says to set at 4600rpm, I think that is high, but is debatable.
 

·
Trained (ex)Professional, , 1953-2018 RIP,
Joined
·
16,232 Posts
Basically Intakes are ATDC = degrees after top dead center (102 for yours according to the chart) and exhaust are BTDC = degrees before top dead center (106 for yours according to the chart).
To expand on this just a bit, Alfa cam lobe centers (which is actually called cam lobe centerline), refers to the number of degrees of crankshaft rotation from top dead center (TDC) when the valve is fully open. An intake cam timed at 102 means that the intake valve will be fully open when the crankshaft is 102 degrees ATDC on the induction stroke. An exhaust cam timed at 106 has the valve fully open when the crank is 106 degrees BTDC on the exhaust stroke.

Roland,
If the cams need adjusting, loosen (no need to remove) the large nut first (after bending the lockplate out of the way). This will reduce the stress on the small vernier bolt. Then remove the small nut and vernier bolt. If the bolt is not on the top portion of the cam, note how far off the timing marks are and then rotate the engine until the bolt is on top. Moving the bolt one hole is approximately equal to one half the width of the timing mark. Snug the small bolt and large nut and recheck the timing. If okay, tighten everything up.
 

·
Registered
Joined
·
3,585 Posts
Tifiosi

Slacker:
No problem for me. Most are looking for more knowledge and information. All your long post did was rant. Where did it prove me wrong?
Roland was asking for help I offered some insite. We also gained a bit of insite on others.:)

Richard your cam knowledge is unquestioned, as on this thread, is rudeness and obfuscation. It’s not about proving others wrong, it is about Alfas. Maybe Roland needs different cams, maybe your 104/104 or 102/104 or 102/102 is a better suggestion than my reading of 102/106 setting for the current cams, just as likely the FI may need work/adjustment. But in any event the method I and others suggested to mark and set the cams is basically the same you suggested after being derisive and obfuscatory (ramping has zero to do with setting these cams). You demonstrate knowledge of theory and application, but Roland’s query was also about how to set these cams that were ordered for this engine, you offered cheap, unsubstantiated shots at fellow BB members. I’m using the board to assist and learn. What’s up with your slash and burn? You’re the guy who has been dismissive, rude and not answered questions posed or acknowledged sound reasoned advice given by others. Look in the mirror when you stick your tongue out.
 
1 - 20 of 34 Posts
Top