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post #1 of 14 (permalink) Old 06-18-2006, 12:22 PM Thread Starter
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sticky valve?

Hello All,
Happy Fathers Day to all you Dads out there.
I got an early father’s day gift last week with the purchase of a red 1988 Spider veloce!
I’m so happy with it!
My father had a ’54-’55 Spider when I was a youngster and I loved playing in it especially under the tonneau cover over the passenger side. I remember that lovely sent of leather mixed with gasoline. European cars just have a wonderful smell don’t they?
Anyway, I bought it from a couple near the Coast here. I saw an ad in the local paper while vacationing and on a lark, asked my “better half” permission to check-it out. She agreed – what a sweetheart!
The ad said “runs great” – we all know what that means, Right? Well upon the arrival of the car with the owner I knew there wasn’t something quite right. It sounded very rough and certainly not that mellow, rich sound I remembered as a kid. Upon the initial dialog with the owner, I questioned him about the rough running. He said that’s the way it always sounded to him. I was bewildered as well as suspicious at first that he was trying to pull something over on me. Test driving it seemed fine although it was lacking in power (I thought), cornering was good, braking was fine, gearbox and Trans sounded/felt great but the engine was way-off. After popping the hood I asked his permission to pull the cables off the plugs in sequence to find the offending cylinder, he agreed and it appeared to be cyl #2. It had a healthy and fat spark coming from the plug boot so I thought it was a simple fix of a fouled plug or something along the lines of that or a plugged fuel injector. Nothing major. He mentioned that it needed to be smog tested for the current year tags – prolly fail with that bad cylinder I would think. After haggling and pointing out body damage (mostly superficial/minor) and a driver’s door problem of a over-extension exercise causing the door to be miss-aligned as well as the obvious engine situation, we finally agreed on a lowered price. I just couldn’t pass on it. I was ecstatic, my wife was happy for me; all was well with the world.
After driving it home last week I quickly pulled the plugs and indeed found a fuel fouled plug in cylinder 2. All other plugs had a nice brownish-tan appearance. Swapped with all new Champion plugs gapped to .026”. Rechecked the firing order, 1-3-4-2. Check. Started it up and still ran crappy. Now I started pulling the air box off and checked the connectors to the fuel injectors. All appeared good and tight with no corrosion, but it looked as though No. 2’s injector had been replaced once before. It had been attached to the fuel rail upon a nipple to the rail clamped with a fuel hose clamp rather than the other type of clamp, which I guess, is the bosch factory type clamp. After no difference in engine operation I carefully listened to the exhaust manifold. Lacking a auto stethoscope, I did it the old-fashioned/low tech (caveman) way of sticking my thumb into my ear while grasping a screw-driver touching the engine. I now suspect a stuck exhaust valve. How common is this and how would it occur? Lack of lubrication, bent valve, warped head caused by overheating? The temp gauge seems to read close to 200 deg. It has air-conditioning (broken) and the condenser coils probably block some airflow to the radiator.
I’ll be doing a cylinder compression test later today to verify stuck/open valve. Where is the best place to disconnect the fuel pump when turning the engine over? I don’t have a shop manual yet and I’ve been reading threads here mentioning an Alfa’s “Bible” manual. Where would I purchase that from?
TIA

[I]Ubi fumus, ibi ignis.[/I]
F.M. Guidi
[FONT="Trebuchet MS"][I][B]'88 Spider Veloce[/B][/I][/FONT]

Last edited by Bianchi_Guelfo; 06-18-2006 at 12:56 PM.
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post #2 of 14 (permalink) Old 06-18-2006, 12:38 PM
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the "Bible" may be purchased at Amazon, Alfa Romeo Owner's Bible: A Hands-On Guide to Getting the Most from Your Alfa (Alfa Romeo) by Pat Braden (Paperback - Jun 1994),I cant help,wi the rest but there will others on here who can. Best of luck.

Last edited by adenzeno; 06-18-2006 at 12:41 PM.
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post #3 of 14 (permalink) Old 06-18-2006, 12:58 PM Thread Starter
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Thanks adenzeno!
I located it on Amazon and ordered one right now.

[I]Ubi fumus, ibi ignis.[/I]
F.M. Guidi
[FONT="Trebuchet MS"][I][B]'88 Spider Veloce[/B][/I][/FONT]
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post #4 of 14 (permalink) Old 06-18-2006, 08:05 PM
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To shut off fuel pump, remove rear parcel shelf--5-6 screws and some velcro. The fuel pump fuse is the BIG RED one (& only) just outboard of the ECU.
When I was troubleshooting my top end issues I made a leakdown tester from this link. Worked pretty good, unfortunately it told me more that I ever wanted to know .
Good Luck!

Paul
'86 Spider Graduate
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post #5 of 14 (permalink) Old 06-19-2006, 12:27 PM
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The home-made leak down tester will be a useful tool to have. Actually, all you really need is a way to pressurize the cylinder in question. The guages on a 'real' leak down tester just give a way to measure how much leak there might be. If you just get/make an adapter to be able to apply about 80 psi of air pressure and then position the piston at TDC with valves closed (** be careful - the engine can turn suddenly if you do this**) you can then listen for the air escaping to diagnosis problems.

Having said all that, allow me to mention one other possibility I recently had on our '84 Spider. It had a missfire that I thought was due to old spark plug wires. I replaced the wires & resistor ends which improved but did not eliminate the missfiring. I then thought it might be a bad injector until I ruled that out by removing the injector and watching it squirt fuel when the engine was cranked (air flow meter's flap propped open).

It turned out to be the wires (even the new wires!) were cross-firing. I re-routed the wires to seperate them and re-arranged the order I had placed them through the loom at the front of the cam cover and since then all has been well! It seemed logical to put the wires through the loom 1-2-3-4. Silly me - it's an Italian car - logic does not apply.

- - Eric
don't read this
~ 1984 Spider Veloce ~
- -~ 1981 GTV-6 ~
Mebane, North Carolina


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post #6 of 14 (permalink) Old 06-19-2006, 06:27 PM
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Yeah, The engine can and will turn, regardless of my best efforts to find exact TDC and 'lock' the crank by shifting to 1st/2nd. I had my best luck if I left the spark plugs installed for all but the cylinder in question.

Paul
'86 Spider Graduate
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post #7 of 14 (permalink) Old 06-19-2006, 08:26 PM Thread Starter
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Very Interesting!

Thanks for all the suggestions.
This is what I have discovered thus far.

Checked compression and recorded the following:

Cyl. #1 – 165#
Cyl. #2 – <20#
Cyl. #3 – 185#
Cyl. #4 – 155#


Popped the valve cover off and did a cursorily check for problems. Removed the first exhaust camshaft bearing cap and made an interesting discovery. Look at the attached photos to see the results of what appears to be a poor casting. Compare it to the other bearing cap #2. What looks like worm-holes in the bearing surface are the voids caused by a probable cold melt of aluminum. It was machined and whether or not it was visible to Q.C. at the time or was still just under the surface, remains speculative.
Has anyone come across this?
Are bearing caps available someplace other than a junked engine?
Consequently the gaps on cylinder 1 & 2 are tight – like there isn’t any gap!
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[I]Ubi fumus, ibi ignis.[/I]
F.M. Guidi
[FONT="Trebuchet MS"][I][B]'88 Spider Veloce[/B][/I][/FONT]
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post #8 of 14 (permalink) Old 06-20-2006, 05:26 AM
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Wow, that is weird. The cam bearing caps are specific to each head and even specific to their position on the head - machined in place I assume. If you got a replacement you'd have to figure out a way to line bore it to be usable.

What does the head side of the cam bearing surface look like? I assume the cap must have been a poor casting. But I don't know that the porosity means it is unusable. The cam bearings are not a highly stressed part - that is why they can be simply machined into the aluminum.

Have you tried the leak-down test? And what do you mean by the 'gaps are tight'? Do you mean the valve clearance? It could either be incorrect shims or the valve seats are receding &/or the stems are stretching. Shims would be an easy fix. Otherwise you're looking at replacing valves & or seats.

- - Eric
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~ 1984 Spider Veloce ~
- -~ 1981 GTV-6 ~
Mebane, North Carolina


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post #9 of 14 (permalink) Old 06-20-2006, 06:03 AM
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Not sure what cold melt of aluminum is- looks more like porosity of the caps when they were poured. Is it something that would cause engine failure?
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post #10 of 14 (permalink) Old 06-20-2006, 08:47 AM Thread Starter
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Quote:
Not sure what cold melt of aluminum is- looks more like porosity of the caps when they were poured.
When the aluminum pour is not of sufficient temperature and/or the mold is not properly warmed-up you get a porous casting. I learned that from my own experience doing castings.

Quote:
The cam bearing caps are specific to each head and even specific to their position on the head - machined in place I assume. If you got a replacement you'd have to figure out a way to line bore it to be usable
Yeah, I figured they were specific. I realize there isn’t too much tension being applied toward the three caps but it makes me somewhat nervous seeing such a weak part. I wonder what else is made like that in my engine. Also, the cap nuts were loose on that particular cap when I removed it. What is the torque specification on those nuts? The engine side of the bearing looks ok but it should really be measured for wear. I don't have the setup for that.

When I say the “gaps are tight” I mean, for whatever reason, cylinder 1 & 2 valve clearance gaps are nonexistent. Apparently, it’s keeping cylinder 2’s exhaust open all the time. I’ll try to adjust the gap with the correct shims when I get my shop manual and learn the proper procedure. From what I’ve read so far, you measure the valve “clearance” (I use the term ‘gap’ from working on VW engines!) when the piston for the cylinder is at TDC, compare it to the specified clearance and adjust with the necessary shim thickness.

[I]Ubi fumus, ibi ignis.[/I]
F.M. Guidi
[FONT="Trebuchet MS"][I][B]'88 Spider Veloce[/B][/I][/FONT]
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post #11 of 14 (permalink) Old 06-20-2006, 08:59 AM
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What I should have said is that I'm not sure that the porosity is a problem, but line boring the caps won't do any good since it will make the caps larger than the cam journals.

Is it time for a new head?
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post #12 of 14 (permalink) Old 06-20-2006, 09:56 AM
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Yes, line boring will be a problem. The machinist would need to skim off some of the mating surface of the replacement cap then line bore it out to match the existing bearing axis. I suspect a replacement head (with known good caps) would be easier/cheaper.

First thing I'd do is see if those valves do close and seal adequately. Either do a leak down test with the cams removed or remove the shims (but don't start it that way). Myself, I'd remove the cams - then you can turn the crankshaft to test each cylinder and know the valves are (should be...) closed. Just be sure you understand how to re-time the engine. Check first which way the distributor rotor points when #1 is at TDC on compression stroke. Seems like 1/2 of the Alfas out there are 180 degrees off!

If the valves still leak during such a test, tap on the stems with a small hammer & brass drift (to avoid damage to the stem). That may knock off offending bits of carbon and improve the readings. If it passes that test, I'd get the correct shims and see how it runs - using the cam cap as is. Watch the valve clearances closely for a few thousand miles. If they stay in spec you'll be all set. If they keep getting tighter & tighter you'll have to plan on a valve job soon. In which case I'd probably go for a replacement head.

Cam bearing cap nut torque is 14.8 - 16.2ft/lbs, 20-22 Nm 'wet' (oiled threads)

BTW, have you seen this:
http://alfacentro.com/main.html (scroll down to find the 'Shim-O-Meter')

- - Eric
don't read this
~ 1984 Spider Veloce ~
- -~ 1981 GTV-6 ~
Mebane, North Carolina


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post #13 of 14 (permalink) Old 06-21-2006, 09:14 AM Thread Starter
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Thanks for all the help so far, “ghnl” and others.
Is there any procedure for the valve adjusting that you know of anywhere in this forum? Or for that matter, anywhere on the ‘Net?
I was wondering if all that unburned fuel mix coming out of the leaking No. 2’s cylinder for who-knows-how-long, ruined the catalytic converter?
TIA

[I]Ubi fumus, ibi ignis.[/I]
F.M. Guidi
[FONT="Trebuchet MS"][I][B]'88 Spider Veloce[/B][/I][/FONT]
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post #14 of 14 (permalink) Old 06-21-2006, 09:54 AM
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Well, you don't 'adjust the valves' per se, you change out the shims between the valve's stem and the cam shaft to vary the clearance. If the clearance is really less than zero it'll be difficult to determine what size shim you need - usually there would be some clearance - either too much or too little. You'd measure the clearance then measure the shim (it is inside the bucket on top of the valve stem) to determine what the correct size should be. I guess you could assemble it with no shims (bucket only) and measure that clearance and then calculate what size shim to get to bring it into spec.

The 'Shim-O-Meter' in the link I referenced will do the calculations for you!

It is helpful to measure and record all the shims that are in there for future reference. Then, should you find the need to 'adjust the valves' in the future, you'll know what size is in there and can easily calculate what size is needed (thus only having to remove the cam shaft once you get your new shims). If you're lucky, sometimes all you need to do is swap some shims around.

- - Eric
don't read this
~ 1984 Spider Veloce ~
- -~ 1981 GTV-6 ~
Mebane, North Carolina


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