90 repair/ tidy up.

Started by Typhoon90, July 14, 2010, 06:06:12 PM

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Typhoon90

#30
I've driven the car to work all week, it's running better every day. I think this car sat for a few months before being sold. It's an amazing vehicle, even though it desperately needs new brakes and an alignment, it's still a really enjoyable car to drive. It's an amazing handler even stock, body roll isn't THAT bad, I'e owned far worse that were much newer! It's a very neutral chassis and has surprisingly good power to weight, but it's no rocket. Even more surprising is how nice the ride is and the NVH levels are very low too. It feels like a late 90's car.
What has surprised me is how tractable the 2.5 is in day to day driving and that it has a definite powerband above 4000 rpm. It just sounds beautiful when the revs get above that.


Regards, Andrew.

Typhoon90

Oh, she's still not track ready! The brakes are woeful, I'd head for the nearest sand trap with any sort of spirited driving! The rear calipers may or may not be doing much, I know they're making an awful metallic rubbing sound and the handbrake is definitely sticking. One f the frotn calipers is not etting ful pressur eeither, it likes very much to turn right.
But I'm driving it sedately, just making a mental list of things to tweak and adjust. I have rebuild kits for the calipers, new pads, rotors and braided lines on the way from various suppliers, so she'll be spot on once the brakes are done.
When that is finished, I'll put it on a  local dyno and check the A/F ratios. I don't care about the numbers, I just want to ensure it's not lean so I can drive it in the manner for which it was intended without worry. It'll also get a nice performance four wheel alignment.
Then I'll ease into it with a few quiet track days, bed things in, get used to the car. Once I am happy with the car, I'll see what I think it needs to get round a track better, but I have to tune the driver first. :P

Regards, Andrew.

Typhoon90

So I've once again found the "Alfas are hard to work on" line a myth...one hour to change the timing belt.
I'll give the front of the engine a good clean whilst the belt is off and replace all the drive belts to, cheap insurance, especially for something that's going to spin 6500 rpm a fair bit.
I might also give the rocker covers a coat of wrinkle finish paint when I remove them tomorrow for a valve adjustment, and give the Alfa script a brushed finish. The stock Alfa rocker covers seem to be made of corrodium alloy, they look shite.
Finally have a tracking number for my brake pads from the US as well. So I can get stuck in to rebuilding the brakes.

I love these engines, they're built very nicely.

Regards, Andrew.

VeeSix

Hello Andrew, i have never done a valve adjustment and would like to on my current 2.5 project, give me the details on how you do yours and any problems you come across plus the tools you use, i have had a close listen to the valves the other day when i was doing a oil change and two cylinders have a fairly tappety noise coming from them, let us know when you do the check on yours ;)
1985 Alfa Romeo GTV6 V6 2.5 12V 
1986 Alfa Romeo 90 V6 2.5 12V
1990 Alfa Romeo 75 V6 3.0 12V Potenziata
1990 Alfa Romeo 164 V6 3.0 12V Zender
1991 Alfa Romeo 164 V6 3.0 12V QV
1992 Alfa Romeo 164 V6 3.0 12V QV

Typhoon90

As it happens, I just sat down from adjusting the exhaust valves on the 90. There are two methods of adjustment on the single cam V6, the exhaust uses an adjustable ball with a lock nut and the intake is shim over valve bucket follower.
The exhaust valves were all tight on my car, one of the lobes is marked almost all the way round.
So, the exhaust valves are simple enough to adjust. Pop one of the plastic cam covers off, remove rocker covers (you'll have to remove intake plumbing on driver's side and there is one tricky bolt under the master cylinder, you WILL need an 11mm open end spanner to get it). I used a spanner on the cam pulley to turn the engine by hand.
The process is to wind the engine over by hand until a cam lobe is pointing directly AWAY from the exhaust follower, then find a suitably sized feeler gauge and try to insert it between follower and camshaft. If the clearance is correct, the feeler gauge will drag through the gap, too loose and no resistance, too tight and it won't go into the gap.
So, if the gap needs adjustment, loosen the locknut on the exhaust rocker and turn the inner adjuster whilst trying to move the feeler gauge in and out between camshaft and follower. Once you have some drag, stop and tighten rocker arm lock nut. I held the inner adjusting screw from spinning with a pair of pliers, you just have to ensure it doesn't move when you tighten the locknut. Once everything is tight, recheck the gap. Then move on to next exhaust valve.
The intake valves are harder to check, you really need some bent feeler gauges. The process for checking is the same, insert feeler gauge, ensuring cam lobe is pointing AWAY from cam follower. However, the adjustment is much harder. You have to measure the gap you have, remove camshaft, measure shim thickness and add to the gap you measured, then subtract from this measurement the correct valve clearance. This gives you your new correct shim thickness, which you now have to go out and buy one of. Repeat five times!
Fortunately for me, all the intake valves were tolerably close to correct.


Regards, Andrew.