My Alfa Romeo 33 rebuild - FIRST TIMER

[timinator]

Hi Chris,

Sorry about the current difficulty. Just curious about your valve springs. Have read your post several times and have not seen any reference to them. As a rule on a rebuilt engine the valve springs are replaced. At least in my shop they are since springs are a maintenance item. More to the point, when the valve job is done, all the details about the springs are checked. Free length, squareness, seat pressure, open pressure, stem height from head spring seat, and stem clearance are determined. Many engines do not use the same spring for both intake and exhaust.

Improper spring pressure can cause erratic behavior from hydraulic lifters. It can also cause cam failure. Might be something to check into if you did not receive a complete record of specification from your machinist. Good luck.

Tim

[Brit01]

Hi Tim,

I don't any mechanic here in Uruguay would do such a thorough job with the springs to be honest. (or even know how to do that)
I did have them checked, valve seals changes, and seats checked and cleaned. But did not know about the springs. And I can bet my life the mechanics don't have a clue about the Alfa springs characteristics here.

I know the boxer head springs are extremely robust but now another thing to worry about. mmmm....

Maybe one time in it's life the wrong spring has been places in the exhaust valve on the right head?

I will investigate if springs are available here as a routine change to new ones.

BUT one thing to emphasize that the ticking noise is only really evident at idle and a bit more, when oil pressure is at the lowest. I would expect there to be noise when the springs are working harder and faster no?
And weak or failing springs normally have an effect on the hydraulic tappet where it over-pumps with oil and tends to prevent the valve from closing properly.
Please correct me if I'm wrong.

Guy: What do you think?

They have a whole set of new springs for 110 USD from the same supplier of cam supports.

Many thanks.

well from the specs shown at least I can measure the spring length with valve closed at home. I do not have the tools to remove the springs unfortunately. That would need to be done at a garage again.

[Brit01]

Both exhaust and inlet springs are the same length I see so they can't get mixed up.
I measured the outer spring with valve closed and it matched the 32.5mm on the spec sheet.

But as you said they should be measured with a torque meter.
But being under torque shouldn't cause this ticking noise when idling, only create problems of lashing at higher revs I understand.

[Guy Croft]

It's kind of Tim to offer advice but it won't be the springs.

They don't make any noise even when fractured. And OE springs are under such mild load and so lowly stressed compared with their stiffness characteristics they tend to last for years and years. A spring defect would show as a wear witness on tappet or cam and you have none.

Leave them alone is my advice since you asked, FWIW!

G

[Brit01]

Thanks Guy for your reassurance that it won't be the springs affecting the tappets in this case.

Just trying to organize the importation of the cam supports into the country now.

Not sure when it will be. Sooner than later I hope.

Regards

[TomLouwrier]

hi Chris,

No comments on it so far, but I must say I agree with you that -from your pictures- those bores seem to have a clear wear pattern, especially #1.

Are these signs of severe wear of just some polishing from normal use?

bucket 1 TLO.JPG (62.91 KiB) Viewed 8552 times

The bores in the used/good carrier may be better but we can't tell until you clean them and repost. Of course you can then also slide a tappet into both and compare the feel. Use a thin lubricant like wd40, no engine oil.
Try to rock them in two planes: along the cam lobe's line of movement (which is what would cause wear) and 90 degrees from that, along the cam shaft's axis (which would be not worn at all).
Note any difference in play, let us know what you find.

regards
Tom

[Brit01]

especially #1.

yes #one is where the ticking is and also where the previous broken tappet was located along with the destroyed lobe.

Of course you can then also slide a tappet into both and compare the feel. Use a thin lubricant like wd40, no engine oil.
Try to rock them in two planes: along the cam lobe's line of movement (which is what would cause wear) and 90 degrees from that, along the cam shaft's axis (which would be not worn at all).
Note any difference in play, let us know what you find.

Yes I have done this already with WD40. In the spare used bore they rocked even more in both directions than my current one!! And they have many scratches - obviously lots of foreign material has entered them at one time. Also some scratches around the cam bore as if the lobes picked up debris and etched them into the casting.

Regards

[Brit01]

spare cam box has just been taken away to be measured accurately at a workshop - just out of curiousity to see what the readings are.

[Brit01]

35.020mm! (max clearance 35.025mm)

I am surprised. Apparently the old spare box is ok and not oval despite the scratches the workshop said it was fine.
He also said the NOS supports from the factory are not always exact and there may not be any difference.


He's going to measure my current one and also the tappet.

mmm.. what to do? Test the old one out or go for the NOS cam supports?

Head gaskets each time are not cheap either.

[Brit01]

Results:

Factory specs:

Bucket diameter: 35 mm - 35.025 mm

Tappet/bucket gap 0.025 mm - 0.066 mm

Spare used cam box:
35.020mm internal diameter
gap between new tappet and bucket: 0.050 - 0.058mm

Current problematic cam box:
gap between tappet and bucket: 0.070 - 0.080 mm
and oval.

So the spare cam box is JUST within tappet/bucket backlash specs (0.058mm) max allowed 0.066mm.

Worth trying out?

[Urbancamo]

I would try with that new used cam box, it is reasonably tighter than previous. 8 thousands sounds a little too loose when the bucket is only 30 mm in diameter.
After that, i cannot spot any more faults with this engine by the given info so far. Everything seems to be in good, working condition.

Always nice to see measurements, trust on them, never guess anything with engines. Golden rule.

[Brit01]

Thanks for the opinion.

Yes we've decided to give it a go. After a lot of cleaning (still soaking), it looks better, Much more cylindrical as the measurements revealed. Apart from some scratches on the bores the backlash is less.

I used some wet 1200 paper with oil on the bores just to make sure they were smooth and no edges from scratches were protruding that could damage the surfaces of the new tappets.

If it runs smoothly and no ticking appears with this right one we'll probably swap the left hand box also as the initial photos I took also reveal worn edges (even though there is no ticking). They could wear down the new tappets/lobes prematurely if the bores are slightly oval.

[timinator]

Hi Chris,

Please excuse my ignorance. I assumed that your engine was some sort of exotic horsepower beast with a 7500rpm redline. Since no one seemed to know much about it, and you mentioned running 20w-50 or higher weight oil, I jumped to the wrong conclusion. Seat pressures of 150lbs and over the nose of +400lbs was what came to mind. As GC said springs are of no concern.

Little problems like this pop up and cause grief from time to time. I am sure you will figure it out soon.

Tim

[Brit01]

Please excuse my ignorance

Of course. No apologies necessary. I'm very grateful for all the comments/suggestions and assistance given with my engine on this forum.

I assumed that your engine was some sort of exotic horsepower beast with a 7500rpm redline

I wish. One day it will be converted into a beast!

50 viscosity oil is the recommended oil from Alfa for this model/year.
But the boxers do like to be revved. Great overrun sound at 5500. It redlines into about 6500.
But I never push it above 5500.

Yep after a good cleaning (mind you there is still some old stuff I can't get off, maybe a soak in a hot oven will shift the old oil stains?) the bores look nice and cylindrical, much better than the current 'oval' ones that were ticking my tappets.

If this cam box works out then I'll grab the other half from the seller.
He hasn't even charged me yet. "Just try it out first they said"
Nice fellas.

Keep you updated. Maybe another week before I can get it back on the block.

thank you

[Brit01]

just a thought.

I know you bevel off the edges of the oil holes on the crankshaft leading to the rod ends to improve lubrication on your engines.

Can this same method be applied to the oil holes in the bores where the hydraulic tappets fit?

Well before it goes on for a test I still want it painted. It was a very dull dark aluminum colour. Been outside or in a damp place for some time by the looks of it.