My Alfa Romeo 33 rebuild - FIRST TIMER

[WhizzMan]

I myself would want to know for what reason you'd want to polish a crank if there is no evidence of even bearing wear. What criteria do you use to determine if a polish is required or beneficial?

[Brit01]

Good question whizzman.

I will upload high def photos and wait for Guy's opinion.

Today arrived:
All crankcase gaskets, oil seals, o-rings, etc etc. Whole kit from Justsuds. Nice surprise as I expected just the 2 gaskets and seals. :)

Also mechanical oil pressure gauge purchased and Mann Germany made oil filters. (hard to find here)


Also to note I found out that the Valvoline 20w/50 oil I used to break in the rings IS MINERAL and not semi as I previously thought. Better.

I did also find some Motul 300V le mans 20w/60 synthetic oil today which I didn't know they imported.

Still not sure what oil I'll use for long term use.

Either Motul semi 15w/50
Motul 300v full 15w/50
or Motul 300v full 20w/60.

[Brit01]

Fitted my new mechanical oil pressure gauge today to try it out before I drop the engine to inspect the main bearings thoroughly.

Adapter I purchased to fit at the oil filter plug did not fit properly.
Had some other brass reduces and managed to fit it on the main oil channel that follows after the oil filter.

Nice classic black design (back lit with a 5w lamp).
Didn't get a chance to get the engine very hot but gave it a quick spin looking for oil leaks.
Liked it very much.



Still reading up about the oils and which one to use.

After a test (after rebuid) with the cheaper Valvoline 20w/50 I might go for the Motul 15w/50 300v full synthetic (double ester).

Then next summer try the 300v 20w/60 to compare the pressure and performance differences.

Considering also installing an electric fuel pump with regulator and gauge.

Recently I've had some issues when left too long in the hot summer.
Fuel in carbs evaporate and the mechanical pump doesn't suck enough to fill the carbs again. So I have to remove the air intakes and prime the carbs to get it going again.

[Guy Croft]

Polishing is a 'relative' thing.

How much depends on the state of the crank.

If the journals are within limits and exhibit perhaps a bit of minor scoring I would just give them a scrub with Scotchbrite to get rid of any rough bits and gum deposits. Some might say 'why?' - well, I'd do it..

We're not talking putting it in a crank grinder and taking 0.001" off, y'all understand?

G

[Brit01]

We're not talking putting it in a crank grinder and taking 0.001" off, y'all understand?

I'm with you there Guy.

I understood 'polishing' as just a thorough cleaning and taking off any grime/gum to leave a nice smooth surface for the new beaings.

Chris

[Guy Croft]

Good-oh.

When done with abrasive bands the polishing must always be done contra-direction of rotation so as not to raise the grain of the journal against the bearing.

With Scotchbrite & by hand this is not an issue at all.

G

[Brit01]

Thanks Guy as always.

I have a question regarding instruments.

What is the name of the instrument you use to measure the exact maximum valve lift and lobe heights?
The gauge with the digital display and probe?

Did some searches on google but didn't find much. Maybe I used the wrong verbiage.

Also where do you source these?

[Guy Croft]

DTI - dial type indicator - dial gauge for short.

Try Mitutoyo - in my view best you can get. A lot of their stuff is still made in Japan - a country famous for precision equipment - a lot of this stuff (incl that form the formerly famous UK form Moore & Wright) is made in Asia these days and not as good as it was, to put it mildly.

G

[Brit01]

Thank you Guy.

[Guy Croft]

You're welcome - I know you need to know things asap - and you are unfailingly quick to reply Chris.

I do notice and I personally appreciate it - it is always nice to see on this site.

I also like the way you courteously acknowledge every single thing written for you (by anyone).

I do sometimes wish the response times here were a bit quicker all-round.


Sincerely,

G

[Urbancamo]

Little more for measuring devices:

Mitutoyo is Rolls-Royce of measuring equipment.

If looking for long term use, better buy quality products but pretty accurate measurements can be made with relatively cheaper equipments too.

IMG_5145 (Small).jpg (42.03 KiB) Viewed 8085 times

I have this Russian made analogue DTI (adjustable support is from China) and it's very nice piece for bargain price. They make very good quality measurement devices. I have also set of micrometers, chinese made copies of Mitutoyo ones.
Showed them to my machinist buddy and he agreed, feels and looks exactly the same and are reasonable accurate for basic garage use.
When measurements are very critical and important, better quality measuring equipment is needed.

Mitutoyo (Small).jpg (18.79 KiB) Viewed 8086 times

Borrowed this Mitutoyo Borematic 3-point digital bore gauge from local factory to identify that my engine bores were terribly worn-out. It was time to rebore. This thing easily gets you confused, because it's capable of measure thousands of millimetres...

[Brit01]

I see there a lot of Mitutoyo products out there.
Some digital and some old school needle gauges.

I wouldn't risk sending any of these by post to S.America.

Have to wait for a trip to the UK or when someone visits.

But very nice pieces of equipment to have for future precision work.

Lifetime hobby for me now. Or maybe my passion will develop into something more lucrative later in life.

Regards,

Chris

[Brit01]

Something interesting I found out today.

The inner valve spring of the Alfa boxer is just very slightly progressive nearer the head.
Not sure about Fiat/Lancia. Apparently to prevent 'bounce' at high revs.

Have to inspect mine carefully as some people's springs have been put the wrong way around.

[WhizzMan]

I see there a lot of Mitutoyo products out there.
Some digital and some old school needle gauges.

I wouldn't risk sending any of these by post to S.America.

A quality vendor will pack these adequately. You can have your local machine shop verify their accuracy after arrival. I'd do that even if you bring them in the country yourself. For all you know, they were dropped in transit before they got to vendor were you bought them.

Mitutoyo in general make remarkably sturdy equipment, given the precision of the measurements you take with them. They are by no means indestructible, but some rattling and shaking about packed in bubble wrap, inside a cardboard box, filled with foam, usually doesn't get them off calibration at all.

[Brit01]

but some rattling and shaking about packed in bubble wrap, inside a cardboard box,

Thanks for the advice.

Still I am a bit cautious about sending valuable items here.
Last package I received (rotor arm and distributor cap) had a gaping hole through both sides like it had been stabbed with a pole!!
Luckily it sliced just in between the 2 pieces.

Received a parcel today (cam support), took 2 months to arrive. Thought it had got lost.

Last years Christmas card from my parents arrived in March as a bundle of wet paper totally unrecognizable.

Best to wait for a trip to the UK or a friend visiting.

wink.

ah by the way - mechanical oil pressure gauges: wish I had installed one earlier and not made the mistake of buying one with an electronic sensor.

Very different readings indeed.

@ 3000 rpm - ~ 50 psi
@ 4000 rpm - ~ 60 psi

But still on the low side when idling just 10 psi at 850 rpm.

I hope the new cam box and new main bearings will fix this.
Should be about 15 psi when idling.