Lifter bore wear in a big block Guzzi?

[bigbikerrick]

Hello Folks, the other day while assembling the top end on my eldorado, a question came to mind. The lifters on a big block run up and down in the aluminum block, and there is no replaceable sleeve of any sort where the lifters run.
 This seems like an area that would wear, since its steel running against aluminum. I have never read anything about checking clearances or fit between the  lifter and the hole in the block. A friend that was visiting me while I was assembling my engine asked me this, and I was stumped!
Do these blocks ever "wear out" or the lifters get loose in their bores?
They are not lubricated by an oil pressure film, just oil that drips down the pushrods, and works its way between the lifter and the block, right?
mine seemed to fit fairly tight, with 40K miles on the block, almost as if no wear has taken place.....What gives here?
Thanks
Rick.

[jwinwi]

 

[RinkRat II]

   Lifter bore....22.0mm-22.021mm
     Tappet dia......21.978mm-21.996mm
       Oversize tappets sold 0.05 and 0.10mm over
          Tappet to bore  clearance 0.004-0.043mm

         Paul B

[Antietam Classic Cycle]

Even on the most worn out, poorly maintained old Guzzi engine, I've never found the lifter bore worn.

[pete roper]

I have on very rare occasions replaced tappets with oversized ones but this has always been done as a very last resort to try and quieter down bikes with noisy top ends!

Older doundfins especially tended to get 'Clanky', especially on the left for some reason. Usually re-facing the rocker tips and installing new pins and bushes fixed it up but on some occasions it didn't and although the 'Clankiness' never seemed to cause any damage it did upset a couple of customers so much they kept on at me to chase it. Gradually, after replacing part after part, cam, lifters, retainer plate, pushrods etc. the only thing that hadn't been done was the lifter bores. So O/S tappets were bought and the block duly reamed and everything refitted and, wonder of wonders! The motors were whisper quiet! For about 5,000 miles. Then the 'Clank' gradually returned.

Make of that what you will....

Pete (Who is now so used to riding an early 'Roller' 8V that produces an 'Industrial Deafness Inducing' racket even when running perfectly that a 'Clanky' roundfin sounds like the gentle tweeting of birds on a spring morning!)

[bigbikerrick]

Excellent information, Guys! I had no idea lifters were available in oversize dimensions. I also never knew that lifter bore wear, although uncommon, could be a source of noise, to consider when evaluating weird engine noises.
thanks alot,
Rick.

[jacksonracingcomau]

Imhe
Like gudgeon pins, rocker spindles etc etc, the opposite to what you think happens
The hard part wears out not the soft
I have changed lifters that had perfect face, no pitting at all
But sides worn out to cock in a sock fit in cases, appropriate noise fixed with std new
Have both oversizes in stock for 30+ years, still haven't needed them.
Simple test, finger in lifter, wiggle to feel play, if it rocks try new one
Measure sides with mic to confirm but visual gives em away too

Have actually broken lifters too, from same wear, again new std fixed, Pete's one well extreme but someone has to get them. Bet all osize are now very old, not a fast moving item, guess I will die with mine but if anyone needs.......

[Antietam Classic Cycle]

Revisiting this old post. Rebuilding a customer's 850 Le Mans engine and find that all the lifter bores are "egg-shaped" and one looks like a bit of material has flaked off the bottom (closest the cam). Three are a little out of spec., the damaged one a lot. Lifters are all in spec.

The question is: are oversized lifters/tappets really available, and if so, where?

[RinkRat II]

  Cadre's fiche shows the part No.s but you'd have to call and check availability.
    GU10045801...  .005mm
     GU10045802... 0.10mm 

  Haven't checked since 2018. 

    Paul B. 

[Antietam Classic Cycle]

  Cadre's fiche shows the part No.s but you'd have to call and check availability.
    GU10045801...  .005mm
     GU10045802... 0.10mm 

  Haven't checked since 2018. 

    Paul B. 

Thanks. Found a set of 1st over in Yurp.

[bigbikerrick]

Its always nice,when a plan comes together!   Just curious, Charlie, what is yurp?
Rick.

[Antietam Classic Cycle]

Its always nice,when a plan comes together!   Just curious, Charlie, what is yurp?
Rick.

Europe. 

[jacksonracingcomau]

Missed this one but Charlie found em anyway
As I posted earlier in this thread I have a set of first and a set of second oversize if anyone ever finds this thread again.
I’ve had them for 40 years and never needed them so it’s not a common thing
PM me if you need them, sell at current market price for std ones

[Frenchfrog]

I came across a case where the bores were well worn many years ago in the UK ...but the bike was in an awful overall  state and with high mileage.

[Alfetta]

steel on aluminum is actually a very good bearing surface. most modern car engines actually run the cams directly in the aluminum head without inserted bearings.

In the case of Guzzi lifters, the force is mostly linear and the bore doesn't have to do much more than guide the lifter. unlike a cam shaft bearings that are bucking the forces of the valve springs directly.

its a good solid design.

[Antietam Classic Cycle]

This particular Le Mans engine is a huge mess. All of the lifter bores are worn and one has damage at the bottom closest to the cam.





I'm not sure 1st over will clean it up, so 2nd over may be required.

[guzzisteve]

Interesting to me. So, is it from not rotating?

[jacksonracingcomau]

This particular Le Mans engine is a huge mess. All of the lifter bores are worn and one has damage at the bottom closest to the cam.





I'm not sure 1st over will clean it up, so 2nd over may be required.

Here if you need them but maybe cases are binfodder, run dry (or 30 year old oil) for long enough, the cam journals might be donald as well

[Antietam Classic Cycle]

Here if you need them but maybe cases are binfodder, run dry (or 30 year old oil) for long enough, the cam journals might be donald as well

I checked the cam and journals - both are near perfect. I sent you an email about the 2nd over followers.

[jacksonracingcomau]

I checked the cam and journals - both are near perfect. I sent you an email about the 2nd over followers.

Old email no longer used, I sent you pm with new one, hope that worked, if not try pm me

[MattP]

if the lifters are fine i would sleeve them

[moto-uno]

  It's been a while since I was last into my Le Mans 2 motor , but if my memory serves me (kinda questionable) I was sure the
cam lobes ran somewhat off center and would tend to cause the lifters to slowly rotate .  Peter

[Frenchfrog]

And the lifters are very slightly domed too to help make that happen ...never had reground ones but I do wonder if they replicate that feature?

[Moparnut72]

This is a video by Uncle Tony of Uncle Tony's Garage explaining lifter and camshaft design and the reasons why. Well worth a view, I am sure you will learn something if not a lot. Applies to what is being discussed here. Check it out.
kk

https://youtu.be/7M-yopGZO94?si=lhyuG-a0Sn0AxzOm

[moto-uno]

   ^  Well I'm truly shocked , in this video he seems to reference  "Mopar"  engines    !  Peter

[Moparnut72]

Gee, go figure.   
kk