Piston Pin Circlips

[Jerry Wyss]

Does anybody know of a good replacement for the "piston pin circlips" on a Picco

"Disc Rotor" 45 "Silver Head". Mark Anderson & Eric Boulet (still does) used to

run these engines exclusively in their "Mutt" Sport 40's. My engines specific "P"

Number is "P-418 P-45 MARINE EXR" Part is called "Wrist Pin Retainer P40/45.

Thanks for your help

 

[Tunnelbill]

Jerry,

Years ago I was using the OPS 45 clip with not problems.

 

[Jerry Wyss]

Jerry,
  Years ago I was using the OPS 45 clip with not problems.

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Thanks Bill

 

[ChrisCapaldi]

CMB 45 clips also work well. You have to cut them down allittle to get them to fit. I have not had one fail in 8 years of use in Picco Bluehead and Blackhead 45s.

Chris

 

[Jerry Wyss]

CMB 45 clips also work well.  You have to cut them down allittle to get them to fit.  I have not had one fail in 8 years of use in Picco Bluehead and Blackhead 45s.Chris

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Thanks Chris, I'll get both Types

 

[Nigtmare]

Good old OPS.... Takes you out of a jam every time

Hi Jerry how is my RPM rod comming along? :-? :lol: Nick

 

[Jerry Wyss]

Hey Buddy! I haven't seen one I got one for a K&B 7.5 Which I would trade

for a Picco 45 Disc Rotor One

 

[Nigtmare]

I wonder if some other brand of an engine will fit an ops 45? You would think if the stroke is the same, the rods should be the same also. I guess the throw will make difference too, crank pin, rist pin, and so on :lol:

 

[Jerry Wyss]

Yeah Gawd, I wouldn't want to go there :blink: Some of that stuff is hard to measure accurately,,but I gotta do it soon,,make 3 head buttons for a Thunder

Tiger OB and (I'm not looking forward to this) raising the "transfer ports" UGH!!

Looked into doing it with a "milling machine" (the ports mod) and the thing I have

to build to hold that "tiny" sleeve is way much more than I want to do So it's

"Dremel" or nuthin' I guess.

but just for grins the big end "ID" of the K&B RPM rod is ---.244

the small end "ID" is-------------------------------------------------.208

And there apart "center to center" is -----------------------------1.322

Thats a "tight" measurement, ( no rod clearance)

 

[Mike Stewart]

shim under the sleeve to raise transfer ports.

 

[Jerry Wyss]

shim under the sleeve to raise transfer ports.

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OOOOOOOOOO, You Just Became My Favorite Mike I've heard of that but got

no indication like that from the person recomended this mod. What is the "perfered" methoed of maintaining the correct head space, take it off the top of the sleeve or relieving the head button? :huh:

OOPs,,that would raise my exhaust port timing also on the sleeves I have cut already, and there's several that have higher exh timing . Would work good on a new sleeve though. I'm still waiting on a "Dial Indicator" from "MSC" I'll check it out and see which will be better. Thanks again

 

[TimD]

Shimming the sleeve is one way to do it and is the easiest way if you are making a new head to go with it. If you raise the sleeve the head to piston clearance increases.

Problem with the TT engine is the P&L "nip at TDC" isn't that great (even new ones) plus the sleeve fit in the case isn't very tight, and raising the sleeve makes it worse. Cutting the ports will still maintain the same "nip" at TDC. The timings are VERY conservative on the TT sleeves I've seen.

Be sure to check the port passages in the case after adjusting the transfers and "adjust them" if there is a big mismatch.

 

[Jerry Wyss]

Shimming the sleeve is one way to do it and is the easiest way if you are making a new head to go with it. If you raise the sleeve the head to piston clearance increases.
Problem with the TT engine is the P&L "nip at TDC" isn't that great (even new ones) plus the sleeve fit in the case isn't very tight, and raising the sleeve makes it worse. Cutting the ports will still maintain the same "nip" at TDC. The timings are VERY conservative on the TT sleeves I've seen.

Be sure to check the port passages in the case after adjusting the transfers and "adjust them" if there is a big mismatch.

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The terms "P&L" and "nip" I'm not familiar with,,sorry Tim, i feel like an idiot..

I've also been trying to run the larger bore TT carby,,and it would "seem"raising

the intake,transfer,,(whatever their called ports) at the "top" of these ports could

benefit from the larger carb,(works on cars) but I'm unsure whether it would be

"too much" for the engine to handle :unsure: thanks for your help

 

[TimD]

Shimming the sleeve is one way to do it and is the easiest way if you are making a new head to go with it. If you raise the sleeve the head to piston clearance increases.
Problem with the TT engine is the P&L "nip at TDC" isn't that great (even new ones) plus the sleeve fit in the case isn't very tight, and raising the sleeve makes it worse. Cutting the ports will still maintain the same "nip" at TDC. The timings are VERY conservative on the TT sleeves I've seen.

Be sure to check the port passages in the case after adjusting the transfers and "adjust them" if there is a big mismatch.

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The terms "P&L" and "nip" I'm not familiar with,,sorry Tim, i feel like an idiot..

I've also been trying to run the larger bore TT carby,,and it would "seem"raising

the intake,transfer,,(whatever their called ports) at the "top" of these ports could

benefit from the larger carb,(works on cars) but I'm unsure whether it would be

"too much" for the engine to handle :unsure: thanks for your help

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P&L = Piston and Liner. Nip = piston and liner fit as it approaches top dead centre.

I used the 9mm bore carb after modifications to it. I machined a taper into the underside of the carb - without it the carb is harder to tune.

 

[Jerry Wyss]

I have your carb mod on my list from conversation a few months ago.

The larger carb I have is 8mm and all the others are 7mm,,there was just one engine that I bought out of 8 I've bought over the years and just out of the "blue"

one came with the larger one :huh:

I guess "nip"= "pinch" in the US :lol:

 

[TimD]

The inboard version (TT PRO-21MR I think it was called) had a 9mm bore carb. I'll have a look and see if I still have one.

 

[Jerry Wyss]

The inboard version (TT PRO-21MR I think it was called) had a 9mm bore carb. I'll have a look and see if I still have one.

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Righty "O"

Just one other question Tim, In the machining prosess of the new "buttons", is it

"possible" or even "reasonable" to "CC" the glow plug by itself and subtract that

measurement while we're in the stage of making the "bubble"?? Seems like it would be easier to stop and "CC" what we have, and then drill and tap for the

plug last,,Good idea?? Bad??

 

[TimD]

Yes, you could do that. The section of the button where the plug washer sits needs to be machined to get the plug depth right when doing it that way. If you leave a little extra there in the beggining, you can skim some off later if the plug is too far away from the bowl.

 

[Jerry Wyss]

Yes, you could do that. The section of the button where the plug washer sits needs to be machined to get the plug depth right when doing it that way. If you leave a little extra there in the beggining, you can skim some off later if the plug is too far away from the bowl.

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Thats good news, we are starting Wed. We ( my jeweler friend) built an "inertia"

bearing extracting devise that works perdy good today. Thanks

 

[Jerry Wyss]

This post is mainly for TimD, I was wondering why TT deceided to have that large

a volume of bubble,,,could it have been for an airplane engine that would normaly

turn half as much RPM? With such "modest" port timings it seems to me to be nothing more than a muffled airplane engine.

One other thing, does the "air cooled" car engine head bubble have a similar arrangement of what I'm trying to make or is it like the "water cooled" that comes with the OB?

Thanks for your help