ESE's works engine tuner

[pete376403]

I worked on 2 stroke 16V149 Detroits Diesels that had 4 turbos, two bypass superchargers, intercooling, ceramic coated piston tops and chambers to produce just under 1 hp per cubic inch in the 1980s. The piston skirt and top were seperate and they used 4 exhaust valves per cylinder.

Used for industrial and military generators and marine propulsion. They were something to behold. Leaky, noisy and prone to fires caused by oil spray from turbo oil lines soaking lagging and catching fire. I had to rescue a coworker once using a firefighting oxygen unit when he was overcome by fumes from a fire.

The bypass kicking off could be heard through supposedly soundproof enclosures and felt as a pressure change.

I got to thinking about the role crankcase pressures played a part in two stroke operation with them because when all cylinder block leaks were sealed, a catastrophic failure was likely imminent.

Just googled that engine type - pretty cool.

[wobbly]

VRO , your press fit guess was close but the final number depends upon two main factors.
Solid pin or hollow pin , and crank material/heat treat.
For a hollow pin and or a case hardened only material ( 4140 ) the number is 0.08 to 0.1mm.
For a solid pin and or thru hardened tool steel ( EN36B ) the number is 0.05 to 0.06mm.
Pin diameter has a smaller effect , wherein a big ( 25mm ) pin needs less press fit than a smaller ( 20mm ) due to the circumferential interference area.

[Muhr]

Hi someone who has some good suggestions on rubber quality for the shock absorption to the clutch basket.

[husaberg]

Hi someone who has some good suggestions on rubber quality for the shock absorption to the clutch basket.

don't use rubber
use urethane instead
ask Grumph what or what Shore range.

[Muhr]

don't use rubber
use urethane instead
ask Grumph what or what Shore range.

Thank you Husa, I will do a little research into what I can get my hands on. Yes, then it is these shore values, for which there are several different measurement methods. I know very little, but may try to do a simulation and see if I can understand something

[husaberg]

paging Greg

Steve Ward told me the other day he uses genuine on his fleet - at $15 each...Pretty sure we'll be nowhere near that expensive.

The materal supplier cocked up the order and it's arriving today - approx a week late - so the test set will be off to Dave Monday - PM me a postal adress Dave please.

[peewee]

[Flettner]

Urethane? I think thats what its called. I made a wee die and get these molded for me, special.

[wobbly]

I had a Hinson clutch cush drive destroy itself , due to having 100RWHp put thru it I suppose.
I had 70 shore urethane bar made up , has worked perfectly since.

[vro46i]

VRO , your press fit guess was close but the final number depends upon two main factors.
Solid pin or hollow pin , and crank material/heat treat.
For a hollow pin and or a case hardened only material ( 4140 ) the number is 0.08 to 0.1mm.
For a solid pin and or thru hardened tool steel ( EN36B ) the number is 0.05 to 0.06mm.
Pin diameter has a smaller effect , wherein a big ( 25mm ) pin needs less press fit than a smaller ( 20mm ) due to the circumferential interference area.

Thanks Wob, much appreciated,

It is a solid 24mm pin replacement, going into the original suzuki crank web. I can assume anything about the material without a proof test with a vickers hardness tester or equivalent.

[Muhr]

I hope I can find some options in the 8mm sheet that I can water cut.
wobbly, hope to be able to approach your loads in my 50cc. 75nm and about 300nm on the clutch and shock loads on significantly more

Vro

If it is not as hard on the side you are cutting more on, there is a risk that it will start rolling off material when you start pressing on the pin. Evidence of experience

[Muhr]

Found this, may be useful sometime


Before I show you the calculation, you should be aware that there is not a direct relationship between a Shore scale and Young’s Modulus! The calculation allows you to approximate ‘E’ based on a range of Shore-A (20 to 80) or Shore-D (30 to 85) durometers for simple static analysis.** If you routinely work with plastic and rubber materials, you should be using SOLIDWORKS Simulation Premium with the actual stress-strain curve for the material(s) you design with!

For a durometer given in Shore-A, multiply this value by 0.0235. Then subtract 0.6403 from this result. The next step is to find the inverse base-e logarithm of this new result. The answer is an approximation for Young’s Modulus in megapascals (MPa). To convert this to pounds per square inch (psi), simply multiply this number by 145.0377.

Shore-A to Young’s Modulus (in MPa):
=EXP((Shore-A Durometer)*0.0235-0.6403)

Shore-D to Young’s Modulus (in MPa):
=EXP((Shore-D Durometer + 50)*0.0235-0.6403)

[wobbly]

Most all Jap factory cranks are induction hardened around the pin bore and the bearing surfaces.
You are going bigger in diameter , but may well have bored thru all the hardened material when moving the hole.
My guess would be to replicate the original interference in this case - and use Loctite Bearing Fit as a sort of lube and to help with retention.

[vro46i]

Most all Jap factory cranks are induction hardened around the pin bore and the bearing surfaces.
You are going bigger in diameter , but may well have bored thru all the hardened material when moving the hole.
My guess would be to replicate the original interference in this case - and use Loctite Bearing Fit as a sort of lube and to help with retention.

Hi Wob, I was pondering that question, but thank you for confirming it for me.
I'll have another meeting with the machinist to ensure that we are replicating the factory interference fit.

[vro46i]

I hope I can find some options in the 8mm sheet that I can water cut.
wobbly, hope to be able to approach your loads in my 50cc. 75nm and about 300nm on the clutch and shock loads on significantly more

Vro

If it is not as hard on the side you are cutting more on, there is a risk that it will start rolling off material when you start pressing on the pin. Evidence of experience

Hi Muhr, I appreciate your advice.
Based on your comment, I will have to design a localised support press plate to minimise the anticipated deformation on the 'soft side' of the new pin hole.
I'll measure up the crank web dimensions and see what I can come with that is effective.

Cheers