Engine designs that have problems 22

[enginesrus]

Since the one thread I started, is headed way off topic, reason for this.
Engine designs that have problems or have had them.
I'll start with the 3 valve Triton.
This guy explains. Has data from others that deal with the same problems.

https://www.youtube.com/watch?v=xcN_WcGr4BU

 

[SnTMan]

I've got two old Nissan pickups, both 4 bangers.
The 94 has a single row timing chain with some really long, slender cast iron guide/ tensioner elements. At ~170 k it swallowed some fractured pieces of same. Some pieces went into the oil pan where they remain today. I'm careful to avoid negative G's

Meanwhile the 84 with a double row chain has no problems at 250 k. The better designed, built of the two in many ways.

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[enginesrus]

BrianPetersen (Mechanical)
8 May 22 03:08
Timing chain guides are a GOOD thing in that they avoid the chain whipping around.
----------------------------------------------------------------
Problem is many of them seem to fail. Pulleys like used on timing belt applications would be a better though more expensive choice, to stop the whipping around.

 

[spsalso]

Honda, in the '60's, used a chain to run the overhead camshaft on their twin cylinder motorcycle engines. It's interesting that there was a take-up roller for the chain. To adjust the take-up roller, you undid a bolt and a spring would shove the roller into the chain. Then you tightened the bolt, taking the spring back out of the system. The bolt was external on the engine.

spsalso

 

[JohnRBaker]

Yes, I had two 305 Honda Superhawk motorcycles, a 1965 and a 1968 model. And yes, that's how they kept the camshaft chain tight:

This is the 1965 Superhawk, after I rebuilt and painted it Candyapple Blue (this was the bike I owned when we got married and I was forced to buy a car as my soon-to-be wife refused to go on a honeymoon on the back of a bike):

June 1967 (Kodak Brownie Twin 20)

And this is the 1968 Superhawk that I rebuilt and painted, only this time I only used the gold Candyapple undercoat and then the clear top coat, skipping the color coat:

April 1974 (Minolta SRT-101)




John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[Brian Malone]

JohnRBaker - nice Superhawk! It is of the era of motorcycles that used the cylinders and engine cases as structural frame components - who needs a front down tube!

 

[JayMaechtlen]

The Honda CB750 used a cam chain follower - it had the same spring loaded thing where you'd loosen a lock bolt to let it adjust, then re-tighten.
re the mentioned engine above - 80k km seems like an absurdly short lifespan for a cam chain. I wonder if that is a misquote or a misunderstanding?
Yeah, overall I'd rather have a timing chain than a belt, I am sure the chain is not as quiet and a bit more costly, but...
And on the topic of engines good and bad - while I had great luck with GM/Buick V6, both 3.8, 3300, and 3800, my current car and its predecessor have the Chev 3.6.
DOHC, vvt, and lots of scary cam chains. I understand it is 8-12 shop hours to swap the timing chains.
But they last well over 150k miles given at least casual oil changes, and run great. (well, my first had over 150k when it got totaled, its replacement has only 120k miles)
So far so good...



Jay Maechtlen

http://www.laserpubs.com/techcomm

 

[JayMaechtlen]

and that 'wizard' that whines about the Triton 3v - how about you flush the dang thing out, replace the parts that are actually bad, and run the sucker?
And his usual customers will probably keep them maintained, so the issue will probably not recurr.
I wonder if you could connect an oil supply at the oil filter mount, and pump solvent then oil through the system to clean it out?


Jay Maechtlen

http://www.laserpubs.com/techcomm

 

[JohnRBaker]

JohnRBaker - nice Superhawk!

Thank you. Now that I live in SoCal, I kind of wish I still had at least of those bikes today (I lived in Michigan when I was driving them).

It is of the era of motorcycles that used the cylinders and engine cases as structural frame components - who needs a front down tube!

No, the engine was not an integral part of the frame on the Honda CB72/77 series (the CB72 was 247 cc and CB77 was 305 cc). Bikes from companies like Ducati, they were structurally more part of the frame. However, the most notorious of that style of bike was the Vincent Black Shadow, a bike that was very unsafe. It was great as long as the didn't want to stop or turn corners. It had perhaps the worst brakes of any large motorcycle and because there was no real frame, it tended to flex which made it very unstable when turning. That being said, going straight it was one of the fastest motorcycles of it's time. I never drove one and have only seen them in museums, like this one, a 1952 Vincent Black Shadow as seen in the 'Sturgis Motorcycle Museum & Hall of Fame' in Sturgis, South Dakota:

October 2009 (Sony A100)

To give you and idea about how people felt about this overpowered (55 hp) English bike (with English brakes and ignition system), journalist and author Hunter S. Thompson once wrote that "If you rode the Black Shadow at top speed for any length of time, you would almost certainly die. That is why there are not many life members of the Vincent Black Shadow Society." The bike is mentioned several times in Thompson's 1971 novel, 'Fear and Loathing in Las Vegas'.

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[TugboatEng]

Brian Malone, engines are stressed members in all modern motorcycle frames to my knowledge. The swingarm pivot is located in the engine case.

 

[TugboatEng]

On the subject of timing chains, the Euros are bad at applying plastics. The timing chain guides on Euro engines will fail. It seems like they buy plastics by name but forget that polyamide can have a very wide range of properties based on resin within the same plastic name. Otherwise, most other engines manufacturers have timing chain systems that will regularly last the life of the rest of the vehicle.

 

[BiPolarMoment]

@TugboatEng (Re: Brian Malone); I read that as being literally integrated into the frame such that the bike would not even be assembled if not for the motor being present ("who needs a front down tube!"). The engine being a "stressed member" seems like a necessity, but if anything due to consequence of the 'packaging' rather than a desire to do so. Of course, now I need to go check my bike to see if indeed the swingarm actually connects to the engine directly-- I'm fairly certain it does not, otherwise similar to the way I interpreted Brian's comment above, you then couldn't remove the engine without effectively disassembling the bike (in this case the rear).

 

[BrianPetersen]

Most bikes don't have the swingarm pivot integrated with the crankcases, but that alone doesn't stop the engine from being part of the structure. It contributes to the stiffness via the engine mounts. It's not unusual nowadays for the front engine mounts in particular, to be designed to be stiff in certain directions but allow compliance in other directions.

 

[BiPolarMoment]

Yes; nearly unavoidable, it makes sense to take advantage of it. I thought that's what I was alluding to but :shrug:.

 

[Brian Malone]

Thanks to all for the info on the use of the engine as a stressed frame member. I have owned only motocross and enduro motorcycles and quite unaware of the constructions used for the large street bikes.

 

[thebard3]

My sister had a 1970 Chevy Vega. It was my job to keep it running. If there are any still left in the world, this engine has problems. I think they were burning oil before you finished the test drive.

https://en.wikipedia.org/wiki/Chevrolet_2300_engine

Brad Waybright

The more you know, the more you know you don't know.

 

[BiPolarMoment]

...Chevy Vega...

Found this after looking at the wiki page.

 

[CWB1]

My folks gave away their '76 Vega wagon two years ago, great lil car with well over 200k on it. It became a spare vehicle ~1990 and part of me wishes I'd kept it to restore but unfortunately I have too many projects and not enough time.

 

[Alistair_Heaton]

Surprised nobody mentioned rotax yet.

The Armstrong 500 was a dog.

And the aviation engines keep pilots in practice for forced landings

 

[enginesrus]

Or Rotec

https://www.youtube.com/watch?v=LlPtMVijIzs

 

[SnTMan]

I had a 76 Vega wagon. OK car, but the door seals leaked rainwater into the car. Nothing I could do fixed it. I had to drill holes in the footwells to let the water out

The problem with sloppy work is that the supply FAR EXCEEDS the demand