The Road to Drag Week 2014 - June 22

[Bullitt]

Funny I didn't see that much timing variation in 2006 during my testing.  The original stock chains were not as good as the chains I was running in 2006, based on the chain pull-test data, so maybe they stretched more than the ones I was using.  I still think the data is suspicious, especially the data for the right cam, which is the red line in the graphs on the previous page.  With no change in engine speed, that right cam is retarding 3-4 degrees in that graph.  I don't believe that...

In any case, my precision sensors are on the way and I will be able to test with them installed this weekend.  Should be an interesting comparision...

Is it possible the chain is stretching more due to higher valve spring tension?

And I am not sure the gear drive would be intentionally that noisy.  The high pressure oil pump and camshaft in my 6.0 Diesel are gear driven (as are 7.3 Powerstrokes and 5.9 Cummins) and do not exhibit that old school gear drive sound.

Josh

[jayb]

More chain stretch due to higher valve spring pressure is certainly possible; what's confusing to me is the behavior of the left cam, which advanced a few degrees at higher engine speeds when I tested the other SOHC in 2006, and now appears to be retarding, like the right cam.  I don't think I can chalk that behavior up to valve spring pressure.

On the gears, I'll bet your diesel gears aren't straight cut.  Straight cut gears like the ones in the pictures earlier in the thread are really noisy, but stronger than angle cut gears.

[fe66comet]

You ready Jay, you had a long recovery from the last engine LOL. I would like to see the results of your new and improved engine.

[Bullitt]

More chain stretch due to higher valve spring pressure is certainly possible; what's confusing to me is the behavior of the left cam, which advanced a few degrees at higher engine speeds when I tested the other SOHC in 2006, and now appears to be retarding, like the right cam.  I don't think I can chalk that behavior up to valve spring pressure.

On the gears, I'll bet your diesel gears aren't straight cut.  Straight cut gears like the ones in the pictures earlier in the thread are really noisy, but stronger than angle cut gears.

That's true, they are angle cut on the diesel.

I got to thinking about the Ford Indy 255.  I have been around a couple of those as they were started and ran, and did not exhibit the infamous gear drive noise.



Josh

[Qikbbstang]

FYI friend of mine built a NASCAR cup motor by collecting parts and pieces and of course buying a bunch of new stuff. Most amazing was what looked like a stock SBF timing cover with of course the large bolt hole that gets a dry-sump stud, but the interesting thing was the long Teflon guide that required significant filling/build up of aluminum inside the cover to support the Teflon strip. It was literally kissing the chain. When you think of NASCAR teams addressing chain stabilization on a simple little crank:cam drive chain ........and that monster chain on the SOHC....................

[Bullitt]

Nascar uses timing belts and has for nearly 2 decades.

Josh

[Qikbbstang]

The one in my friends less then 10 year old Cup motor (previous Gen) is solid aluminum (not bolted in) with the Teflon on the face. His is much more parallel with the chain then the one shown FWIW.   

http://www.circletrack.com/enginetech/ctrp_1003_nascar_sprint_cup_engine/photo_12.html

[sumfoo1]

More chain stretch due to higher valve spring pressure is certainly possible; what's confusing to me is the behavior of the left cam, which advanced a few degrees at higher engine speeds when I tested the other SOHC in 2006, and now appears to be retarding, like the right cam.  I don't think I can chalk that behavior up to valve spring pressure.

On the gears, I'll bet your diesel gears aren't straight cut.  Straight cut gears like the ones in the pictures earlier in the thread are really noisy, but stronger than angle cut gears.

just put a straight cut dog box behind it... you'll never hear the cam gears again... (well i guess when the clutch is in.... or you're in neutral)

[Bullitt]

The one in my friends less then 10 year old Cup motor (previous Gen) is solid aluminum (not bolted in) with the Teflon on the face. His is much more parallel with the chain then the one shown FWIW.   

http://www.circletrack.com/enginetech/ctrp_1003_nascar_sprint_cup_engine/photo_12.html

You're link leads to an open wheel modified Outlaw style engine and not a full on Nascar Winston Cup/Nextel/Sprint Cup engine.

The big boys use belts, the lesser classes use whatever.

Josh

[TomP]

Not sure on that Josh. Read all the other picture captions. This one is interesting.
http://www.circletrack.com/enginetech/ctrp_1003_nascar_sprint_cup_engine/photo_14.html

Has adjustable rockers UNLIKE current Cup motors. So they must use lash caps like SOHC's used to? Since SOHC adjustable rockers seem to be a problem maybe non adjustable are the better way.
Perhaps they found the chain is better than a belt, that billet timing cover doesn't appear to have been made for a lesser series.

[Bullitt]

Not sure on that Josh. Read all the other picture captions. This one is interesting.
http://www.circletrack.com/enginetech/ctrp_1003_nascar_sprint_cup_engine/photo_14.html

Has adjustable rockers UNLIKE current Cup motors. So they must use lash caps like SOHC's used to? Since SOHC adjustable rockers seem to be a problem maybe non adjustable are the better way.
Perhaps they found the chain is better than a belt, that billet timing cover doesn't appear to have been made for a lesser series.

Once again, BB's link is to an Open Wheel World of Outlaw's engine.

Notice the external timing belt of the Ford FR9 Sprint Cup Nascar Engine



The Yates/Ford 1991+ Nascar Timing Belt set-up



Josh