SS1 Racecar progress - 2009 Season

Raz987 · Post by **Raz987** » Tue Jul 21, 2009 8:42 pm

Tried to get a bottom pulley machined today, didn't have quite the effect I was after...
This was a result of machining the unused ribs off and then approx 4mm off the front face.

Post by **philhoward** » Tue Jul 21, 2009 8:52 pm

Thats not good....i guess it was the last straw for the "harmonic damper"..?

Post by **reliant-reviver** » Tue Jul 21, 2009 8:52 pm

What are you trying to achieve? Is it is simply a lighter pulley you are after?
I noticed that my spare CA18et has a single width steel bottom pulley without the dampening weight, not sure what car the engine was original from?

Raz987 · Post by **Raz987** » Tue Jul 21, 2009 9:18 pm

reliant-reviver wrote:What are you trying to achieve? Is it is simply a lighter pulley you are after?
I noticed that my spare CA18et has a single width steel bottom pulley without the dampening weight, not sure what car the engine was original from?

Yeah I'm basically trying to do what I can for cheap/free gains, the bottom pulley is quite heavy so I though I'd get the excess machined off, but I guess there isn't really any excess

Luckily I have a spare...
What does the harmonic damper do?

Post by **philhoward** » Tue Jul 21, 2009 9:23 pm

It's a vibration damper - saves the manufacturer balancing the bottom end assembly to higher tolerance to achieve a smoother engine.

As far as balancing goes - its not just about smoothness, but power can be lost if the engine isn't as smooth as it can be - power is used making the 'orrible vibration, rather than going out the back of the crank...

Post by **Coupe Racing** » Tue Jul 21, 2009 9:46 pm

as mentioned earlier

I still feel that anything you alter on the bottom end - IE flywheel , damper etc will affect the balance of the engine and its ability to rev.

Counter balance weights next ?????

Hope you get out again soon Raz - its a good read

Steve

stewb · Post by **stewb** » Thu Jul 23, 2009 9:32 pm

I had exactly the same experience with my old ET pulley when I attempted to machine it to fit a trigger wheel for the Emerald ECU......The lightest one to use would be a "V" belt type damper with an ally pulley trurned up to suit (the harmonic damper on the V belt type has a pressed steel outer pulley bolted to it rather than the all in one setup on the later poly vee type pulley shown in the pics).

The harmonic balance isn't actually there to make the balancing any easier for the manufacturers, it's actually there to damp out second & third order vibrations in the crankshaft which can cause all manner of issues at certain speeds. I know that Pintos which rev hard without a harmonic pulley are prone to throwing their flywheels off....... I'm sure the later A series engines suffer similar problems if the incorrect parts are used. It's quite involved - I did do a fair amount of reading on the subject but have since forgotten most of it......

Stew

Raz987 · Post by **Raz987** » Thu Jul 23, 2009 11:48 pm

Coupe' Racing wrote: Hope you get out again soon Raz - its a good read

Thanks Steve, I do my best to keep it updated

Fitted the Autosprint camshaft to the "new" engine tonight

Can anyone tell me the torque setting for the bolts that hold the rockers on? Also, how should the offset lobe that bolts to the rear of the camshaft be orientated?

shrewsbury_streetracer · Post by **shrewsbury_streetracer** » Fri Jul 24, 2009 9:50 am

Hi Raz,

Spoke to Stu B about the offset lobe. We came to the conclusion that it doesn't matter. All it was there for was to drive a fuel pump on another model nissan so basically as long as it was going up and down the actual timing was not important.
[img]http://i205.photobucket.com/albums ... .jpg[/img]

not sure if you will be able to read the text so will email it to you as well.

Did you replace the camshaft seal?

Raz987 · Post by **Raz987** » Sun Jul 26, 2009 5:00 pm

New engine looks a lot better now it's been cleaned up:

I fitted the new Autosprint camshaft this week, unfortunately I stripped the rocker bolt head threads very easily >:(

Shiny new timing wheel

Painted all the pulleys:

Started stripping my spare head in case I need it. Surprisingly all the original studs are still in place on the exhaust side!

Raz987 · Post by **Raz987** » Fri Jul 31, 2009 3:14 pm

Do I need to replace the tensioner when I replace the cambelt?

shrewsbury_streetracer · Post by **shrewsbury_streetracer** » Fri Jul 31, 2009 3:55 pm

Most people do these days. Another one of those things that you may as well do or you may regret it.

stewb · Post by **stewb** » Sun Aug 02, 2009 9:45 pm

Not heard of an ET one fail but it's fairly common on the DET - one of the engines I bought for parts had a disintegrated tensioner which had made a bit of a mess......

Can't buy peace of mind!!

Stew

Raz987 · Post by **Raz987** » Tue Aug 11, 2009 6:09 pm

Can anyone direct me towards a guide to timing up the engine after changing the cam belt?

Post by **philhoward** » Tue Aug 11, 2009 8:49 pm

http://shworth.com/siop/index.php?main_ ... 111702465c

Sorry - cheap shot....

The "club" manual is a reprint of the Nissan S12 engine/gearbox manual BTW...If you can't find one closer, you're welcome to borrow mine (at Curborough from tomorrow setting up, though).

Never done a Ti belt myself - and most of the others are packing ready for a trip to Curborough!