Dyno'd the 352 again this morning....

[blykins]

Let me begin by saying that this engine sounds so good.  I'd like to just sit and listen to it idling.  Even with the idle set at 1500 rpm, it has a really radical sound to it. 

Let me continue by saying that I didn't make any head way on horsepower. 

If you remember the last time, we ended up at 42° total timing to make 433 hp @ 6800 and 405 lb-ft of torque.   We got the engine running and I set the timing at 36° this time, just so I could sneak up on the power like I did last time. 

The first pull was a 5500 rpm blast to just check the A/F ratios, oil pressure, etc. 

Second pull was to 7000 and we were rewarded with......435 hp and 400 lb-ft of torque. 

So I thought, well, we are already doing good, because we are making what we did last time with only 36° of timing.   So I bumped the timing up to 42° and made another pull.  Exactly the same horsepower. 

I'm scratching my head at this point because the only changes to the engine were a little deeper oil pan, and ported heads.   In my mind we should be making some steam, so I pulled a spark plug to check things out.   Once again, I saw a green tint on the tip. 

This happened to me last time.  I started with an Autolite 45 plug because it's at around 10.3:1 compression and the cam is pretty big.  I got the green tint last time, so I ran and bought some Autolite 124's and the engine immediately responded and picked up horsepower and the tip stayed white. 

Not sure why we are dealing with this again, but I had to cut the dyno session way short.  I have AR32's and AR33's here at the shop, but it never dawned on me to take them with me. 

So, that's where I am.  I left JJ at the dyno and in the next couple weeks I'll take some more plugs and go try again.

I will say that the ported heads raised the peak hp rpm to 7200.   At least I was able to see some change from the last time it was dyno'd. 

I'll try and post a video of it idling.  Didn't get any pulls on film.

[frnkeore]

At what rpm was the 400 lb-ft at?

It looks to me that your at higher rpm but, with less torque.

If your at 7.2k and 433 hp, your down 16 lb-ft on torque.

What's the torque now, @ 6.8k?

[blykins]

At what rpm was the 400 lb-ft at?

It looks to me that your at higher rpm but, with less torque.

If your at 7.2k and 433 hp, your down 16 lb-ft on torque.

What's the torque now, @ 6.8k?

The "400 lb-ft" was just a general statement, meaning that it didn't pick much up over the 405.   

[Joe-JDC]

Did you try the timing at 38*,40*,41* before going to 42*?  That would be the first engine I have ported the heads for in 49 years that did not increase in horsepower.  WOT working properly?  Joe-JDC

[blykins]

Joe, it's not the heads.

I need to get another plug in it.

[blykins]

I just wanted to follow my last post up with another and say that *in no means* was I blaming this on Joe or his head work.   

My intent was to just give an update and to post up on the spark plug issue. 

When I changed from a 45 to a 124 last time, the issue went away, but now it's came back and I'm left scratching my bald head.   I will all but guarantee that it will pick up 25-30 hp the instant I change plugs again, but I don't have a tangible reason why I have to change plugs.   This is a 10.25:1 engine and the DCR is coming out to be in the mid 7's I think.  We were dyno'ing on 110 race gas. 

[Katz427]

I had "green" spark plugs in a couple of engines, at a point about 9 years ago. It wasn't near St. Patty's day so I took a couple to my engineer, an older gent with lots of metallurgy experience. He looked them over, said he believed it was "nickle" content in the center or side electrode. His advice was " try a colder plug". Which I did, it was a colder heat range than what we normally ran.

[Katz427]

Too add , to my comments, I do remember this gent ( our version of William Conley ) looked closely at the center electrode and said that he saw some signs of corrosion. I never really did pinpoint the problem, I did suspect the batch of fuel. But, the step colder plug solved the problem, and I continued with the test.

[blykins]

A green plug certainly indicates that it's too hot. 

The issue is that I didn't bring any other plugs with me.

The other issue is that I can't figure out why it turned green this time.  Nothing changed except head flow and the 124's were sufficient last time.

[1968galaxie]

Hello Brent,

Experimentation is fun indeed. Cool build and testing. You are a lucky man to be able to build these test engines and find out what they are capable of. Thank you for letting us see these builds!

The colder plug certainly may help - what was the afr during the test?
Could the intake be a restriction to the increased flow cylinder heads?
Not sure if the manifold was flowed with the cylinder head after porting or not.

Anyhow - fun times ahead. 7000 rpm FE is music!

[blykins]

Hello Brent,

Experimentation is fun indeed. Cool build and testing. You are a lucky man to be able to build these test engines and find out what they are capable of. Thank you for letting us see these builds!

The colder plug certainly may help - what was the afr during the test?
Could the intake be a restriction to the increased flow cylinder heads?
Not sure if the manifold was flowed with the cylinder head after porting or not.

Anyhow - fun times ahead. 7000 rpm FE is music!

A/F was 12.5-13. 

The intake was flowed by Joe when he ported it.  It's capable of the task. 

[blykins]

You can hear it idle on the tail end of this video:

https://m.youtube.com/watch?v=uQbvapfDalo

[70tp]

Perfect idle.   Sounds “frisky”

[Stangman]

The green tipped plugs ya know I have seen this before and I had no idea that meant it was a hot plug. Does it also mean that it’s lean.

[blykins]

The green tipped plugs ya know I have seen this before and I had no idea that meant it was a hot plug. Does it also mean that it’s lean.

It can be lean at the same time but a green tinge doesn’t mean that it’s necessarily lean.  In my case the A/F was right where I wanted it.