[81TATurbo]

I'm running a Butler stroker 467. Compression is only (according to Butler techs) 9.1 or 9.2. Im running stock 6X heads. They were just rebuilt with new guides, valves and the dual springs on 1.5 roller rocker. The whole motor is roller as per their recommendation. The plug they recommended was the NGK-R5674-6. I'm wondering if that plug is too hot for my compression ratio? The problem I'm having is pinging/pre detonation in the higher rpm. This is with the engine at running temperature (there is a 160 themostat in it). Now with that, if it's a colder day say early in the morning, there is no pinging at WOT. The same goes for if the motor is warm (120-130) but not yet at peak operating temp. I've changed the springs in the distributor to lighter ones and that didn't help so I took some timing out and that didn't help either. I'm not sure what my builder gapped the plugs at but ill be checking that next. Suggestion? Thanks!

[PunchT37]

Take a pic of a plug or 2 and post. Take a pic of the ground strap where it makes it`s bend to the threads.

[81TATurbo]

Ok. I’ll have to try and do that tomorrow after I get up. I’m working midnights right now

[25stevem]

There’s a lot of things to check out that could be making for this condition.

I would first confirm TDC, and do this twice to be sure.
If your using a adjustment timing light, use it set for zero in case the internal electronics are screwed up, which takes place more then you would think.

A safe timing setting with your year balancer would measure 2 1/8” around which would provide a safe 34 to 36 degrees for your compression ratio.

Next confirm that your timing does not just continue to rise once the motor gets to 4500 rpm.

Light tension springs may make things worse as I have seen the timing bounce all around at high rpm due to there lack of control.

Also all you have done with the light springs is to bring the added amount of centrifugal advance in sooner.
With that change I would have at first backed the base timing down by 2 degrees.

You did not post up any info as to what carb you are running, or if it’s stock.

Since your new motor likely has a bigger car then stock if you where still running a stock Q-jet that would have been on motor with 6X heads then your secondary’s are way too lean and you should not even be going for full throttle and or high rpm.

On a new untuned motor with 100 or so miles on it your plugs should be showing a tan going into a brown color which would indicate a safe slightly rich condition, especially after two full throttle runs.
If after that they are still a whitish tan then your jetting is very lean.

Also note that at times plugs have been found these days to be mislabeled.

[Cliff R]

What camshaft?.....Specs?

What distributor? Lighter springs wouldn't do anything but bring total time in earlier and make it ping sooner.

[25stevem]

Your NGK R5674 is the equivalent of a AC delco R43TS
Which if label correct should not by any means be too hot.
You need to look elsewhere other then plug heat range.

[81TATurbo]

Originally Posted by Cliff R

What camshaft?.....Specs?

What distributor? Lighter springs wouldn't do anything but bring total time in earlier and make it ping sooner.

Cam is a custom grind from Butler:
Butler Comp SP Street Performance Billet Roller Cam 282/288, 230/236, .510/.521, 112

Stock distributor but with an MSD cap, coil and rotor. Also running a digital 6AL box

Carb is an Edelbrock 750 mated to an Edelbrock Performer Pontiac intake. Had the carb rejetted but not sure of the specs. I can get them

There’s about 700km’s (435 miles) roughly on the motor right now.

I don’t have a timing gun to check timing but I can acquire one. Should I go back to a bit heavier spring in the meantime to bring the cenrifugal advance in later and see if that helps?

Not sure about the balancer measurement.
How do I find out if the timing continues to rise after 4500? Also, could I maybe try without the vacuum advanced hooked up and see if it performs better?

I’m not that savvy with some of this stuff and time is limited (shift work, kids) but I’m thankful for the help and will work out this issue with your recommendations 👍

[PunchT37]

I would not be changing springs without a timing light. That`s also a low rpm/high air speed intake on a 467. I am aware of shaker fitment on higher intakes. Not the best manifold for a 467.


In the mean time, have you tried a new tank of gas? Different octane?

[25stevem]

How was the timing ever set in the first place if you do not have a timing light?
This is a very basic necessity, I would not even consider putting 50 miles on a motor, no less over 400 like you have done without knowing where my timing was set!

[Cliff R]

Good cam choice for the CID and compression ratio but it is very good at cylinder filling early in the RPM range so not surprised it's a little sensitive for detonation when things warm up some. I used/tested that cam years before Butler offered it in a 455 with a little less than 9 to 1 compression and it had high cranking pressure and made gobs of vacuum at idle.

Put the stronger springs back in the distributor and verify what the total advance is. Once you come up with a number, 34 degrees for example, retard the timing 2 degrees at a time until it quits pinging at WOT. I would also run the highest octane pump gas available in your area.......Cliff

[81TATurbo]

I’ve gone through about 4 tanks of gas now. All I run is Shell 92. I can also get Sunoco 94 at the Petro Canada here but I don’t trust that it is what it says. That is all I have here in my hometown. There is a place that sells 108 racing fuel but it is really expensive and I don’t want to get into that.

Timing was done by my builder and another buddy that is good with doing timings and carb settings (I’ve know both for over 25 years) Doesn’t make it right with the money I have invested I know. Dont know what the actual setting is but I will get a timing gun and check it within the next few days. I’m an idiot relying on others I guess. I’ll admit that. I trust them but maybe I shouldn’t be so trusting.

I had that intake so that is what I used. I also have fitment issues but not because of a shaker but because it was originally a Turbo car.

I had it out today and it runs strong and is exceptional while cruising and also around town (mild to medium go petal input). It’s just that ping in the higher rpm. I’ll do the timing and the springs Friday and see how it does.

[25stevem]

The first thing I would do even without a timing light would be to get the car fully warmed up and then retard the timing such that the idle speed drops by 100 rpm.

Then correct for that change with a idle speed adjustment on the carb.

Even just ping at high rpm and heavy throttle can take its toll on the rod bearings , so you want to stop that even if the car is not quite as much fun to drive until you find out what’s going on.

[Cliff R]

I'd also recommend a better intake. At your power level the Performer is restrictive. I tried to test one years ago on my old 455 and had to abort the testing due to developing hesitation/stumble/bog going quickly to full throttle and some noticeable surging at WOT plus audible detonation. Not sure why all that happened but it went away immediately when I went back to the factory iron intake. At that time my engine was making a little over 500hp and topped with KRE aluminum "D" port heads and a custom ground Comp HR cam with 284/296 @.006", and 230/242 @ .050 on a 112LSA.

I also tested the Holley Street Dominator, Tomohawk, HO and RPM intakes and had zero issues anyplace.......FWIW......

[25stevem]

Even though like I posted I don't think the heat range of your plugs is the issue here is a photo chart of what to look for.

[81TATurbo]

How much initial timing should I have and how much total timing and at what RPM?

[PunchT37]

12 degrees initial and 32 to 36 total @ 3000 rpm`s is a good place to start. Then, let the engine tell you what it wants.

I would start at 32 total since you`re pinging already.

If you have vacuum advance, leave it off and plugged while diong this.

[chrisp]

Pull plugs & check for possible head gasket leak , plug or plugs will be bright white.

[81TATurbo]

The plugs and they look good. Tan going to brown color.
I’ll try 32° at 3000 RPM to start. This is with the vacuum advance disconnected correct?
Just hate bringing it up that high in park with no load on it

[PunchT37]

Originally Posted by 81TATurbo

The plugs and they look good. Tan going to brown color.
I’ll try 32° at 3000 RPM to start. This is with the vacuum advance disconnected correct?
Just hate bringing it up that high in park with no load on it

Correct. Disconnected.


Don`t worry about 3000 rpm`s in park.

[81TATurbo]

OK so I think I worry too much. Did some tuning and set the timing at 34°. Did some more playing around and I think the noise I hear at high rpm is my clutch fan. The reason I say that is because while doing the timing the fan started making noise around 2600 RPM. On the road I can floor it off the line and have no ‘ping’ under load until higher RPM when the fan is spinning much faster. Also if I sit with it in park and give it a couple good revs the fan makes a slight noise. That might also explain why there is no noise in cooler weather and when the car is not hot. At this point the fan isn’t spinning as fast to cool the motor cause the clutch is engaged. I’m not sure what’s going on with it as it has a brand new clutch in it. I wanted to buy a heavy duty clutch and ended up ordering an extra heavy duty clutch. Could that be too much perhaps?

Also, it seemed to run better with no advance (I forgot to hook it back up). Could I get away without it?