[BGus16]

Hi Scott70, yes I found one of my time slips from a year ago.
Rear tires are old T/A radials 255/60/15 which I plan to replace soon.

R/T .117
60' 2.165
330 5.761
1/8 8.684
MPH 84.46
1000 11.197
1/4 13.306
MPH 107.28

In regards to the other post about cranking compression I believe the last time I did one my psi were in the 165-169 psi range if that sounds about right for this setup.

Hope this helps
Barry

[pmd400]

Originally Posted by krisr

If you have an adjustable timing set, try retarding the cam 4* and see what it does first. It'll only cost you some silicon and time.

No adjustable timing set unfortunately

[pmd400]

Originally Posted by pastry_chef

On the OPs engine would be interesting to see the air/fuel ratio at part throttle.
Two 600's is a lot of venturi for a mild engine, Edelbrock's usually need to be dialed for the application. This could be very lean.

Cruise at expressway speed where there does not seem to be a pinging issue is about 14:1 afr.
Carb is currently set up parallel linkage. With pedal depressed so both carb primaries are open as far as they can be without going into secondaries the engine pings badly. AFR low to mid 13:1
Wide open throttle, engine pings. Perhaps a bit rich at around 12:1 AFR

[pastry_chef]

What changed?

Originally Posted by pmd400

This engine certainly doesn't have any audible detonation. Timing is set at 10 initial plus an extra 24 centrifugal in at 3000rpm. Vac advance is 16 at full manifold vacuum. Air/fuel ratio is around 14:1 cruise and 12:1 wot.
When comparing cams advertised duration its important to ensure the duration is measured at the same lift. 1 can't say the 2802 has a heap more seat timing then the straub cam for example, because they are measured at different lift rise.
Is saying that, this engine doesn't feel particularly fast. I don't think it would put down a good et. But it does cruise at 70mph at 2000rpm with good economy and great throttle response.

[tom s]

Not near enough carbs for a 461.A pair of 3705 AFBs would be the ticket after rejetting.Tom

[pmd400]

Originally Posted by pastry_chef

What changed?

I think lack of experience identifying pinging. I had the carbs set up progressive. When I squeezed the throttle so the primary on the front carb starts to open the engine ran poorly. I then set the carbs up parallel thinking it might be a setup problem. Iv come to realise that it is now pinging and always was. All my tuning experience is with low comp and stock cams, so I’d never actually heard pinging.

[pmd400]

Iv mentioned in other threads how the car doesn’t feel fast. Most think a 455 with 230cfm intake flow should. They say not enough cam. Everyone who shows dyno sheets on this forum for an iron head 455 is certainly running wider LSA than 108, greater .050 than 224 and greater .006 than 270. Another cam expert, mike jones, reccomended this cam.
With that 4.21" stroke, you need some duration.

This cam will peak @ 5,100rpm, have plenty of vacuum, and a smooth idle. I would not go any smaller
Cam# P455, H71330-110
228/228 @.050"
.330"/.330" Lobe Lift
.544"/.54" Valve lift w/1.65 rockers
110 LSA
107 ICL

The fact he believes this is the absolute smallest then maybe something on the low 230s is best

[pastry_chef]

Worth reading.
http://forums.maxperformanceinc.com/...d.php?t=776169

If you are truly pinging at part throttle there is obviously more going on.

Comparing flat tappet cams, 5 degrees @ .050 is minor difference power wise.

For you, Len Caverly suggested 230 @ .050 on 108 LSA, he owns his own dyno and has a TON of knowledge and experience.

Originally Posted by LCaverly post_id=630885 time=1476753703 user_id=24184

230-236 on a 108 lsa 104 icl .536-.540 this would be a custom grind using comps XE lobes. 455's really like a 108, monster torque and really good power, anything tighter and vacuum becomes a problem and anything wider you give up torque and power. you won;t have to worry about to tall a gear or a heavy car.
Len C

[pmd400]

Another example of a 455 with less compression, wider LSA and greater duration then the cam in my engine. Perhaps there is something more going on. I have an afr gauge and verified the timing. The timing is so far retarded that when I come off the throttle suddenly the engine backfires out the exhaust. If the timing isn’t too far advanced, the afr not to lean what else could be wrong other than cam to small for compression?

[pastry_chef]

Running 30 degrees of ignition timing will not cause your car to backfire out the exhaust when you let off.
Sign 2

Did you degree the cam during install?

[Stan Weiss]

Originally Posted by pastry_chef

Running 30 degrees of ignition timing will not cause your car to backfire out the exhaust when you let off.
Sign 2

Did you degree the cam during install?

X2

Also doing you ever do a cranking compression test?

Stan

[pmd400]

I don’t have a compression tester. At 36* there’s no backfire. At 30* there is. Google told be retarded timing can cause this. Could a wiped lifter/cam cause these issues?

[Cliff R]

The cam is too small and LSA too tight.

Nothing wrong with tight LSA provided the camshaft is big enough, but the WORST cam you will ever put in a 455 build will be a relatively small cam on a tight LSA.......IF having just a little more DIRECT experience with this sort of thing than most who will read this accounts for anything on this Forum..........Cliff

[pastry_chef]

Originally Posted by pmd400

Could a wiped lifter/cam cause these issues?

Unfortunately yes, I was thinking that last night.
Before that... the cam must be degree'd, or at least measure the intake tappet lift at TDC and report here or to Chris.

LSA comments in the crapper. The CRITICAL matter is the intake closing point. This cam "correctly installed" will close the valve within a few of the Voodoo 703 Paul Carter dyno'd or the cams that Len C and Jones suggested.

Examples:
268 deg in at 107 centerline
274 deg in at 104 centerline

I'm sure you probably know but the gas rating is not the same as USA.. your 98 is about the same as USA premium.

[Sprocket]

I ran a 223/231 110 LSA cam for over 15 years in my 9.3:1 iron-head 455 in the Texas heat. Zero detonation. As in none, whether it was 91, 92, or 93 octane from the local pump. This was in a heavy 4200 lb car with auto trans and air conditioning and four passengers. I was able to get my car to 13-flat in the quarter mile without trying (no testing or tuning beyond street feel tuning and a vacuum gauge) and that time was achieved consistently on a 102-degree day. So the idea that 220's is too small, or a 110 LSA is too tight, is just plain B.S. The cam is just another factor in engine building. Move one direction or another, be it with duration, lift, centerline, or lobe separation, is relatively insignificant incrementally. Overworrying about the cam ignores all of the other factors that comprise an engine's performance. Unless it is ground wrong or somehow just way off in "size", a cam is not going to make or break an engine any more than the carb, distributor, heads, converter, etc.

Back to the OP's situation, something is wrong with his air/fuel delivery or ignition curve other than just the cam unless there is something physically wrong with the cam, i.e. bad grind initially or degenerative lobe syndrome.

[ponyakr]

All factory 455's were under cammed.

Except for the SD455, all the rest got an 066, 067, or 068. Pitiful.

http://www.wallaceracing.com/enginesearch4.htm

[STEELCITYFIREBIRD]

Originally Posted by pmd400

I don’t have a compression tester. At 36* there’s no backfire. At 30* there is. Google told be retarded timing can cause this. Could a wiped lifter/cam cause these issues?

A wiped lobe is a wiped lobe, irrelevant of ignition timing.

Any exhaust leaks from the 'bargain' 1 5/8" headers?

Any other bargain parts? Dizzy?

[STEELCITYFIREBIRD]

Originally Posted by pmd400

I think lack of experience identifying pinging. I had the carbs set up progressive. When I squeezed the throttle so the primary on the front carb starts to open the engine ran poorly. I then set the carbs up parallel thinking it might be a setup problem. Iv come to realize that it is now pinging and always was. All my tuning experience is with low comp and stock cams, so I’d never actually heard pinging.

You want the rear carb to open first with progressive linkage, unless they are reverse mounted.


Something tells me you have some fouled plugs to deal with, and likely lots of carbon/soot buildup possibly also.

[pmd400]

Originally Posted by STEELCITYFIREBIRD

A wiped lobe is a wiped lobe, irrelevant of ignition timing.

Any exhaust leaks from the 'bargain' 1 5/8" headers?

Any other bargain parts? Dizzy?

The 1 5/8 headers didn’t get used. Horrible quality. Has 1 3/4 hooker headers. Dizzy is a factory points with pertronix igniter. Without looking through my notes I think it has 24* of mech advance all in by 3000rpm. Timing curve was done by me on the engine(balancer has degree marking), not by a 3rd party who my have stuffed up. AFR shows no lean condition.

[pmd400]

Originally Posted by STEELCITYFIREBIRD

You want the rear carb to open first with progressive linkage, unless they are reverse mounted.


Something tells me you have some fouled plugs to deal with, and likely lots of carbon/soot buildup possibly also.

Iv run the engine with both progressive and straight linkage. Everything iv read suggests progressive vs straight is a personal preference. From playing with both straight and progressive iv learnt its personal preference or perhaps combination specific as to what runs best. Plugs aren’t fouled. Dual quads don’t automatically foul the plugs. I do have an AFR gauge. It’s not running at 10:1 afr.