Timing and KRE's...?
 

I am going to the track this weekend, and I was wondering about The KRE's and timing.
I read Cliff's posts about how 30 total seems to be the sweet spot, but this seems low to me.
What is the initial set at? Vaccum advance hooked up?

My car is a 67 GTO
461 400
Crower 60919 cam
3000 10 inch Cont. Converter
3.42 gears. 10.5 rear.
KRE's 310 D ports.
Th 400.
Offey dual quad ,,,,twin 600's progressive set up. Alot of CFM's I know, but very streetable.
Dougs headers, 3 inch exhaust with cut outs.
Right now The car is at 16 intial and 36 total, Mostly street driven.
At the track, 30 is better? Will it burn right?
I am going with 3 chebby boy's, so I have to look good here.
Thanks in advance....
I would also be interested in shift points too. Right now I shift at 5000rpm's.

I have HP 330 heads with 13.25:1 Compression. Jeff suggested I ran 30-32 and shift at 6,200 rpm. (4 bolt main, half filled, lifter bore brace, .660 lift (.705 gross valve lift) 461 ci.

I had the KRE D-ports on my 463 and found 32 total to be best. Picked up a tenth going from 30 to 32 and slowed down a little at 34.

The KRE combustion chamber is more efficient design than convential Pontiac requiring less lead to light the fire. Typically with say a 6x head a 455 likes 34 vs a 400 at 36(at same compression ratio). I would start at 30 degrees total then try 32 if it likes it you will know. If you gain nothing or lose, head the other direction. Initial varies from car to car depending on compression cam and the starter ability. 12--14 is typical initial. Vac advance is of no consequence at the track but useful for mileage/idle quality purposes depending how its hooked up. Its very application specific but 10-15 degrees additional advvance from vacuum over your total mechanical timing aids mileage and sometimes even engine cooling. Hooking to direct vacuum source (below throttle plate) or timed(ported) vacuum advance vacuum above throttle plate= low or no vacuum adv at idle). Again your engine will "tell" you what it likes. Again dont worry about vac advance for track use. You want 30 degrees total all in before 2500 and if your car likes 16 initial it is going to need the curve shortened to run both. If you cant shorten the curve then do keep the total Mechanical advance at 30 degrees and run vacuum advance to help with idle but I warn you that it wont like it as much as properly curving the distributor.

FYI 2 600's is NOT too much carburetion. Run (2) the same size as you would with a single 4. I have 2 750's on my wifes 406 with no signs of being overcarbureted. Do NOT believe anyone who tells you different. see the following link in the front it shows carb sizing and elsewhere in the same catalog it tells you what I said about sizing, choose as you would a street car. http://www.exeterautosupply.com/

I have the 65CC d ports on my 446 engine and it liked 34 total with 9.5CR and 91 pump gas.Tom

KRE's
 

I went to the track this weekend my KRE's liked it when I dropped from 36 to 32. Picked up ET from 11.30 to 11.28 and 1 MPH.

Tom S Here is a tip use regular pump gas go back to 30 to 32 degrees total timing and it will run faster. 91 octane is more than you need . Higher octane burns slower that why you are running more timing than some. That goes for anyone else that is running more than normal timing. Drop down a grade of gas and lower your timing and you will be amazed how well it runs.
KEN
HAVE A GREAT DAY

screwed up,10.5CR!Tom

Tom you are correct you are on the edge of 87 octane if your combo is perfect carb, icl 0 deck you can get away with it. we have done it on dyno and gained about 5HP,but probably not the best for the average customer to try. If you do try go back to 30 degrees and increase timing 1 degree at time till power starts to fall off.
KEN
HAVE A GREAT DAY

Not to hijack the thread, but I have a question. I am building my 455 and it will have the KRE heads. The distributor that I have is a Mallory Comp 9000. The paperwork says it has 24degrees of advance. So to get 30 degrees total timing I will need to run 6 degrees initial timing. Does this sound reasonable?

this would explain a little about my combo as well. With the 56cc head and flat top o deck 455 i was running 38 degrees of timing on motor with 112 premium sonoco fuel and a number 8 ngk. When i sprayed 225 to it i took out 10 degrees of timing but had a hint of detonation on the plugs. So i would probably fine with the 112 fuel and a colder plug if i set the motor timing at 30-32 and took ten out from there. Hmmmm....did i make any sense.

Redta sounds correct. Best to ask Jeff best way to set up your Distributor he is the expert in that end.
Ken

Brand X, that would be a good start. Then just read the plugs from there.

Find out what timing the motor likes NA then pull your nitrous timing from that. Don't worry what the starting number is when pulling for spray.

Ken,the only tuning we did was on timing.We tried everything from 30 to 38 with the 91 gas.The motor liked 34 the best.Exact same setup except iron heads and 9.5 CR,that combo liked 38 the best.I think the small chamber KRE Dports are diff from the larger chamber Dports.HP was almost the same,480ish for 434CI.Tom

Redta,you can adjust the amount of advance in the distributor.Mallory sells a kit with "keys" that you use like feeler guages to set the advance.It also comes with springs to adj. the spark curve.Depends on your combo how much initial timing you need,but Im sure you need at least 12* initial,mine liked 20* minimum.I ended up locking mine out at 30*.

Would the lower octane still apply, at say, a 10.5 CR ?
I put a 18 degree bushing ( black ) in the distributer last night. I hope to fire it up tonight. I will see what the idle is at 12*. Where can you get different bushings for the MSD distr?...Say I need a 10* or 12 * or 14* for more initial....for example? MSD's kit, the smallest is a 18 degree. I will see if I need it.
How much power gain you think I would be looking at? Dropping from 36 to 30?

FWIW...strapped my 69 GTO to the chasis dyno...generated 17 more peak hp simply moving from 34 degrees down to 30...where is seemed to like it best. Now the dyno ain't the dragstrip...so once I try it at the track, I might bump it up a degree or two to see what happens. But so far...12 initial, 18 mech...30 total seems to be my magic number

455, 40 over, 0 Deck
out of the box KRE heads, port matched to RPM intake, tuned Q-jet, Dougs headers
Crower 60919, 1.65 scorpion roller rockers
4-spd
3.42 gear
best run 424 hp at the rear wheels, 487 ft/lbs torque

RR ,

Running the black bushing also. Set at 12*. What springs did you go with. I am running a different cam with lower DCR. Did you see the post recently from Rocky about MSD advances? The car seemed more responsive. But as said before, the track only tells.

Mike are those Dyno numbers with the 30* setting?

Thanks
Tom

I have one light and one medium spring.

Well, all is in.
Timing set for 12 initial and 30 total.
At idle I have 11 inches of vaccum and a somewhat smooth idle, once it warms up, and the restarts are fine. I set the idle for about 900 and it's pretty good.
I also hooked up my A/F monitor and At idle till about 2700rpm it reads about 13.
I will run her tomarrow and see what the reading is at WOT.

You guys are lucky. After I did my swap to the KRE heads and Hyd roller from the 16d's and a flat tappet I have 30 initial for timing Yes I said 30 degrees initial timing with still more coming in if I bring up the rpm's. My post is at the bottom of page 7 of this race section titled ( Timing problem help and opinions wanted). I don't mean to jack this post but since there are alot of you talking about KRE heads and timing I figured what the heck.
Thanks Donald

70man I went back and read your posts. I would like to know what you found out. I think a lot of times 0. on balancer isn't indexed to tdc on #1 but you checked that. I think I would borrow a MSD distributor from someone and try that. If you haven't got it fixed yet give Jeff another call and pick his brain.
KEN
HAVE A GREAT DAY

Armadillo...Yes...dyno power levels quoted were at 30 degrees total, up 17 hp from where I started at 34 degrees...no other changes. Then went to the carb. Was using a Qjet...thought I was a little rich...so leaned out the secondary rods to 45s. No apprec iable change...so back to 41s.

I noticed some guys using the MSD distributor, as am I. If you have the chance, it's worthwhile putting it on a distributor machine to see how it performs. It's a quality piece, but I was surprised with what I found...at least in my case. Once getting to the upper half of the rpm range, timing started jumping around a fair bit. Using medium and light spring...maybe they were stretched...but weights flung out so fast they were tapping the cap and causing some bouncing around in the timing. Didn't really notice it as a problem so much while driving...but made a difference in measured power output once corrected.

MSD is a great product...but verify its performance. Likely goes for any make of distributor...factory or otherwise

Very interesting... just more things that need to be looked at.

Mike and RR thanks. I just did the conversion before the dyno and had 422 hp at 5800 with 430 tq from 4400 to 5000. I know that the track will tell more, I was looking more for shift points with the dyno info. I am also using a blue and light silver. When I changed the springs and bushing I made sure to lube everything up. I use a different cam xe280r.

Tom

My 455 with KRE idles best [ highest idle speed, highest idle vacuum & smoothest idle ] with 32 degrees initial timing. Best performance at WOT is with 26-27 degrees. I have dished pistons, 34 cc dish, which make for a more compact chamber & quicker burn. So the 27 deg sounds about right compared to those running around 30 total with flat top pistons.
32 initial at idle is obtained with 12 deg initial with the extra 20 coming from a Crane adjustable vacuum advance unit, hooked to manifold vacuum. At WOT the, the vac adv has no influence. Good story in Dec 2007 PHR magazine on what vac adv did for the idle on a 535hp sbc.