Motor is seated and ready for it first 1/8 mile stomp

[Cudafever]

Jetted my carb up 6 steps, when to our local track(1/8 mile) and did some 2nt gears stomps to get heat in the plug and check fuel

Still need a little bit more fuel but timing is still to high. Took the color from the ground strap all the way to the weld on the base of the plug.(NGK 3930)

Took 2 more degrees out of it and did several more 2nt gear stomp with a new plug.

The burn mark stops just above the weld....... at this point my Total Timing is at 28*?????

408 12.75 compression,RHS heads, Low end designed Hyd Roller, 2800 stall, 456 gears

My best et with the 340 was 9.57( remember this is at a 6500 foot elevation track!)
First run out of the box netted me a 8.31 and my 60s are now 1.9s to 1.88 in stead of the 2.2s of before.
Our adj altitude started out today at 8500 feet and climbed to 9540 by the end of the day. this is actually good air for this track.

A couple other notes, ran a 25/75 mix of 91 pump gas and 112 racing fuel. 112 because it was what i had available to me at the time.
For the most part dead hooking, so I'm happy with my new slicks!!!

At only 28* total timing my initial is only around 10 and its not happy at idle. by 2000 rpm my advance is all in so just a little throttle and it sounds a lot better.

Do i just need to put a colder plug in it and advance the timing or do these rhs heads(quench designed head) only need 28* of timing?????

 

[SpareParts]

Timing seems low to me. Even extremely efficient cylinder heads (which I wouldn't claim these to be) take more timing then that.
Maybe it's an elevation thing though, I have zero clue how to tune for that

 

[Cudafever]

Thanks for the replay. I fill the same, timing is way to low.
Usually you have to add more timing as you climb in altitude. for example when i raced at 4400 feet my best mph was with the timing at 36*. when i move to Wyoming and stared racing up here I ended up with 40* timing to make it all work.

Timing it by ear it wants 40* as well(40 total) in reality its probably wanting 40*make initial around 20*
I made a 2nt gear stomp at 40* and it didn't ping or knock(running 112 fuel) but when i pulled my first plug, i dropped it to 35. It seamed to like that better, but had to drop it all the way back to 28 before it quit burning the plating off the ground strap all the way to the weld.

I know re curving my dist will help the sound and idle quality(probably get a better 60' time as well) but i have to find my total timing, before i can set my initial.

My gut tells me that i need a colder plug(I went one step colder then factory), then turn the timing back up! I just don't want to damage a eng that took me 3 years to build.

 

[A body]

Wyo.... must be Douglas. My cousin used to race there. Quite a few nice mopars in the Casper area....

 

[Cudafever]

Na, the 4400 foot track was RMR(1/4 mile) in Utah and the 6500 foot 1/8 mile track is one me and a hand full of Gear Heads helped to start from an old abandon air strip in Evanston Wy. Just across the border from Utah.

Just a chunk of tar that we brought back from the dead and call it a race track.
these are a few photo of our first year. Notise the honda generator next to the tree.

type in Hypoxia Drag Way or go to U tube and type Hypoxia Drag Way, there's some good videos out there:burnout:

 

[flyfish]

How big is the cam? From your description it sounds like you have too much compression and too small a cam to run anything but straight race gas. It should pick up over a tenth in the 1/8 upping the timing from 27° to 34° (I know mine picks up 3 tenths in the 1/4 doing this).

 

[moparlover]

i'm pretty sure you need a cooler plug. on NGK's lower numbers are hotter so a 6 is hotter than 7.

NGK -7 are more for race and -6 is more for street and you are running what i think are BPR5EP which are street only, very hot plugs

'6's are still to hot go with a -7 or heck with that compression maybe even -8

but you are way way to hot right now

BP6ES is probably good send a message to OU812 / Brian at IMM see what he says

 

[Cudafever]

How big is the cam? From your description it sounds like you have too much compression and too small a cam to run anything but straight race gas. It should pick up over a tenth in the 1/8 upping the timing from 27° to 34° (I know mine picks up 3 tenths in the 1/4 doing this).

i'm pretty sure you need a cooler plug. on NGK's lower numbers are hotter so a 6 is hotter than 7.

NGK -7 are more for race and -6 is more for street and you are running what i think are BPR5EP which are street only, very hot plugs

'6's are still to hot go with a -7 or heck with that compression maybe even -8

but you are way way to hot right now

BP6ES is probably good send a message to OU812 / Brian at IMM see what he says

flyfish That is true.
I had brian at IMM spec this cam out for me with the concept of stretching my P.O.S. 11 inch TQ with the high altitude that i live in. Its a HYD roller 562/550 lift 242/[email protected] on a 102 intake center that i advanced 2 degree.

That makes me fill better about it being "just" a spark plug heat range!!!!

moparlover
No i stepped up to a BCP6ES(5/8 Spark Plug) (Box number 4930) with my new motor.
I don't know if one step colder is going to be enough?

Hate buying 12 spark plugs(4 for dialing in the fuel/timing) and to find out i need 12 more of even a colder plug............

Think i will order one of each, and do some more testing.(7 and a 8 heat range)

 

[D-50394]

How much is your cranking cylinder pressure ? I Bet it is real high with that much compression and that small of a cam.

 

[Cudafever]

How much is your cranking cylinder pressure ? I Bet it is real high with that much compression and that small of a cam.

lol yeah it probably is!
I haven't done one yet because a couple of spark plugs are telling me that the ring have not completely sealed yet.

It don't smoke or smell like oil or and thing like that. just needs some more runs on it.

I'm changing carbs, might do a compression check while I'm waiting for my carb kit.

When i had 20* initial in it, it didn't kick back on the starter and its a stock SB started, so maybe it wont be that high........at 6500 feet:glasses7:

 

[423dak]

I agree with flyfish. What octane do you get by mixing the fuel?? I faught this all summer being cheap and mixing fuel. I tried straight Av gas which didn't work. I then switched to straight 110 Sunoco and the car picked up 0.70 seconds in the quarter. That is a 12-1 cr engine. I could not believe it either, but I have the slips and the grin to prove it. The thing should run in the 7.30 range I would think. My 360 at sea level will run 7.1's. Food for thought.

 

[crackedback]

At that DA, you can take about 12-14% off the ET and add the same to mph for a sea level comparison.

6 steps of jetting? Why? That's a huge step and at altitude may be a hinderance. What did you see that prompted the step up.

I don't find total timing using the plug strap. At the strip, it's always by what the engine wants via best MPH. Pump gas is really hard for tuning via plugs anymore. If it's pinging, you likely need better fuel. IMO, that engine should have no less than 30* total timing to run well.

 

[Cudafever]

At the strip, it's always by what the engine wants via best MPH.

when i can get the ground strap to burn the plating above the weld, that is what i will do as well.
6 steps of jet because that's what i had on hand
(58s to 64s). and because it's a 600 holley. Vac secondary.

I has a 750 vac plate in the back. choke removed and all that. but its just not working and leaning out to much at 6000 rpm.

Trying to rebuild a 750 double pumper that been under my bench for way to long. thought i was going destroy the rear metering block before it finally gave and came apart.

The 600 was installed to brake in the motor because it was the only Known Good Carb i had.

I mix 91 and 112 only because there was a 1/4 tank of 91 in the tank to start with.

I also have a 850 Demon but it was on a 500+ ford eng and has holes drilled in all 4 butterfly. so I'm going after the 750 first.

 

[Cudafever]

At that DA, you can take about 12-14% off the ET and add the same to mph for a sea level comparison.

8.31=7.15 Wooo Hooow and there's more in it.

 

[Cudafever]

I talked to Brian at Imm about it and when he realized i was running a 600 vac sec carb he just laughed at me and told me,Your not running a constrictor plate RACE!!!!

He felt that the plugs were the right heat range and the carb as the problem.

So off came the 600 and my freshly rebuilt 750 double pumper when on. 68 in from 78 in back(power valve in front.)
It needs a smaller power valve, but took it racing any ways. timing is back up to 38 total and plug ground strap burns plating to the bend.

running 8.40 8.50(1/8mile)#-oRealize that i had turn up my shift light i turned it back down and wolah 8.30-8.27

As far as traction gos, if i leave from a idle instead of 2000 stall, it hooks, buy it makes my reaction time real bad. going to have to work on that as well. Maybe i will just start Deep staging

 

[70aarcuda]

How much is your cranking cylinder pressure ? I Bet it is real high with that much compression and that small of a cam.

your elevation will also have a negative effect on your cranking pressure....

I usually have my carb about 4 jets leaner then stock at 6000 ft DA...and that was on gasoline..

 

[Cudafever]

your elevation will also have a negative effect on your cranking pressure.... I usually have my carb about 4 jets leaner then stock at 6000 ft DA...and that was on gasoline..

Our DA was around 87-8800 foot yesterday.
I don't know what jetting these 750 dp come with stock, but it seem just about right for up here. Base circle has all but a full turn of color on it now.

It time for a compression check on it just to have a base line on it.

And guess on what it will be? All plugs out, throttle wide open, and cranking until the needle quits bouncing.........................