Dist/carb tuning question

will Tim what he types and what you say are two different things and set for 24 @ 3000 is 24 total advance and you don't add in the base timing to the figure.

It's real easy to figure out the actual advance with a quality timing light and you can actual set the rpm with the right light as well so if you have not reach full advance by 3k then you have it all curved wrong but then again your just guessing because you or he didn't do the work and haven't verifiy the actual timing at all, you are going by what you where told so speak in terms that are relevent not that I get 24 more degrees of advance over base timing at 3k horse ***************, max, total, final advance for a stock cam at 36-38 degress BTDC will ping ping ping like no tomorrow. Again get your head out of the book and spec sheet and live in the real world with real perfomance all around not just out of the hole.

Greg, just ignore Chris- he'll disagree with me no matter what I say, and since I like my DUI he has to say that its junk.

Set your base timing to 12 degrees, try the smaller jets, and report back.

sorry if you don't know the difference between total/final advance and built-in distributor advance two completely different things and when talking about dist advance you should be refering to actual advance on the motor and checking it while the motor is running not from some spec sheet joe blow provided.

Again it all goes back to the skill of the hand turning the wrenches you can either do it your self or get someone else 2000 miles away that will get you close, sorry you choose the later sorry you don't have the skill to do it your self, do you really think Doc would have went with the Unilite if he thought the DUI was better? Do you really? I don't. Do you really think you have more experince and first hand knowledge about the HEI distributor's design, functionalty and inner workings or ignitions systems in general than someone that actually worked on them for a living while they where still in production? some one that had to fix all of the little warrenty issue's that had to be fixed to improve the product? doubt it but then again I'm not a EE I don't focus on a small aspect of the big picture I have to look at the whole picture because it's the sum of the parts not some small electrical curcuit that doesn't move.

BuffaloBFN wrote: 79nautique wrote: sorry if you don't know the difference between total/final advance and built-in distributor advance two completely different things and when talking about dist advance you should be refering to actual advance on the motor and checking it while the motor is running not from some spec sheet joe blow provided. I did verify TDC and have marked my balancer for 28 and 35 degrees. A well qualified friend told me how!

the well qualify friend should have had a quality timing light as that is the most accurate method to determind total advance at a given RPM and that is what is important. And the big mark and big notch are the best marks to keep lined up but then you have to have the tools for the job to do it right at least.

There were 2 gaskets on the PV...both of the new ones I bought came with 1. Maybe this was a problem?

The verdict is in...a 750 is entirely too large for my application. I put the edelbrock/weber 600 back on it and I have full throttle response, smooth idle at 600(550 in gear), and a smile to prove it!

3 cheers from Amy and I to the Boat Dr.!!!   

He has patiently walked me through the workings of a carb, and I now have a much better understanding of V/E. Doc, I told you wrong about the prop. I pulled the receipt, and it's a 14x14 with a 200 rpm cup that needs to be removed. That and the flame arrestor sticking up higher again are the only things to work out for the moment.

Thanks for everyone's input; oil change first thing in the morning, and I'll make sure to finish seating the rings tomorrow!

SNobsessed wrote: Greg - I bet you sleep good tonight having this figured out!

Ya Mon!    

id be curious to see what your vacuum readings will be now, the smaller throat should increase the readings to where they should be, are you stuck with the carb? can you return? i think the doc hit the nail on the head, stock cam, no increase on intake air and the 600 would seem a touch small but it isnt.
I would think if you went with a hotter cam to where the valves opened taller and stayed open longer the 750 wouldve suited the engine fine.....its a fine line, glad you got her straightened out

restriction creates vacuum, the writing was on the wall and the restriction is the throat of the carb, good call

GottaSki wrote: 79nautique wrote: Look at this way it sure sounds like Tim's and yours are curved exactly the same way, 24 degrees of advance is built in on both regardless of base setting but the odd thing is you have two completely different cam profiles and two completely different motors and since they are not apples to apples then how in the hell can the advance profiles be the same? I think Chris is still onto something here, when mapping timing on a 425HP model, I was amazed at the final timing the engine liked. I would do a disservice spouting numbers, but it was markedly more than the SBF numbers I was used to (35-36 for a 351). These two distributers having the exact same span is suspicious to me too. It may run fine now, but I suspect there is untapped potential in the engine with enough research, patience and skeptacism in the dist/carb hardware to find it and sort it out. I suggest find the initial the boat likes for a hard launch (usually the most it can take without a labored hot start) find the final the boat likes (have someone drive while twising the dist till no positive affect, then pull a lttle back for a comfort margin, measure this timing. Compare to baseline for similare engines. Subtract the two, and set the span on the advance to this number. this optimizes the min and max. Then play with the curve after you correct some carburation.

why do all that like a real mechanic would when you all ready have the so called experts doing it for you at performance distributors where it was bought from.

why because they are un-educated in the skill of adjusting a dist. correctly.

how much vacuum? get a reading at the same port and RPM, im curious, you were at 13 to 14 at 700 rpm before

BuffaloBFN wrote: Eric, I'll try to get those #'s today, but I was using the port on the carb that is no longer there. Think I found(with help) what I need...carb

sorry try again the inlet is not the style you need.

BuffaloBFN wrote: 79nautique wrote: BuffaloBFN wrote: Eric, I'll try to get those #'s today, but I was using the port on the carb that is no longer there. Think I found(with help) what I need...carb sorry try again the inlet is not the style you need. The fuel inlet?

no the AIR inlet

Chris, if you know something, I wish you'd explain. The carb will ship today...

Thanks Chris, I appreciate your patience. I called and asked the tech guy and the pic may not be an exact match. He said it would be like the one you posted. If it's not right, maybe I'll have to switch the bowl.

As you say, it runs darn well with the 600...until I get a boat full of people. This is only my feeling, but comparing to the 750 it now wants a little more. The other thing is my cover won't close with the edelbrock and I don't want to raise it up any more.