BETTER NOW! Thoughts on new rebuilt engine (vent)
- Thread starter Ronbo
- Start date
OK, hope I can hit everything here.
Vacuum- 16 at idle, which I figured is good enough for now. (Cheap-o vacuum gauge which I have never seen go past 18.)
Pertronix- I have the first version, tape is still on there nice and tight, I'll pick up a set of points and condenser and slap it in this weekend for ha-ha's but I'm pretty sure it wont make a difference, never know until you try though! I can always throw them in the tool box as back up. (I honestly thought I had a set in there from the swap but must have chucked them a few years after the conversion.)
Timing- Ok, there are two slots 18 and 13 for the centrifufal advance. Distributor machines are nice but there is no way I'll have access to one to "correctly" re-curve so I took a shot with the light/heavy combo as it worked pretty good in the past. Remember, harmonic balancer has NOT slipped (verified again with the wood dowel in the hole trick) and initial timing is set off the timing tab up towards the water pump. Vacuum is on a ported source. With the advance in the 18 slot and initial so far advanced, how come this thing isnt pinging right off idle? That is the mystery.
Carb- Shot, I was out beating on it last night and the secondaries open intermittently which tells me way too much vacuum is getting past the throttle shaft. By 1/8" I mean ALL around the shaft. At idle I can move the shaft and the idle will get rough, clearly a problem. The carb is not new and I rebuilt it before putting it on again.
Valve Timing- I put the timing chain on with the dots on the two cams lined up on each other (I think, it was about a year ago when I did it). Could it have something to do with that?
I hate to do a compression test (because of what I might find) but I think its going to be necessary. I think I covered most of it.
Ron
Vacuum- 16 at idle, which I figured is good enough for now. (Cheap-o vacuum gauge which I have never seen go past 18.)
Pertronix- I have the first version, tape is still on there nice and tight, I'll pick up a set of points and condenser and slap it in this weekend for ha-ha's but I'm pretty sure it wont make a difference, never know until you try though! I can always throw them in the tool box as back up. (I honestly thought I had a set in there from the swap but must have chucked them a few years after the conversion.)
Timing- Ok, there are two slots 18 and 13 for the centrifufal advance. Distributor machines are nice but there is no way I'll have access to one to "correctly" re-curve so I took a shot with the light/heavy combo as it worked pretty good in the past. Remember, harmonic balancer has NOT slipped (verified again with the wood dowel in the hole trick) and initial timing is set off the timing tab up towards the water pump. Vacuum is on a ported source. With the advance in the 18 slot and initial so far advanced, how come this thing isnt pinging right off idle? That is the mystery.
Carb- Shot, I was out beating on it last night and the secondaries open intermittently which tells me way too much vacuum is getting past the throttle shaft. By 1/8" I mean ALL around the shaft. At idle I can move the shaft and the idle will get rough, clearly a problem. The carb is not new and I rebuilt it before putting it on again.
Valve Timing- I put the timing chain on with the dots on the two cams lined up on each other (I think, it was about a year ago when I did it). Could it have something to do with that?
I hate to do a compression test (because of what I might find) but I think its going to be necessary. I think I covered most of it.
Ron
16" at idle seems low for a stock cam. It should be pulling somewhere near 20" or more. Time for a compression check, but keep in mind, you may still be breaking in the engine if the mileage has been low.
A vacuum leak could also cause a low manifold vac reading too.
A vacuum leak could also cause a low manifold vac reading too.
Gene Fiore
Famous Member
Just wondering...did you change the camshaft when you did the rebuild and if so, did you degree it?
pedal2themetal45
Famous Member
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Ronbo
"QIOTE"
Carb- Shot, I was out beating on it last night and the secondaries open intermittently which tells me way too much vacuum is getting past the throttle shaft. By 1/8" I mean ALL around the shaft. At idle I can move the shaft and the idle will get rough, clearly a problem. The carb is not new and I rebuilt it before putting it on again.
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********************SECONDARIES*****************
What carb and what motor are we working on??? The bronco with the 300 or the 68 stang????????
Maybe too much carb ???????????????
Tim
Ronbo
"QIOTE"
Carb- Shot, I was out beating on it last night and the secondaries open intermittently which tells me way too much vacuum is getting past the throttle shaft. By 1/8" I mean ALL around the shaft. At idle I can move the shaft and the idle will get rough, clearly a problem. The carb is not new and I rebuilt it before putting it on again.
***********************************************************
********************SECONDARIES*****************
What carb and what motor are we working on??? The bronco with the 300 or the 68 stang????????
Maybe too much carb ???????????????
Tim
Sounds like you have several ideas to go after already.
The last 3 motors I have built I have degreed the cams and found 2 out of the 3 would have been off (in one case 8*) if I just threw them in and trusted everyone. These were all stock cranks with big name new cams and premium chain sets. This only works if you have the cam card. I think of how much time I would have wasted trying to get the one that was 8* off to run right....... Glad I spent the time to confirm that stuff.
The last 3 motors I have built I have degreed the cams and found 2 out of the 3 would have been off (in one case 8*) if I just threw them in and trusted everyone. These were all stock cranks with big name new cams and premium chain sets. This only works if you have the cam card. I think of how much time I would have wasted trying to get the one that was 8* off to run right....... Glad I spent the time to confirm that stuff.
Yeah, dist. comes out tomorrow and goes back in the 13 slot. I think (hope), given all that timing, that because the carb shaft is so worn that maybe the vacuum advance is not working. I did put the ol' mity-vac on there and pump it up to make sure it was moving but all that was out of the car. I thrashed it a bit today and the secondaries did not open every time and when they did the car took off like I remembered.
Is it wrong to think that maybe the synchronized Weber is probably better all around? I mean if you have to lay into that miserly one barrel to get moving, it ain't going to happen!
Its the stock cam without degreeing
I always thought it was a vacuum leak somewhere I guess I was looking in the wrong places.
I went to one of the local "hot-rod" shops about bushing it and he thought I was crazy. Also asked same guy about doing the Offy triple intake and he was like "why would you waste money on that?" Nough said there I guess. He is in his 60s so I figured he would know about it.
Is it wrong to think that maybe the synchronized Weber is probably better all around? I mean if you have to lay into that miserly one barrel to get moving, it ain't going to happen!
Its the stock cam without degreeing
I always thought it was a vacuum leak somewhere I guess I was looking in the wrong places.I went to one of the local "hot-rod" shops about bushing it and he thought I was crazy. Also asked same guy about doing the Offy triple intake and he was like "why would you waste money on that?" Nough said there I guess. He is in his 60s so I figured he would know about it.
Next time I get back to Augusta (actually, Martinez) I'll try to stop by and look it over with you.
Ron, it sounds as though there are a good few things to check out. I've arrived at a similar point of (overall) dismay because I've realised the "old fogeys" are too frequently ignorant themselves.
Start with the compression test - if possible, run the motor until your thermostat opens. Then work like greased lightning to perform wet and dry checks. (Helps to lay out all the tools first like a surgeon's table.)
If it's down then you really need to start checking out why. It could be as simple as a CC issue, or deep as a mistimed cam. A standard cam should give good vacuum when correctly set up, as Jack mentions.
Start with the compression test - if possible, run the motor until your thermostat opens. Then work like greased lightning to perform wet and dry checks. (Helps to lay out all the tools first like a surgeon's table.)
If it's down then you really need to start checking out why. It could be as simple as a CC issue, or deep as a mistimed cam. A standard cam should give good vacuum when correctly set up, as Jack mentions.
Jack, I didn't realize you travelled to the Augusta area! I'm over in Groovy Town (Grovetown).
Addo,
I Guess I'm going to have to do a compression test this weekend to rid myself of that nagging suspicion
I really just want to throw another carb on and see what happens but them things ain't cheap!
I put the dist back to the 13 slot last night and will throw points in to see what happens. The carb is in seriously rough shape so it probably wont make a noticeable difference.
Addo,
I Guess I'm going to have to do a compression test this weekend to rid myself of that nagging suspicion
I really just want to throw another carb on and see what happens but them things ain't cheap!I put the dist back to the 13 slot last night and will throw points in to see what happens. The carb is in seriously rough shape so it probably wont make a noticeable difference.
What you describe sounds like what I experienced with a 2300 that jumped timing. Engine was gutless, and vacuum low. I could put all sorts of advance into the dizzy, and no pinging. Reset cam timing, and it came to life anew.
Just for kicks, how is the internal resistance of the coil? Plug wires? How's the voltage to the P1? Which coil? Are you using an extra resistor or just the standard ballast resistor?
Just for kicks, how is the internal resistance of the coil? Plug wires? How's the voltage to the P1? Which coil? Are you using an extra resistor or just the standard ballast resistor?
Jamie Miles
Well-known member
FalconSedanDelivery":2t0miity said:
I have had four of them fail. Two of them on the same car (one while just driving down the road), one on another car, and one on an old fork lift where I work. They are crap. The only thing saying that shows is someone's personal experience. Plainly calling out someone as lacking class and knowledge due to their personal experience with a product to me sounds a little like the pot calling the kettle back in this instance.
Just to throw this into the mix... I'm an "old fogey" but have never claimed to know it all. If I don't learn something every day, then I've had a bad day 
Jamie Miles":zmgd1v8c said:
OTOH, I've never had one fail (all P-I units). Does my good experience with seven or eight installed units balance out your bad experience?
I have seen a couple that did fail. Both were victims of a severe over voltage caused by a bad alternator that had a failed regulator. Oh, and one where a buddy of mine thought he was supposed to remove the tape that held the magnets into the holder. Duh!
LaGrasta":2w1n7jwq said:
Mine was more like $62 + the Flamethrower coil. Not one regret, but I do carry a set of points and condenser with me.
A
Anonymous
Guest
thanks again to bort. i will contact my broker and buy all the pertronix or parent co. stock available.
