Mopar Muscle Association UK

Honestly you should be able to feel / hear the secondaries open, its just whether they are opening fully

meanwhile, new goodies arrived. just recieved a new set of 3.5 rear and a Locker for the 8 & 3/4. just got to find someone to assemble it all now

Miles, if your not trying yourself then...
Paul, Southern Axles in Watford.... nearest i know
Geof Hauser in Northants..... next nearest i know
sorry cant be more help

I wouldn't think that you should actually feel the secondaries open, not if it is a square bore carb.

Surely it should be a seamless process ?

I would expect that you could feel secondaries open on a spread bore carb, like a ThermoQuad or a Quadrajet as they have enormous secondaries in comparison with the primaries. The transition into the secondaries is wholly engine vacuum dependant. Even then, it should be relatively seamless in feel but, and especially with any cold air induction system, it will be fairly noisy.

Three barrel Holleys tend to to provide a noisy step into secondaries as well, at least those that I have seen and heard.

You're right Sandy, when set up correctly you can neither feel or hear if the secondaries are opening or not. If you can feel the secondaries opening they are almost certainly coming in too late.

secondaries are opening, and as you guys suggest, its a seamless process. I only knew it had worked when the cable tie attached to the secondary linkage showed movement.
i replaced the cork gasket betwen the diaphram housing and carb block with an o ring that is probably preventing even marginal vacuum loss.

Yep , as others pointed out , if you can feel the motor bogging there coming in too early.

I could always hear the difference as the secondaries opened on my 78 Dodge truck and feel at as i accelerated at a steady rate
Not just mashing it off the line
JMO

http://www.moparuk.com/forums/viewtopic ... 9&start=30

Mods, any chance of taking this thead from this point in onto my 'Dart beater into the 13s' Workshop section, as I guess thats now where it belongs?

& as if by magic, it continues here.

Time for a quick update.
Pulled the motor out today to check why oil pressure was weired and head gaskets blown. Gaskets were on correctly and torqued down properly. mike spotted a small blow by on one of the bores, so that might explain it.

Pulled the botom end and checked no 2 & 4 Mains. Not good! Down to bronze on the bearings on both. checked a rod bearing and and it was fine. Should add that the mains dropped straight out of the mains caps almost as if they were the wrong type of fit, which they're not...

Going to pull the crank this week and see what the news is. Luckily I ordered new main bearings along with the new high comp pistons and replacement oil pump.
Be lucky to see it back together for the Nats

Bad luck Miles.

Maybe pull all rod bearings , especially #s 5 & 6 as these are fed via #4 main , same with #s 1 & 2 being fed via #2 main , would think the rod bearings took some grief off the mains.

Check the crank for run out , although if the crank was bent #3 thrust bearing would be toast.

I'd be checking the size of main bearing against crank journal...................ideally you want around .0025" on mains & rods , although the machine shop will check this out for you.

Are you using standard bearings in #4 cam journal?

Adam,
Its all stock +10, clevite bearings. All renewed with reground crank and all new cam bearings 12-15,000 miles back.
Hopefully, i'l have the crank out by tonight/tomorrow and have a clearer picture

There is no way the bearings should be worn down in such a small mileage, in my view.

Has to be either the bearing clearances were too tight or (and it sounds more likely) there was a lack of oiling to those bearings. You are going to have to check/clean every oil passage and replace the pump.

Take out all the oilway blanking plugs and clean it right through. But don't forget to put one back or you will be back to square one again in a hurry.

Dave, interesting thought on tight clearences. When i originally tightened the mains cps the crank would bind. i had the machine shop re-cut the mains to the correct diameter and rebuild the short block.
They could have got it wrong. Also, there is the prospect of the bearings being fitted incorrectly regarding oil hole replacement. I wont know until crank is out, but the two mains I pulled had bearings with oil holes that lined up with nothing. Off hand, I dont know if clevite main bearings have oiling holes on both halfs of the bearing.

Just checked the mains. 1 & 5 are ok, 2,3 &4 are worn to the copper. the thrust bearing is not uniformly worn, it is less worn at the outer edges where the mains caps meet the block.