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-   -   671 weiand blower on 351w (problems) (http://www.hotrodders.com/forum/671-weiand-blower-351w-problems-185446.html)

mustang 671 10-03-2010 12:32 PM

671 weiand blower on 351w (problems)
 
Hi all. im a new member and have been reading some posts regarding blowers. seems to be alot of great advise on this forum so here goes !!!

i have a starting problem with my eleanor ford mustang 67. it has a 351w bored over 30+thou.
its now at 5.89 litres rather than 5.7l
compression ratio of 7.48 to 1

spec of engine equipment.
high volume canton sump with windage tray and scraper
high volume oil pump
re-ground balanced crank
crane supercharger crank specs are -- fair to moderate ride,rpm 3.400-3.800 cruise rates at 8.5-1 max
degrees duration 226d @ .05"
degrees advertised 286d @ .05"
lobe seperation 112d
open and close intake 6d and exhaust 40d
gross lift .502"

crane hydraulic lifters on roller rockers
comlete engine has studs and nuts from arp
forged rods with hyperutectic pistons ( keith blacks)
edelbrock performer heads (need to find the spec but are good for a blower)
high volume engine run fuel pump
weiand 6/71 blower with 2x holley 600 vac secs carbs all rebuilt polished etc

other updates to the engine.

i have an ecu which reads from euipment i have fitted which are,

tps sensor
knock sensors
crank sensor
vacum sensor (manifold)
atmosphere sensor

i have also fited water methanol infection for coolant in to the manifold via 4x injectors. ( not yet running though)

i have a rattler balancer on the crank and have had my botom pulley machined to fit over it rather than bolted to the front of it ( to save space )

bottom pulley = 45 teeth
top pulley = 51 teeth

divided = 0.88 so its being underdriven

its been worked to get me up to 7psi ?? is this correct at around 6000rpm ?

i have a c6 re built auto box. fitted is -

high stall torque coinverter 3000 i think ( has welded bits to it ? its an b&m one for supercharging)

manual reverse shift pattern being run by a b&m mega shifter.

i have fitted a heavy duty hitachi starter motor recently due to the stock one not being a happy chappy. it also turns the engine 300 rpm quicker.


THE PROBLEMS I HAVE

1, when cranking sometimes i here the starter motor making a noise like its being forced back (like a clonk noise on it) when this happens the starter then does not turn and i have to put a socket on to the front top pulley and turn the engine slightly to disingage the starter cog ?? thats what the nosie sounds like.

2 alot of the time when trying to start i will get blow backs of unburned fuel out of the top of carbs. enough to blow the unfastned lids which sit ontop of the round k&n filters ???

3 when it runs ( eventually after alot of cranking and coughing and starter knocking) it will not idle less than 1700 ish. after a while it will just stop running and cough

i feel i have a fueling issue and also a ign timing issue. i have had so much advise and people saying so many different things to do.

the car has not been on the road or driven like this yet as i dont want to load up the engine, i am worried about bore wash and am now not going to start it until i have looked into the issue further.

4 the omex ecu i have is great as i plug it in to my laptop and can change everything. so with that in mind what timing would you reccomend ???

start up ?
idle ??

the company that has been working with me on the ecu have provided me with a base map which they say should get me started. which it has. but its not right and i feel i need some hard core supercharging advise.

the tyres on the back are 375s on 18s

i have tried to answer all the usual questions that have been asked of in the posts i have read.

i am after advise on the points 1-4 and also any general tips and help you think i could do with.

the jets in the carbs have been sized by dave powell at performance unlimited. will find out what they are but he feels they are ok to start with. rather it rich to begin with

please see the engine running on you tube to hear the lowest rpm i can get it to. http://www.youtube.com/watch?v=Qvc7PnhtmH0

i will not get the water meth inj working until the egine is running smothly and fully ran in . it has millers running in oil which will be dumped after 500 miles at max of 300 rpms.

thanks guys let me know your thoguths. regards shaun .

will post some pics below in a bit. ta

68NovaSS 10-03-2010 05:41 PM

What kind of timing are you running? You want about 18 deg at idle, and 34 to 36 total advance, and have it all in by about 3k rpms.

The starter issue could be timing related as well. As for the starter sticking, that sounds like a clearance issue, you may need to shim the starter until you have the thickness of a paper clip between the teeth when engaged. You'd have to pull the gear into the flywheel to check that.

Sneezing the blower (spitting out the carbs) is either timing way off or cranking the motor while opening the throttle...a no no with a blower motor.

What's your fuel pressure at the carbs? 7 - 9 pounds is a good starting point.

The high idle sounds like your pulling air in somewhere, check around the back side of the blower at the manifold. Maybe a vacume line off? Idling shouldn't be a part of it, but are the carbs blower referenced?

With timing and all set correctly, pump it two or three times, that motor should fire off within one revolution with a bang. Blower motors are like that, mine is.

F-BIRD'88 10-03-2010 06:21 PM

Agree'ed check the alignment of the starter and starter drive action.

Idle speed and starting: Blower motors like a lot of initial and not much total advance.

As a base line lock out the advance curve and set the locked frozen timing at 28deg BTDC. It will range from 28deg to 34deg depending on wether you employ boost retard or methanol injection or high octane fuel. Start at 28deg.

The vacuum sec carbs will need to be dialed in to work with the blower correctly.
Start by removing both carbs and presetting the pri and sec throttle opening/idle transfer slot exposure at idle Aprox .020" on all.

As said above the starting proceedure is critical.
Pump it one /twice then close the throttle and kick it over. It will fire instantly. When it does, catch the throttle to 2500rpm and warm it up.
Do not wing the throttle when its cold. Let it warm up.
Once there is some heat in the blower case, manifold and carbs you can set up the idle. Set the idle mixture, then fine tune the idle speed. You must keep all 8 barrels throttles even at idle. It should idle at 900-1000 once fully warmed up.
Do not open the throttle when cranking/starting.
Once it catrches, raise the rpm to 2500-3000 but do not wing the throttle.
The carbs accelerator pump shooters and cams/linkage will need tuning.

If the moto4r is hard to crank when hot wiht the locked timing, install a ignition power interupt switch. Crank it over,throttles closed 1-2-3 and hit the spark switch.

The carbs will need blower motor calibrating , Jetting, idle and high speed air bleed tuning and possible idle feed restriction tuning. The power valves need to be boost referenced. The poer valve channel restriction may need tweeking.
I would consider upgrading the 600 vac sec carbs main bodies to the Proform HP style main bodies and billet base/throttle plate to gain some tuning flexability/capability. Essentually you'll be resusing the fuel bowls,metering blocks,metering plates and vac diaphram housing. The sec metering plates and be swapped,drilled or modded to accept screw in holley main jets.

At minimum you will need rejetting and boost referenced power valves and connected vac sec housings.

techinspector1 10-03-2010 06:23 PM

Max pressure for a Holley is 6 1/2 psi at the bowl inlet. Regulate your pressure to 6 psi. No need to run the pressure right up against the wall. More pressure will blow fuel past the needle and seat and into the manifold and create tuning nightmares like you are describing.

F-BIRD'88 10-03-2010 06:29 PM

Quote:

Originally Posted by techinspector1
Max pressure for a Holley is 6 1/2 psi at the bowl inlet. Regulate your pressure to 6 psi. No need to run the pressure right up against the wall. More pressure will blow fuel past the needle and seat and into the manifold and create tuning nightmares like you are describing.

Further you may want to upgrade the 600 vac sec carbs needle seat assemblies to the hi flow .110".

mustang 671 10-04-2010 11:09 AM

this is what i wanted !!!!! you guys are great, thankyou so much.

ok. my 600 holleys have had uprated power valves and the springs are stronger (somewhere in the carb ?)

as my carbs are back to back and not side to side i could only fit 1 x metering plate on the rear carb as there wasnt enough room on the front one as it would hit the rear primary casing ( thats on the secs ).

i explained this to the performance guy my side and he said that in a perfect world i should go side to side but he felt i could get them flowing well as its only 1x carb that doesnt have jets in the secondary metering plate.

i have a book on carbs for supercharges and also the well known supercharging book that is mentioned on here. i am happy with the weiand blower and feel i can get a nice reilable ride out of it and hopefully around 600bhp ??

i will check what timing it has at present and check the starter motor cog.

i feel that i need to get it running better and then start fine tuning the carbs to get the lumps and flat spots out of them as i go ??

at some stage i need to go to the rolling road that specialises in my ecu software and get it tweeked , but how long should i wait until giving it some on a dyno ??

good point on the possible air issue. i will double chech that one. that does add up as it gets bloody hot at the end of the headers. glowing red !! i do have exhaust wrap though so i expect a bit.

i have checked the float bowls and they do not have leaks. one of my needles was sticky so i changed that.

my money is on timing and carb set up issues.

guys , on my holleys can you reccomend from the start what mods i can do to my carbs that would need doing anyway ? (ie set up for supercharging ) i bought it as a set from a guy who had them on his car for a short while before the wife decided to take him to the cleaners. but i didnt hear the car running. so i would like to treat them like they are not set up for blowers !!any good advise ? or should i get it running first then start drilling, moding and changing bodies ??

with all that said once running what sort of power do you all reckon ? its been a long 10 yr project this

did you look on the you tube clip ?

thanks alot guys. awsome !!!!!!!!! :thumbup:

mustang 671 10-04-2010 11:11 AM

oh sorry one more thing. how does my cam set up sound ?????? ta

mustang 671 10-04-2010 02:33 PM

check out the ecu i have. may help some people on here ??
http://www.omextechnology.co.uk/

ok i have emailed the company and listed out what you have suggested. i think they may send me a new map to upload to the ecu. if its easy then i think i could change the settings to be more in line with your suggestions.will wait and see.

now on the ecu software it says changes of 1 incrament in my timimng alimanet setting box = 30 degrees. i have it set at 1.35 . so i presume thats about 41 degress ish? but advanced or retarded ? i will find out as im not sure.

on the crank trigger wheel it has a missing tooth and that shows tdcat piston number 1 when it is at the strobe timing light. so thats reading correctly. obviously waiting for the 4 strokes and passes of the missing tooth to come around. suck squeeze bank blow ah !!!

the only sensors i have for now are

map sensor ( srewed into the inlet manifold which senses manifold presure)
tps sensor ( on side of carb primary butterfly spindle)
crank sensor ( trigger wheel on front of pulley )
knock sensors ( one each side of the block inbetween the 2 middle cylinders)

i remember they set the timmimg to be set depending on the current tps sensor reading. it reads from 30 to 241. its a little elctric devise that i have mounted on the side of the primary throttle spindle bar. so it shows closed and wot as readings of - close =30 ( ie butterflys on both carbs closed) and my foot to the floor with carbs wide open = wot @241 reading. hope that makes sense ? so they have made the ecu read the timing from where the tps sensor is. so the timimng will change depending on the tps reading.

thought i should mention that.

will let you know

thanks shaun

mustang 671 10-05-2010 03:31 AM

how much power from 671 weiand on v8
 
hi all. have had some great advise about my timimg issue which i will resolve at the weekend.

how much power do you think i will be getting ?? also whats the max boost i should go for. but i do want a nice weekend driver and not a hairy pig !!

also does my cam sound ok for supercharging ??

******************

68NovaSS 10-05-2010 07:21 AM

This post was merged with a duplicate post, engine specs edited out are in the first post of this thread. :thumbup:


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