Hi I've just finished building a lx hatch its got a 253 with a trimatic and a 2200 stall. Problem I have is I was told by dyno mechanic to put a 600 vac sec holley on so I bought a brand new one. The car has been to dyno 3 times and is still no right. The engine has a small cam performer manifold electronic distributor. the engine ran perfect years ago with a quadrajet but as it sat for 7 years it needs a rebuild. $300 to rebuild or $385 for new 600 holley I mad the wrong choice and went the new carby. I have been told to go the 570 street avenger but im thinking the 465 holley might be a better choice. Im well over the 600 holley and happy to buy another new carby but want to buy the right one. Any advice and suggestions would be appreciated.
holden 253 what carburetor
#2
_oldjohnno_
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Posted 16 June 2013 - 01:19 PM
You have two choices here, firstly you could find someone with half a brain to tune your Holley. The proverbial brown dog can do this. Or you could give up on the Holley and throw on a 500 Edelbrock. But either way find a better (less retarded) tuner.
#3
_armed_
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Posted 16 June 2013 - 01:37 PM
Thanks Clint not on the forum to bag anyone could of mentioned the well known dyno mechanic but a bad tradesman always bags another and it doesn't fix anything just make two that cant rectify the problem. Guys any knowledgeable suggestion on carby selection.
#4
_LS1 Taxi_
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Posted 16 June 2013 - 02:35 PM
For 2 bbl. WW2 strombergs & Holley 350's have worked well for me on 253's in the past.
For 4 bbl. Had a nice running 253 with a quaddie once. Ran really smooth.
#5
_oldjohnno_
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Posted 16 June 2013 - 02:52 PM
Thanks Clint not on the forum to bag anyone could of mentioned the well known dyno mechanic but a bad tradesman always bags another and it doesn't fix anything just make two that cant rectify the problem. Guys any knowledgeable suggestion on carby selection.
I guess the point I was trying to make is that the carb you have now should work OK, and that if the tuner can't get it tuned 100% then he's unlikely to be able to tune any other carb optimally either. In other words, the problem you have is very likely not the carb, it's the tuner.
#6
_armed_
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Posted 16 June 2013 - 07:09 PM
you could be right on the mechanic not being able to tune the carb 100%. My doubts are that I've heard a 600 is to big by more than a few people. The problem I have with the current 600 is right about when its time for the secondarys to come on or just when there in the car pops and jerks around. The car cruise no problem and flat out no problem pulls all the way, trouble is all under load in mid rpm range. changing jets, power valve, vac sec spring have only a small effect. Turning the carb into a mechanical sec by putting a screw in the butterfly linkage to make the secondarys come on has 95% solved the issue but caused another if you try to take of heavy it bogs down due to over fueling. Maybe another mechanic but would like to here more advice on other peoples 253 carb selections. Any one got some feed back on the 570 street avenger or a 465. Thanks LS1rana im thinking I should of got the quaddie reconditioned.
#7
_oldjohnno_
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Posted 16 June 2013 - 08:09 PM
I'm assuming it's an 1850? These often tend to run lean from just off idle to about 1/4 throttle and benefit from a couple thou more idle jet. Does the problem get better or worse as the engine warms up? Are you absolutely sure there are no vacuum leaks? Is the secondary check ball still in place? You don't have anything silly like an open spacer under it?
For a mild 253 a 600 is a bit on the big side, but even so it should still run cleanly right throughout the range with a dual plane manifold like yours. If you've got your heart set on replacing it you won't go past an airvalve style carb like an Edelbrock or a Qjet for a mild street car, either would be a better choice than a 570 or a 465. But having said that, any of the carbs mentioned will run cleanly if they are properly set up. The 500 Edelbrock would probably be the best in out-of-the-box configuration though.
#8
_armed_
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Posted 16 June 2013 - 09:24 PM
engine does have low vacuum possible due to cam i've gone right through the car and checked for vacuum leaks even pulled manifold of and put new gaskets didn't help. Before I took it back to dyno for the 3rd time engine was a bit fumie so I even re-rung and put new shells check heads and re-lapped the valves in a bit over the top but when your over it and getting no were with the tune this was what I was prepared to do to get it right. The ball is still in place. yes the carb is the 1850. The problem does get worse when engine warms up. There is no open spacer under it.
#9
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Posted 17 June 2013 - 07:13 AM
My personal choice would have been a Q-Jet, but as oldjohnno has mentioned, it should be able to be tuned to run clean through all conditions.
#10
_oldjohnno_
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Posted 17 June 2013 - 07:34 AM
the carb is the 1850. The problem does get worse when engine warms up.
Ok, so now we know that it's getting too much fuel rather than not enough. Am I right in saying that it's OK at idle and at full throttle and while cruising at a steady throttle, but coughs when you give it more throttle while cruising? Is it ok from off idle to say 1/4 throttle? Can you tell me what mainjets, pump nozzle, pump cam and PV you are using now? Have you checked that the main air bleeds are clear?
ps If you're unfamiliar with Holley tuning there is a one-page crash course here: http://oldjohnno.id.au/page390.html
Edited by oldjohnno, 17 June 2013 - 07:45 AM.
#11
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Posted 17 June 2013 - 08:55 AM
Is the spark upto scratch, ie nice bright blue spark?
No amount of carby tuning will tune around a weak spark.
Is the advance set correctly?
IMO a 600 out of the box should only need a idle mixture tune to get cracking on a cammed 253.
#12
_oldjohnno_
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Posted 17 June 2013 - 09:53 AM
Is the spark upto scratch, ie nice bright blue spark?
No amount of carby tuning will tune around a weak spark.
Is the advance set correctly?
IMO a 600 out of the box should only need a idle mixture tune to get cracking on a cammed 253.
That crossed my mind too, if old mate was tuning by a/f an ignition misfire would show up as a lean condition and it wouldn't improve no matter how much more fuel he threw at it. And agreed, the carb really shouldn't need too much at all, maybe couple of numbers up on the mainjet but not too much more.
#13
_armed_
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Posted 17 June 2013 - 03:19 PM
I've tried another electronic distributor and coil. I ran a wire direct from battery to coil to check if I was loosing any power whiles driving, it drove the same. total advance was set on 32. As you described above oldjohnno is spot on to how the car is running. I will pull bowl of carb and check main jet size and check on the main air bleeds aswell. On the classic 1850 can you change the pump nozzle and cam size cant recall mechanic saying he change them so im assuming they are standard the carb was brand new not reco. I myself have tried all colored springs for secondarys and changed the power valve to a 4.5 mechanic put back to a 6.5. Another thing the pipes to the carby from the pollution canister mechanic has blocked both of them. Its got new fuel pump new hoses at tank end and engine bay end. The car has nearly new everything as it was a bare shell build up resto. Thanks for the help.
#14
_armed_
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Posted 17 June 2013 - 05:11 PM
just checked carb details main jets are 68, pump nozzle is 31, pump cam is orange 41R-466, pv is 6.5 and the air bleeds are all clear.
#15
_oldjohnno_
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Posted 17 June 2013 - 07:12 PM
If you are cruising along at say 1/4 throttle, then open it to say 1/2 or 3/4 throttle, does it cough and then recover again after a second or two or does it misfire for some time? And if you open the throttle very slowly is it ok?
#16
_armed_
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Posted 17 June 2013 - 07:37 PM
yes it will misfire for some time. slowly its seems ok and full throttle its ok but driving it 1/2 to 3/4 throttle it breaks down bad
#17
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Posted 18 June 2013 - 06:10 AM
#18
_oldjohnno_
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Posted 18 June 2013 - 07:49 PM
Assuming it's rich - and if it gets worse as the engine warms up it is rich - the next step is to find out where the extra fuel is coming from. The primary jetting is about where I'd expect it to be, and the fact that it doesn't respond much to jet changes suggests that the fault is probably on the secondary side. It'd be worth dropping the secondary bowl off and having a close look at the metering plate. These are in a couple of layers with a gasket between the layers and another between the plate and body. Check that the gaskets are good, the faces are flat, nothing is cracked and everything pulls up nice and tight. Probably also pay to check the number on the plate just in case it somehow had the wrong one fitted.
#19
_armed_
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Posted 18 June 2013 - 08:44 PM
Thanks oldjohnno it would seem unlikely being brand new carb but it probably wouldn't be the first time a carb has slipped out of Holley with a faulty or wrong part on it will check secondary side. Willing to check and listen to all advise. Need to get this sorted driving me nuts. I'm starting to think I've tried two distributors out could both have the same issue. Spent a lot of money at dyno mechanic so far been back 3 times do I count my loses and go else where but to whom. Any suggestions I need a mechanic in S/E victoria that can tune a carbie engine and fault find what is wrong not just change parts and guess, this car needs to be tuned to street ability not 0 to flat out. Its only a 253 with a cam 600vac sec holley 2200stall trimatic 3.55 diff gears.
#20
_lh.355_
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Posted 22 June 2013 - 08:13 PM
Hi , I had a quady on my 253 and changed to a 465 with one inch spacer . Just think its a good fit, good on the juice and plenty of fun when the loud pedal goes down.Most advice i got was not to go to big.
#21
_armed_
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Posted 23 June 2013 - 04:30 PM
thanks lh355
I am really considering a 465. Hume performance claim they have a street avenger in the 465 can anyone confirm its a 465 before I purchase it. As no one else seems to selI a 465 street avenger I sent a email to us holley they said the smallest in the street avenger is a 570.
After speaking to another dyno mechanic he also has strongly suggested 465cfm he said the 600 will never be right something to do with not being able to get enough air to get the fuel/air calibrated right on a 253. Just looking into the street avenger a bit more before I make my carb purchase.
#22
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Posted 23 June 2013 - 05:43 PM
I had a 253 4 speed in a HQ I rebuilt and I had a Q- jet it was too big ....then I changed it to a holley 465 from Hume performance it changed the motor for the better....it reved harder and felt like it had plenty of balls down low.......I remember the advice given to me by Hume performance smaller is better.....
I hope this helps
#23
_armed_
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Posted 23 June 2013 - 06:16 PM
thanks big kev can you remember if it was the original gold anodised classic 465 holley or if it was the polished 465 street avenger that hume performance sell
#24
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Posted 23 June 2013 - 06:33 PM
Peter this was 20yrs ago so I would say it was gold anodised type.... not sure these days what is the difference between what your looking at but it was 465 cfm
at the time many people were telling me 465 so I followed they advice
#25
_wombat_
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Posted 24 June 2013 - 09:42 AM
i'm thinking of going with a 390 cfm 4 barrel to keep the air speed up,
make it a bit more responsive and it will "feel" more powerful. will be
stockish small valve heads with a TQ20 spec cam grind 253 combo.
carby is 525 bucks from VPW.
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