72 340 4sp runs hard to 4k rpm and no more. fuel pressure fine. changed rev box on firewall no change. crane 270 cam 480 lift 228 dur. orginal 4 barrell and now changed to six pack last month. it did the same with four barrell...compres is 155lbs on all cylinders..any ideals?
70 cuda 440 6 pak
How is the distributor timed? What valve springs are you using?
5 degrees initial, springs bought as a matched set with cam. original dist with new wires. it will rev to 5k with no load on it, but it seems to pop out of the 2 outboard carbs when i did take it up to 5k. thanks for your time, i'm stumped
70 cuda 440 6 pak
The only cam I find with those timing and lift numbers is the Crane Energizer 284 H12, 284/284, 228/228, .480/.480. How was the cam timed? Dot to dot or with a degree wheel? 155#, what elevation are you at? Stock 1972 pistons? The cam could also be way too advanced. If the cam is timed and the springs are set up correctly, I would first change the distributor timing. 5 degrees initial isn't enough for that cam. I would use at least 14-15 degrees and limit the mechanical advance to 17-18 degrees for a total of 32 degrees to start. The stock distributor could have as much as 40 degrees mechanical and if the vacuum advance is still hooked up you could have way too much advance total.
i called crane, the motor, LA 340, was rebuilt in 1997, they gave me the specs on cam. i do not how cam was timed. he said if lined up dot to dot it would have 5 degrees advance. i live in okla so not high elevation. kb pistons flat tops with relief, 10.7-1 if 62cc heads or 9.5-1 with 72cc heads. they are the stock orginal heads. with 91 octane+104 added, it rattled hard at 10 degrees total 34 degrees. wouldn't start when backed down to zero. 5 degrees is where it would start and run without rattling. i had to plug air emulsions in center carb just to get it to idle. since car was redone by previous owner in 97 it has had less than 1k miles put on it. i was thinking distributor or valve springs at this point. if my wife only drove it it would just fine, but i can't keep my foot out of it...
70 cuda 440 6 pak
is this a STOCK point type distributor??? is this a chrysler electronic ignition distributor and firewall mounted module? if so.. please invest 6 bucks in a braided ground strap from HELP at almost every parts store.. mount that from a cleaned mounting bolt on the back of the head to the mounting bolt of the ignition module to shorten the spark return path of the high voltage spark..do you have a points conversion installed???do you own a digital volt meter...perform the 4 part test.. only takes a minute.. if you have a point type distributor.. does it have a small braided ground strap between the points hold down screw and the distributor housing. if points.. do you have a dwell meter to set or check the adjustment of the points and to monitor the dwell angle during engine operation.. HF has 40 buck digital dwell meters LCD Automotive Multimeter with Tachometer Kit Item #95670because of the sweep of the breaker plate. the dwell changes with the vacuum advance movement..the dwell can also move when there is wear in the distributor bushings.. or when the oil pump drive shaft bushing is worn or eaten out and the drive shaft pushes the distributor shaft out of alignment.. usually ruining the distributor.. you will also want to monitor the voltage on the positive side of the ignition coil..at higher rpms.. you need more current to saturate the primary windings..if your ignition switch or bulk head connectors are limiting current flow.. you may not have enough positive connection to supply that side of the ignition system..you can also perform a voltage drop test with the engine running and the headlights on.. between the positive battery post and the alternator output terminal.. this should be less than 0.7 volts.. if you get more.. you have an issue..perform the same test between the positive battery terminal and the blue wires to the ballast resistor.. that's the ignition switch side.. again. less than 0.7 volts is expected.. the alternator output goes all the way around and thru the bulk head connector then the amp meter terminal.. the other amp meter terminal has a pair of wires. one to feed the car.. one that goes back thru the bulk head connector and over to the threaded stud on the starter relay.. where that leads down to the starter and then up to the battery positive.. thats a LONG way to go to charge a battery and the reason i want you to perform the voltage drop tests on the negative side.. tests 1 thru 4.. and the last two just above to check the positive side of the circuit..if you get more than 0.7 volts.. try taking one nut off the back of the amp meter.. move that wire over on top of the other nut.. then put the loose nut back on to hold that down.. this bypasses the amp meter for a test.. .. retest the voltage drop between the positive battery post and the alternator output terminal.. please disconnect the battery when you are moving the amp meter wiring..and DON'T ever pull the battery cable to check the charging system.. you can damage the alternator diodes.. this is 2014.. use a digital volt meter..
no points, this has a factory electronic ignition. no ground strap but i will be putting it on tomorrow. i do have digital volt meter and will perform these tests also. hopefully will find a simple fix for this car. thank's for your time and input.
70 cuda 440 6 pak
ground wire.. AS quick as possible..please be sure to clean the back of the head where you are going to mount it to.. and a star washer under the ground wire on both ends.. you will need two sizes.. 3/8 id for the engine.. 1/4" for the module end.. pull the cap and rotor.. take a look at the reluctor.. see the left rotation arrow and the right rotation arrow.. which way is the PIN in.. i think the small block is a clockwise rotation.. so that would be the right arrow in the image belowlook at the terminals inside the cap... the 8 terminals.. is the arcing burn marks evenly across the terminal flats in the cap? |--| or are the burn marks all the way to one edge of each cap terminal | -| or even| |- on the edge of the flat.. that would indicate that the reluctor is installed wrong..i cannot recall right now which pin slot.. one is for big block cars.. one is for small block cars.. if the burn marks are at the top of the cap on some positions.. change the rotor.. its assembled wrong and i bet its colored blue.. the outside blade end should be square and machined.. not rounded.. somebody put a batch of them together backward a dozen years back.. you will also want to find your feeler gauges.. and check the gap between the reluctor and the pickup coil with a BRASS FEELER gauge.. or a plastic version..0.008 or 0.010.. is the proper gap..
thanks again. i will post as soon as i know
70 cuda 440 6 pak
stock heads are around 70cc so comp and 155 is not too high. at only 5* initial sounds like u have only 29* total, could use a lil more. maybe carbs are way lean? what spark plugs (heat range?) and how do they look after a good top end blast. and springs for performance need to be installed and measured and checked by an amount of know how
IQ52:The only cam I find with those timing and lift numbers is the Crane Energizer 284 H12, 284/284, 228/228, .480/.480. How was the cam timed? Dot to dot or with a degree wheel? 155#, what elevation are you at? Stock 1972 pistons? The cam could also be way too advanced. If the cam is timed and the springs are set up correctly, I would first change the distributor timing. 5 degrees initial isn't enough for that cam. I would use at least 14-15 degrees and limit the mechanical advance to 17-18 degrees for a total of 32 degrees to start. The stock distributor could have as much as 40 degrees mechanical and if the vacuum advance is still hooked up you could have way too much advance total.+132 degrees total is a safe place to start, then back track why it is pinging.Setting initial timing (static) is only one of several advance mechanisms, which include vacuum advance and centrifugal advance.,. the 3 combined amount to total advance.
When The Flag Drops.,. The Bull ***t Stops.,. P. Engineer, Engine Builder
Good questions asked so far, some pertain to...but arent enough by themselves to cause what you describedMy thoughts...Initial timing setting will effect the power/tune, but to address your problem with being able to rev over 4k, the initial initial being 5* is not the problem its wether or not you have 30* total/full advance or better, and even if you had only 28* total full adv timing, it would still be able to rev past 4k.Popping out the carb can be a lean condition, weak valve springs, bad cam lobe , ignition malfunction...a few things.Here the new springs installed at the recommended height?Have you looked at the plugs for color and or specs from detonation?Did the problem start after the cam install?If so...did you double check valve lift to rule out a bad ex lobe?