MattJeavons 7 Posted February 5, 2015 G'day All, Looking for some crossflow advice.... 250 crossy - 200 rods combo - 500 holley - stage 2 dynotec cam - running MSD programmable with a EST dizzy....crow H/D springs etc.... Originally thought the carb was too small (was running a 350) - however same problem... Once I get past 4k revs - more like 4500 - it will stop revving and run very rough - and if I back off the throttle - it's as rough as guts then steadys again - close to stall - but no worries.... This happens either under load or free-revving in neutral.... Fuel side is golden - and tried different coils - keep coming back to either valve springs (these are brand new) or the EST dizzy. Keep readings how the EST has the wrong phasing - so I've backed off the timing and same prob - Any advice on what to check for next?? cheers, matt Share this post Link to post Share on other sites
gerg 10,871 Posted February 5, 2015 I reckon valves are floating and your lifters are pumping up. Stock springs are marginal even with a standard cam. You say you've got Crow springs but no specs, and "stage 2" dynotec cam could be anything. Do you have specs for that? Are you running a high volume oil pump? 1 PRO250 reacted to this Share this post Link to post Share on other sites
MattJeavons 7 Posted February 5, 2015 G'day Gerg, Using the 7738-12 springs - 110lb pressure with the inner dampner - and retainers and collets to suit..... The cam specs : 2000-4800 valve timing @ 0.006"inlet opens 40 (BTDC) closes 71 (ABDC) Dur 292 exhaust opens 82 (BBDC) closes 29 (ATDC) Dur 292 valve timing @ 0.50" inlet opens 3 (BTDC) closes 31(ABDC) Dur 214 exhaust opens 45 (BBDC) closes -11 (ATDC) Dur 214 lift at 0.495" and yes - running a high volume oil pump......the more I read about that - maybe should've left the standard one in there! Share this post Link to post Share on other sites
Thom 6,650 Posted February 5, 2015 What lifters ar you using? you may have to swap to a set of anti-pump ups Share this post Link to post Share on other sites
gerg 10,871 Posted February 5, 2015 Thanks for putting the specs up... Makes it much easier for us to nut it out. 110 on the seat is decent, but not mind-blowing. Cam looks to be nothing too drastic, lift is below 0.500" so shouldn't be an issue for your valve train. Duration is interesting, 292 advertised but 214 @ 0.050". That means a pretty long, gentle ramp up and down, meaning float shouldn't be an issue. My Clevo has a similar duration with 206/214" @0.050" but advertised is only 270/280, and it has 0.512" lift. No probs with valve float to 5500 at all. There are some speedway guys who might chime in with some suggestions if they see this thread. This is just a theory, but the hi-vol pump could be pumping too much volume at those revs for the relief to deal with, causing pressure to spike and pump up your lifters. I know for a fact that high oil pressure even for a split second can pump up your lifters and give the same symptoms as with valve float. Although not caused by the same problem, i had this lifter thing happen when my original oil pump had a sticky relief so that on startup, it would cause the oil pressure to spike. My engine would die or run like shit on 3 cylinders before the lifters bled down and came good again. Even blew off several oil filters, and made lots of mess! Changed it for a standard Melling pump and never thought about it again. Share this post Link to post Share on other sites
Thom 6,650 Posted February 5, 2015 although a crossy can still rev with the stock webber and dizzy Share this post Link to post Share on other sites
MattJeavons 7 Posted February 5, 2015 Thanks Thom - for pointing out my MSD and EST and 500 holley are whipped in the arse by a stock webber and dizzy lol..... That's whats been pissing me off the most - pumped some money into a few solid bits and pieces then can't rev past 4,000 ; running down the 1/4 mile knowing you can't rev it up is more the frustrating... Only running standard lifters - prob no more than 2 years old.....would it be worth throwing some anti-pump up jobs in there? Got a standard, electronic, dizzy here - was going to throw it in on the weekend just to see what happens - at least that would let me eliminate spark/dizzy as the problem? Thanks for the help lads - this has been driving me nuts for weeks..... Share this post Link to post Share on other sites
MattJeavons 7 Posted February 5, 2015 stupid question - going down the anti-pump lifter path - I can use my YT rockers? (they aren't the adjustable type - street terra from memory) If the high volume oil pump and lifters are an issue - could that be the solution? or am I missing a trick - don't feel like breaking a valve at the track lol Share this post Link to post Share on other sites
Thom 6,650 Posted February 5, 2015 The high volume pump definitely won't help, especially when used with standard lifters Share this post Link to post Share on other sites
ando76 4,354 Posted February 5, 2015 I to have read all that stuff about EST dizzy phasing - to me it is all crap. My skid ute runs one - my race car used to run one and the two x-flow speedway engines I built for customers last year both run them - all without issue. You don't mention what timing you are running with your Programmable - what timing is in it at 4000 -4500? What inlet manifold are you running? The fact that it happens with load or without (free reving) concerns me. It could very well be a fuel delivery problem as you say it runs very rough and then settles. Do you have adequate fuel pressure (6psi minimum) all the time? Are you confident of your tacho? Don't get me started on the High volume oil pump. The regulars on here will tell you how I can rant on about how fekking useless they are, and that's not just because I build and sell custom standard volume oil pumps. If those crow springs are 2 years old like the lifters then they will be flogged, I can guarantee that. Just ask Clevo120 how long the set lasted in his customers engine. They really are crap. Get rid of the high volume pump before you get the anti pump ups. 2 gerg and Thom reacted to this Share this post Link to post Share on other sites
tpak addict 1,909 Posted February 5, 2015 Could be a MSD issue...... Don't know much about them but can they have a spark cutout??? Share this post Link to post Share on other sites
gerg 10,871 Posted February 5, 2015 Ohhhh yes! How stupid of me Jack... Never thought about the phasing. You MUST check dizzy phasing when installing MSD programmable as the timing could have the spark jumping to the previous cylinder. You'll need to sacrifice a dizzy cap by drilling/cutting a hole next to a terminal to see what the spark is doing throughout the rpm range. If it starts in the middle of the rotor tip then sweeps to one end, you need to adjust it. Ideally, you want the full range of spark advance to be covered across the entire width of the tip, and not have to jump any distance to fire. Getting this right was the most time-consuming part of installing the MSD-programmable box. Actual tuning on the computer was much easier: i got 90% there within 10 minutes. Just how you adjust an EST trigger wheel is beyond my knowledge but I'm sure some crossy heads on here know how to. Share this post Link to post Share on other sites
PRO250 1,506 Posted February 5, 2015 Just to check id stick a stock dissy in that just to make sure that's not what it ishow much preload is on the rockers? might be another thing to look at Share this post Link to post Share on other sites
MattJeavons 7 Posted February 6, 2015 Phasing is something I've read about with the EST dizzys and MSD programmables - lots of ppl recommending using the TFI dizzy instead but buggered if any of my local wreckers have one..... In saying that - Ando - happy to hear you haven't had any issues with it - never thought i had a problem until now. Long story short - was running without a tacho until only the last month - thats when i noticed the 4k limit....hooking up the lappy to the MSD unit - the tacho and software are very close - so fairly confident the tacho is right... In terms of timing - nothing radical - 14 base to 30 tops all in by 4k. At first I thought that was the issue - but after moving the timing around substantially - nothing changed. Tried backing the timing right off - same prob. Gerg - I was going to check the phasing next - but as you said - even if it was out - there is no way to adjust it anyways. Few more details that may help : Valve springs are brand new - the lifters are prob a few years old now though. Running the 500 on a redline manifold. Standard plugs - BP5ES - was thinking of going colder - but didn't think that was my prob. Thinking i should swap out to the normal oil pump and try a set of anti-pump up lifters ; while i'm there i'll recheck the springs but confident i installed those correctly - but definately worth the check again.. Thanks for all the help lads!! This is the first engine i've built - so trying to nut out bugs is bloody good fun but just as frustrating lol Share this post Link to post Share on other sites
tpak addict 1,909 Posted February 6, 2015 Cars can be just as frustrating as woman....... Just when you thought you have it worked out the rules change for no apparent reason... lol 1 dougie77 reacted to this Share this post Link to post Share on other sites
bear351c 10,270 Posted February 6, 2015 Fuel starvation?? How many fuel filters are you running? When were they changed? Which pump ya runnin'? Could hook up a fuel pressure gauge to the carby and drive it around a bit. 500 Holley sounds way too big for a redline, 350 should be enough. Share this post Link to post Share on other sites
slydog 7,873 Posted February 6, 2015 although a crossy can still rev with the stock webber and dizzy I witnessed this live...was a scarey moment for me. 1 Thom reacted to this Share this post Link to post Share on other sites
ando76 4,354 Posted February 6, 2015 I have NEVER and I mean NEVER checked the phasing of an EST dizzy and I have NEVER had an issue with them. The hall sensor can fail and that will usually lead to no go at all. You can change the phasing of the EST dizzy. It is just a matter of removing the wheel and drilling another hole in the wheel section where it mounts in the dizzy and using a nail or similar in place of the original pin. Ok the valve springs are new - have you checked you are not getting coil bind? Turn the motor over until you are at peak lift and make sure you have at least .060 gap between the springs. If you have less than that you are asking for big trouble - especially with a crap spring. Is your rocker geometry correct? i.e the inside of the pushrod is not getting stuck on the back of the lifter? I'm still suspect on fuel supply and metering as the Redline manifolds are basically crap as proved in many flow tests. Want proof - look at the STREET MACHINE valiant project - they lost 40cfm of flow when they bolted on the redline manifold and surprise - surprise it would not make any power and was getting very uneven cylinder fill causing it to run like a bag of shit. Was the camshaft dialled in correctly or just bolted in DOT to DOT? Was a new double row cam chain installed? Share this post Link to post Share on other sites
Thom 6,650 Posted February 6, 2015 although a crossy can still rev with the stock webber and dizzy I witnessed this live...was a scarey moment for me. It's still stock and it still won't die 1 slydog reacted to this Share this post Link to post Share on other sites
MattJeavons 7 Posted February 6, 2015 Bear - just changed the fuel filter to be sure - cut the old one open - was dirty - but not feral.....there is another filter that sits between the carby bown and speed flow fittings.....it's clean - but could that cause a prob?? Also recently change to a new fuel pump - this was all in trying to eliminate fuel as the problem... In terms of changes... It started with stock valve springs / 350 holley.. Same problem... So i changed to heavy duty springs (with the dampners) etc along with switching to a bigger carb... Ando - going to rip the valve cover off and check the geometry again - but pretty confident that was golden - but def going to check All i thought i had left was fuel and spark - hence the fuel pump/filters.....then the bigger carb - no dice... The camshaft was installed dot to dot with a double chain - didn't appear to be any issues there and glad the EST dizzy seems to not be the cause... Stupid question - if the lifters were pumping up or i'm getting coil bind - wouldn't i have thrown a valve into the piston? o Cheers!! Share this post Link to post Share on other sites
slydog 7,873 Posted February 6, 2015 Dot to dot is only ever a guess at best, the cam could be anywhere TBH. Should always atleast check lift @ TDC to the cam card. You could have in effect installed the cam retarded or advanced without knowing. Yes it can cause issues though I think yours are possibly valve train issues. Share this post Link to post Share on other sites
ando76 4,354 Posted February 6, 2015 It could have punched a valve into a piston if it got float due to bind but with under .500" lift I doubt it. Bit hard to diagnose without a picture at least. perhaps throw a picture up of an inlet or exhaust - which ever has the greatest lift on your cam at full lift so we can see what is going on with the springs or the rocker geometry. Like Rob said cam could be anywhere - although CROW are a bit better that Rob's favourite cam grinder. They all have to be checked regardless IMHO - but I know plenty that don't bother and get away with it but all you need is a bad blank and the pin position could be out to get proper set up. But really I think there is something else going on here. I take it that the plugs are reading okay - I would probably be going to 6s over 5s but really there is something not happening here and we need to get on top of it. Photos will help. Share this post Link to post Share on other sites
matt_lamb_160 252 Posted February 6, 2015 EST dizzy are out of phase, but only by enough to be an issue when starting with very high comp. Share this post Link to post Share on other sites
matt_lamb_160 252 Posted February 6, 2015 ... And when you use a significant amount of retard through the MSD programable. On there own or with locked timing, no issues. 1 slydog reacted to this Share this post Link to post Share on other sites
matt_lamb_160 252 Posted February 6, 2015 It's a not a crow, it's a dynotec. I'd measure it all up. It is likely something simpler though. Share this post Link to post Share on other sites
