jrock4224 Posted October 11, 2012 Report Share Posted October 11, 2012 locked threads how did i miss this ....i musta been psting there if its locked Quote Link to comment
Eagle_Adam Posted October 11, 2012 Report Share Posted October 11, 2012 lolz^^ :rofl: Quote Link to comment
jrock4224 Posted October 11, 2012 Report Share Posted October 11, 2012 adam ...tristin isjust defending his boy toy.....he sent me a pic of the tw of them huggin at golden gardens Quote Link to comment
Tristin Posted October 11, 2012 Report Share Posted October 11, 2012 Lol no defending... Only hugging I was doing was with the beauty in the black dress (I wish). Qtip and Skip know the girl. Quote Link to comment
jrock4224 Posted October 11, 2012 Report Share Posted October 11, 2012 yes it was hip to hip if u know what i mean... borderline grinding.... Quote Link to comment
Silky_Johnson Posted October 30, 2012 Author Report Share Posted October 30, 2012 Okay, my carbs are driving me nuts! (I think) I've got the shakiest vibrating idle, and nothing seems to fix it. Engine is timed. I timed the distributor to 12* with a timing light. Valves are adjusted to .008/.010 cold. The carbs (dual Mikuni PHH 40) are synced, but I need to do something to the linkage eventually. At least one of the plastic bushings on the rod on top of the manifold seems to have some unwanted play. All of the idle mixture screws are out about 2.5 turns, which tells me that the pilot jest are probably just a little on the lean side. Right now I've got 65 size jets for the pilots. I'll probably go up to 70s. For the mains and main air jets, I think I have 135s and 155s (I'll have to confirm later). I'd like to throw in maybe 150s (main) and 180s or 200s (main air) just to be on the safe side. The main circuit on Mikunis is pretty forgiving. I thought that I found my problem a week or so back when I spotted one of the venturis had come loose. I tightened that back down, and while it helped, I've still got a super rough idle. I thought that I found the source of the problem last weekend when I was under the car and found out that the bolts from the transmission to the rear (transmission) crossmember were loose. I got that fixed and wasn't really happy about discovering the modified crossmember that the PO hacked up. It all went back together, but it wasn't easy. At this point, firmly bolting the transmission to the rubber mount seems to have only compounded my problem. Rather than taking away the vibrations, it just seemed to transmit more of the vibrations to the car. From the way things sound, I'll be lucky if my motor mounts and transmission mount don't break loose this winter... _________________________________________________________________________ SYMPTOMS: Rough idle - engine and transmission (including shifter) shakes side to side probably around 2mm at idle. If I give it gas, it smooths out. With the starter circuit engaged on my Mikunis, it's smoother (but the idle is also faster). Turning out the idle screws doesn't help the rough idle unless they are WAY out. At that point, the goon may as well just be a gas fumes generator... At low RPMs, everything seems fine. I'm pretty dang sure the pilot circuit is running lean, so it's a little down on power, but it runs smooth. I can tell when the carbs are switching from the pilot circuit to the mains, and there's a point of hesitation, as well as a time that it sounds like one or two runners haven't caught up with the others. It's like there's a lean spot between the pilots and the mains. Does this make sense? The worst symptom right now is that since I have actually bolted down the transmission, 3rd and 4th gears start to feel pretty rough after switching to the mains around 2500 RPMs, and it stays that way throughout the rest of the power band. At wide open throttle, I don't notice is as much, but it is noticeable just cruising. And now my 5th gear starts to whine from around 2300 RPMs to 3000 RPMs. I don't think the tranny is the problem, but maybe my driveline needs balanced? I'm inclined to think not as the engine vibration is pretty violent and could be fighting the drivetrain at higher RPMs? And the vibration coinsides with RPM, not actual speed. The only other symptom that I notice is that I can hear what I'll describe as a puffing sound coming from the engine bay. It's not a ticking sound like an exhaust leak, but like puffs of air timed with the RPMs of the engine. I thought this was an intake leak somewhere, but spraying DW40 around the insulators and other joints doesn't make it run any better. __________________________________________________________________________ So now I'm looking for ideas. I have gaskets to clean and rebuild the carbs, so maybe that's the best first step? I also have an mystery regrind for a cam with .480 lift. I don't know what the duration and all that other stuff is. Would a cam with huge overlap cause the idle to be so messed up? At this point, I'm tempted to throw in another stock L20B cam just to see what happens. Would it be a stupid idea to put the stock cam back in? I would of course put back in the stock lash pads and other necessary parts. What kind of a performance hit would I take with a stock cam? At this point, I'm tired of fiddling with the carbs to no avail. I would throw a Weber 38 outlaw on there just to keep things simple, but with my cam/valve setup I've heard it would be a waste to go downdraft... Any thoughts on what I should do next? Quote Link to comment
banzai510(hainz) Posted October 30, 2012 Report Share Posted October 30, 2012 I have bolted my 40s on from stock L16 to a 475 cam L16 match ported manifold and nothing really changed on how it ran. I think Im running 135 main 160 air on my L16. My bushing would alwasy slip out till I superglued/or 5 min Expoxyed it in there. this helped. I assume you synce this up bst as possible. I notice on mine on intial set up that one carb the long length had to be longer before it reaaly pushed the carb open so I set that up close as possible before sync n the carbs. Cam ? What is huge over lap. If you have 275-280 duration I DONT think thats huge overlap anyways Really it alot less as you have to take up the valve lash anyways. Your not really getting 480 lift either. MY carb at at spec with the pump nozzle and idle size what ever it is for a 40mm. I seen a guy buy a set of mikunis and has off idle proplems. He told me later the guy rebuild the carbs wrong installing the accell pump diaphrame backwards as for vibration you can always jack up the vehicle and put in gear. Quote Link to comment
jrock4224 Posted October 30, 2012 Report Share Posted October 30, 2012 whats the old drag racers addage....more carbuerators, more problems.....get just joels su carb set up and run it....(i dont think its for sale...) su's were by far the easiest dual carb set up i have ever fucked with....but if anybodys a expert on this it would be hainz....he will get u sorted out.....my question is, has it done this since the begininng or is it a new probelm that popped up since u first got it running Quote Link to comment
Silky_Johnson Posted October 30, 2012 Author Report Share Posted October 30, 2012 Yeah I'm not a cam guy. I didn't even know that I had anything other than stock until I started tearing things apart. I measured it, and I've got .480 lobe lift. I don't know any other specs because it doesn't have any markings on it. I read something on here about Mike saying that a cam with "huge overlap" doesn't have good vacuum at low RPMs... wasn't sure what he meant, and maybe I misunderstood. I'm just looking for all causes of the problem. At this point, I'm 98% sure that the vibrations are engine related. jrock, the only way I would get SUs was if they were modded by Steve Epperly. Bad news is that someone recognized my car at Canby two years ago and said that on of the previous owners never paid Steve for some of the parts in my car. I was told to not let Steve see it or he'd come over with a wrench and start pulling things off. The shakey idle has been since day one of my ownership. I used the head and carbs off of my engine for the rebuild, so I assume that one of those two things are the culprit. The head was check out and not leaking passed the valves. I have otherwise adjusted everything that could go wrong on the head (accept for swapping in another cam), so now I'm blaming the carbs. I suppose a carb rebuild weekend is in my future... Quote Link to comment
Sealik Posted October 31, 2012 Report Share Posted October 31, 2012 ...."the only way I would get SUs was if they were modded by Steve Epperly...." There's only a few, which are documented in the DQ articles ..."but like puffs of air timed with the RPMs of the engineMods???"... I would give it a leak down test to confirm no air is getting past the valves Vacuum gauge........ There is also a cranking vacuum test you can do....not yet sure how to decipher results on a engine with higher duration/lift ? though. Wideband A/F ratio gauge is much handy when tuning carbs....etc. Splurge....buy yourself an early xmas gift..... :D http://www.atlanticz.ca/zclub/techtips/vacuum/ Quote Link to comment
banzai510(hainz) Posted October 31, 2012 Report Share Posted October 31, 2012 maybe you could screw around with those idle mixture setting. But be honest I try not to fuck around with these things. I have just been lucky they bolted on and ran so good. My idle is so smooth. Quote Link to comment
Silky_Johnson Posted October 31, 2012 Author Report Share Posted October 31, 2012 Well, I have heard horror stories from my dad having to rebuild the SUs on his MG every year back in the late '70s. He didn't like the brass bits wearing out all of the time. SUs seem problematic (but maybe not Japanese Hitachis?), and I thought that I read that Epperly had a way to remedy the more typical failings by boring out and replacing brass stuff with steel bearings and such. The shop that bored out the cylinders also did a leak down test on the head, and it checked out. They said nothing is leaking past the valves. I'll probably do a test myself in the near future. Hainz, my Mikunis maybe bolted up and were good at one time, but since I bought the car, they were lean. The guy before me had compensated for this by retarding the timing. When I was running the L18, I started out with 57.5 pilot jets (which seems reasonable), but the engine bogged down big time in low RPMs. I thought it was too rich, so I put in 55 jets. That was a mistake. Noise was worse, and performance was terrible. I then tried 60s. It got better. And I finally ended up running the 65s on my L18. It ran the best with the 65s, but I never tried any larger jets, because I have to buy new jets every time. At this point, I now have the PCV hooked up to the manifold, so that is likely leaning out the mixture slightly. I'd like to get a wideband air/fuel gauge, but I think I can get this figured out doing running tests. By the way Hainz, just messing around with the mixture screw is only like a bandaid. From what I have read, if the mixture screw needs to be turned out more than 2 turns, your pilots are too lean. I have also found that screwing out the idle mixture also increases gas smell throughout the RPM range, whereas increasing jet sizes doesn't necessarily. I'm just going to rebuild the carbs (to ensure no leaks) and mess around with richer jets for now. My mystery cam still bothers me. It seems like this thing is really high strung for racing. The power band is pretty high, and I think that could be part of the problem. Does anyone have cam recommendations? I was looking at comp cams. Which one of the comp cams would be good for fun street/daily driver use? http://www.compcams.com/Company/CC/cam-specs/cam-search-results.aspx?sc=64&sm=By%20Engine%20Family Should I just stick the stock cam back in, or would that be a mistake. Stock cammed 510s beat me off of the line every time, probably partly to do with my carb tuning, but also partly because the power band doesn't kick in until after 2500. Quote Link to comment
Sealik Posted October 31, 2012 Report Share Posted October 31, 2012 Well, I have heard horror stories from my dad having to rebuild the SUs on his MG every year back in the late '70s. He didn't like the brass bits wearing out all of the time. SUs seem problematic (but maybe not Japanese Hitachis?), and I thought that I read that Epperly had a way to remedy the more typical failings by boring out and replacing brass stuff with steel bearings and such. If one was going to run SUs....the brass throttle shaft bushings should be replaced because they are 40 years old. Some...like Z therapy use roller bearings. Mine were replaced with the 'cheaper' brass bushings...good for another 30 years. Your engine should run smooth after you get the revs up...into the power band. I'm running 46mm SUs in my LZ with a .490 lift cam. But.....duration is only 260 and the cam is set on No 3 (advanced) sprocket hole. Soooooo....with 4.38s in the rear....I can throttle it at 2000 RPM....no bog or hesitation. Out of the hole....?.......Very quick 1 Quote Link to comment
banzai510(hainz) Posted October 31, 2012 Report Share Posted October 31, 2012 I dont run a PCV sytem. Have you tried maybe disconnect it??????? plug the hole and open vent the crank case. BUt reaaly IM only Guessing!!!!!! if you wan power sooner move sprocket to #3 Quote Link to comment
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