| Author | Message | ||
| Bill Sebestyen (Bill308)
Member Username: Bill308 Post Number: 358 Registered: 5-2001 |
The stock vent system would be hard to improve upon. There are no valves in it, it is fairly large in diameter, and it discharges into the air filter housing, which is not likely to be above atmospheric pressure. Depending on the amount of blowby gases, line losses should be very low. The only down side I see is if there is a lot of bypass gas and oil vapor, that may dilute the intake charge and possibly foul the plugs. If this is the case, then and engine rebuild may be in order. | ||
| Paul Newman (Newman)
Member Username: Newman Post Number: 520 Registered: 12-2001 |
There was alot of talk about krankvents from nick about a year ago and now I hear nothing about it. I was hearing claims of a HP increase with this breather but Im sceptical. I would think that by reducing the crankcase pressure to almost zero, would only aid in reducing oil seepage and the power gains would be undetectible by my a.s.s or a dyno. Has anyone verified the advantages or do people just think they look nice? | ||
| Mark (Markg)
Member Username: Markg Post Number: 271 Registered: 2-2001 |
Krank Vent, K&N, cat test pipes and Magnacore wires so far....car runs grat at lower altitudes! Next upgrade: Nick's direct fire ignition followed by relocating .... maybe Vegas area | ||
| Matt Morgan (Kermit)
Junior Member Username: Kermit Post Number: 56 Registered: 8-2001 |
To clear up a point on how things work. The standard PVC consists of a spring loaded steel valve that relies on the "pulses" of pressure to unseat the valve and allow outward flow. It takes to begin with, whatever crankcase pressure to overcome the valve and allow the release of gases. This of course does not take into account the inertia factor, that being how much push does it really take to move a steel valve off the seat. At an RPM of only 6000 this is naturally going to take a bit to actuate. The pressure that is below the approximately 3 lbs of spring are always going to be in the crankcase. Being a curious fellow, I dissected a Krank Vent. The valve isn't spring loaded at all, it is a disc shaped valve that weighed .7 grams. Obviously this takes a minuscule amount of push to open. With the nature of these blowby pulses being very light ( almost as soft as a baby's breath) it is easy to see how well it works. I personally use them on all my vehicles, Harley included. And yes they are a lot more than $3.00 PVC valves, but as I have seen the results, they are worth every cent. Or I sure as Heck would not have more that one. | ||
| Hans E. Hansen (4re_gt4)
Junior Member Username: 4re_gt4 Post Number: 209 Registered: 4-2002 |
A good shot of NOS will fix BOTH an altitude and an attitude problem!!! | ||
| Paul Newman (Newman)
Member Username: Newman Post Number: 518 Registered: 12-2001 |
Mark, you need a good shot of NOS to fix your altitude problem! What other mods have you done? | ||
| '75 308 GT4 (Peter)
Intermediate Member Username: Peter Post Number: 2057 Registered: 12-2000 |
Bill, mine doesn't pop out but turns slightly. If I align the handle in line with the engine, after a drive I'll check it and it turns about 45°. Never any more than that. So I stopped aligning it straight and always put it in "crooked". Always stays put. I figured maybe the flow of oil in the sump spins the stick, the blade with the "Min/Max" markings acting like a paddle... It takes a tug to pull mine out, but not with alot of effort. | ||
| Bill Sebestyen (Bill308)
Member Username: Bill308 Post Number: 357 Registered: 5-2001 |
Thanks for the ongoing discussion. The carb 308's do not have a PCV valve per se, but rather an oil separator circuit. Oil plus vapor is routed from the valve covers to a connecting pipe and then to an oil/vapor separator. Oil is returned to the sump and vapor is delivered to the air filter housing, on the carb side of the air filter. At the air filter box, is a fine mesh screen. When hot and running without the air filter assembly in place, for carb tuning purposes, I noticed some blow by gases exiting the hose to the absent air filter housing. At idle, this gave no concern, but at high rpm under load, it may be significant and indicate poor sealing of the rings. The fit of the dipstick to the tube is smoochy at best. Very little effort is required to extract the dip stick. Perhaps some teflon tape wrapped around the relief in the dipstick handle, under the O-ring, will increase the sealing pressure of the O-ring and eliminate the symptom? This may not be a long term solution, but I'd sure like to get a few more years before and engine rebuild is required. | ||
| Mark (Markg)
Member Username: Markg Post Number: 270 Registered: 2-2001 |
Paul - don't know for sure, I did several 'modifications' at once..but oil consumption is lower...at 6500 ft altitude nothing really makes my car quick! | ||
| Dave328GTB (Hardtop)
Member Username: Hardtop Post Number: 259 Registered: 1-2002 |
I solved this problem in a former 308 I had with a new O ring. Dave | ||
| Paul (Pcelenta)
Junior Member Username: Pcelenta Post Number: 150 Registered: 7-2002 |
mark, so was it worth it? | ||
| Mark (Markg)
Member Username: Markg Post Number: 268 Registered: 2-2001 |
Krank Vent is Nick's soloution - got one on my '82 GTSi. Crank preasure vents to 2 hoses )attached to PCV valves enclosed in fancy stainless tubes on each valve cover), that run down engine compartment and terminate about 3" off the road. | ||
| Dan B. (Dan_the_man)
New member Username: Dan_the_man Post Number: 16 Registered: 9-2002 |
Bill, I too have this issue on my 79 308. It is crank case pressure. it can be from several problems, but most likely your engine is experiencing more blow-by than the PCV system can handle. Do not try and force plug your dip stick tube. you will need to vent the crank case enough to correct this problem, but also keep in mind that you want to filter the air going into and out of the crank case. Nick's Ferrari parts has a link to a company that offers a type of "valve" ( I forget what they actually call it) that promotes negative crank case pressures. you may want to check that out. As for forcing the dip stick to stay in, the pressure will only find another way out. This will lead to front crank seal leaks and rear main seal leaks. Good negative crank pressure can also help to promote some performance gain. If you can create negative pressure under the piston then you will in effect create a higher pressure drop across the piston, which equates to more force on the piston per ignition cycle and will lend itself to faster rev's. In contrast the opposite holds true if you have positive crankcase pressure. These engines rev into the 8's thus you may see a better top end motor when you correct this problem. For those not in the know, "blow-by" refers to the amount of cylinder pressure that gets past the piston rings and into the crank case. ALL vehicles experience blow-by. the PCV system is designed to create a "vacuum" via the engine induction system to remove this additional pressure. Thus all engines should have this system serviced (which mostly consist of replacing a $3.00 PCV valve). again, seal leakage will eventually result from failure to maintain positive crankcase Ventilation (PVC). Daniel | ||
| Bill Sebestyen (Bill308)
Member Username: Bill308 Post Number: 351 Registered: 5-2001 |
Well I guess no one else has this particular problem. Crank case pressure, a slightly loose O-ring seal, and vibration are the possible causes I can think of. I guess I'll first try a slightly larger O-ring, if I can find one, and see if this makes a difference. Beano, of course, is always an option, but I'm skeptical. {  } | ||
| magoo (Magoo)
Advanced Member Username: Magoo Post Number: 3159 Registered: 2-2001 |
Oh Martin, I knew I could depend on your usual cheerful response. Regards | ||
| martin J weiner,M.D. (Mw360)
Member Username: Mw360 Post Number: 576 Registered: 5-2001 |
Magoo, I got it! DUH !!!!! Regards, | ||
| magoo (Magoo)
Advanced Member Username: Magoo Post Number: 3158 Registered: 2-2001 |
Kidding of course Bill. Get it? Beano, Gas,.... Oh well seemed like a good joke at the time. | ||
| magoo (Magoo)
Advanced Member Username: Magoo Post Number: 3157 Registered: 2-2001 |
Hell man, I'm trying to help you. I don't have time to fart around. | ||
| Bill Sebestyen (Bill308)
Member Username: Bill308 Post Number: 350 Registered: 5-2001 |
You guys are a gas. | ||
| Dave (Maranelloman)
Member Username: Maranelloman Post Number: 420 Registered: 1-2002 |
What magoo means is, use Beano... Thanks, folks. I'll be here all week... | ||
| magoo (Magoo)
Advanced Member Username: Magoo Post Number: 3149 Registered: 2-2001 |
Bill, Be sure your crankcase is venting properly. It may be crankcase pressure causing it. Check the vent tube where it comes up into the air box. Just a suggestion. | ||
| Dave (Maranelloman)
Member Username: Maranelloman Post Number: 419 Registered: 1-2002 |
This sounds like a personal problem. Rob, perhaps you need to create a new section, much like the Off Topic section, called Personal & Hygiene Issues... | ||
| Mitchell Le (Yelcab1)
Member Username: Yelcab1 Post Number: 411 Registered: 11-2001 |
Nope, did you try a bigger O-ring? | ||
| Bill Sebestyen (Bill308)
Member Username: Bill308 Post Number: 348 Registered: 5-2001 |
I've noticed that every time I check, my oil dip stick pops up from it's seated position on my 78 308. Does anyone else experience this? |