I just finished a freshen on the 283 and a conversion to a Turbo 400 in my 58 3200 BBW. The Motor is a decent condition 283 bored 60 over. Bottom end was fine, So I got fresh heads. Larger 192 Intake valves. Not sure what cam. It's not huge, the truck idles well. Torker intake,Holley 650. NOT the best headers, but 2.5 inch exhaust, Flowmaster40's, Full tailpipe out the back. Runs great, runs strong. But I get Engine fumes in the cab. Not exhaust, Crankcase fumes. I have Corvette aluminum Finned Valve covers. New PCV on one side. Breather on the other. The breather can't be full, it doesn't leak hardly any oil. I just redid the engine bay, and have plugged most of the holes. There is maybe a couple bolt holes left. The engine is tight, with no leaks, But I can't get why the fumes would be so bad. It definately seems to be worse from hard deceleration. I know my door seals could be tighter, and yes i should fix all the holes that come any where near the cab...But this seems excessive. i feel like I need to hook up an Evap cannister, but not sure how I'd make that look right in a 58...Any way.... Thanks in advance for any help!
are the cab vents in the kick panels open? how is the seal at the back of the hood? does the back of the hood close down all the way?
Squirrel, I just put new seals on the cab vents. The cables are stiff and they don't close tight though... I'll try to help them shut tighter. Hood seal is there but the back of the hood is up a bit. I'll try to adjust that also. Thanks for the tips. Gears, I don't think I have a breather at the back of the block. Least I didn't see one when the engine was out. The original breather/oil filler has been blocked though. What would a rear one look like? It also has a VERY cobbed electric fan that was installed as a puller, but it is actually a pusher. I was wondering if when it spins from air rushing through moveing down the road, Could the backwards spinning fan blades be making too much air turbulence under the hood? Thanks again for the help!!! I love this place!
The apache I had seemed to do the same thing, and the problem was the kick panel vents(replaced seals and still leaked) finally just sealed them off and the smell went away.
I will try the vent seals, but does that mean I'll have to deal with the smell every time I use my "Factory A.C."?
Thought I found it...Cracked vacume line to the PVC. Must have just broke, because it was fine when I first installed it. I replaced it and even rerouted it to the manifold instead of the Carb base. Still no change. The PCV is new, when I remove the breather on the drivers side I can feel "pull" through the hole. I've partially blocked the incoming air to the kick panel vents and closed the doors as tight as I can. The smell comes in definately worse after hard acceleration, and I definately smell it more from the drivers seat than the pass. seat. Breather is on the drivers valve cover. We drove in a cruise over 200 miles yesterday and my head was killing me by the end of it!! HELP!!! This is definately worse than before the motor work. The only difference now I can think of is I haven't installed my exhaust H pipe. Could this contribute?? ANY HELP PLEASE??!!
"Bottom end was fine" so you did a compression test? "breather doesn't leak hardly any oil" - you shouldn't be getting any leakage have you checked the gasket here? How about valve cover gaskets especially toward the back of the block. These covers are easy to over tighten and deform. On deceleration is the most likely period for covers to leak dripping onto the exhaust and fresh oil is sometimes hard to see. You didn't say if you were -Burning- any oil? Rings (compression test) or valve seals? Your air vents, if not closing tightly are only allowing you to be aware of the problem. If your engine is running properly the vents would not pull vapors into the cab. Never a problem when they were new. Hope this helps. Terry
i have a 59 and the cab isnt sealed great and dont have that prob but if you have a 283 it will have a oil breather behind the intake on the back of the block that ran under the intake in the lifter valley you could be geting blowby out of it
You did put a freeze plug in the hole that the road draft tube went in at the back of the block? Unless you are running the PCV valve out of that spot. The other thing would be the seal at the back of the intake especially if you used the rubber seal rather than silicone on it. I've had a lot of trouble with leaks there over the years.
Don't forget the intake manifold end seals ... If not installed right, crankcase vapors can leak out from there.
I have a similar issue. I put in new donuts, took up my tranny cover and used make a gasket. Also replaced the brake fluid fill plug. Not completely sorted but better.
Is draft tube missing and the hole not plugged? The hole is less than two inches from the base of the distributor, toward the driver's side, almost behind the oil pressure sensor mount
First off, Thank you so much for the help! OK, Terry, Shamed me into a recompression test. Hadn't done it out of laziness, and wanting to feel "done" after a long upgrade...Comp. is as follows, 1-120psi, Wet-125, 3-125,5-125,7-135, 2-115,wet-125, 4-150, 6-140,8-140. I redid the low ones wet to check for bad rings. Didn't think the result was too remarkable. The compression was very similar before the new heads. Maybe a bit lower on the passenger side, and certainly better on No.1 which was down to 50psi from a poorly sealing intake valve. The heads I replaced were the same size combustion chambered, 64 CC, but larger valves. From 1.72..or 1.74..? to the 1.92 intake, from 1.50 to 1.60 exh. Exact same castings, Heavt duty bronze guides, and Viton umbrella seals. I didn't expect anything more than an evening out of the compression. That seems to be what I got. The motor is bored .060 over. Does the compression still sound low? It runs excellent, no smoke, though I havent driven behind it yet, but none I can see. I have driven it at least 500 miles and it hasn't used an appreciable amount of oil. (might be down 1/8 inch on the stick) The draft tube is plugged with a bronze frost plug, as is the front fill tube hole. It has an Edlebrock torker intake. I did use the rubber end seals. (Fel-pro) and was very careful about torque, even though you can't get a torque wrench on the bolts, I'm pretty good at "hand-Pounds". The back and front of the block are completly dry of oil. As is around the valve covers. The smell is definately not burning oil. it's crankcase vapors for sure... I'm sorry this is so long winded... I asked about the breather because on hard acceleration when there's no vacume pull through it, doesn't it still act as a vent for combustion gasses? Maybe it's just "Full"? The grommet is fine BTW. But after the cruise this past weekend, there was some oil on my VC's Apachegail, I did have my trans cover off to mount my shifter...maybe I'll try a sealer there too...Thanks! And again to all...TIA!! I love this place!! JR. PS. Tried to attach some pics...Not very good with this stuff...If I was my sig. would have a pic..lol
Alot of those trucks get cab corners put in them, but don't get the floor metal replaced also that attaches to the corner. I had one and everytime I'd drive down a gravel road I'd get dust cropped, until I found out that I didn't seal under the cab corner area.
Is the pcv valve plumbed into the carb base or the manifold? Don't know about the Holley but some carbs including Edelbrocks have specific ports for the pcv and if you tie into the wrong port the valve will not function properly. Is the pcv valve factory specific for the 283? Valves are rated at different spring tensions for different applications. Can you remove the valve cover breather and replace it with a grommet that has a hose nipple on it? Then install a fitting on the base of your air cleaner, inside of the filter area so that your getting clean air to your engine and connect a hose from the air cleaner to the breather nipple. There are fittings available to install in the air cleaner for this purpose that have oil traps on the inside of the air cleaner to catch any blowby. GM used this routing for years. Some cheap things to try. Terry
Terry, I've had the PCV connected to the carb. and the Manifold, no change with either. The "original" valve that was on before the build, was connected with a chrome breather cap. I changed it to another valve with a 90 degree top and a direct connecting hose and clamp to be sure it's tight. I did just have them find me a valve in that style. The problem was there with either set up tho. I suppose I can try the vent hose hook up...I'm not thrilled with how it will look..I know I'll get busted for that here..but...
PS Sorry for the Billet wheels on my truck. As soon as I can afford to change it to five lug it will get my Crager SS's....( That I've owned for almost 30 years)
Sounds like you need to rebuild the lower end i.e. rings and also valve seals. I would try the valve seals first. Too much blow by. Sealing up the cab is a band aide.
Brand new heads, Bronze valve guides, Viton umbrella seals,Stainless valves, and hardened seats as stated in my earlier posts... Is there any way to measure blowby? I have very little or no visible evidence of it...
Well, there are tools for it. http://www.aa1car.com/library/engine_blowby.htm I guess the more affordable version would be to take out the dipstick tube and see if it's puffing out stinky clouds. But that's obviously imprecise. If all the other possibilities are ruled out, maybe you are just getting some flow back out through the breather. Maybe the engine vacuum isn't great enough at certain points, or the PCV valve spring pressure is wrong and it's not opening to let crankcase vapor get sucked through the intake. Terry's suggestion of plumbing the breather hole to the air cleaner is good. I guess, to see if it makes a difference before you drill a hole in the nice shiny scoop, you could plumb in the line, but run it back to the bed of the truck, away from the cab. If the smell goes away, then that at least shows where it's coming from. And you can plumb it more permanently at your convenience, in a way that fits the look of your truck.
I believe the PCV spring pressure is Ok because at idle I can put my thumb over the breather hole and suction will build. Quite a bit of it too. You can hear it hiss when your thumb is removed after only a couple seconds. I like the idea of trying a breather hose out the back just to see if it helps. That will pinpoint where my problem comes from. I was going to order a new breather just to try it. But they're harder to find than I thought (3/4 in. instead of the common 1.25in.) So before I bother I think I'll try your idea Mazza. If it does work, maybe one of those breathers with a hose nipple on it, then plumb it to the bottom of my air cleaner...? Thanks again for all the help! JR.
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