How to make power in a carbed 2.8?

[IXLR8]

Well i mean i beleive what your saying about the backfire... but i see it blowing the oil cap off first... without the pcv hooked up the oil cap just pops right out without a problem...

You can see the fittings in this pic. http://60degreev6.com/gallery/files/...7_original.jpg

You can?

It's way too blurry to make anything out.

[IXLR8]

Well have an edelbrock intake as well.. if that is what your talking about with one side of the runners being smaller... Well I also had the 3.4 lower intake manifold off the camaro, so i took the injector holes and tapped them put plugs in each hole, then took a aluminum plate and cut it out to fit over the lower intake. I mounted the original edelbrock upper intake to the camaro lower manifold. made a huge difference on upper range power.. wasnt that hard and was very cheap to do... good luck.. sry to jack your thread man

[95SleeperAcheiva]

2.8 GM? In a Jeep? I shouldn't be surprised they in isuzu's too. Tell ya what I did....
I had a 1985 S-10 Blazer with a 2.8. I bought .512" cam from summit racing for it, got a roller timing chain, the edelbrock 4 brl carb intake, and a edlebrock 600 carb. I did some major port and polish work to the headsand here's where it got fun. On one side of the intake the runners had an opening of about 1" x 2", on the otherside they were 1" x 1", there is a passage way for the EGR under the ports so they had to shrink it down to allow for crappy emissions, How they planne don a motor running right with left bank to right bank differances that much is beyond me. So, I cut the egr passage out of the bottom of the intake and removed the entire floor of the intake passage for that bank, added some aluminum plate to make up the runner walls back to the proper height to match the other bank, and then welded in a new floor, sans egr passage, and welded off what was left of the egr passage. What I got was a 2.8 that liked to break things, transmissions, torque converters, diff carriers, axles, leaf springs, and one axle tube. Have fun, she launched like a V-8!

[Ray Hamilton]

well i have had mine like this for about 30,000miles and havent had a problem with it.. No I dont its completly sealed off because the valve covers leak

The hose to the air cleaner allows the PCV to draw clean air from the air cleaner through the block by means of manifold vacuum through the PCV valve. Every engine I ever had that started blowing oil out everywhere had a broken ring or piston, hence too much "blow by", that is, pressure in the block. The way you have it set up, as the wiki tells you, if your engine backfires for some reason it could ignite the fumes in the crankcase and blow the pan off the engine, don't laugh, it's happened. This by having an unrestricted line directly to full manifold vacuum. Good luck with that setup.

[Ray Hamilton]

It has full vacuum to the front cover and a vent line from the rear cover to just ahead of the TB. The front line is restricted to around 3/16" diameter to limit air flow. The whole arrangement surprised me. I guess there is a reason for it but wonder how it will work when the engine starts getting some blowby.

Another odd thing about it was the size of the connector on the valve cover. It is the same size and configuration as the fuel rail connector and is around 4" away from it. It would be really bad to hook your fuel supply line up to the valve cover. You can see the fittings in this pic. http://60degreev6.com/gallery/files/...7_original.jpg

They've figured out a better way of a metered vacuum leak. Or maybe they have a timer on it so you trade it in JUST before any problems start showing their ugly heads!

[cardana24]

So does anyone have any dyno proof or track times to show that there were substantial power gains from any of the mods that have been listed? Does anyone have a link to a set of headers I can buy? I think my PCV is working fine so I would rather not cut it. Would a cat back exaust help at all? What is the optimal size for these engines? 2 1/4"? Thanks for any help.

[CNCguy]

On the LZ9 where does the hose come from that goes to the valve cover? Full manifold vacuum or ported? Or to the air cleaner? With after market covers you can put a push in breather in each cover and block the vacuum line. That makes it like the old time engines that just had a pipe running out of the block for ventilation. However, when the engine cooled it drew moisture into the block. Just like when the master cylinder was under the floorboard, drew in moisture and ruined the brake system. Early 50's it was moved to the firewall.
http://en.wikipedia.org/wiki/PCV_valve. You can't run full manifold vacuum from one side of the engine to the other, it'll cause a full vacuum leak and the vacuum from the source will suck the oil out, making it smoke at the least. About not being able to get your fill cap off, do you have a hose on the other side of your engine going into the air cleaner?

It has full vacuum to the front cover and a vent line from the rear cover to just ahead of the TB. The front line is restricted to around 3/16" diameter to limit air flow. The whole arrangement surprised me. I guess there is a reason for it but wonder how it will work when the engine starts getting some blowby.

Another odd thing about it was the size of the connector on the valve cover. It is the same size and configuration as the fuel rail connector and is around 4" away from it. It would be really bad to hook your fuel supply line up to the valve cover. You can see the fittings in this pic. http://60degreev6.com/gallery/files/...7_original.jpg

[IXLR8]

well i have had mine like this for about 30,000miles and havent had a problem with it.. No I dont its completly sealed off because the valve covers leak

[Ray Hamilton]

On the LZ9 where does the hose come from that goes to the valve cover? Full manifold vacuum or ported? Or to the air cleaner? With after market covers you can put a push in breather in each cover and block the vacuum line. That makes it like the old time engines that just had a pipe running out of the block for ventilation. However, when the engine cooled it drew moisture into the block. Just like when the master cylinder was under the floorboard, drew in moisture and ruined the brake system. Early 50's it was moved to the firewall.
http://en.wikipedia.org/wiki/PCV_valve. You can't run full manifold vacuum from one side of the engine to the other, it'll cause a full vacuum leak and the vacuum from the source will suck the oil out, making it smoke at the least. About not being able to get your fill cap off, do you have a hose on the other side of your engine going into the air cleaner?

[IXLR8]

It works quite nice try it out......

[CNCguy]

A year ago I would have laughed about opening up the PCV valve. But not so much now since I found that the LZ9 doesn't use one. It has a straight hose into the valve cover with no valve. I have never seen that before but it would make sense that it would keep the crankcase under vacuum.

[IXLR8]

mine was not clogged it was brand new i was just messing around with stuff... and the pcv valve normaly does cause vacuum in the crankcase but the one way valve limits it. when you take the one way valve out it creates alot more... its really hard to pull the oil cap off while the truck is running... The main reason i did this is because I have Chrome valve covers, and they leaked. now that i have modified the pcv valve i have not had a leak anywhere on this motor... the rear main seal quit leaking as well.

[cardana24]

so has any one dynoed any of the mods, or does anyone have time slips from before these mods and after mods?

well to make a lil more power out of that old engine try this and tell me what you think.... most ppl are gonna think im crazy but i did it to my truck and it seems to make a nice lil difference.... take your old PCV valve and grind the end off of it to get the lilttle valve out... then stick it back in its original spot.... this will cause a vacuum to be created in the crankcase, should make a lil difference... try it out... if you dont like it your out what $2.00.... im getting a nice 3mpg more out of my blazer from doing this... the engine runs noticeable smoother at idle......

What do you think the PCV is supposed to do?

You'rs was probably clogged.