Suspect Posted September 5, 2011 Report Share Posted September 5, 2011 My L20b has a broke valve guide causing a knock. I've decided to swap in a L18 from another truck. I didn't realize that the crank vent tube on a L20b was pointed upright and the L18 is sideways. I have to use the intake and exhaust manifold on the L18 from the L20b but the sideways vent tube hits the exhaust manifold. I pulled the tube from both motors but it looks like either tube will work, just not enough room to clear the exhaust manifold. Do you think it will be ok if I left it with no tube? Quote Link to comment
Guest kamakazi620 Posted September 5, 2011 Report Share Posted September 5, 2011 You'll have to run a non smog manifold ................YO!!! Quote Link to comment
Suspect Posted September 5, 2011 Author Report Share Posted September 5, 2011 You'll have to run a non smog manifold ................YO!!! That would be the easy fix other than the exhaust downpipe is different. Then I'd have to change that. I'm getting rid of the truck after this winter and I want to keep all the non emission stuff off the L18. Quote Link to comment
datzenmike Posted September 5, 2011 Report Share Posted September 5, 2011 Swap the L18 head onto the L20B and go. Can't see how a broken guide will cause a knock. But if you are sure it isn't just the timing chain and is definitely in the head, just swap it. Quote Link to comment
Suspect Posted September 5, 2011 Author Report Share Posted September 5, 2011 Swap the L18 head onto the L20B and go. Can't see how a broken guide will cause a knock. But if you are sure it isn't just the timing chain and is definitely in the head, just swap it. Well I bwas going to swap a different head on the L20 but I still need the clutch and flywheel off it for my LZ motor. What would happen if I just stuck a freeze plug in the lower crank vent? It would just vent up the timing to the valve cover? Quote Link to comment
datzenmike Posted September 5, 2011 Report Share Posted September 5, 2011 If the L20B is a known good runner swap the head and keep rollin'. You don't want a used clutch on a larger torque LZ motor so all it comes down to is finding a 225mm 6 bolt flywheel. Most 720s had them. Quote Link to comment
Suspect Posted September 5, 2011 Author Report Share Posted September 5, 2011 That's a good point about the clutch. I'm selling the truck after I get it going, may drive it another winter. Id like to hang on to the L20. Its not a life or death project, just like to have a good sounding motor in the 77. Quote Link to comment
bbqbill Posted September 6, 2011 Report Share Posted September 6, 2011 please let me know when and if you are selling the truck in the spring ,i will be looken for a 2nd ride come spring ,thanks Quote Link to comment
Suspect Posted September 6, 2011 Author Report Share Posted September 6, 2011 please let me know when and if you are selling the truck in the spring ,i will be looken for a 2nd ride come spring ,thanks I had it sold but I backed out of it last summer. I will let you know if I decide to sell it. Its a good truck, I drove it probably 4 - 5 years now, just developed a top end knock. To make it nice, it would need rockers, cab corners, fender, and some body work on the bed. Its a custom king cab someone made in Florida back in 1990. I might trade the doors off it for a different truck I'm restoring. Quote Link to comment
bbqbill Posted September 7, 2011 Report Share Posted September 7, 2011 is it the green truck?i asked about it this ummer,i thought it was sold. Quote Link to comment
Suspect Posted September 8, 2011 Author Report Share Posted September 8, 2011 is it the green truck?i asked about it this ummer,i thought it was sold. Yea its the green one and I did have it sold then I backed out of it. I figured I had more use for the truck than the money. Plus I had a friend and a couple people wanting it all at the same time and I was holding it for my friend and anyone on this forum. I also had it on craigslist but no one wanted to give anything for it, just a 240sx with a bad motor. That guy wanted me to swap the motor in the 620 and trade it for the 240. If it was a nicer car I would have, just fixed it to make some money. That car looked like hell and it wasn't even a fastback. Quote Link to comment
Suspect Posted September 12, 2011 Author Report Share Posted September 12, 2011 Well I finally got the L18 put in and running. I pulled it last week then got sidetracked. All this weekend it has rained on and off. It seemed like every time I went out to work on it, it would rain. Today I decided to get it done, then had to haul a 67 Impala SS. After I got back, stuck with it and got it done. I still have to hook up the alternator and find some better plug wires but other than that, its ready to roll. Quote Link to comment
banzai510(hainz) Posted September 12, 2011 Report Share Posted September 12, 2011 PS dont plug the crank case vent!!!!!!!!!if any thing keep it open. WHY!!!!!!!! would you plug it?????????????????? Quote Link to comment
Suspect Posted September 12, 2011 Author Report Share Posted September 12, 2011 I didn't plug it, I got a 1" freeze plug, drilled a hole in it, took 5/16" steel line and welded it in. I bent it around the manifold and its headed up towards the air cleaner. Its just open now, got to figure out what to do with it. If it was plugged, wouldn't it have just vented up the timing chain out the valve cover? Quote Link to comment
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