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I noticed my motor is seizing sometimes while cranking, not every time but most of the time. Like it'll roll over then suddenly stop dead. It seems like something is binding and its making me nervous that I'm going to break something if I keep cranking it or running it. I still need to set the idle and timing so I understand it might not be running great at this point, but the seizing makes me think something important needs to be dealt with before I continue

It took a lot of fiddling to keep the manual choke cable from binding, I think I got it situated finally. I fired it up today, no exhaust yet, and it still needs to be tuned, but it lives! It sounds sweet without the exhaust, I still need to get a Y pipe made for it

I've been thinking, since I'm not using an EGR system anyway I don't really need my Thermal Vacuum Valve. I was just planning on leaving it there as a plug but I don't see any reason not to just plumb my intake coolant line in right there. Maybe I'm overlooking something but since its in the same pre-thermostat bypass area, it seems perfect. Plus then I wouldn't have to try and squeeze a T into one of those tight hose curves. I was trying to get this finished up and get my carb on this weekend, but so far I've had trouble finding one of these (see pic below) 1/4 NPT heater hose nipples, at least locally. The TVV port would be the same deal, just a little bit bigger threading.

Is it safe to assume I don't need to use any kind of heat shield with the L16 intake since its cooled/warmed by the coolant runners? The heat shield from the previous intake wouldn't fit, plus there is that giant hole in the middle so it doesn't seem like it would do too much anyway. Did they use any kind of shield in their native L16 environment though? And what about the carburetor heat shield and spacer? What's the purpose of that spacer anyway? It does fit on the L16 intake, but I'd have to cut a slot for the coolant hose that the other one didn't have. Is it needed? Totally useless? Heat shield and spacer on the old intake Heat shield and spacer on the new intake

I got the holes drilled out, I followed the advice of hainz in an old thread that suggested to drill them out only to 1/4". When attaching the coolant line to the intake, does it T into the line coming from below the thermostat housing, or does it replace that line? I got a plug for one of the two holes in the new intake, but I'm not sure which to use for PCV and which to plug, one is a straight shot and the other is a right angle, would one be preferable to the other? Finally, I tried to adjust my valve lash, but didn't have a flat enough wrench that fit the lower nut, its pretty narrow under the spring retainer wires, is there a specialty tool for servicing those? I mean everybody has to set their valves, what's typical procedure for that? Coolant holes drilled at 1/4" What is this line for and do I tee into it with the coolant line coming off the L16 intake? Is one of these more preferable than the other?

So I got the L16 intake from laotsu (thanks) and after a trip I'm ready to keep working on it. Can I drill these holes while the head is still in place? I'm worried about lots of chips getting into the water jacket, tips?

Thanks for the thought hainz, $25 still seems totally fair for an intake to me though. I paid $30 I think for my exhaust mani. And thanks for offering from your secret stash laotsu, it'll go to good use. More updates to come after I get everything together.

Sounds good to me, pm sent

I do like the idea of running an intake with coolant in it for the reasons you mentioned earlier: This kept the intake air at a more constant temperature and the engine was easier to drive, easier to tune, gave better mileage and lower pollution. Just so I'm clear on my options here though, If I don't have and can't find one of those intakes and need to get the truck running soon for other reasons (which I do need to) then I can just run what I've got? Downsides are crankiness when cold, worse mileage, and maybe less consistent performance? Like this:

I don't understand much about the specifics of how the intake pre-heating functions. So I can run my current intake as is without pre-heating from either being bolted to a matching exhaust manifold or without coolant lines in the intake? Is the pre-heating more a matter of efficiency than basic functionality? That is its not necessary at all?

I bought a matching flange from mklotz, and Eagle Adam gave me an old Y pipe, but it's in poor shape, I think I'll just show them and say "make this". I'm not sure where I'm going to find and intake yet though. Craigslist and classifieds on here doesn't seem to have much. I like the idea of converting to coolant run intake like datzenmike said. Thanks for suggesting, I had no idea you could do that.

Thanks Hainz, I did watch part of that video already, but I skipped around. Thanks for the link to the complete thing, I kept jumping back and forth on the youtube videos. Datzenmike, the exhaust I was planning on using is the one on the right, I think its an L16 manifold? As far as the intake, you're saying I COULD use the one that I have but I'd want to seal up the exhaust port really well? I have a U67 head btw, so I don't seem to have any coolant channels coming out of the head near any of the ports. Sadly, I did center punch as good as I could, of course the surface is never flat so it was probably off a bit. The hole appeared centered, but as I went up in size it drifted further and further off center. I reamed it pretty hard and destroyed a few dremel bits, at that point the hole was tapered, bigger at the opening than deeper in. Today I attacked it some more with a better drill bit. I wish I'd had some scrap aluminum or something around, but the hardest thing I could find was a scrap of black walnut. I drilled a guide hole in the wooden block and lined it up over the messed up bolt and hole. I filled the hole with WD40 for cutting fluid and went to town on it. The problem was that the drill was grabbing a lot harder on one side (duh) and so it kept seizing and eventually wore the guide hole oblong. Even so I got all of the old stud out and was able to retap the hole oversized, but it was unfortunately slightly crooked because of the soft guide block, so the stud is now at a slight angle. I wanted to use a solid threaded insert (EZ Lock style) to keep all the bolts the same size, but the tap size for the insert was getting pretty big, and the water jacket where the thermostat housing attaches is pretty close to the hole and I didn't want to risk busting through. Guide block setup Shiney new threads The stud at an angle :(

Here are a few shots of the old and new exhaust manifolds. I'm still trying to figure out if I can use my old intake with this new exhaust manifold since they wouldn't be bolted together in this configuration. Intake, bolt together style old and new exhaust manifolds welded shut holes drilled out tubes

Its been a while since I posted, almost a year since I bought my 620, and progress has been slow. I drove the truck for a few months but then started having issues with the brakes, and it started running really rough so I parked it for a while and eventually got back to it. I had vacuum leaks, exhaust leaks, and it just needed some going over. The plan is to have it to be my daily driver soon. I'm now in the middle of a weber install, de-smog, and exhaust manifold re-gasket and switch. Currently the manifolds are off and I'm figuring out how to run all the new vacuum lines and cap some of the smog stuff (most of it was deactivated or not running when I bought the truck anyway). My main hangup at the moment is trying to remove a sheared off stud. There was some sort of fault/corrosion in the stud shaft itself and there was only a tiny bit of metal still connecting the two halves of it. I removed the thermostat cover piece and distributor to get better access, but still wasn't able to drill it centered and after going up several sizes the hole is way off center. I dremeled it out and drilled some more, its not quite round though and I might have to increase the size a bit and retap in a larger size, I've never tried a helicoil, maybe that's what's best in this situation. Showing the tiny bit of bolt that was still attached The broken off stud location of stud, not my head just a pic I found After some drilling Is there supposed to be that much oil in the distributor attachment spot? Looks like somebody stuck some jb weld in the EGR

Well since it was new, maybe I can still get an exchange for it.