Hello guys,

just need a technical advise for my LG4 project described here: https://www.thirdgen.org/forums/carb...982-trans.html

I've got an LG4 manifold (14101074) which was sandblasted by a friend. A few days ago, I noticed that of the ports is messed up, see picture. Originally, there must been a threaded brass pipe or something like that?

Any chance to reuse this manifold? Any ideas how to solve this problem? I think the best way would be to drill a new thread, but I just want to hear some meanings...

Best regards and thanks a lot!

Marcel

 

Yes that looks easily salvageable. You can drill & tap it for a new fitting.

There was a 3/8" pipe quick-connect type of thing there before. Problem was, it was made out of some kind of crappy chinesium, and dissolved in the coolant and fell to pieces, as those always do. Those things are impossible to remove gracefully once that happens, so someone drilled it out to get rid of the remnants.

Best thing to do is to make it into a ½" pipe thread and use a standard brass heater hose nipple in it. That's the hot side of the heater which therefore needs a nipple for 5/8" hose.

 

my '84 does not have that boss on the manifold. my '87 has the boss but it is plugged.

the presence of a plug in the forward boss where the earlier LG4's had a TVS for the evap system also leads me to believe that you have a later intake manifold.

Yup. '87 intake by the bolt holes.

 

Thanks a lot for your replies and please sorry about my late reply!

This is definitely a later manifold. It is taken from an 86' car, but the engine is '87 LG4 with a roller camshaft.

If I understood everything right, I have to keep my eyes open for a "standard brass heater nipple for a 5/8 hose". I think this will not be easy here in Germany, but maybe I have to cheat and use the metric alternative.

Thanks a lot!

Marcel

PS: Some thing I thought about yesterday: Do I have to worry about the fact that this manifold was sandblasted? Any advices how to get ALL the sand out of it? I think it would be very bad if there gets any sand down to the cylinders, I guess...

 

I take them to a car wash and use the hot soapy water to blow it all out. You WILL get a bath so do it on a warm day if you can.

 

Thanks a lot! So I will take this thing to my local car cleaning place in the next days and hope to get everything out.

 

@sofakingdom: Just to get sure, you mean something like that above?

 

Yes.

 

Thanks a lot! The guy drilled that hole meant it too good - the hole is around 14,12 mm (0,556 inch) in diameter. Would somebody please tell the perfect core hole diameter for an 1/2" NPT fitting? For a metric guy like me, this different kind of threads and units are very confusing...

I highly appreciate your help!

Best regards,

Marcel

 

Tried to paste a chart but formatting problem.
Here is a link to the info you need.
http://www.carbidedepot.com/formulas-tap-pipe.htm

 

They have that in germany. Any store with plumbing hardware will. Plumbing here uses npt threads...

 

Thank you all, guys!

After reading the page bigal55 has posted (and https://en.wikipedia.org/wiki/National_pipe_thread), I will go with a 3/8" pipe thread and nipple. It fits the current size of the hole, which seems to been a 1/4" connection before it was drilled out!

A 1/2" nipple will be ordered, too. Just as a spare and Plan B if something with the 3/8" connection goes wrong.