Hello this is my first thread on HT sorry if i mess up!

Ok so i own a 91 CRX DX, i put tons of work into it, i started by building a new LS/Vtec I started with the block than the head than the trans, engine bay full wire tuck, painted looks great, I finally got the oil primed, bled the coolant system, filled the trans etc. When i started the motor everything sounded like it was supposed to, ecxept the engine seems to overheat, "according to the gauge which im not sure its accurate due to the fact that I have a lazer thermometer that says the engine is at about 170F at the head, gauge says is all the way on HOT" after bleeding the coolant system like 10 times and leaving it overnight with a funnel with honda coolant in it overnight the engine sucked in more coolant but it still seems to overheat "again im not sure if its a faulty gauge, sending unit or not, lazer thermometer says 170F" the thing that now scares the crap out of me is the fact that when the engine runs for about 4-6 minutes i start hearing a tapping noise, to me it sounds like its coming from the top of the motor on the side closest to the trans, before i tare down my fresh build i would like some input from people that have built hondas before. I went to a tech school called UTI i was a mechanic for about 6 years and have built other engines before this is my first Honda build, please let me know if you have any sudjestions or ideas, below is a list of parts i used on the build.

HEAD: B16A2, b16 stock cams, crower valvetrain, tri-angular valve job, all new retainers "titanium i think" ported and polished all new bought it assembled from a good friend it was brand new never installed on a car and built by a shop, also i think the valves are oversized "not 100% on that"

BLOCK: B18B1 "I put it together my self" Manley forged pistons 81mm 9:1 compression ratio, Manley rings, Eagle Rods, ARP head studs, ARP rod bolts, factory LS crank "stock", Clevitte bearings, GSR oil pump and water pump "brand new Honda parts", Golden Eagle LS/Vtec conversion kit, b16 head gasket, brand new honda thermostat, ACT 8lb pressure plate and stage 5 clutch.

When i put the block together i cleaned it my self, hoaned the cylinders than i checked to make sure everything is within spec, taper on cylinders mains etc, the only thing i did not do was check the Piston to Valve clearance i hope thats not the problem... please let me know if you have questions, i have all the tools i can possibly need, all bolts were torqued to spec using a Snap-On digital torque wrench that i know its dead on spec.

 

Much like any sending unit, you can test it by measuring the senders resistance.
first cold, then hot. See if it falls within spec.
Though I'm sure you've checked valve lash, check it again

 

Thanks for the Reply, I will check the sending unit, as for the lash i checked it and adjusted it but it was like 103F out that day so im waiting for a cooler day to check it as cool as possible don't know if it will make a difference but WTV.

 

does anyone think that i have valves touching pistons, when the engine warms up? and not when its cold is that a possibility?

 

I really doubt it at only 9.1:1 compression ratio, thats not very high. I've heard of oversized valves touching EACH OTHER in B series before though. Have you tried using a large screwdriver as a stethoscope to hopefully narrow down where the noise is coming from?

 

Definitely not the case. If the valves were touching anything, besides the seats, they would be damaged and the vehicle would not run

And I agree. Try a stethoscope to pin point where it's coming from. Injectors have also been known to tick. Try honing in on them as well

 

yeah my plan now is to figure out weather or not the engien is overheating first so i can atleast run it for more than 5 minutes, so tomorrow i will re-check valve lash "cold" check resistance on the sending unit, once thats done and i'm sure its not overheating i will check with the stethoscope "I have one". I did not think 9:1 would be a problem thats why I never checked for valve to piston clearance, I have heard of valves hiting eachother as well and i dont think thats the case but i have not ruled that out either, like i said before i'm not 100% on the size of the valves so who knows. Guys i appreceate the help and will keep updating the thread as soon as i find something out.

 

gl on finding the prob, hope its nothing big

 

Ok so i checked valve lash and its all within spec, the sending unit is bad, I monitored engine temp using my lazer thermometer again for about 20 minutes and the engine temp never went over 195F, rad fan turned on and off a couple times, as for the tapping/knocking sound i was hearing it went away alltogether after running it for about 20 minutes, turned the engine off let it cool down and fired it back up monitored temp again and no tapping, i checked with the stethoscope on the top of the engine and the bottom and it all sound good, besides the missleading gauge in the dash the engine seems to run 100%. Thanks guys for your help I guess I just needed some ***** to let the engine run and do its thing, I will post pictures of my build if you want to check it out and i'm looking forward to beating on it lol.