celica-gts

I am building a b18b1 and i cant seem to get damn compression on the engine. The block has a new oem crank with king bearings probe robs and cp 81.5mm 9:1 compression the head has stock valve train the head has a mild port and polish on it as well as arp headstuds and new hg . i dont think i am getting my valves seated correctly or something. the first time i got the engine all togethor i set the timing and went to rotate it by hand and it just didn't feel tight enough so i put the tranny on and the starter and tested the compression i got 60 50 90 120 the frist time so i thought maybe i did a shity job seating the valves so i pulled the head off and lapped the valves again put it back togethor and i got 80 90 60 60 so wtf maybe i didnt get them good enough again so i pulled it off and tried again this time i got 90 60 10 and 90. so what the hell is going on am i just not getting the valves seated right or what i am using coarse then fine compound. i spin it side to side untell the pitch changes bang it once or twice and do it again i do this a total of three times for coarse and fine. i am putting the springs on by setting a rag wrapped up tightly under the valves im doing and using a spring compressor to put the valves on. someone please help im lost.

Tom-Guy

If you have an unbroken shiny line around seat and valve faces then everything is fine in that department. Honestly, a four million mile head might seal shitty but it still seals enough to run. Also, the valves aren't fully seated until you run the engine ~30 seconds or so, the tiny imperfections are hammered flat during engine operation.


Most likely your valve lash is wrong.

Smith-02

check compression with cam installed

celica-gts

how else would you check it? the cams are installed and using the starter to spin the engine over not by hand to get the compression. would the valve lash really mess the compression up that much? i am pretty sure it is set correct

nascarfan

i have never seen a problem with lapping the valves, no matter how shitty or quick the process was as long you can see contact all the way around
last month i did a quick lap on my ls, checked the valve lash which was not even close, set it and started up fine

Tom-Guy

Yes, and "pretty sure" means you never set your lash. :1

BigBird

I'm going to assume the rings are clocked properly.

celica-gts

no i did set the lash and i relapped again today good very good theres contact all the way around. and by clocked rings do you mean ground to the right specs. if that is what you are refearing to then yes they where put on a ring filler and ground to spec. the lastest update is 90 85 10 90. i am still lost. all the help is greatly appricated guys keep it coming

BigBird

No I meant like this http://www.theoldone.com/articles/en...20Clocking.jpg

celica-gts

ya i did that before putting the pistons in