I just installed my new(as in just freshly done, 0 miles on it)CNC ported h22 cylinder head that included a 3 angle valve job, oversized valves, new valve seats and guides.

A basemap was put on the car by mike@cct, I started the car and let it warm up to check for compression and leakdown.

Upon leakdown testing i noticed air was being blown out of my intake manifold on EVERY CYLINDER and CYLINDER 2-4 had 20% leakdown, with cylinder number one having almost 40% leakage, all of it blowing out of the intake manifold, indicating leakage past the intake valves. I even removed the cams to ensure all of teh intake valves were closed and got the same results.

I removed the head to check to see if the valves were bent and there was absolutely no v2v or p2v contact, i even removed all of the intake valves to check if they were bent visually and they were not.

So my question to you guys would be, is this acceptable? Normal? What would you suggest I do?

Thanks

 

Are you 100% sure the valves are closed?

 

forgot to mention that I tested it with no cams in the head, so yes all valves were most certainly closed during that test.

 

who did the head work?

 

I'd rather not start any bashing, so as to who did the head will remain anonymous at this point. I just would like to get some more opinions on the matter concerning the leakage.

 

did you let the fans come on??? Ideally, on a fresh build you need to allow the car to fully warm up... if this isn't a freshly built car and it just has a new head on it, i'd be sure that the valves were seat properly..

 

Have you checked the deck and surfaces? Toss the head back on and just torque the headstuds lightly...20-30 pounds. Hit it with a leaker and see if the results are the same.

 

If this is a race VJ then yes this is acceptable. You have not gone thru a heat cycle yes for the valves to properly seat. Break in the motor, then check leak down.

 

what machine was used to cut the vj?

 

Who said it was?

 

I'm sorry but leakage regardless of type of valve job is not acceptable.if you have leakage out of the intake valves on a new head it's either because the valve lash is tight (hanging the valve open) or the valve job was not done right.you should have taken the head back instead of taking it apart so it don't turn into one of those "well you took it apart sooo...." deals. Since you already have it apart do a quick check and lap the valves to check how well they sit in the seat.

 

I have only seen a couple heads with bad leakdown and it came down to a bad valve job.

Especially if you mentioned you have all new valves. I would agree that the valve job is unacceptable.

That sucks man.

 

Break the motor in and then check it, been through this with new heads before..

 

I'm sorry but you don't know what your trying to post on. If this were a stock VJ then maybe you would have a point. Many, Many races heads have very high leakage before they seat properly. How in the world do you lap in a narrow margin, lol.

 

Exactly..

 

I concur based on my own experiences.

 

ditto, happened to me with a single cam last year

 

I don't know what im trying to post on?? I have had several what you call "race heads" done over at Portflow wether it be standard or oversized valves.He has always "pressure and vacuum checked" all heads and not once have I had and issue with leakage.I tried to short cut one time and save a guy some money at a local machine shop and after starting the engine the car had a rough idle due to a crappy valve job.So if a engine has a rod knock on start up will you run it hoping it goes away?? To OP you already have the head off.it won't hurt to take it back or get a second opinion from a different shop.

 

Lol. That is an amazingly stupid question/post.

 

I believe your sarcasm detector is not working :-P

 

I would talk to the place that did your head to see if this is "normal" for them...

 

Austin, depending on how the vj was cut and what was used to cut it you may have some leakage until its run but w/ the intake seats you have in the head the valves will most likely seat themselves ASSUMING they are not bent.

20% is a bit much, however its worth a shot breaking it in on the dyno then checking it again.

if the head is still apart i would take the valves to a GOOD machine shop who has a lathe. spin them and see if they are bent. DO NOT trust any local machine shops to turn them on a grinder to see if they are bent. i can spin them for you if you like.

if they are straight put them back in and break it in on the dyno then recheck leakdown

DO NOT just assume they are straight because you dont see any marks on the pistons.

 

:thumbsup

its very common to have leakage on a new head with new valves and valvejob, seen it many times...after the first run etc it seats properly and 20% leak typically goes to almost 0%...its jsut a breakin needed.

 

Excuse my ignorance but what is it between that valve and seat that needs to be broken in?

 

nothing, "broken in" isnt the correct term...