Yet another compression issue

[Chezedik]

Here I am again, talking about this. I have the following compression reading: 0-0-122-128. I have a cometic .120" gasket and am running dual 248's. I know that my valve lash is too tight, I was going to fix it when it got warmed up. Here is my Q:

Is too tight of valve lash causing me the low numbers?

here is my thinking: If the lifter is contacting the base circle on the cam, the valve would still be unseated at TDC. Does this make sense?

Also, are the springs different from exhaust to intake? I just had my head rebuilt and the dip**** had the lifters out and mixed them up. I tried checking clearance and now they are all way too tight. If the springs are different and switched, could they cause this problem.

Any advice is appreciated. If I can't remedy this easily enough, I may join the SR camp. I just can't do this much more. Please help, I don't want to have to do that.

[KATwo40]

Spring tension shouldn't make a difference, as the valve stem can't be raised anymore than it's length from the valve seat surface will allow.

Additionally, the spring retainer stops the spring from coming up too high on the stem.

Having the valve lash too tight will hold the valve open on the smallest part of the cam lobe, if the lobe is touching the bucket shim.

Before you do anything else, wait on this head I'm sending you. It has all the valves, springs, shims and buckets in their proper location. The only things missing are cams and cam caps. I'll find a way to make sure none of that stuff gets loose during shipping.

If that doesn't take care of it for you, then chase other problems.

[Chezedik]

I will probably still do some diagnosis. But I am running a cometic, and I have a spare Fel-pro gasket, so I should be good be set no matter what is up. BTW, do I need to surface the head?

[KATwo40]

Shouldn't need to be resurfaced. The engine didn't blow or anything, just disassembled.

[TheOne]

but you do have to make sure the head/block are mirror finish(as in STRAIGHT) to make sure that cometic gasket fits right in(doesn't leak)

sure ya set those 248's right? there's a write-up somewhere on how to set'em right on the spot(DIY adjustable cam sprokets or something like that)

[Chezedik]

Yes, I am sure they are set correctly. Also, Permatex makes a sealer for head gaskets, I have that. BTW, I know what Cometic says to install it dry, but I know a few people that have done it this way, problem free. Also, I am using ARP hardware torqued to 70 lb/ft as suggested by another source. Finally, Cometic gaskets don't have to be installed on a straight head, just a smooth one.

I checked the engine with air and shims and found that some valves were not even fully closing (guess which cyls). So I answered my Q, the only thing wrong with my motor is that it needs to be reshimmed.

[WDRacing]

Good deal, I was going to say that was your problem.

Cheze, we need to talk before you make the swap over to SR. I have a better option that I'm pretty sure you'll dig. Never install a smaller motor brah...never.

No problem with permatex either, I used it on my RB20 with a 2mm cometic HG.

Your never on AIM or I'd hit you up for some conversation. Next time your on, look for WDRacin

WD

[Chezedik]

Now that I know it is just shims, I am full steam ahead. I thought it was a problem with the valves, and I have hurt my back trying to get this together. But I am willing to see this through now. Besides my underhood looks way to sexy to quit now.

[TheOne]

hmm, i never though a shim could be big enough to let a valve stick out, i know you are supposed to put'em back the way they came out and if not check with a dial gauge(forgot its real name), did that to 1 of my heads.

[Chezedik]

Yeah, got it nailed down. Just need to find some. If any of you guys have any shims, please let me know. Maybe we can work something out. Driftking240 (at) sbcglobal (dot) net