iggy1991

What is the lbs of the valves springs in my LO3 motor. I have a new cam and I'm diagnosing a knocking in the heads and it might be too weak of valve springs for the new cam.

Dewey316

you should put in new valve springs anytime you put in a new cam. no matter what they are rated at, after 100k miles, they are going to be much weaker. much in the same way suspension springs 'sag' if you question a valve spring, i would replace them. you will likely notice some added performance from doing it. you can get a good set for under $100.

BTW, what are the cam specs anyway?

vjo90RS8

iTrader: (1)

you can get some Z28 springs from www.sdpc2000.com or ebay that handle up to .480 lift for only $24. What are your cam specs?

iggy1991

The cam I installed is the comp cams PN# 08-500-8 its the XR258HR 206 212 .48 .488 112 1000-5000rpm
Summit recommends these springs CCA-981-16.
Specifications:
* Outside diameter: 1.254 in.
* Inside diameter: .880 in.
* Seat load: 105 lbs. at 1.700 in.
* Open load: 295 lbs. at 1.250 in.
* Coil bind: 1.150 in.
* Rate: 423 lbs.

As I said I'm trying to diagnose a valve train knock. Its noticeable between 2500 and 3500. The engine is seriously lacking in power when it starts to knock. I didn't do this when I first rebuilt the engine only after I fixed a rear manifold oil leak. And the oil pressure acts really funny. It will drop to the red zone when in drive at idle.

I'd rather just find the problem instead of throwing money at it like I have been.

Dewey316

did you ever think a knock could be related to no oil pressure i hate to be the one to bring it up, but with lack of oil pressure, your valvetrain knock, may be some other kind of knock, that will not be fixed with a set of valve springs.

iggy1991

Its crossed my mind everytime I hear it and see the gauge. I when I rebuilt the motor I put in a HV oil pump with a new shaft. After the break in I had no trouble with the engine except a oil leak in the back of the manifold(I didn't put enough RTV down to seal the manifold). After I fixed that I had this dam knock.

A week later I stripped the engine to find the problem. took off manifold, valve covers, oil pan, pulled the lifters and push rods. I replaced the oil pump with a stock oil pump cause I heard that HV arn't good cause they drain the pan too quickly. Soaked the lifters in fresh oil. cleaned it all, didn't find anything blocking the oil passages. Used a oil primer to see if there was something wrong. Oil is getting circulated. I don't remeber the oil pressure dropping below half way on the gauge (ever), before this all started. I'm seriuosly ready to dump the car for a honda.(cringe)


I'm ruling out a bottom end problem cause its new and it sounds like a rocker arm tick only much louder. Like there is something not taking up the slack in the valve train, hydraulic lifters. Other than that I'm lost and I'm tired of fixing something all the time.

Dewey316

you might try to hook up a pressure gauge other than the stocker. they are pretty bad. but if you really have no oil pressure at idle, i would suspect rod knock.

iggy1991

connecting rod or push rod

Dewey316

connecting rod if there is no oil pressure, but you couldn't tell without doing a teardown. i would see if you can get a mechanical pressure gauge hooked up to the oil pressure sending unit connector somehow, just to verify if you actualy have oil pressure or not.

iggy1991

hmm...know of anyone who makes one or has made one before.

I'm also wondering how the connection rods would knock. I could see it happening if a rod spun a bearing but I don't feel any play/knock when I rotate the crank myself. It all feels as solid as when I put it together but like you said I wouldn't know unless I tore it down and rebuilt it again.

Would screwing in the sending unit (the sensor above the oil filter right?) too much restrict the flow of the oil in the oil passage. Cause I did screw that in another turn when I fixed the manifold oil leak. Guess I'll try that today when I get home.

iggy1991

This is exactly my problem:
https://www.thirdgen.org/techbb2/sho...62#post1542462

At least I hope.

iggy1991

OK lets say that the problem is connecting rod knock. Do I have to unbolt each rod end and look at the bearings to see if there's play. If I do this can I reuse the bearings or do I have to get new ones. Also what about the mains. Should I look at the bearings for the mains too.

I took off the oil pan and I've been looking at the rotating assembly and I can't see anything wrong and I'm afraid to unbolt the mains or rods.

iggy1991

OK I took off the # 1 and #2 rod caps. The bearings look like crap. See the pics.

Can I just put new bearings on and hope for the best.

iggy1991

another one

iggy1991

The upper rod bearing is wiped to the copper.

Now What do I do.

kevinc

Fire your engine builder. That's a bad assembly, somebody didn't know how to use a micrometer or even plasti-gauge. Looks like the guy just slapped it together and hoped for the best.

My guess is the rods weren't resized, and/or the block/crank oil passages weren't cleaned out. Those little channels dug into the bearing are debris being dragged across it.

25THRSS

So what are the stock L03 valve springs actually rated to?

Dewey316

i am not sure, it shoudlnt' matter though, if you are replacing a cam, spend the few extra dollars and get a good set of performance valve springs.


Iggy: that is as i suspected. the lack of oil pressure told me there was more to this than some valvetrain noise. unfortinatly it might be time to have the whole thing rebuilt again.... depends on what else is damaged due to the lack of proper oiling.

kevinc

Whoops...guess my "fire your engine builder" line above isn't applicable, looks like you did the build:

https://www.thirdgen.org/techbb2/sho...hreadid=199786

And after all that grief about the need to mic your crank and bearings, looks like you didn't do it. Still unsure if bearing clearances are critical...even if you're not building a "700 hp monster"?

iggy1991

Well heres the thing. After all that "Do I really need to check", I did do the checking. I used plastigauge to check every bearing clearance and it came out just fine. Right where the shop told me it would. (.002 I believe) I think the reason this all happened was because when I took off the manifold I spilled coolant in the block. I did change the oil before I fired up the engine again but who knows. It just looks like alot of dirt got to the bearings either from the coolant spill or the shop didn't clean the block properly.

I haven't given up yet.

swerve-driver

Right- Don't give up. I think an ideal clearance is about 0.0025" Some may dispute that, but I have seen some good articles/graphs backing that up in terms of heat generated at various clearnaces and the load capacity of oil at various clearances. Experience as well.
It seems you were within spec, but on the tight end. Also, if you like to build engines, please continue, but invest in a good dial bore gage or snap gauge and micorometer set. Plastigage is crap and those pictures or your rod caps show why. Also when re-building, everything has to be clean. I know it is tough to get clearances right and keep everything clean, but it you don't you can't hide it. It always turns up.
Before reparing your engine, consider where all that copper and burrs and filings have gone. I can practically gaurantee they are not all in the filter. They are hanging around waiting to get to work on the next set of bearings that get put into that motor.

S-D

iggy1991

Thats what I'm afraid of. I'm gonna try to clean as much as I can. Is there anyway to get oil to flow through the block without a cank or bearings installed. I'm thinking just use the oil primer and put the pickup in oil and that will flush fresh oil through the block and to the bearing holes to get any particles traped in there out.
Its just a shot to prevent this again. The ideal thing to do is a full tear down again but I can't do that, time and money and my dad saying that he told me so is keeping me from doing that.

25THRSS

I'm not replacing my cam. I have 1.6 rockers. My original question still stands.

swerve-driver

You'd just be recycling the stuff throughout the motor. You are right- the best thing to do is get the block out of the car and wash it with soap and water. Blast out all the passages with a garden hose with a sprayer. Even if it takes all day, it will be clean and ready for assembly. I just don;t see you saving anything by not washing the block and all other components completely. If your dad is giving you grief now, imagine what it will be like if the engine fails again?!?! Like I said before, skipped steps always turn up later down the road.
S-D