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track73 · 12-18-2007, 09:01 PM

Have you done a compression test?

steve · 12-18-2007, 09:05 PM

i was told it had around 5k on it when i got it. i have not put more than 4k on it. so i figure about 10k is a good guess. i have no reason to believe i was lied to about mileage but i DO believe it had pe-existing issues that may finally be showing themselves. i bet i have not helped it much but i am more cautious than i probably sound. the noise is definately valve train, i expected to see a broken rocker or bent pushrod ect. when i pulled the valve cover but all eight on that side were rockin along like always,,,,i am thinking lifter (i hope).

i had a pushrod fail on #6 right after i bought it. the sound seems to be coming from #6 or #4....maybe the matching lifter finally went....

steve · 12-18-2007, 09:07 PM

i can do a compression test on that side tomorrow...last time i did one they were all between 195 and 205,,,

SWEETJUDGE · 12-18-2007, 09:19 PM

you wont see a bent pusrod unless its really bent. pull all pushrods Keep in order clean & inspect for odd wear or heat marks, then roll them on a piece of glass. If it wobbles its bent. Also pull the lifters keep in order. Lifters are NOT flat they are beveled. place lifters on a straight edge & check for wear or day light in the center of lifter.
Ive also heard of people using the wrong lifters & the oil holes or rings not quit linning up

Jack Gifford · 12-19-2007, 03:51 AM

Quote:

Originally Posted by SWEETJUDGE

... i think you will need an old housing so the oil gets to where it needs to go...

No, you're thinking of Chevy. On a Pontiac, you just need a way to turn the pump CCW (viewed from the top).

steve · 12-19-2007, 09:14 AM

gonna pull some parts today to have a look if i get a chance. would you guys agree that if the valve train is making a noise like a valve that is way out of adjustment (but visually apears to be operating right) that the lifters would be a good place to start... if the oil filter looks clean when i cut it ?

what symptoms would i get if i had a piston with a hole in it ?

65gto69 · 12-19-2007, 09:40 AM

Steve,

You need to pull that motor and tear it down. Stop assuming what is wrong and only pulling this off or that off. All this time wasted, that motor could have been out and apart and inspected, hell you might have foung the problem, fixed it and be putting it back together by now.

Constantly starting this motor up once a month and burning the crap out of the tires, is not going to make the problem go away.

You have a rare motor there and if you damage it, you will be sorry. 400's and 455's are plentiful although the 455's are getting scarce, but when your 421 is gone, it is gone.

Have you looked at pricing these 421 & 428 lately, they are bringing some big money for rebuildable cores.

Give your keys to the wife, finish the 400, pull the 421, put the 400 in, fix the 421. You might be able to have the 421 back in by the end of the season.

Give me a call, the hoist is waiting.

Mark

steve · 12-19-2007, 10:12 AM

i guess my problem is i have a good imagination. i keep imagining a scenario like i pull the motor and tear it down to find that it was simply a collapsed lifter ! i wish i had a mechanic local i could trust. (i have had a few bad experiences). i simply need someone with a good deal of experience to diagnose.

i would be happy to pay a forum member who was willing to come over and listen if they think they can help diagnose.

i have not been abusing the car...simply running small tests to see what changes i get. i would not have done a burn-out if i felt that i was risking a catastrophe....the help and input i get here is invaluable to me. (i dont want people to think i take the input for granted and keep ignoring suggestions at my own peril). i do think many would be more conservative than me and parked it though.

i am not afraid of the cost..even if i had to repair a trashed cylinder ect...its not that i am rich i just can afford the hobby i am into and the main reason i am into it is to learn and do as much as i can myself.....even if i have to learn things the hard way. i am sure many of the boards smartest members had a time early in their "career" when they were in my shoes (i hope

)

the thought of paying someone $$$$ to do the work is hard to swallow but i may end up there.......

PS. this hobby of mine is "self imposed therapy" for me. i find few things make me happier than the mind over matter experience i get from tackling mechanical problems and winning....especially ones i have no business attempting. i think some do this just cause they like to cruise in shiny old cars. not me. i would rather be working on it than driving it ! i dont know if this clears up where i am coming from but maybe it will get me some sympathy from pontiac fans that think i am destroying rare pontiac parts at my whim ...

mark, you may get i call if santa does not vring me a hoist

THANKS !!!

steve · 12-19-2007, 10:27 AM

the 400 is moving along (the 3bbl is just sitting there for fun). mached up and ready for timingset, cam, lifters.....

steve · 12-19-2007, 10:32 AM

forgot the pics

65gto69 · 12-19-2007, 11:03 AM

Steve,

You can still do a lot of the work yourself, it is very easy to tear down a motor and rebuild. Just have to check, re-check and re-re-check your measurements and cleanliness.

Take the motor apart, and post pics of the crank, bearings, pump, lifters, etc. I am sure the borard members will help you diagnose any problems that maybe wrong with the motor when seeing pics. It is just too hard to speculate when you can't see or hear the problems.

From here if any machine work needs to be done, it can be machined, new bearings purchased. Get the parts back and put it back together. You don't need a machine shop to build the motor, just need them to machine the parts. You will be surprised at how much money you can save just building the motor yourself.

Mark

johnta1 · 12-19-2007, 02:51 PM

I say park it and pull the engine.
I'd guess it spun a rod bearing and now the piston is hitting the head.
Might check the valves for being bent also.

chiphead · 12-19-2007, 03:05 PM

My gut is telling me this motor is too wounded to be fixable in-car. What are you gonna do when you fire it up again and a rod comes out the side? You need to pull the starter so you don't have the temptation to start it again.

Finish the 400 correctly, do the engine swap, and get the 400 dialed in. Do the autopsy on the 421 later when you have time.

steve · 12-19-2007, 03:40 PM

Quote:

Originally Posted by chiphead

My gut is telling me this motor is too wounded to be fixable in-car. What are you gonna do when you fire it up again and a rod comes out the side? You need to pull the starter so you don't have the temptation to start it again.

Finish the 400 correctly, do the engine swap, and get the 400 dialed in. Do the autopsy on the 421 later when you have time.

chiphead,

could not bring myself to even look at it yet today...

i took the day to think and get my head around it, your comments sum up exactly how i am beginning to feel.......

steve · 12-19-2007, 04:04 PM

i got off the couch and took a look......i can spin all but one pushrod on the passenger side easily with my fingers. also all the rockers except the one with the pushrod i cant spin are in the same position. it was not like this about 50miles ago when i re-set the lash.

flat cam ?

BILTIT · 12-19-2007, 04:17 PM

Why does one pushrod look different?

steve · 12-19-2007, 04:33 PM

that is the one i replaced shortly after i bought the car. actually i believe the pushrod was failing and the guy who sold it to me did not even know how to take the valve cover off. he took it to a shop and they wanted big bucks to "fix" the car. he decided to sell (he told me the mechanic offered him 8,000

) i paid 10k.

the pushrod wore completely through where it contacted the guide plate and broke the tip off in the head........another pushrod showed the same wear points so i replaced 2 of them and actually flipped two over so the wear was near the lifter. i suppose that wasnt such a great ides either.

http://forums.maxperformanceinc.com/...d.php?t=475753

chiphead · 12-19-2007, 09:26 PM

Hmm, looks like you've had problems with mix-matched valvetrain parts. I still dont see a dead lifter killing all the oil pressure. Didn't you have other strange engine issues? Something else is going on, and finding that something will require pulling the engine.

This is just a guess... I'd bet you open the oil pan, and find a bunch of issues due to mismatched parts selection by the original builder.

steve · 12-19-2007, 09:45 PM

you are on to something there....this motor had a P4B intake on it when i got i ! it now runs great with a T2. not to mention the HEI was trashed, the holley pump is mounted sideways, the holley 800 had a fragged float, ect.

i also never felt i was getting enough oil to the heads, i could adjust lash with the car running and get no oil on the engine bay. i had to rev it a little get a trickle from the rockers.

maybe i am lucky it ran as long as it did.

steve · 12-19-2007, 09:51 PM

Quote:

Originally Posted by chiphead

This is just a guess... I'd bet you open the oil pan, and find a bunch of issues due to mismatched parts selection by the original builder.

do you mean stuff laying in the pan ?

i have changed the oil every 500 miles or so and cut open a bunch of filters with only the last few showing this......

http://forums.maxperformanceinc.com/...d.php?t=536869

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