53 Pontiac Straight * help

[Guest De Soto Frank]

When you have time, run another compression check and just before you check a cylinder, take a pump-can with 10W-30 oil and shoot about 3-pumps in the sparkplug hole, away from the manifold (towards the piston, not over the valves).

Then screw-in your gauge and take your readings...the oil will seal the rings long enough to get a "wet" reading. Do NOT oil ALL the cylinders at the same time...repeat the process just prior to checking a given cylinder...

Also, tie the throttle open...so that the cylinders can breathe as easily as possible.

Except for #2, all cylinders seem to be within 10# of each other, which is deemed "acceptable"; but...40# is low...try again w/oil... should be able to make at least 60 -80 #...

Are the head-bolts only "finger-tight" ?

I think the leak-down test is in order...

AND, the next time the head comes-off, it should be checked for warpage.

In the meantime, get some Kroil and start soaking those manifold bolts...

Keep us posted...

[RocketDude]

No way it would have started with compression that low. With all cyls that low, I'm back to valve timing........

[Guest Silverghost]

Will the 70 Riviera be your Wife's Valentine's Day gift from you???

If so...She is a very Lucky Lady!!!

Sure beats Flowers, Chocolates, or a Diamond ring ( Just an old Carbon Rock anyway!!!)

Or...Is SHE buying these old cars for You ???

[Guest JT]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Something strange that I remarked as I was doing the compression test. Cylinders 1-4 were dry, i.e. no liquid gas residue on plugs. Cylinders 5-8 were all wet with gas. </div></div>

I'm a little confused by this. Did you have all the plugs removed (as you should) when doing the compression test? Was the engine turning over well when testing?

[Guest mena]

An obstruction in the intake (mouse nest) will cause low compresion, and dry plugs.

A cracked intake or bad gasket will cause dry plugs, but not low compression.

Was the head off, or on when you felt air in the exhaust manifold

[Guest JDHolmes]

Simplest answers first.

When air test was done, head was off. In cylinders 7 and 8, water blew out of intake valves. Droplets blew out of 6. Solid air flow out of five.

Head bolts were tightened down, not finger tight. They were firmly tightened, but did not have torque wrench to assure 60 lbs. It was close though.

JT...I removed one spark plug at a time for the compression test. All others were in place. Motor turned over fine/normally. However, I remarked the plug head when taking each out. 1-4 were dry, 5-8 were damp with gas.

Mena...head was off when I felt air from exhaust manifold. The plate on the back of the exhaust manifold that I reattached, had a manufactured hole behind the plate which warms the air to open the choke on the car (tube from choke to top at that location). This "hole" had debris...maybe had a mouse.

However, I don't know that a mouse could have gotten into the intake manifold (though some other type of debris may have). The car had the breather on, with oil, which would have required a very industrious mouse to enter the carb to make it to the intake. I'm not totally discounting this possibility and will give the intake a thorough cleaning when it comes off.

will add oil to each cylinder and redo compression test. After which, leak down test will be done.

Silverghost...the deal for the Rivi didn't go through last night. No title, no keys=no money. The owner will be reapplying for duplicate title and when that comes in, we'll make the deal. If things work out, I'm on the way to OK to buy a 40 Chevy tomorrow. And no, my wife didn't buy me either though she said she would if she had the money. She just prefers to drive new cars, have pretty "bling" and clothes while I choose to lead a meager life and have more disposable cash for big toys = cars and such.

Thanks again all. Just know that you've played a big part in getting Herman up and running. He'll certainly be happy to be on the road again.

[Guest JT]

JD, you should be doing the compression test with all the plugs removed and the throttle open. Try if first without adding any oil to cylinders and then one at a time adding a small amount of oil.

[Guest De Soto Frank]

JD,

It's okay to remove all the plugs when you're doing your compression test...your battery will last longer, for one thing...

Also, you'll hear the engine "bump" against the compression (if any) on the cylinder you're testing...

Sounds like that sheet metal "plate" on the manifold is what most folks refer to as a "choke stove", and just serves to heat-up the air going to the choke thermostat. Not critical at this point, and has nothing whatsoever to do with "compression"...

How is the cam gear secured to the cam shaft ? The shop manual shows a picture with the gears and chain installed - I see a big nut on the cam shaft, I presume there's a key and key-way to keep the cam gear properly "indexed" with the camshaft ?

RE "Valentimes Day"..."Bling" is its own reward... my wife prefers to drive newer stuff too: 2000 Neue Beetle ( What's the German word for "junk" ?)

Good luck with Herman!

[Guest JDHolmes]

Cam gear is installed on a key/keyway and then bolt and washer into cam end. Only possible to install gear on camshaft in one way.

[Guest De Soto Frank]

That's what I thought...

[Guest JDHolmes]

Sunday update....

Today, I did another two compression checks as suggested. All plugs were removed, carb linkage removed and locked open.

First test was "dry" to use Frank's terminology.

#1 = 45 psi; #2 = 20 psi; #3 = 90 psi; #4 = 60 psi; #5 = 85 psi; #6 = 90 psi; #7 = 70 psi; #8 = 65 psi.

I then sprayed in about three blasts of wd40 toward the piston area. These are the "wet" compression readings.

#1 = 55psi; #2 = 40psi; #3 = 90 psi; #4 = 65 psi; #5 = 90 psi; #6 = 90 psi; #7 = 105 psi; #8 = 100 psi.

I'm guessing that the lack of increase in 3 was due to poor spraying into the chamber and because it was at 90 psi, didn't feel the need to redo that cylinder. #7 and #8 got 4 squirts due to poor positioning/trying to get position into the cylinder.

After this, I did the blowdown test. I used the compression gauge and gently bumped the starter until the cylinder read pressure, putting piston at top of cylinder. I ran my compressor up to 100 psi, put the car in gear and parking brake engaged. In cylinder #1, I had no blowby/no escaping air. Thinking my pressure was too low, I ran the compressor up to 135 psi and repeated. I turned the compressor off, maintaining tank pressure.

There was no air escaping any of the cylinders. I determined this both by checking air fill pipe, exhaust pipe, carb, and valve covered area (still open). I also had absolutely no pressure leak down from my tank gauge during the test of any cylinder. I left each cylinder pressurized between 1-2 minutes.

So, tell me, did I do the blowdown test wrong? Very strange that cylinder 2 which at best, has had 40 psi wet, had no leakage whatsoever.

I stopped at this point. I'm sick and it's about 35 in my garage...very unusual here.

Thoughts and comments please.

thanks

Jeff

[Guest De Soto Frank]

Jeff,

You need to use motor oil to "seal the rings" for the "wet test"...WD-40 is too light.

The fact that there was minimal (but some) improvement in most of the readings suggests that there is some leakage past the rings.

When you feel better, repeat the test using at least 10W30 motor oil from a pump-can ( 3-4 pumps per cylinder) .

[Guest JT]

Jeff, when doing your compression test are you giving each cylinder several revolutions to read max compression?

[Guest ZondaC12]

yeah crank it several times, the reading will go up a little each time until max is reached.

ive been following this thread, its an exciting read. i dont remember if its been mentioned before, but are you sure that the battery is as its best, same with the starter motor, and that its cranking as fast as it should? also is the spark strong? when i did a compression check on my 38 buick, i just had wires sitting there by the holes, couldnt really help that, and occassionally i was startled by pops and barely visible flames coming from a couple of the plug holes--the mixture was being pumped out and the wire sparking with the block was igniting it! if that can happen that certainly with even some compression it should fire.

[Guest mena]

Hey Jeff:

As I am sure you realize, Having 20 psi compression, and no air leak down makes no sense what so ever. Assuming that all of your tests are acurate, (I BELIEVE THEY ARE) The only explanation (that I can think of) in the #2 cylinder is a bent connecting rod preventing the piston from going all he way to the top.

Did you notice if the piston was comig all the way up when the head was off.

[Guest JDHolmes]

Thanks again folks for the thoughtful responses.

When doing the compression check, the motor made at least five passes over the compression gauge. This I could see from watching the gauge.

Zonda, the battery is newer (four months old), is full, and is charged every time that I go through this thing. A few months ago, I upgraded my charger to an industrial starter/charger with 6v and 12v. Starter was the first item rebuilt about 3-4 months ago. Sometimes it seems to turn over sluggishly, but most of the time, seems normal. The spark is strong and wires are away from block at present. Previously, distributor removed, rewired, and cleaned. New parts all around for "tune-up" components. The car is slowly being rebuilt/renewed as I try and get is started

Mena, great thought! It makes ABSOLUTELY no sense to me. With no compression, one would expect air to bypass some component. I was especially very careful when doing the blow down test on this cylinder since I expected air bypass due to the low compression readings. I even used a cigarette lighter at oil filler and exhaust pipe (not carb of course) to see if the flame would flicker. No flicker. No pressure loss from tank gauge.

And yes, when the head was off, I paid particular attention to each piston because I was checking for full pressure stroke and the seating of the valves. And while I didn't measure, the depth also seemed normal.

After the tests Sunday. I pulled the carb again and blew air down each of the intake holes. The hole servicing 5-8 was certainly very clear as air/gas/oil blew out of spark plug holes. I bumped the motor around make sure that I had good flow to those cylinders. However, when I did the same to the other hole, servicing 1-4, there was a good deal of resistance, even gas blowing back up and little blowing from the spark plug holes, though there was airflow.

While this has nothing to do with the compression issues, it seems that there may be some restriction in the intake manifold to cylinders 1-4. This could explain the lack of gas on spark plugs when I did the compression tests last week where 5-8 had gas on them, but 1-4 were dry.

To recap, and tell me where I'm wrong.

Low compression indicates open valves or bad rings. However, if valves were not seated properly, or if rings could easily be bypassed by pressure, I would have noticed a definate airflow and/or loss of pressure during blow down test. Incorrect timing chain installation have resulted in the same loss of pressure due to open valves at compression.

If block was cracked to water jacket in #2, could this explain low compression? I would think yes. But would there also not be an indication of water in the oil (was drained and normal a month ago..0 miles on oil change). It seems a cracked block would also lose pressure in blow down test.

I'm just sitting here scratching my head now. I do appreciate all your help and time helping me track down this gremlin.

[Guest JT]

I think I would go ahead and pull the intake/exhaust manifold and check for a blockage.

[Guest Silverghost]

JD: I still think it is possible that 1/2 the intake could be blocked by debris or a mouse nest!!!

I doubt you have a cracked block or head... If cracked it would not show a 20 lbs compression reading...it would still be much much higher with a crack!!!

Try to clear any intake blockage and then try to FIRE IT UP again...If carb is ok...ignition system working and dist. properly indexed and timed it should start!!!

I am still not sure timing chain and sprockets are properly indexed???

Just put plugs, wires, & Dist. back and try to start this beast!!! You may have to rotate Dist. position until it fires!!!

Good Luck...Give it a shot!!!

[Guest mena]

I agree with JT.

You are not pulling air into the cylinder, therefore you have nothing to compress.

I know you don't want to pull the intake, so perhaps you can pull the carb and thread a rubber hose (1/2 inch or so)duct taped to a shop vac down the intake. Might be interesting to see what you come up with.

[Oxnard Montalvo]

Troubleshooting via cyberspace is a frustrating endeavor. I admire your willingness to consider all suggestions and ability to try, try again.

That being said, here's another two cents.

I agree with JT, at this point pulling the intake may be you next, best move.

If the intake is blocked it <span style="font-weight: bold">could</span> explain the compression readings being generally lower on one cylinder bank. If a partial vacuum is created on the intake stroke only partial compression will result on the compression stroke.

In other words ya can't compress what ya can't suck in.

An intake blockage also allows for all your other test results which point to generally sound rings and valves.

The one thing that bothers me is WHAT could create such a blockage? If it were mice I would think the compressor would have blown the nest/carcass out.

Good Luck.

[Oxnard Montalvo]

mena, you owe me a sip of coke.

[Guest mena]

Hey Oxnard

I am fairly new to the post. Why do I owe you a sip of coke

[Oxnard Montalvo]

When I was a boy, if two people said the same thing at the same time the object was to be the first to say "You owe me a sip of coke." Silly, but effective if you like coke.

Our posts said the same thing and were submitted at the same time, so dagnabit you "owe me a sip of coke."

Welcome.

[Guest JDHolmes]

Thanks guys (and gals if there were any here).

It makes sense that if it can't get air, it can't compress it, hence the lower readings on 1 and 2 certainly.

I'll try the hose trick first, just cause I really, really, really don't want to pull the manifold.

Barring success with the hose, off comes the manifold. I'll get the bolts soaking now. Bought a gallon of PB Blaster last week just to be prepared.

On another note, it's really great to have all this help and advise and a great place to come for help and fellowship (and commiseration). All of your help has made these tasks less frustrating and my mood more calm (always a good thing per my wife).

[Guest mena]

OK oxnard:

Coke it is.

I hope the vacuum trick solves the problem

[Guest mena]

Hi JD:

Is there anything new to report?

Tell me you vacuumed out a packet of hundred dollar bills.

Mena

[Guest Silverghost]

JD: I hope you have not given-up on the origional straight-8 and decided to drop-in a small block Chevy 350 and turbo-hydro 350 trans???

Do you have "THE BEAST" running yet???

The World wants to know !!!

[Guest JDHolmes]

Hehehe...Mena

I wish I had vacuumed out anything. I used several different hose diameters (3) and could never really get a satisfactory suction on a hose size that I could weave into the intake. SO........

bolts are being PB Blasted. One is loose, 2 and 3 are ... not. I didn't go past that for the time being. I do love old vehicles, but one thing is for certain...engineering wise, they leave a lot to desire. Getting a wrench on #2 and #4 intake bolts is an interesting proposition and still be able to pull/push/pound in the correct direction.

I am being gentle and taking my time...obviously...i don't want to replace bolts.

[Guest ZondaC12]

yeah...rusty bolts, our worst nightmare. just keep dousing 'em, nudge 'em from time to time. if the rust hasn't "welded" the bolts tight, they'll come out eventually.

[Guest Silverghost]

JD: Newer "Modern" cars are not any better for service!!!

In many respects they are A Nightmare!!!

In fact... They are really not built at the factory with service in mind!!!

They just want to put them together quickly!!!

A mechanic friend is always running into problems with jobs that used to be a very simple repair.

In the "Old Days" replaceing an engine belt was an easy 15-30 min job...

Today with these front wheel drives he must remove upper motor mounts, water pump & radiator hoses and many accessories...To get the belt off & on!!!

Some of these are a 3-4 hour jobs!!!

He has a very hard time explaining to one of his customers what a repacement belt cost $35 for the part and $350 for labor!!!

They think he is ripping-them-off!!!

In the past this job cost $50 Part & Labor!!!

Stick with these great old cars!!!

They are much more fun to work on yourself!!!

Ever try to replace sparkplugs on some of these new cars???

WHERE ARE THEY??? CAN YOU EVEN GET AT THEM???

I don't know what the engineers were thining???!!!( I AM an Engineer by the way!!! Among other things???)

[Guest ZondaC12]

yeah the spark plugs are way down there, and nothing's worse than those <span style="font-style: italic">plastic covers</span> over almost everything. it obvious manufacturers dont want you working on your own car now. they want you to pay them to do it.

[Guest Silverghost]

I bet those plastic covers were designed to hide the engine so you can't see what you are REALLY buying!!!

AND...How hard they are to service!!!

I Myself would rather SEE the mechanicals & design... There is NOTHING more beautiful than a great engine in all it's glory!!!

I suppose they might be ashamed of their engines!!! So...They HIDE them with Plastic!!!

As if there is not enough Plastic on new cars these days!!!

[Guest JDHolmes]

Agreed on the older vs newer vehicles. I don't buy new vehicles and try not to work on them. The "newest" vehicle I have is an 83 Ford truck. Still workable.

My wife drives a 2001 Sebring. Just hit 96000 miles and stalled out on the freeway. One shop diagnosed as cam sensor. Still under extended warranty so she took it to Chrysler. 3 weeks and $8000 she has a new motor and new heads. I NEVER touch that engine. Just looking under the hood makes my stomach turn.

And no, I'm not giving up on Herman's motor. He's staying original. He's just tooooo gooood to turn into a rod or something non-original. So...i'll just keep pecking away at it and eventually, he'll cruise down the road, of that I'm sure.

By the way, I just bought a 70 Riviera yesterday that will be another ongoing project. But that unique styling and 455 were just too much to pass up...and she's solid with only trunk lid rust for less than $1000. And I drove her home from the owners place. Needs a tune up but I can feel the power waiting under that hood. And, it may be one of the finest driving/riding automobiles I've ever been in.

Sunday will be a work day for Herman and hopefully, bolt will be off and this episode resolved.

[Guest ZondaC12]

good luck on sunday, we're all hopefull! its such a weird problem, and has take so long to diagnose! but youll be be happier than you can imagine, when that thing finally ROARS to life. nothing like the feeling you get when you get the engine running.

any chance you'd be able to make a video of it running, and post it online? (www.putfile.com is free and easy to use). you have to have a digital video camera, though, or a video capture card in your computer, so it is rather exclusive to some people unfortunately.

[Guest mena]

Hey JD

What did you find out.

Mena

[Guest JDHolmes]

Well...the saga continues....unfortunately.

Pulled the manifolds. No blockages, however, gaskets were shredded on the first four cylinders. Why? Who knows, but they were. Ordered new manifold gaskets. Cleaned out motors side with wire wheel/vacuum, cutting down on crud, cleaned manifold as much as I could reach with current tools.

Put manifold back on. There is a small gap on exhaust side (1/16 or less) of 4 and five between manifold and block. (Can see light at top when drop light below....serendipity...light fell into motor, I saw light coming through gaps.

Put the motor all back together, carb, valve covers (cleaned, primed, repainted original color, new gaskets), plugs, wires...you know the routine.

Turned the key to try and start it and CLICK.

The long and short of it, sadly, is that for whatever reason, the motor is locked up. Starter won't turn it. 160lbs (torque wrench) won't turn the crank. Pulled the starter. Can't turn the flywheel. Locked up solider than an old maid's......................

Pulled the head again. Soaked it down with Marvel's. Checked the starter for operation (yes, it works).

Funny thing I noticed however. Piston 3 at top of chamber and piston 6 at top of chamber. Others at varying degrees down. HOWEVER, valves completely closed on 1 and 2 though one valve on each cylinder should be in some state of openness.

I'm tossing in the towel so to speak. Gonna drain oil, drop the pan and start the disassembly process for rebuilding the motor. It's been down for 8 months now so I'm going to bite the bullet and rebuild it. At least then it will run and give me the chance to do all the restoration under the hood at once rather than piecemeal.