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RAV was right, Compression, call me stupid & ?s
Posted by: Mark M ()
Date: February 08, 2009 05:11PM

Couple weeks ago I posted a You tube link to my running engine. [www.youtube.com]

Although it sounds great and revs well, RAV_AIR caught the hesitation. He was right, no accelerator circuit on the right side. Fixed that.

Bought a cheap compression tester at Harbor: here are the results. Ran dry twice, then oil squirt. Throttle wide open, engine warm, plugs all out. Numbers are dry/oil squirt

#1 60/65
#2 115/120
#3 115/130
#4 115/120
#5 60/75
#6 115/120

Hmmm, even I know something's not good about 1 and 5, both on same side. Fire it up, running fine, no knocking, still a chirp from somewhere - not the belt for sure - almost sounds like it's from the HB, but not sure. I pull plug wires one at a time, spark is great, but I can pull all three of right bank and nothing changes. Pull each one on left and idle drops. Look in right carb, rev engine - accelerator pump works, but nothing from the venturi. DOH! Guess I never was running on the right side. Amazing how well these things will run on 3 cylinders!!!

Okay, stop shaking your head and help me with the compression numbers. And what's chirping? it's a high pitch and goes away when I bring RPMs up. Loose head on right side that's also causing low compression on 1 & 5?

Mark

Mark M
Project: 64 Spyder Vert running 80 hp heads and carbs
1st Vair: 65 Corsa 140
St. Louis, MO
Show Me Corvair Club &
CORSA member

"If it's not broken, you're not driving it hard enough"

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Re: Low Compression / Chirping
Posted by: MattNall ()
Date: February 08, 2009 05:14PM

Most likely leaking head gaskets..

O Pull the rockers on that side and retorque to 32 ft lb...

Then retest compression...

No improvement? pull that head and lap the valve... no need to grind them..

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Re: RAV was right, Compression, call me stupid & ?s
Posted by: RAV_AIR ()
Date: February 08, 2009 05:18PM

it's too bad St Louis is 5-7 hours from me or I'd come down there and help you out.

I'm happy that I was right about something not being right though. Only cause I don't get the chance to know some shit very often. lol.

Could be valves adjusted too tightly on 1 and 5 and not letting them seat all the way. that would cause your numbers not to go up much even with the oil test-which i notice they didn't.

pull the valve cover and check JUST those cylinders' valve adjustment per what the book says on crank placement..

"So where do they put the engines in these things?"
"They put em where they belong....in the rear."
1964 500 coupe
Topeka, KS
Searching for a complete 95 to rebuild. (changed my mind)
If this is still in my sig, I'm still looking.
Moderator

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Re: RAV was right, Compression, call me stupid & ?s
Posted by: Mark M ()
Date: February 08, 2009 06:29PM

Matt,

Would a leaky head gasket cause only two of the cylinders to read low? Should I try re-adjustin valves first as RAV suggests? That's what I was going to try.

If I do pull the head, do I re-torque all head bolts or just the ones at the rockers?

Mark M
Project: 64 Spyder Vert running 80 hp heads and carbs
1st Vair: 65 Corsa 140
St. Louis, MO
Show Me Corvair Club &
CORSA member

"If it's not broken, you're not driving it hard enough"

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Re: RAV was right, Compression, call me stupid & ?s
Posted by: Anonymous User ()
Date: February 08, 2009 06:38PM

2nd the leaky gaskets, mine sounded like a chirping bird till I retorqued. Only did it under load though, at first I thought it was detonation.

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Re: RAV was right, Compression, call me stupid & ?s
Posted by: MattNall ()
Date: February 08, 2009 06:41PM

Head gaskets whistle!!!! YES could be the two end holes leaking

1 Do as Ravvy sez... on Cyl. #1 & 5 back off both rockers 1/4 turn CCW

Then retest...

IF it doesn't come up at all.... then retorque, otherwise back the 4 off 1/8 turn more and retest, etc.. until it stops rising.

When retorquing... remove ALL 6 rockers... lube UPPER STUDS!!!

Then retorque working in a circle from the center out. ALL 12 !!

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Re: RAV was right, Compression, call me stupid & ?s
Posted by: ScottS ()
Date: February 08, 2009 06:46PM

Would a leaky head gasket cause only two of the cylinders to read low? Should I try re-adjustin valves first as RAV suggests? That's what I was going to try.

If I do pull the head, do I re-torque all head bolts or just the ones at the rockers?

Mark= your fisrt question, I understand why you ask- the cylinders have individual gaskets , top and bottom,

I would adjust the valves on the low cylinders first as everyone has suggested -

If that deosn't help- re-read matts post- I would not try to torque the heads until all the nuts/studs are freed up or you run the risk of pullinc a cyl stud out of the block-keep in mind the rocker studs are also head bolts-

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Re: RAV was right, Compression, call me stupid & ?s
Posted by: Mark M ()
Date: February 09, 2009 07:06AM

MattNall Wrote:
-------------------------------------------------------

>
> When retorquing... remove ALL 6 rockers...
> lube UPPER STUDS!!!
>

Is this a job for PB Blaster? Can I shoot the studs and retorque, or let it sit a couple hours?

Mark

Mark M
Project: 64 Spyder Vert running 80 hp heads and carbs
1st Vair: 65 Corsa 140
St. Louis, MO
Show Me Corvair Club &
CORSA member

"If it's not broken, you're not driving it hard enough"

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Re: RAV was right, Compression, call me stupid & ?s
Posted by: MattNall ()
Date: February 09, 2009 07:23AM

PB Blaster is fine... shoot them then let set for a couple of hours.

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Re: RAV was right, Compression, call me stupid & ?s
Posted by: Mark M ()
Date: February 14, 2009 04:00PM

Worked on the car today and followed advice from this thread. Backed off rocker nuts on cylinders 1 and 5, got both up to about 90. Compression on all other cylinders is about 120 - 125. I also had a chirping that could be a loose head. Decided to do a cold adjust on both sides and torque all the head nuts and studs. What the heck, I need to learn how anyway.

Rockers, nuts, balls and rods all look very good. Couldn't check lifter end of the ones on the right because the muffler was in the way. Three of the rocker studs on the left pulled out when I tried to loosen the rocker nut, but I got them back in. used zero lash plus 1/2 turn on valves.

Torqued all head nuts and rocker studs to 30 ft lbs per advice on a related thread. Pulled all plugs on right side - too tired to pull all of them - center hole still 120, #1 still 90, #5 up to 100. Chirping is definitely #5. With compression gauge in that hole I get the chirp, when testing other holes and plug out of 5, no chirp. Checked one hole on left and compression is 125. So, lots of work, not much change.

Let me know what you think of these next steps.
1. Back off 1 and 5 to see if there is improvement - maybe I got overzealous on the 1/2 turn or zero lash, but I think not.
2. Seems like some of the head nuts were already at torque when I wrenched them. Could they have been tight from rust and not really at torque? A couple seemed very tight and I didn't want to pull a head stud out so I backed them off a little before torquing them. I could pull the right side again, pull the nuts off, loosen the studs and retorque.

If I need to replace head gaskets and/or lap valves can I pull the head easily with the engine in the car? I'd rather not pull the engine until I can test to see if I have a clutch.

Let me know.

Mark

Mark M
Project: 64 Spyder Vert running 80 hp heads and carbs
1st Vair: 65 Corsa 140
St. Louis, MO
Show Me Corvair Club &
CORSA member

"If it's not broken, you're not driving it hard enough"

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Re: RAV was right, Compression, call me stupid & ?s
Posted by: RAV_AIR ()
Date: February 14, 2009 04:16PM

all you have to do to pull a head is pull off your exhaust and take off the rear motor mount, then lower the back of the engine. it helps if the back of the car is also on jackstands.

I don't know what else to tell you. head gaskets and maybe the spark plug isn't seating? has to be air.

"So where do they put the engines in these things?"
"They put em where they belong....in the rear."
1964 500 coupe
Topeka, KS
Searching for a complete 95 to rebuild. (changed my mind)
If this is still in my sig, I'm still looking.
Moderator

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Re: RAV was right, Compression, call me stupid & ?s
Posted by: MattNall ()
Date: February 14, 2009 04:18PM

Yes, a head can be pulled in the car. Carb stud is the only thing that needs to be removed for ease..

The too tight nuts may just be [ close" but over by 1 or 2 ft .lb. ]

I'd forget the 2-4-6 head..

Back off the rockers on 1 and 5... retest... if still low and of course because of the chiping... pull that head...

To TEST Valve seat condition... with GASOLINE

Head stripped of carb and exhaust manifold.

Set with exhaust tubes facing up..

Pour a few ounces in each tube... holding head steady.. look at valves... any seepage? a gusher?

Now rotate the head so the intake is up... pour several ounces in carb base port.. Look at intakes... same scenario...

IF no valves are Cracked / Warped / Burnt away... you can LAP them.

Buy a small tin of Lapping compound at your flaps... it has coarse and fine grits

Remove valve spring... inspect valveface , stem / guide condion for obvious problems...

If OK coat seat with Coarse grit... slip valve in guide.

Old school says to got CCW the CW, etc... I just chuck in a drill and spin at low rpm for 1 minute...

Then remove valve.. inspect face to see if it is SHINEY all the way around...

If not repeat...

Then go to FINE....2 times... re-assemble and Check with gasoline [ after all 6 valves are done...



Edited 1 time(s). Last edit at 02/14/2009 04:21PM by MattNall.

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Re: RAV was right, Compression, call me stupid & ?s
Posted by: Mark M ()
Date: February 14, 2009 04:35PM

I was afraid you were gonna' say somethin' like that. Oh well, I bought this car for two reasons - to have a sweet ride and to learn all the things I've always wanted to know.

Sure wish super-glue would work.

Thanks

Mark M
Project: 64 Spyder Vert running 80 hp heads and carbs
1st Vair: 65 Corsa 140
St. Louis, MO
Show Me Corvair Club &
CORSA member

"If it's not broken, you're not driving it hard enough"

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Re: RAV was right, Compression, call me stupid & ?s
Posted by: RAV_AIR ()
Date: February 14, 2009 04:55PM

>Sure wish super-glue would work<

Yeah, really. dropped a valve seat? super-glue it. broken piston? super-glue it. broke a fan belt... super-glue it!

lol!

"So where do they put the engines in these things?"
"They put em where they belong....in the rear."
1964 500 coupe
Topeka, KS
Searching for a complete 95 to rebuild. (changed my mind)
If this is still in my sig, I'm still looking.
Moderator

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Re: RAV was right, Compression, call me stupid & ?s
Posted by: vaporloc ()
Date: February 14, 2009 06:35PM

Hi Mark.. I went out and pulled the plugs out of the 65 140 Corsa vert. I bought. Just to see what kind of compression it had after I read your post.. Well my compression gauge is made by Amflo.. It only goes to 160 PSI.. All 6 jugs run the gauge out of numbers. (tested cold).. It put the gauge on the A where is say's AMFLO.. I was wondering if it is opposite of yours and it is too high?? Maybe loose rocker arms. It does clatter for about 5 or 6 minutes until it warms up.. I was told the engine was rebuilt before I bought it.. Hardly driven after that..

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Re: RAV was right, Compression, call me stupid & ?s
Posted by: Mark M ()
Date: February 14, 2009 08:31PM

Jerry,

Mine is a cheap one from Harbor Freight and I suspect it may read a little low. The three cylinders that are running are very smooth and I get no smoke out of the tailpipe, readings on those are consistent and about 120 - 125.

It is the kind that screws in and never seems like it gets really tight.

Mark M
Project: 64 Spyder Vert running 80 hp heads and carbs
1st Vair: 65 Corsa 140
St. Louis, MO
Show Me Corvair Club &
CORSA member

"If it's not broken, you're not driving it hard enough"

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Re: RAV was right, Compression, call me stupid & ?s
Posted by: Tom Z ()
Date: February 15, 2009 04:11AM

..Mark,is this the '64 turbo project',with 95/110 carbs instead of turbo? the right head may be warped..btw,on every engine build I chase all fasteners/holes with proper CHASER nut-not a die- and tap for water-pumper blocks,,threads all screw by hand,drop of oil on threads (unless sealant is required)..with the head off,hold a flat straight edge across the jugs gasket surface,too..

Tom Z,,Rochester NY

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Re: RAV was right, Compression, call me stupid & ?s
Posted by: Mark M ()
Date: February 15, 2009 06:06AM

Tom,

Yes, that's the car - heads are 62-63 80 - 84 hp. Thanks for the tip on threads, I did read that rocker studs get anti-seeze. I thought about the head being warped and hope it is not. My plan was to get the car driving with this engine and work on the body while I drive and enjoy.

Mark M
Project: 64 Spyder Vert running 80 hp heads and carbs
1st Vair: 65 Corsa 140
St. Louis, MO
Show Me Corvair Club &
CORSA member

"If it's not broken, you're not driving it hard enough"

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Re: RAV was right, Compression, call me stupid & ?s
Posted by: cnicol ()
Date: February 15, 2009 09:39AM

Just put a bee in your bonnet... The comment about having three studs unscrew leads me to add that the studs are in interference fit. If they get unscrewed, you need to verify that it takes a high-enough torque when they go back in. If there's insufficient torque, the studs will pull out when the engine warms up or maybe even when you are torquing the head. There were over size studs (some still around) and if it's close, I've used Loctite's "Stud and bearing mount" on the threads successfully. Also note when you put a stud back in, the depth is critical. Not enough and the stud may pull out, too much (all it takes is two threads) and certain studs will contact a connecting rod as it spins inside. Judge depth by using a straight edge across the other studs. In your case, since the nut was on the stud, depth should be fine. The whistle means that you car's engine needs a mate! I agree with RAV, head gasket or spark plug seat.

The head in the picture had a whistle too. See head gasket at right.

Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
61 Seamist Jade Rampside 140 PG
60 Monza coupe (sold, sniff sniff)
66 Sprint Corsa convt - First car! Re-purchased 43 years later
2+2 gnatsuM 5691

+17 Tons of parts

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Re: RAV was right, Compression, call me stupid & ?s
Posted by: Mark M ()
Date: February 15, 2009 06:18PM

Thanks everyone,

Craig, the nuts that go on the upper head studs were fine - nothing pulled out. It was the rocker studs that came out when I was taking the rocker nuts off - and that was on the good side of the engine. Little work to get a couple to go back in since the studs weren't quite in the center of the hole - I'm guessing that's a common predicament since they are so long and flex.

I'm going to back off on 1 and 5 to see if I get improvement, but either way I will have to deal with the chirp. If compression improves maybe I'll try to go to 32 lbs torque and see if I can kill the chirp, but no one has suggested that idea. Hope it's just a gasket, like yours.

Don't quite understand how to hold a straightedge on the head surface since the gaskets fit down in the combustion chambers, but maybe it will make more sense when I try it. I have the turbo heads and seems like the face of the head is not smooth enough to tell if it is warped.

Never pulled a head before so this will be an adventure.

Can you replace a spark plug seat?

Mark M
Project: 64 Spyder Vert running 80 hp heads and carbs
1st Vair: 65 Corsa 140
St. Louis, MO
Show Me Corvair Club &
CORSA member

"If it's not broken, you're not driving it hard enough"

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