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Joined: Aug 2004
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Shade Tree Mechanic
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OP
Shade Tree Mechanic
Joined: Aug 2004
Posts: 72 |
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Joined: Dec 2001
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Technical Advisor ChatMaster - 10,000
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Technical Advisor ChatMaster - 10,000
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I hope I am not reading your post correct. Not at all surprised you have head gasket problems based on the test you did for me with the single spark plug. so the next step is to sand the block flat You are headed for big problems if you actually perform the operation stated. First: Take the HEAD to a machine shop and have IT measured for warpage. If it is the dirty bird it can be shaved, if enough metal is left. DON'T TRY TO SAND THE BLOCK, ESPECIALLY IN THE CAR. If you are knowledgeable as to how to measure the block and find it is not straight, it must be removed from the car, disassembled, and shaved by a milling machine. 
RAY Chevradioman http://www.vccacolumbiariverregion.org/1925 Superior K Roadster 1928 Convertible, Sport, Cabriolet 1933 Eagle, Coupe 1941 Master Deluxe 5-Passenger Coupe 1950 Styleline Deluxe 4-Door Sedan 1950 Styleline Deluxe Convertible 2002 Pontiac, Montana, Passenger Van 2014 Impala, 4-Door Sedan, White Diamond, LTZ 2017 Silverado, Double Cab, Z71, 4X4, White, Standard Bed, LTZ If you need a shoulder to cry on, pull off to the side of the road. Death is the number 1 killer in the world.
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Joined: Nov 2001
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Tech Advisor ChatMaster - 25,000
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Tech Advisor ChatMaster - 25,000
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The Mangy Old Mutt
"If It's Not Junk.....It's Not Treasure!"
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Joined: May 2002
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ChatMaster - 6,000
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ChatMaster - 6,000
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Richard
I most definitely agree with Ray and Skip. The block needs to be completely bare or you will never get all the shavings out of the oil galleries, ring grooves or any other crevice there may be.
The head can be done with valves in but is hard to get properly clean though.
If the block is .002 or more off straight definitely strip and machine both. While its apart check bores for ovality and taper, if suspect fix it with NEW parts. I would also check crankshaft and bearings as well. A lot of work but you shouldn't need to do it again.
Do it proper the first time, it is much easier and cheaper.
Tony
1938 1/2 ton Hope to drive it before I retire
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Joined: Aug 2004
Posts: 72
Shade Tree Mechanic
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OP
Shade Tree Mechanic
Joined: Aug 2004
Posts: 72 |
Yes, I agree with everyone, I'm going to pull the motor and take it to the machine shop, evidentally it wass't done properly the first time around...Thanks...,Richard
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Joined: Dec 2002
Posts: 689
Oil Can Mechanic
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Oil Can Mechanic
Joined: Dec 2002
Posts: 689 |
All:
I'd like to learn just how much distortion or warpage is acceptable for both the head and block. I just checked my 'spare' late-model '35 head and I can see a little daylight under my straight edge in the middle cylinders...maybe a few thousandths. Is there a different tolerance for head vs. block? Does the head gasket compensate for slight differences in the head and block being out of plane?
Thanks in advance for your input!
Coach
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ChatMaster - 25,000
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ChatMaster - 25,000
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With modern cars they allow up to about .002"...lay the straight edge on the flat surface (there are special straight edges made for that use) and slip a feeler gauge thru the space to measure.The older head gaskets were quite thick and forgivingI prefer the old solid asbestos type (black gaskets used in production) rather than the copper outter. asbestos filled gaskets.The head usually will have more warpage than the block but after 70 years of abuse anything is possible.
Gene Schneider
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Joined: Aug 2004
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Shade Tree Mechanic
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OP
Shade Tree Mechanic
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Posts: 72 |
Hi Coachhill, My manual says no more than .003 gap.( with a straight edge) My block was .006 Richard
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Joined: Dec 2002
Posts: 689
Oil Can Mechanic
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Oil Can Mechanic
Joined: Dec 2002
Posts: 689 |
I checked both the head and the block with 2 different straightedges (both sides of each) and found the block to be nearly dead flat. The spare head is about .003" to .005", depending on my being able to hold the straightedge in one hand and a feeler gauge in the other at the same time. I need to clean it a little better and scrape of the remaining gunk to get a better read on it.
I wonder if the old cast iron 'gives' a little when you torque down the head bolts. Any chance it could flatten out a bit? Maybe just a thou or two?
Coach
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Joined: Jan 2002
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ChatMaster - 25,000
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ChatMaster - 25,000
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I would't be afraid to use that head.I am sure millions of heads with that warpage were used over the years with no problems.
Yes, the casting will flex a bit.Even the block can flex if head bolts are tightened too tight -.The bolts around the cylinders can cause the bores to become distorted also.
Gene Schneider
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Joined: Dec 2002
Posts: 689
Oil Can Mechanic
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Oil Can Mechanic
Joined: Dec 2002
Posts: 689 |
Thanks Gene. This particular "spare" head was on the car when I got it 30+ years ago. It ran fine and when I pulled it off the gasket showed no signs of damage.
Coach
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Joined: May 2002
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ChatMaster - 6,000
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ChatMaster - 6,000
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I dont use heads with more than .002 warpage (6 cyl or .0015 for 4 cyl) as I have seen too many leak with less especially if there is ANY warpage in the block.
Gene is right about overtightened head bolts warping the block and distorting bores, in extreme cases can cause engine to lock up.
Coachill
Get that head machined and save yourself hassles if you need to use it later.
Tony
1938 1/2 ton Hope to drive it before I retire
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