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Old 10-19-2018, 11:14 AM   #21
Jim Brierley
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Default Re: Honing Cylinders

.003" is not enough clearance, period!
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Old 10-19-2018, 12:24 PM   #22
Badpuppy
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Default Re: Honing Cylinders

Good radiator info here -
http://www.motormayhem.net/model-a-f...ooling-system/

If you have a 2-row radiator, scrap it. Otherwise check flow rate before you spend the rent money on a new one.
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Old 10-19-2018, 12:42 PM   #23
BRENT in 10-uh-C
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Default Re: Honing Cylinders

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Quote:
Originally Posted by Badpuppy View Post
Good radiator info here -
http://www.motormayhem.net/model-a-f...ooling-system/

If you have a 2-row radiator, scrap it. Otherwise check flow rate before you spend the rent money on a new one.

Believe what you wish but that site is full of bad information IMO. It mentions using a 50/50 mixture of antifreeze to raise the boiling point. That is fine in a pressurized system but all of the antifreeze mfgs will tell you that their mixture needs to be pressurized to actually raise the boiling point over straight water.


Next, it mentions a lower radiator hose is leaking and suggests that the hose needs to be replaced. How does the advisor know whether the leak is at the radiator outlet pipe or the radiator connector?


It also mentions he thinks the coolant temperature should be 190°. It appears this is someone who has compiled a website based off of information from someone else and not from actual first-hand experience.


I will also tell you that a two-row radiator will cool a Model-A engine in average driving conditions. With most high-compression heads, you actually increase the water capacity because the chamber roof is lowered. Most bad reps that the two-tube radiators get is because the fins have detached from the tubes due to vibrations and work-hardening of the fins. The only advantage a three-row has in this scenario is there is additional fins to help dissipate the heat.


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Old 10-19-2018, 02:11 PM   #24
Dave in MN
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Default Re: Honing Cylinders

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Originally Posted by Jim Brierley View Post
.003" is not enough clearance, period!
I totally agree with Jim! If you plan to use solid skirt pistons. (Like Snyder's and most other national vendors supply.)

Measured from actual piston size to actual bore with an accurate bore gauge, as Brent suggests in an earlier post, the clearance should be no less than .0035" from the widest portion of the piston and the rear cylinder would be better if it were a couple tenths more. If you plan to run hard occasionally, .004" clearance on all cylinders would be better. The rear cylinder is almost always the first one to seize when there is not enough clearance. The "Siamese" portion of the cylinders is the next likely area to seize as your engine exhibits. This narrow area between the cylinders is a hot spot in the walls.

The required clearance should be developed using only a rigid hone. Any hone other than a rigid hone will not give you a true cylinder and then it is important to know how to operate the hone. The dollars you plan to invest in a hone would be better spent at a competent engine shop. Let them get it right for you.

I can show you additional pistons that were installed with .003" clearance. They are stacked on a window sill where I maintain a "Bad Practices" wall of shame. If you need to see them, I will post some photos.

I know it is often hard to determine what advice you should ignore and what advice you should take from an open forum.
My advice as to determine which to follow in this case is to pay attention to the gents that build engines.
Jim Brierley has built lots of performance and general service engines.
Brent Terry has lots of experience with engines.
I have built over 180 engines in the past ten years and repaired a number of others that were not completed correct, including some with too little clearance between the pistons and cylinder walls.
Hope your project goes well. Good Day!
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Old 10-19-2018, 02:31 PM   #25
30 Closed Cab PU
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Default Re: Honing Cylinders

Quote:
Originally Posted by Badpuppy View Post
Good radiator info here -
http://www.motormayhem.net/model-a-f...ooling-system/

If you have a 2-row radiator, scrap it. Otherwise check flow rate before you spend the rent money on a new one.

The only good 2 row is if it is a Brassworks.
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Old 10-21-2018, 03:12 PM   #26
Dodge
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Default Re: Honing Cylinders

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I think you should take the engine out of the car and tear it down. Take to a machine shop with proper honing equipment and do it right. If the engine is apart you can lay it on its side and use muriatic acid to eat the aluminum away. DON’T get it anywhere near the Babbitt or it will remove that for you also. The aluminum will be so hard and stuck so well to the cylinder walls you may damage the cylinder walls trying to scrape it off with anything else.
Just trying to hone it off is not a good idea for the stones or the cylinder wall either. As Brent has stated it could make the bore egg shaped.
My 2 cents
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Old 10-22-2018, 04:01 PM   #27
Patrick L.
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Default Re: Honing Cylinders

I too would recommend that the engine go to a reputable engine shop. They may want to first bore the engine just enough to true and clean the bores then hone. Like in #4, I still like to add a bit more clearance. Better a bit loose than a bit tight. If they don't assemble the engine for you, then clean, clean and clean again with warm soapy water.
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Old 10-23-2018, 03:35 PM   #28
Dan McEachern
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Default Re: Honing Cylinders

You can remove the galled aluminum using hardware store muratic acid and a qtip- this will not hurt the cylinder wall. Or you can hone it off with a rigid hone. Comments regarding wall clearance are all good- .0035 is probably as tight as I would be comfortable with.
No one mentioned checking the ring gap unless I missed it. Probably not the issue but worth checking.
To measure the piston skirt, do it 90 degrees to the pin and probably half way between the bottom of the skirt and the pin would be a good starting point. Be aware that the skirts are not round and are smaller parallel to the pin. Hope this helps.
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Old 10-23-2018, 04:45 PM   #29
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Default Re: Honing Cylinders

Good to see Dan chime in. Excellent advice.
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Old 10-23-2018, 06:19 PM   #30
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Default Re: Honing Cylinders

Muriatic acid does not dissolve aluminum. Lye (sodium hydroxide) does. Muriatic acid does etch iron and steel. It removes the aluminum by dissolving a thin layer of iron underneath it that it is stuck to. If you just want to remove the aluminum, use lye. Drano is lye. Be careful with either one.
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Old 10-24-2018, 11:57 AM   #31
G_Don
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Default Re: Honing Cylinders

I'm going to try those acids to see if it gets rid of the aluminum. I'm ordering pistons today and will hopefully get them by Friday so I can do this all over the weekend.

Going to borrow a set of bore gauges, a mic and a hone from work. I'll be sure to keep you all posted when I start honing the cylinders.

Thanks again for all your help!
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Old 10-24-2018, 11:26 PM   #32
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Default Re: Honing Cylinders

Just the fumes from muriatic acid will rust your block and cam, and anything within 10 feet of it. I wouldn't get that acid anywhere close to your engine.
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Old 11-03-2018, 05:34 AM   #33
G_Don
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Default Re: Honing Cylinders

I took measurements on the first two cylinders with a dial bore gauge and mic set to 3.955". Hope the way I laid it out is clear.

Cylinder 1: top
3/9 oclock: 3.9551"
12/6oclock: 3.9562"
10/5oclock: 3.9552"
2/8oclock: 3.9566"

Cylinder 1: bottom
3/9 oclock: 3.9557"
12/6oclock: 3.9562"
10/5oclock: 3.9565"
2/8oclock: 3.9554"

Cylinder 2: top
3/9 oclock: 3.9545"
12/6oclock: 3.9555"
10/5oclock: 3.9552"
2/8oclock: 3.9552"

Cylinder 2: bottom
3/9 oclock: 3.9548"
12/6oclock: 3.9558"
10/5oclock: 3.9562"
2/8oclock: 3.9553"

The pistons I bought from snyders measure 3.952" using a mic.

I purchased a lisle rigid 4 stone cylinder hone which came with stones of 80,180 and 280. I purchased a 500 grit stone separately.

My question is that it seems as though the cylinders arent very cylindrical. Im assuming a taper of 0.001" and being out of round approximately 0.001" is not acceptable? I'm on the verge of 0.004" clearance total (clearance is measured diametrically and not radially, correct?).

Would using a 500 grit cylinder hone be take out too much material? Do the measuremnets I took seem like the block needs to be rebored out to a 0.100", as honing wouldnt be enough to correct the 0.001" taper and out of round?

Thanks for your help
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Old 11-03-2018, 05:48 AM   #34
Tom Wesenberg
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Default Re: Honing Cylinders

I wouldn't worry about .001" out of round.
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Old 11-03-2018, 09:07 AM   #35
Patrick L.
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Default Re: Honing Cylinders

If I understand your numbers, they seem good. Remember the cross-hatch should be as close to 45º [ 20-30º from horizontal] as possible. My thought is that 500 grit is getting pretty fine. I can't recall using any more than 400. Remember to wash,wash,wash with hot soapy water several times, dry and flush walls with ATF until ready for assembly.
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Old 11-03-2018, 01:40 PM   #36
Kurt in NJ
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Default Re: Honing Cylinders

Take a piece of piston ring, about 1/3, use it at an angle as a scraper to remove the aluminum deposits

There will be a lot of debris from honing ---take the engine apart to clean, you won't be able to get what lodges in the webs without removing the crankshaft---and it will be hard to make a full stroke with the hone with the crankshaft in the way

make a stop for the hone so it doesn't catch on anything and the bottom of the stroke--I have a block of wood

make a lot of measurements as you hone to know how taper is going so you can dwell in the small areas
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