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Old 03-10-2019, 09:40 PM   #21
BillLee/Chandler, TX
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Default Re: installed a new 6:1 head now a tapping noise

Roxo, if you haven't yet pulled the pan, how could you see the sides of the pistons? On my engine, with very similar symptoms as you described, nothing was apparent until I could remove the pistons from the cylinders. And you must pull the pan (at least) to do that.
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Old 03-11-2019, 01:40 AM   #22
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Default Re: installed a new 6:1 head now a tapping noise

Roxo wrote
Quote:
One thing I did notice is there is a ridge on the top edge, on just one side of the walls on at least 2 piston cylinders (drivers side). Other side of the walls are smooth.
If you can feel with your fingertip a little stage/level on the load side of the cylinder bore at top dead center, it means that the cylinder is badly worn. Then you can also see well that the honed tracks are polished off. This is called "bore polishing". That looks nice, but it is very bad. The cylinder track must not be mirror-smooth!
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Old 03-11-2019, 09:26 AM   #23
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Default Re: installed a new 6:1 head now a tapping noise

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Originally Posted by BillLee/Chandler, TX View Post
Roxo, if you haven't yet pulled the pan, how could you see the sides of the pistons? On my engine, with very similar symptoms as you described, nothing was apparent until I could remove the pistons from the cylinders. And you must pull the pan (at least) to do that.
Your right I have not inspected the pistons themselves yet. I seen no signs of anything on the cylinder walls as I replaced the head. That does not mean I won't find wear on the pistons. I'm hoping my parts come in today so I can put things back together so I can drop the oil pan in the next few days.
I'm finding the restoration on this truck is much older then I hoped it was. I got this truck for a very good price so rebuilding the engine will not hurt me to bad.
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Old 03-11-2019, 03:35 PM   #24
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Default Re: installed a new 6:1 head now a tapping noise

Not knowing what I am talking about, but if it has adjustable valves in it, does one or more of them need adjusting??? Additional compression may have activated this click.
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Old 03-11-2019, 08:23 PM   #25
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Default Re: installed a new 6:1 head now a tapping noise

I was thinking of putting a high compression head on my car, but now I am thinking that if it is not broke, don't fix it. I live in a rural area and people are forgiving of my slow acceleration and moderate cruising speeds. The extra power sounds like fun, but it also sounds like it puts a lot more strain on the engine. My biggest problem is that I don't have overdrive and I sometimes have to cruise 50 mph for extended periods when I take longer trips to other parts of the state. My rear main is starting to leak a bit, but the old girl runs smooth, does not burn any oil and seems happy.
I guess my question is....I like all the extra HP mods, but how much engine life to I lose?
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Old 03-11-2019, 10:55 PM   #26
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Default Re: installed a new 6:1 head now a tapping noise

Sensible upgrades to a good engine can extend engine life..Higher compression means a more efficient burn,leading to less carbon buildup and longer lasting rings.Mechanical advance distributors prevent inadvertent detonation,one of the main causes of main bearing failure.The model a ford is under carbureted,it starves for fuel,a single down draft,like a stromberg 97,matches the CFM flow of the A engine spot on.Its easy to dump thousands of dollars 'hopping up' a model a engine,it some of the most expensive horsepower you can buy. Getting the engine up to 70 hp or so isn't that expensive,nor that detrimental to the engine health.Building up to 120 hp,using overhead valve conversions,B engine blocks reworked and all the goodies can run in excess of 15k..

No performance upgrade will help a tired engine,other than to accelerate the wear.
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Old 03-12-2019, 06:57 AM   #27
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Default Re: installed a new 6:1 head now a tapping noise

Of course, it's not that easy!


Every engine power means more or less wear, never without. If the power is increased, so is the wear higher. But unfortunately not linear, but squared. (Multiplicator²).
Increasing the compression increases the efficiency of the fuel combustion. But at least two factors are very important for this:

Combustion pressure increases the combustion temperature in the combustion chamber.

Much more serious, however, is the higher load on the crankshaft and connecting rod bearings. This can easily be calculated on the surface of the piston head surface Pressure : cm² / inch² and the increase in compression and the working pressure.

Increasing from 4 to 5 bar / cm² gives about 50% more pressure on the sliding bearing surfaces.
Since the A motor has no pressure circulation lubrication, the crankshaft bearings are quickly at the limit and overloaded, the wear increases disproportionately!

If it was my engine, I would not make an increase in performance. A revised engine with modern bearing tolerance and optimized material pairing yes. But not with an aged engine with an unknown life.
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Old 03-12-2019, 08:03 AM   #28
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Default Re: installed a new 6:1 head now a tapping noise

Babbit has been used in diesel engines developing up to 400psi compression pressure.Properly clearanced main bearings with gravity feed systems will stand the 50% increase in compression pressure,especially with modern engine oils shear and load additives.You have to insure the engine is assembled and machined correctly and be sensible in the upgrades.

Ford designed a head for police application in 1931,with a 25% increase in compression pressure,public demand led to it being sold by dealers. Weiand,Winfield and many others offered high compression heads to meet demand.The engine has proven to be robust enough to handle upgrading.

Countless model a owners today use high compression heads without issue,and enjoy the increase in performance.Its is that easy....
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Old 03-12-2019, 08:30 AM   #29
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Default Re: installed a new 6:1 head now a tapping noise

Roxio - sorry if this thread is getting hijacked, the info is very interesting though.


bdbutton- I agree with Warner's last paragraph.


"If it was my engine, I would not make an increase in performance. A revised engine with modern bearing tolerance and optimized material pairing yes. But not with an aged engine with an unknown life."


Opinion from an armchair mechanic with little actual experience - after talking with a couple of engine builders and restorers I am a firm believer that fixing/upgrading things piecemeal is asking for issues. A system wears and is designed as a system, not as individual components. Updating/improving one part may show a weakness in another part of a system. Most I talked to did not want to, or would not do a valve job without completely rebuilding my motor. Their view was that they had to many jobs come back at them when doing partial jobs, resulting in dissatisfied customers even though the customers were forewarned.


Somewhere recently I read an article/post where someone had actually used a dyno and measured results of using different heads and carburetors. Wish I could find it.
His data showed improving carburetion clearly increased power more than higher compression heads. The data supports Railcarmovers post above. However again, doing so on a worn out motor may be asking for problems.


I will let others chime in if they agree or disagree since I have no 1st hand experience, and am just passing on what I have read, and passing on some info from professional mechanics.
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Old 03-12-2019, 08:38 AM   #30
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Default Re: installed a new 6:1 head now a tapping noise

Dyno sheets? Piriano posted them up..

http://www.modelaparts.net/dynosheet...ynosheets.html
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Old 03-12-2019, 08:42 AM   #31
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Default Re: installed a new 6:1 head now a tapping noise

Dennis Piranio in Tx has done quite a bit of dyno work and published it

http://www.modelaparts.net/

IMHO, just slapping a HC head on any old motor is asking for trouble.
Without some idea of the bottom end condition you can be easily doubling the loading on the bearings (which are marginal at best). Also, there is a tendency to run the motor at higher speeds once the power output is increased. I will stop here.

Can it be done, sure, but be smart about it. John
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Old 03-12-2019, 08:53 AM   #32
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Default Re: installed a new 6:1 head now a tapping noise

This is the info I saw, however thought I had seen a summary of the testing where the conclusion of the testing was to improve airflow/carburation, and there was more testing wanting to be performed. Maybe it is on the link, but can not seem to find it.
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Old 03-12-2019, 09:49 AM   #33
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Default Re: installed a new 6:1 head now a tapping noise

If you listen very closely you will hear a double-tap if it's a loose or slapping piston, as it changes direction at top of stroke.
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Old 03-12-2019, 03:52 PM   #34
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Default Re: installed a new 6:1 head now a tapping noise

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Originally Posted by 30 Closed Cab PU View Post
This is the info I saw, however thought I had seen a summary of the testing where the conclusion of the testing was to improve airflow/carburation, and there was more testing wanting to be performed. Maybe it is on the link, but can not seem to find it.

So here is the info I saw from a previous post, may have confused what I thought about carburation improvements being best.


Post 18 is to the point, buts lots of views/info spread throughout this string.


https://www.fordbarn.com/forum/showt...head+test+data
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Old 03-12-2019, 05:30 PM   #35
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Default Re: installed a new 6:1 head now a tapping noise

The best blend is an improvement in all areas,head,cam carb and exhaust..each area aides the effect of the other.

Good rules of thumb in my opinion,your views may vary..

keep compression at 7 to 1 or under

two updraft carbs better than one updraft carb,one downdraft carb better than two updraft carbs

the more cam lift the better,stock B at .319 measured lift,way better than stock A at .287 measured..B cam has a better profile as well.

Stock exhaust manifold breathes well,header breathes great...open..but you'll wake the dead,almost all the header gain is lost with a resonator.

mechanical advance distributor insures accurate timing at all rpm ranges,and avoid damaging 'ping' the killer of main bearings
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Old 03-12-2019, 10:54 PM   #36
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Default Re: installed a new 6:1 head now a tapping noise

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Originally Posted by steve s View Post
If you listen very closely you will hear a double-tap if it's a loose or slapping piston, as it changes direction at top of stroke.
It's a single tap. I did listen for a double tap. I'm planning on digging deep into the engine next week after I get things put back together. Again I'm waiting on more parts.
I will let you guys know what I find.
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Old 03-13-2019, 09:13 AM   #37
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Default Re: installed a new 6:1 head now a tapping noise

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It's a single tap. I did listen for a double tap. I'm planning on digging deep into the engine next week after I get things put back together. Again I'm waiting on more parts.
I will let you guys know what I find.
If noise started after head swap, digging "deep" may not be answer. Problem is probably "shallow". Head or gasket or plug hitting piston.
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Old 03-13-2019, 11:42 PM   #38
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Default Re: installed a new 6:1 head now a tapping noise

I keep hearing about the deadly ping that will ruin my bearings if I don't have a mechanical advance on my distributer. I retard my timing to start. I only advance it about half way when I am idling and running around town or climbing hills and I only pull it all the way down when I am running 40+MPH. Am I doing enough to avoid the ping that will ruin my bearings or should I just get a mechanical advance for my distributer?
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Old 03-14-2019, 10:36 AM   #39
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Default Re: installed a new 6:1 head now a tapping noise

Before you drop the pan, pull the head and have a look see.
Paul in CT
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Old 03-14-2019, 10:54 AM   #40
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Default Re: installed a new 6:1 head now a tapping noise

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Originally Posted by bdtutton View Post
I keep hearing about the deadly ping that will ruin my bearings if I don't have a mechanical advance on my distributer. I retard my timing to start. I only advance it about half way when I am idling and running around town or climbing hills and I only pull it all the way down when I am running 40+MPH. Am I doing enough to avoid the ping that will ruin my bearings or should I just get a mechanical advance for my distributer?
Are you running a stock compression Head? If yes what you are doing is OK.
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