POLL: The one that really matters

Terry,

I had (have) the same moderate concern about bearing loads. My roadster had newly-babbitted rods installed during a rebuild about 25 years and 6500 miles ago. About 2000 miles ago, I had a Snyder 5.5 head put on. The increase in power and performance was noticeable. 'Loved it! Then, a couple of months ago I began to hear a tapping/knocking sound. All four rod babbits had failed and chunks were found in the oil pan.

Even after examination by a very experienced, excellent Model A mechanic/re-builder, it is not certain what caused the failure. He suspects a bad pour and workmanship on the babbit job, but also points out the increased loads that are imposed on the bearings by high-compression heads. The higher the compression, of course, the higher the loading. If my rod babbits were bad to begin with, my H/C head only served to accelerate the failure that was going to happen anyway after who knows how many more miles.

I have to believe, though, that H/C heads will reduce bearing life but maybe not enough that the average 'A' owner will ever drive enough miles to notice. I have to balance this with stories of the many H/C heads out there that the owners claim many happy thousands of miles with!

I took a gamble (also due to homework and success stories) and had the babbitted rods replaced by the new forged insert rods from Antique Engine Rebuilding. The mechanic also strongly recommended driving a lot less with the spark fully advanced to reduce bearing loading. AND - NO LUGGING!

The inserts are runnung great and the engine is happy again. I'll still stick with the H/C head and just be way more careful when driving. - But, I wouldn't go above a 5.5:1 head! That's just paranoid ole me... These failures are VERY expensive!!

Earle
 
I have one car with a Brumfield head on it,although I have put them on others.I can NOT advance the spark any further down than maybe 1/4 the travel.Even at full throttle sailing down the road it will start to jump,buck,and pound.I monkeyed around with it quite a bit and found it is not a problem.It runs fine,good idle,good top end,runs cooler,better fuel mileage,and it runs,not lugs up hills.I have a low mile roadster that has always been real zippy.I just took it to lunch,(I have not driven it in a year or so)and thought,boy,I need to do something,this thing is doggy.Then I went around a corner and straight up a hill,and it ran up it like it always does.That is when I realized the car was fine,but the little pickup with the Brumfield head had spoiled me.I just found I have had an older Brumfield head for years.Heads are so plentiful that when they show up in a batch of junk I might buy,I just lean them in a shed with a dozen others.I mostly give them away.I went to pick one out a couple of weeks ago for somebody and saw one with a BF cast into it.A local woman had me clean out all her dead husbands extra Model A parts after she sold the car and it was in there.I just thought it was an extra head he had hot tanked and resurfaced.I never even gave it a look then.I did treat it a little extra carefully because it was clean and was bolted to the thin piece of plywood.I have installed one Snyder head,I had the head off a customers pickup because of a rotted head gasket and he said how about installing a high compression head instead of paying $65.to mill it and wait 3-4 days.He must have hit it just right because we had one in 3 days.I was a little leery of the job because the truck was never left outside,and I can't tie up my garage waiting for parts.I know he ran the truck for a year or so until he died,then the truck went to his son.All I ever heard was that the truck ran great,but still not quite as good as mine.
 
I'm paranoid too! You made my point exactly! Did the higher bearing loads cause the failure or were they going to fail anyway? If anyone has a "Machinery's Handbook" there was an excellent part in there, pertaining to bearing metals and variations of alloys. That why I mentioned it in my last post about had the recipe (formula) changed any since Henry's day to accomodate the heavier loading. I don't know how much attention this has been given since 1928, but it is a consideration if only for the improved gasoline. Henry kept his compression low for a reason.
Terry


Earle said:
Terry,

I had (have) the same moderate concern about bearing loads. My roadster had newly-babbitted rods installed during a rebuild about 25 years and 6500 miles ago. About 2000 miles ago, I had a Snyder 5.5 head put on. The increase in power and performance was noticeable. 'Loved it! Then, a couple of months ago I began to hear a tapping/knocking sound. All four rod babbits had failed and chunks were found in the oil pan.

Even after examination by a very experienced, excellent Model A mechanic/re-builder, it is not certain what caused the failure. He suspects a bad pour and workmanship on the babbit job, but also points out the increased loads that are imposed on the bearings by high-compression heads. The higher the compression, of course, the higher the loading. If my rod babbits were bad to begin with, my H/C head only served to accelerate the failure that was going to happen anyway after who knows how many more miles.

I have to believe, though, that H/C heads will reduce bearing life but maybe not enough that the average 'A' owner will ever drive enough miles to notice. I have to balance this with stories of the many H/C heads out there that the owners claim many happy thousands of miles with!

I took a gamble (also due to homework and success stories) and had the babbitted rods replaced by the new forged insert rods from Antique Engine Rebuilding. The mechanic also strongly recommended driving a lot less with the spark fully advanced to reduce bearing loading. AND - NO LUGGING!

The inserts are runnung great and the engine is happy again. I'll still stick with the H/C head and just be way more careful when driving. - But, I wouldn't go above a 5.5:1 head! That's just paranoid ole me... These failures are VERY expensive!!

Earle
Click to expand...
 
Terry,

Henry kept the compression low so the Model A would run on ANY available fuel out there without having a ping or knock problem. Of course if one does not control the timing correctly (and other causes), such as on a steep hill for example, the Model A will knock with the best of 'em to this day. Detonation (ping and knock) can break pistons and ruin babbitt bearings.

For the most part, the available fuel was was low octane somewhwere in the 40 to 60 range. If today's gasoline had been available at the time of the Model A's manufacture, Ford would have lost sales with a compression ratio of only 4.22 to 1.


Larry B.
 
Larry - where were you last summer when I tried to call you, email you and fax you to order a H/C head? Respectfully, not answering/returning calls or posting something on the website link I found doesn't inspire a lot of confidence - despite the fact that I now see you have overwhelming support from your customers. I now have the Snyder's head and it's a great improvement?
 
"Larry - where were you last summer ....?"

Occupied .... with complex machine work! ... the mainstay of my life, not Model A's. Respectfully, when the phone does not answer, nor e-mails and faxes, it's a pretty good indication that a business is not in operation, don't you think? I'd go somewhere else too.

Enjoy your Snyder head.


Larry B.
 
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Larry - Despite my frustration trying to track you down last summer, I sure do appreciate your contributions to this site. Your contributions have been very helpful and informative to me.
 
Yes.

Larry I have one of your heads on my 31 Vicky and I love it! I would not own a Model A with out having one of your high compression heads. I have driven Model A's with out them and there is no comparison in power. Bore it .125 over and stick on a Brumfield Head, you will not be dissapointed!
 
I have one on my four door and love it. I like the fact that I'm not a hazard on the road. Because I can keep up with traffic. I'll be looking for one for my coupe, if I decide to keep it. Thanks....
 
I have one with MODEL A cast into it in big block letters.Years ago somebody showed me a picture of it in an old catalog,I don't remember if it was Monkey Wards,Sears,Western Auto,Whitney,it was one of the old outfits that sold gypsy parts.You don't need a scale to tell the difference.Pick it up with one hand,and pick up a stock head with the other,and I bet there is a 5 pound difference between them.The thickness of the casting between the water passage and the outside edge is very thin on the aftermarket head.You can also see,without measuring a difference in the shape of the combustion chambers.They have lumps,bumps,and bulges that vary from one chamber to the next.I think it is a nice conversation piece,and if it works like it should for you,that makes it even better.
 
Hello Keith

I noticed in your post above (#102) that you stated that you cannot advance your spark lever more than 1/4 the travel with your Brumfield Head or it will "jump, buck and pound." This is not normal with the B-F 5.9.

If all your control mechanisms are correct you should be able to advance the lever anywhere from at least 1/2 to 3/4 (3/4 on most Model A's) if needed for proper advancement at higher speed.

With the Brumfield Heads the fuel mixture burns faster than with a stock head so not as much total advancement is required for the same speed and load. If the Brumfield Heads had been standard equipment when the Model A was new, Ford would have designed the quadrant (travel area) and the dist. advance/retard movement area with less distance for total advancement.

Something, ranging from your initial timing setting (maybe a little too advanced) to the controls (spark rod length / steering column connections, etc.), must be slightly out of whack. The control parts are usually an area in need of restoring or adjustment on most Model A's.


Larry B.
 
Larry, I am new to the hobby and not sure of all the advantages as of yet. At this point I will say No... I need to get my head around the maintenance aspect for right now, and then I might make/take the venture. I will keep you in mind.

Thank you!!!
Tim
 
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