A Case For Replacing the Freeze Plugs

[67c&ccorv]

Why the hostility? Does slamming my opinion somehow make yours more reliable?

No hostility intended Loki...easy son; easy!

I'm a Go on the new tappets, and a No on the line bore.

This thread has drifted some from the original subect but very useful stuff here. Here are a few more opinions for FWIW. In my personal experience new cam bearings should be pulled into place with a threaded rod style tool and then reamed to the required toleramce based on the actual dimension of the new cam, not a factory spec. If this be called "line boring", so be it. Line boring is also part of the "blueprinting" process but that is for high performance engines and does not really concern us here. I have frequently used old tappets with new camshafts without problems. The replacement criterion is condition of the ends of the tappets. I agree with 67 that refacing tappet ends is seldom justifiable except in the case where replacement is impossible or expensive. 67 also makes a good point about bearings needing to be oiled before starting; that is why I have my ignition on an OP switch which prevents starting until oil pressure reaches 7 psi to the extremity of the system.

Line boring bearings?? How do you line bore a bearing? Line boring blocks yes, but bearings. The only scenario where cam bearings would be line bored is if the bearings were made to be line bored/ honed, which means the bearings are grossly undersized. If the machinist removes .001-.010+ of the bearing surface on say half the bearing what compensates for the removed material on the opposite side of the bearing? . If the cam goes in and spins without binding That's as good as it is going to get. Line boring with a properly sized bearing creates an internal oil leak. If an engine is turning 2000 rpm the cam is only spinning 1000rpm
I would never put used tappets on a new camshaft, this is not a place to save a few bucks. I have never built an industrial type engine so maybe this is acceptable. I know that it is not on automotive engines nor is it on big diesel engines, which is where my experience is.

A-4 isn't a D239 with five cam bearings - but it does have two in roughly similar configuration within the block...hopefully this will illustrate what I am talking about when I say "line boring" should be utilized to final fit the cam bearings;

http://youtu.be/uqrgJ45IeSQ

<iframe width="560" height="315" src="http://www.youtube.com/embed/uqrgJ45IeSQ" frameborder="0" allowfullscreen></iframe>

Cheers!

[ndutton]

I know I'm late to the party and the questions have already been answered but I'll offer this from thirty five years ago:

As part of an engine repair I needed to replace a camshaft. There was no warranty on the cam unless a full set of lifters was purchased at the same time on the same invoice. It wasn't a question of would the old ones work.

[hanleyclifford]

Just to Sauce the Thread a Bit

Last winter I installed a new camshaft and bearings from Moyer Marine but did not replace the tappets. When I take the engine down next summer I intend to post some pictures and we can test some hypotheses.

[ILikeRust]

Whenever I decide I don't have enough things to worry about, I pay a visit here to the Moyer forum.

[Carl-T705]

Hanley.... say it isn't so!!! ( lol ) Your test is not conclusive.. you didn't run it 40 years!!! (lol) Cheers, Carl
Bill, These engines run with sea water in them, fresh water, bay mud , 10 year old oil and ground up metal and rust. You have little to worry about.

[Ball Racing]

If you can prove the tappet is flat, you could reuse it on another cam.The A4 does not have the spring pressure, nor the RPM or aggressive lobe face and high lift rates that cars, and race engines have that can wipe the lobe off from a new seating process.
Car engines can eat cams and lifters.
A used tappet that is flat is no different than a new tappet.
Many times on the flathead briggs race motors I built we would put new lifters in "stock" class motors every 5 races or so because they were subject to break.
Never hurt the cam,using several new lifters. The the valves, and springs and pressures were about dead equal in demension to a A4.
The tappet needs to spin in it's bore so it does not develop a flat spot, or a dished spot.
Cams are ground with a touch ,,, small amount of egg, that spins the lifter as it raises the valve.

On my rebuild the tappets were as bad or worse than those pictured above, even a few cab lobes had places.
You can buy the special oil-lube made just for cams, on the start up of fresh engines that helps protect it, and get the break in procedure going.

I honed the tappets on a diamond stone, got alot of the bad out of it, and reused the whole set-up.
I only have about 150 miles on it in my boat, and haven't had to re do the lash adjustment, so they are living at the present.

[ndutton]

What does Don do on his rebuilds and short blocks? I think that would be a worthy example to follow.

[13jeff13]

Last winter I installed a new camshaft and bearings from Moyer Marine but did not replace the tappets. When I take the engine down next summer I intend to post some pictures and we can test some hypotheses.

I'm getting new tappets, mine look pretty pitted. It will be interesting to see if there was any significant wear.


Did you once say you had to have your bearings reamed at one time Hanley??

[13jeff13]

No hostility intended Loki...easy son; easy!









A-4 isn't a D239 with five cam bearings - but it does have two in roughly similar configuration within the block...hopefully this will illustrate what I am talking about when I say "line boring" should be utilized to final fit the cam bearings;

http://youtu.be/uqrgJ45IeSQ

<iframe width="560" height="315" src="http://www.youtube.com/embed/uqrgJ45IeSQ" frameborder="0" allowfullscreen></iframe>

Cheers!

Great Video,, Mine turns as the one in the video does at the end,, without my gear on,, I think with the gear on, it will spin easier. So I'm leaving well enough alone. Great Input though, and I do appreciate everyone's view. It's why we keep coming back.

I will probably spring for the New Tappets.

Thanks


Jeff

[hanleyclifford]

I'm getting new tappets, mine look pretty pitted. It will be interesting to see if there was any significant wear.


Did you once say you had to have your bearings reamed at one time Hanley??

I put in new unreamed bearings and then took the cam and block to a machinist with insructions to ream to .0015" clearance. My oil pressure issue evaporated. (Prior clearance was .003+) Edit: I am still lusting for that alternator.

[13jeff13]

I put in new unreamed bearings and then took the cam and block to a machinist with insructions to ream to .0015" clearance. My oil pressure issue evaporated. (Prior clearance was .003+) Edit: I am still lusting for that alternator.

Yeah...I hear ya...the PO had many Balmar "upgrades",, so I'm going to have to keep her consistant. Got the wider pully, spacer, Balmar Galvanic Isolator,,,,really though i thought of doing some swaps before i just started spending money. Now with income tax refund money coming...I gotta keep her. Plus I had my alternator guy check it out already, one of the many systems that fortunatly is good to go, And I got the regulator for it off ebay for $160. I'm stuck with it

[13jeff13]

Although these freeze plugs are hardy enough to out live these engines, and myself,, Getting to the crud behind them is worth the price of new ones. I spent a good hour digging around in the exhaust manifold with a coat hanger and rinsing in the sink with water and thought I had made some real progress. Then I removed the drain plug and it was solid with crud. SO,, I decided to take out the Freeze Plugs and here is what I found.

Making Headway,,, Thanks to ALL here on the Forum for all the guidance, and excellent advice. I completed the clean out of my Manifold the other day and fashioned up a test system, per the advice here. I can not believe the amount of CRUD / Corrosion, I got out of the manifold. Then I accidentally dropped it hanging it on a hook to paint, , and Got a WHOLE LOT MORE crud out of it,, then I decided to run the power washer at it, on Fine Stream,, a lot of power, and got even more out. I am fairly certain she is as clean as she is going to get, without causing any harm.

Sorry for the size.. Just hit Right Click on your mouse over the picture, and View Image, for a better view.

Jeff