Broke A Pushrod

[Guest]

I just broke a rod in my '59 T-Bird 352. I fished out both pieces with a magnet; it appears that there was no shrapnel, as the broken ends can be butted together with no evidence of missing rod pieces. Is there anything in particular to watch for on this engine when doing a valve job? Any specific maker of cams I should consider for replacement? I want it to run basically stock, not lumpy-lump .... or should I take this opportunity to go to a hotter cam and mill the heads? The oil pan gasket was replaced not long ago -- should I pull the pan again and clean it out in there? All the holes are a consistent 120# except the bad one. I've always gotten very good advice on this forum .... got any more for me? Thanks.

[simplyconnected]

HOLY COW!
I would not be as concerned over the rod as I am of the block! Usually when a rod lets loose, it takes out a lot of damage before the crank stops.

First of all, your engine needs to be pulled. Then you need to make sound decisions regarding a major overhaul. You may want to "fix" your 352 but that will cost more than rebuilding a 390. They are both FE engines which means they are nearly identical on the outside.

390 engines came out in 1961 and Ford put them in everything including Ford cars, trucks, marine, construction equipment, etc. There are a whole lot more used 390s than there are 352s. Ford made small changes to the 390 so vendors still support them with inexpensive parts. 352 parts are higher in cost and fewer in availability.

If you have some money to spend, build a used 390. It will look identical to your 352 in your Thunderbird.

Your heads are built for LEADED gas. To convert them to unleaded, you need a machine shop to cut and install hardened valve seats, replace the valves with stainless, then machine all the mating surfaces so they are square. Machining costs are not cheap and you still end up with cast iron heads.

Instead, I buy and install Edelbrock aluminum heads because they are built for modern fuel, they have Viton seals instead of those useless umbrella seals, they have bronze valve guides, stainless valves, heli-coiled holds and they transfer heat MUCH better than cast iron.

I suggest you stick with a very mild cam like a Comp Cams 240 degree duration. Most modern engines have roller cams so they can use regular oil with no additives. Comp Cams offers roller cams but they are higher in cost because you need the hydraulic roller lifters. <--this is what I buy and use.

You can still find 'flat tappet' cams but they need an oil additive with zinc and phosphorus (ZDDP).

To recap, I suggest you buy a good used 390. All the parts will be there including crank and rods. Have it built with aluminum heads and a hydraulic roller cam, then bolt it to your transmission. - Dave

[Restifier52]

An aluminum intake manifold would be a nice upgrade as well.

[jopizz]

Does he mean he broke a push rod or connecting rod? It sounds like he means push rod if he's talking valves.

John

[Guest]

Sorry if I misled you; a push rod broke, not a connecting rod (less serious than a conn rod but still a problem financially.) I'm hoping and assuming that the damage is limited to the area of the valve train and not the block. Assuming this is so, I'll need to pull the heads, grind the valves and inspect further.
While I'm doing a valve job, should I upgrade to a mild Comp cam and mill the heads (I think so, but how much? Thirty thousandths?)

Dave, I appreciate your advice and will follow it to the letter if major work is required. Is it a good idea to use an additive (like ZDDP) if the seats are not hardened?

[jopizz]

I would be concerned about why the rod broke. Normally the only way they would break is if a valve gets stuck. I doubt it did any major damage. I would tap on the valve that it connects to with a rubber hammer. You should feel a vibration if it's free. If it feels solid then it's probably stuck closed. You need to use a lead substitute in your gas if you don't have hardened valve seats.

John

[simplyconnected]

Call Comp Cams at 800-999-0853. Ask them to suggest a good cam for your engine. Also, ask them what oil additives are required for flat tappet cams. I am eager to hear your answer. - Dave

[Guest]

Dave -

Thanks for all your input. I appreciate it. I did not call Comp Cams because I can't speak on the phone due to the advanced state of my Parkinson's Disease. Besides, I am not enough of a mechanic to have an in-depth conversation about the relative merits of the different cams. Sorry.

After a visual inspection today, everything my mechanic and I can see looks OK, so I've decided to stay with the original cam on my 352. By using some ZDDP (and with a little luck), I hope to avoid engine failure. If time proves that this is a mistake, I'll let you know in a future post.

Thank you again for all your helpful advice. Roger

[Yadkin]

I would still rebuild the heads with hardened valve seats.

[Guest]

Yadkin, John, Dave, Nyles, Restifier,
My heads go into the shop today. If it's halfway affordable, I plan to get the valve seats hardened. If my problems are solved, then I win. If not, there's a 390 in my future. (I've been in love with the 390 ever since I put a modestly built one into a '59 Ranchero -- but that's another story.) Your advice is well received and I thank you. Roger

[simplyconnected]

...Is there anything in particular to watch for on this engine when doing a valve job? Any specific maker of cams I should consider for replacement? I want it to run basically stock, not lumpy-lump .... or should I take this opportunity to go to a hotter cam and mill the heads? The oil pan gasket was replaced not long ago -- should I pull the pan again and clean it out in there? All the holes are a consistent 120# except the bad one. I've always gotten very good advice on this forum .... got any more for me? Thanks.

...I did not call Comp Cams because I can't speak on the phone due to the advanced state of my Parkinson's Disease. Besides, I am not enough of a mechanic to have an in-depth conversation about the relative merits of the different cams. Sorry.

After a visual inspection today, everything my mechanic and I can see looks OK, so I've decided to stay with the original cam on my 352. By using some ZDDP (and with a little luck), I hope to avoid engine failure...

I am dumbfounded and confused. Sorry for your Parkinson's Disease but you have done an about face regarding all of your questions.

You asked about things to watch out for when doing a valve job. We responded by having your exhaust valve seats milled out and replaced with hardened seats AND stainless valves. You cannot harden cast iron because it is, by definition, two percent carbon.

You could just as easily email Comp Cams. They are experts with a full staff of customer service, but now you don't want a cam.

I am a person who hates throwing good money after bad. You can rebuild an engine, one section at a time, and it will cost THE MOST or you can do the whole thing, one time, and it will cost the least. For example, you pull the engine once, tear it down when everything is very accessible, measure and inspect all the rotating assemblies, do all the machining at once and then assemble using modern brass freeze plugs and materials that are designed for today's common engine oil and fuel.

When an engine wears, all the components wear together; cylinder bores become bell-shaped and the crosshatch disappears, rings wear causing wider end gaps and less pressure against the bores. If your rings are old and worn, new or reconditioned heads that seal much better than old heads will put much more demand on your rings causing rapid failure because your engine was built with high compression, to run leaded premium gasoline (that has been replaced with gasohol) and the oil should have ZDDP (zinc and phosphorus) in levels of at least 1,200,000:1 or more for your flat tappet cam.

Three things come to light:
Any good rebuild isn't cheap but it should last 200,000 miles.
The 390 is a much better choice to rebuild, and looking better all the time.
If you cut corners and do 'piece rebuilding' it isn't going to last long and it will cost the most in the long run.

Heads are the heart of an engine. Machining costs to modernize heads (hardened exhaust seat, Viton seals, stainless valves, reconditioned guides, and milled flat on all mating surfaces) will cost much more than a set of new. After spending all that money, you still end up with cast iron heads that are worth about $300 used.

If you're not sure about engines, find out why modern engines last 250,000 miles but original Thunderbird engines only lasted 80,000. They are basically the same design but all the components are made of different materials. Do you still cook with cast iron pans or aluminum? Now you can see the difference in heat transfer as aluminum allows higher compression (and more HP) without pre-ignition and detonation.

Simply ask yourself, 'What do modern engines use?"
I hope this helps. Good luck. - Dave

[Guest]

Progress Report:

I had my 352 heads done with hardened seats at a local shop and now the car won't start at all! I have fire and I have fuel (but no compression) so it seems that I have a ring problem. I found a used 390 (two barrel with 86K) for $500 and a C6 for $250, so I'm getting closer to my long range goal of running a 390 and ditching the 352. I'm thinking to install a used 390; if it runs OK for a couple of years, then I win. If the engine is no good from the start, then I have a 390 to build on.

Does everything from the 352 bolt on to the 390? HEADS? - I want to use the recently done 352 heads, if possible. INTAKE MANIFOLD? - I definitely want to keep my new Edelbrock 1406 carburetor. TRANSMISSION? - Although I like the C6, my original was just rebuilt by a local tranny legend. EXHAUST MANIFOLD? PULLEYS? WATER PUMP? DRIVE SHAFT? ETC. As always, your comments and advice are appreciated!

[jopizz]

Unfortunately your 352 heads won't work on a 390. Everything else will work. I'm confused though. If it started before it should start now. You say there's no compression. I've never seen no compression with rebuilt heads. Even bad rings will give a compression reading. Was the distributor put back in correctly. My guess is that the timing is off.

John

[simplyconnected]

Are these stock Ford heads? If so they should fit.
Edelbrock aluminum heads won't fit a 352 because Edelbrock moved their valves so they could use 2.02" intake valves. These valves hit the cylinder bores on a 352, but they clear390/427 bores. Stock Ford iron heads use smaller valves that fit all FE engines.

If you have no compression, your valves are open. Why? How deep is your lifter preload? - Dave

[jopizz]

Dave,

Thanks for correcting me. I wasn't aware that stock 352 heads were the same as 390 heads. That's good to know.

John