Rajo 4 valve head gasket

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Model T Ford Forum: Forum 2016: Rajo 4 valve head gasket
Top of pagePrevious messageNext messageBottom of page Link to this message  By Seth in Alabama on Monday, June 20, 2016 - 07:20 pm:

Howdy all, as you may have seen in my previous thread I blew the head gasket: http://www.mtfca.com/discus/messages/599638/646241.html?1464484784

The gentlemen at Olson's are AWESOME and made me a new head gasket with full fire ring and shipped it to me, all free of charge. Couldn't be more pleased with them.



Now, for "Seth installs the Rajo head" attempt number 2, I have some questions.

I'm sure the full fire ring will help and make a big difference. Most likely, I can just install it and bam I'll be in business. However, based on my gut instinct, and more importantly the recommendation of both the man at Olson's as well as several folks on the forum, I need some extra support for the gasket where the intake valves used to be.

I've heard a few suggestions: install some hardened valve seats upside down, fill the intake areas with lead, and use old valve heads.

I like the valve seat idea. The seats are cheap. I'm confident if I had the tool I could counterbore the block and install the seats no problem. I even have the thread where Tom Lovejoy did exactly this (but seats right side up) with the engine still in the car. The couple of drawbacks here are that so far the actual counterbore bit (not sure of terminology) that cuts into the block is over $150 alone. Then the tool(s) involved are at least another $300-$500, IF I could even find them on eBay or craigslist. Which I can't. Lastly, I know someone who can counterbore the block for me and he's local with great prices, but, I have to pull the engine and give him just the block for that, AND I've been told I'd need to have the block decked after that to make sure the seats and the block surface are true and flush. I have about $80 for this project for the foreseeable future.

Fill chamber with lead. Lots of questions here. I have googled where lead melts at 621.5 F. I'm fairly certain that's not a problem but do I fill the ENTIRE intake passages of the block? How do I do it? Melt it in a pot or something first and then pour it? What lead do I use? What can I put in the valve guide to keep lead out but won't melt/burn/be stuck in there when the lead cools? I just don't know enough about this. How hard would it be to get the lead out of I ever decide not to run this head? I do think I could melt the lead, my dad reloads his shotguns so I know I could get that lead (if that would work) and I'm pretty sure I could file it nice and smooth and flush with the deck.

Hopefully the 3rd one is the charm. I'm getting some old two-piece valves and I'll get the centers drilled out so they'll allow the push rod through. I have have a Neway valve seat cutting kit so I can massage the block along with the old valve heads to get them nice and flush with the deck. My question with this is what is the forum's recommendation: just install them dry and let the head hold them in place, or maybe use JB weld to help hold them?

One thing to note: again. I have about $80, and am really hoping to get this figured out before 4th of July. If it's not possible it's not possible. But, I think either the lead thing or the valve head thing should get me sorted out without really costing me much. What say ye?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Donnie Brown North Central Arkansas on Monday, June 20, 2016 - 09:41 pm:

Seth, My vote is for lead or valve head/plug. The lead thing is not hard. You should clean the block and valve port very well. Then plug the valve stem hole with a little wad of steel wool. Pack it snug in the valve guide. Leave the top half of the guide open for the lead to run into for a little more support. You may want to leave it sticking out the bottom of the guide so you can remove the steel wool after the pour. You will also need to block of the intake side of the port with a plate to hold the lead in. I would also build a little dam around the top of the valve seat area on the block. This will allow the lead to stand a "little proud" of the block. That way you can file it flush after it cools. You can use high temp silicone gasket maker for the dam, and let it cure overnight. Make sure everything is nice and dry before you pour the lead in place. Any moisture will cause the lead to blow back on you. Wear plenty of good leather gloves, a thick jacket, work boots, or cover your shoes, and use a face shield. More than likely nothing will go wrong, but just in case, wear the proper protective gear. You can melt the lead in any kind of metal pot/ladle that you can pour from. A short piece of pipe large enough for the amount of lead needed for the pour, with a bottom welded in and a handle welded on to hold and pour with will work fine. Make a little pouring lip on the pot to control the pour location with. Square tube for the pot/ladle works good as the lip is just one of the corners. No more than you will be melting, you can just melt it with your torch, or make a nice hot fire with briquettes. Try a "test pour" or two, to get the feel of it. You can just re-melt the "test pour" later to use for the finished job. After the lead melts in you pot, skim off the "dross". But do that just as you are ready to pour, as it will re-form more dross quickly. Then pour quickly, with a good steady pouring motion, and keep the pour "full" as it will shrink as it cools. That is the other reason for the small dam around the valve ports. After everything has cooled off you may want to "peen" the lead some to make it fit tighter into the block.(another reason for the dam). But do not get carried away with the "peening" Just tap it down into the opening some to make sure it is tight and firm. Then file smooth. You can use wheel weights, old Babbitt from rods or ??? for your lead source. Do not worry about it being clean, as any dirt or scale will just float on top of the melted lead and can be skimmed off as "dross" If you use wheel weights the metal clips will also "float" to the top. Also make sure that you have more than enough melted lead to fill the port. You do not want to run out in "mid pour" Let us know how it worked. I plan on doing the lead pour on my 4 valve installation this fall. So its nice you are "blazing a trail" for us who will follow . :-) :-) Have fun and be safe .... Donnie Brown ...


Top of pagePrevious messageNext messageBottom of page Link to this message  By Donnie Brown North Central Arkansas on Monday, June 20, 2016 - 09:48 pm:

Seth: I forgot. Take all precautions to keep the lead out of the cylinders. I am thinking of using some old pistons for a plug, with a small bead of high temp rtv sealer around them for a temporary seal. You do not want any excess lead running down into your rings ...


Top of pagePrevious messageNext messageBottom of page Link to this message  By gene french on Monday, June 20, 2016 - 10:26 pm:

Seth:
the pouring of the intake ports and seat area is a tried and true method from the "old days" ...i think this is mentioned in some of the murry fahnstock (sp) books ...you can block off the intake port on the outside of the block with freeze plugs and make 2 tapered cores to pour around to leave a clearance hole for the push rods( move cores to pour 2nd. port set ) ...the tapered cores will have a pilot end that fits into the existing valve guide to assure positioning ...if the block is clean and dry there should be no problem with blow outs ...preheat the port area to reduce shrinkage and eliminate moisture ...(300-400 deg. F)...this has worked in the past and is simple to do ( not rocket surgury here !) ...if you have questions call ...always an optimist ...Gene French 970-581-2808


Top of pagePrevious messageNext messageBottom of page Link to this message  By Donnie Brown North Central Arkansas on Tuesday, June 21, 2016 - 09:46 am:

Seth: Gene is correct about needing the tapered cores for the push rods. Sorry, I forgot about them. Gene, Thanks for pointing out my mistake. I re read the post above several times, and never noticed I had not addressed the push rod issue. The freeze plugs sound like a good idea, unless they will interfere with the mounting of the dual exhaust manifold you are using. I have two plugs made that replace the stock model T intake, that Im using to mount my dual exhaust.. The plugs are what the clamps that hold on the exhaust clamp to. I did not like the little "round rod" stands that came with the exhaust manifold. So in my case, (and maybe yours) I need to keep the counter bore of the intake port lead free and still useable.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Seth in Alabama on Tuesday, June 21, 2016 - 08:58 pm:

Ok, what would you gents recommend I use as a tapered core for the push rod?

Also, supposing I attempt this route, what would you use to heat up the lead? I have a regular benzo propane torch and he yellow map gas one. Or could I put it in a sacrificial pot on the stove?


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