G'day Can anyone here help I've got my hands on a nice Edmunds head for a Chrysler 251 flathead, just wondering if anyone here has fit one or knows what the torque is for it and what bolts did they use.
I had one on a 218. I reused the stock headbolts after giving them a dip in vineager and wire brushing, and chasing the holes with a br*** spiral brush chucked in a drill. I torqued to 65 # ft. Doing the proper sequence in three cycles starting at 25. Retorque in proper sequence after a heat cycle. Used composit head gasket copper side up, thin film of AP grease on steel side. Get the proper tightening sequence it is critical. Check the block with a straight edge and feeler gauge to ***ure no high spots, and the head to make sure it is true, if not sure, take it to a machine to ***ure its flat, and pay for a trying p*** if needed. The longer engines are not quite as fussy as the shorter dodge and Plymouth engines because there is more material between the cylinder pairs.
Thanks mate It's been to the shop already and it arrives in a couple of days. Was the head thinner than the original I haven't seen one before in Australia
Not sure. A stock head measures 2 inches from the flat of a head bolt to the under side of the edge. But I can't say if the head design was less than that to effect higher compression or that the more squeeze came from the combustion chamber space. Another consideration is spark plug choice. If memory serves the threaded portion of the plug hole is less deep than the stock head. So this will extend the plug farther into the combustion space. You will also notice the plug holes are located differently on the Edmund's. On the stock head the plug is above a valve, so a plug expending to far may be hit by a valve especially if you are planning a higher lift camshaft. It has been 15 years since I messed with mine and it turned out to be a bad casting and leaked coolant between the fins above several cylinders so it came off. I don't recall what plugs I used. So some time doing some measuring and a serving will be needed before you fire it up. Good luck! Keep us informed of what you find. Unfortunately you can't call 1 800 Edmund's for tech advice any more.
Chris..........just a suggestion.....be careful using a copper head gasket against the aluminium head as these two metals are not fond of each other and can set up electrolysis between themselves and/or the studs/bolts, make sure to use some sort of sealing compound on bolts as most go into water jackets............regards,.andyd
When retorqueing the head, make sure the engine is stone cold. Cast heads are torqued hot. Alum. heads are torqued cold. I would wait overnight to retorque. It may take more than one time. I have retorqued one as many as four times. Hope this helps.
I don't know if this is of any help, but I'll throw it out anyway. I am a huge fan of Edmunds heads having them on two Ford flatheads. I particularly like them because of the relocated spark plugs that moves the plugs away from over the exhaust valves. This allows the use of extended tip plugs, which, to me at least, is a big advantage. Another poster said that the "the plug hole is less deep than the stock head". On my heads the opposite is true, which one would expect given the relative strength of aluminum vs. cast iron. Whatever it is, you should measure so you get the proper length threads on the plug; they should engage the threads in the head entirely, but not extend into the combustion chamber. I test fit several different plugs in mine until I found something that fits perfectly. Also, in the flathead Ford community at least, we try to restrict the final torque readings on aluminum heads to 45 ft/lbs. I have never had a sealing problem with any of my heads using this value. Also, what an earlier poster said about torquing the heads cold is correct. Torque them as many times as necessary until the bolts no longer move. Also, I would not use copper gaskets with an aluminum head because of electrolysis problems. These heads are rare and delicate enough without turning them into self-destructing batteries. When I put my last engine together, I needed "big-bore" gaskets. The first set I purchased were copper. After conferring with many people about using them, I decided not to. Luckily, I was able to sell them on eBay for enough money to get a set of composite gaskets. One more piece of unsolicited information. In the flathead Ford world, we strive to get a consistent .050" clearance between the piston crown and the surface of the head. This increases compression and combustion efficiency. Back in the old days, I'd just slap a set of aluminum heads on a rebuilt short block and call it good. With the last two builds, I have taken great care to make sure I get this proper "squish" in the combustion chamber and the resulting engines seem to be crisper with more power than what I used to do. I have never seen this exercise referred to in relation to other flatheads, but I would have to believe it would be of equal benefit to any "L" head engine with a Ricardo combustion chamber.
Thanks for all the feedback I'll definitely look into the copper gasket they did send one out with it. Hopefully it's going on this weekend so I'll let you know how I go
I found that Best brand were able to swap the standard copper head gasket for a steel gasket in their gasket set......andyd
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