Is anyone familiar with the head gaskets for the Nailhead? I bought mine from Carmen Faso when I got them and they are the original beaded steel type like came on the engines from the factory. If you go to the parts store and order the ones Fel-Pro has, what type are they? Are they the same thickness as factory, or are they the newer composite type that are much thicker and kill the compression?
The newer ones are a sandwich of 2 plates of steel with composite in the center. They are thicker, which helps lower compression and seals better IMHO. With the high price of premium gas, I opted for the thicker ones and just retarded my timing a few degrees.:TU:
I want the compression, so I will have to call Carmen Faso and get another set. I made the mistake of putting mine on without putting any of the spray-on sealer on them, so I have a bad oil leak at the rear.
Mine does that too......and I had the block decked and the heads milled. It apppears that the headgaskets are leaking oil around where the pushrods go through and running down the rear of the block. I run synthetic, and the leak really isn't bad so I don't worry about it. And I even used copper sealer! Seems odd though. uzzled:
I think mine is leaking where the oil passage from the rockers dead ends at the block in the rear (there is one at front and rear of head since heads are interchangeable from side to side). While I have the heads off, I am going to clean that passage thoroughly and fill it up with JB weld. That will stop the oil up up at the rocker pedestal and give it no opportunity to leak down where the passage stops at the block! My car is a show car and any oil leak is bad--I could drive it across town and have oil dripping off the bottom of the oil filter when I got back where it ran down from the head. I pulled the engine out on Sat. so I can fix the problem.
I have the same problem,only mine leaks at the front. It is definitely a head gasket issue. I retorqued the heads just to check-they were to spec. Funny thing is, it doesn't always leak. I clean the head to block area and it may be good for 4 weeks or 8 weeks or ?. Outside temp seems not to be cause. I am going to check it after I run it hard to see if that is causing it:3gears: If it is-too bad. It only seeps a little.
I show mine also......I just wipe it off every now and then, as it is a minor leak. I removed the rocker arms, and tried filling the dead end passages with silicone (after thoroughly blowing the oil out and cleaning it).......and did not note any improvement. I never have had that problem before in the past on my old engine. I wonder if the jokers at NAPA who decked my block screwed that up too? They told me the block was off by .005" on one side.......and I can't see the factory making a mistake like that, nor can I imagine a cast iron block warping that much. ou:
I talked to Carmen Faso today and he told me that you have to put the spray sealer on them (like the permatex copper coat) to keep them from leaking. I ordered a new set and am going to put them on with the sealer. Mine was leaking bad enough that I could drive across town and it was dripping off the bottom of the oil filter (lowest point when it runs down the back of the block) when I got back. It was obvious it was coming out of the head gasket right near the top rear corner of the head--left a trail down the back of the block from there. The wind was also catching it and blowing it all over my headers--it ruined a perfect set of ceramic coated headers--those burned oil stains won't come off. I can deal with a leak that just gets the outside of the block wet with oil over time, but a leak that makes it drip off on the ground from a 10 mile ride is totally unacceptable. I have the engine out sitting on the stand and am pulling the heads off tomorrow night. It has less than 300 miles on it.
Brian I had this same problem in my 65 GS, but I also had coolant leak as well as oil in the same area. Looked like hell dripping down the block. On mine, the machinist who originally surfaced the block and heads cut them too rough (was done before I owned the stuff), so even with a Felpro blue gasket and plenty of Permatex Spray Hi-tack on both sides, I still had seepage. The fluids were essentially following the circular machining lines to the edge of the block and dripping out. She ran fine, but the leak at the ends of both heads drove me crazy. Eventually I pulled the motor and decked the block and heads to a much finer finish, once again used Felpro Blue gaskets and High Tack (not spray copper). Problem solved. After my experience I would say that the stock steel gasket would exacerbate the problem, even with a sealer applied. The less expensive non-performance oriented gaskets, like McCords, might actually seal better than the Felpro's. If you aren't hammering the car perhaps you might consider this route. After looking at the cheaper gaskets, my machinist suggested this because they are composite on both sides and tend to fill in the voids. The Felpro blue only have the coating on one side and the other side is a hard painted surface (like the stock steel). I ended up using Felpro plus spray High Tack and so far am OK after a year and maybe 1500 miles. I have close up pics of the roughly machined heads and block if you are interested. Just email me direct. Thanks Pat
I will know more tonight when I pull the heads off and inspect everything. I didn't deck the block when I built the engine--it looked fine and didn't need it. The heads I bought from Carmen Faso and he had them decked to clean them up (it is a set of his big intake valve heads). If I find they are too rough, I will take them to the local machine shop and have them ground. Being cast iron, they were most likely surfaced on a belt sander. I want all the performance and I will defintely run it hard--it is a dual quad, 4-speed car with a big cam and other performance mods, so I want the compression. Only way I will use the composite gaskets would be if I had the heads milled to compensate for the thicker gaskets. I will take some pictures of the heads/block tonight when I take it apart.
Wow, all this ifo will come in handy when I finally put (one of) my 401's together, Thanks! Steel gaskets are 0.015" thick, composites are listed as 0.045" thick in the '66 parts book.....In a 425, that's a difference of approx 0.438 cubic inches, which after some quick calcs, will reduce compression ratio from 10.25 to 9.45:1......wow! Check my math: Swept volume= pi * radius squared * stroke= 53.1679 cu inches At 10.25 CR, that will be a compressed volume of 5.187 cu inches. 0.045" gasket has approx volume of 0.6573 cu in 0.015" gasket has approx volume of 0.2191 cu in that's an increase of 0.4382 cu in with a 0.045" gasket.....for total compressed volume of 5.6253 cu in. soooo... 53.1679 divided by 5.6253 = 9.45 CR! Has anyone here measured everything and computed their actual compression ratio?
I hadn't done the math yet, but you are correct. To keep the stock compression ratio, you would have to deck either the block or the heads by .030" Walt, did the door panels arrive yet?
You'd think the coolant being thinner would leak before the oil would........and those scratches are so fine, you'd think the copper sealer would fill them in. Now I'm wishing I would left the gasket surfaces alone, but I followed the advice of the machine shop. ou: It's really not that bad, I'll just keep wiping it off if it doesn't bother me more now that I know why it's leaking!
O K, The old way; it goes without saying to make sure the heads and block are clean. then coat the new gasket on both sides with aluminum paint, then while it is still tacky put the head on and torque down. Then after start up and warm up retorque the head bolts to spec.
A couple dumb questions from a newbie- 1. I have a '66 401 that the boys at NAPA just rebuilt the short block & heads on. My head gaskets are the Fel Pro Perma Torque 1 (I believe thats the name), they are multi-layer steel and do not have the blue coating. They have 7922-1 and R-2 stamped in them. My question is has anyone had experience w/ these gaskets or know if they obstruct any water passages? There are two round holes in the block & heads approx 11/16" diameter; one between the first & second cylinder bore, one between the third & fourth bore located above (toward the intake)the bores. There are also three round holes approx 5/8" diameter and two oblong holes approx 11/16" x 1-3/16" in the block & heads below (toward exhaust) the cylinder bores. Are all these holes water passages or are they something else? My Fel Pro gaskets do not have any of these holes in them & I'm concerned about potentially blocking off water flow. Surely a household name like Fel Pro wouldn't sell a deficient product, what am I missing? 2. Does anyone know what thickness the head gaskets from the factory were on a 10.25:1 325 HP 401? Thanks to anyone willing to respond.
Those ARE water passages... haven't looked at the heads to see which ones line up and which are blocked though.. lemme go in my garage and look... OKAY, on the heads, the there are passages that will line up with the two 5/8" holes on the top of the block and only the centre hole on the bottom of the block... ALSO there are passages that line up for the long narrow hole at the rear of the block as well as a 1/2" hole at the top rear of the block (right next to a head bolt hole). Hope that helps, wes :TU:
Thanks although I'm still not sure if I can use these gaskets or not. The gaskets only have holes for the 14 head bolts, the two alignment pins, the tall thin slot at the rear of the block and two small (less than 1/2") holes in the front of the block above the top front-most bolt (#3 in the torque sequence). One of these holes is in front of (right) and one is behind (left) the #3 bolt.
I just took a look at my '66 401 (still not done), some original steel shim gaskets, and the Fel-pro gaskets. The Fel-pro's are blue on on side and have 7922-1 stamped in. The openings in the Fel pro are identical the the originals. Many of the holes in the block are blocked off by the gasket...along the outside of the block, there are 5 holes blocked...the 2 round ones at the ends next to the locating pin, the round one in the center, and the two oval ones. On the lifter side, I see two round holes blocked off. I think your gaskets are okay. I'll post some pics shortly. The original gaskets are steel shim, and 0.15" thick. The Fel-pros are 0.040 to 0.045" thick...so they will reduce your compression ratio. See the post 'piston dome volume' for more CR info.:TU:
