I've got a 331 hemi with early donovan 5 rib valve covers and its missing one of the spark plug tubes. I am unsure what tubes I need to run with these covers. Also the spark plug tubes that are in it do not have any o rings or grommets between the tubes and valve covers. These covers are not groved on the inside for the tubes like some of the more modern ones I've seen so im ***uming there should be o rings or grommets between the tubes and covers. Any help would be greatly appreciated.
Don't know the answer but I am guessing vintage covers like that would be designed to use stock tubes? Might get a set of them and see. I modified the stock steel tubes on my 331 by rolling over their top edge so they mash stock rubber seals eliminating leaks due to not using the washers and plug wire pans. Hot Heads and others sell stock type rubber seals. Took this pic several years ago, I think it is your covers? Looks like stock tube to me. probably leaks since there is no provision to retain the rubber seal. Here is the stock washer that the factory designed to mash the rubber seal. Have to use the sparkplug wire pans to make them work. I made this tool to clamp the tubes with about 1/8" sticking up. gentle tapping with a ball-peen hammer folds the edge with no cracks. Here is the result. Installed. Looks like it should be that way! Accel makes a silicone plug wire set with the long boots that fit the hemi. Incidentally I made my own rubber boots by modifying Toyota wire boots from Pic-A-Part. Just need to cut off the inner lip on the boot with a utility knife. There are two styles, need the one with the letter "R" cast on top.
The Desoto 341 in my Ford F100 hardly leaked around the plug tubes. All stock, tubes, grommets, washer and plug wire cover. Lot to be admired for the OEM setup. [emoji106]
Couple things to do--- You can call Donovan and talk to Woody and explain your situation, and maybe get him to cut the "O" ring. Or you can machine the top of the cover for a "LIP" seal, the same ones that they us in the heads. Donovan Makes their own tubes out of steel with a heavy base so that repeated usage does not allow the spark plug hole to ****** out and crack, Remember this is a racing part, The tubes are also on the pricey side
https://www.rbssuperchargers.com/Products/Spark_Plug_Tube_Steel_Donovan_392_Hemi--2610-0072D I found this site and they sell the tubes for the Donovan covers. I do not see how they seal up the top through, may have to contact them. Sorry I was not much help.
Thank you for all the input guys I really appreciate it. I will call donovan and see what they say. I have already spoke with JR at RBS superchargers and although he is a very nice man and super helpful the tubes that he sells are for the newer donovan valve covers wich are groved inside for the tubes so those ones will not work. The tubes that are currently in my motor (although I am missing one) are aluminum and are not tapered at the top. Am I correct in ***uming there is supposed to be an oring up at the top side of the tubes that seal them at the valve cover? It seems like there has to be or it would spew oil out the top. And should there also be seals were the tube tappers down and meets the head at the spark plug because mine currently does not have any seals there either?
I certainly don't know what the "Chrysler Guys" know – But – 15-20 years ago I bought some tubes for my 331. I later was told they were for 426" engines – and too long. I put some O-rings on them to seal to the top of the stock valve covers and they haven't leaked yet. If the valve cover fills up with oil and makes them leak, that's probably the least of my problems. There is no seal at the spark plug, either.
You're supposed to take the washer off the spark plugs & the tube seals the whole thing in the OEM, so should with this.
The tubes seal in the heads are there to prevent oil from entering the spark plug hole when you remove the spark plug and tube. What some racers did was to seal up the end of another spark plug tube and cut a hole just above the seal and pour the oil into the engine thru the tube itself, remove and insert the regular tube and spark plug
218 Buna-N O-Ring, 70A Durometer, Black, 1-1/4" ID, 1-1/2" OD, 1/8" Width (Pack of 100) Return window closed on Jul 8, 2020 $8.07 Bought mine on Amazon. You might want to try these. Bob Walker at Hot Heads recommended I use them to seal around to top of the tube in my non-vintage Donovan covers and tubes Sent from my iPad using H.A.M.B.
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