Thread: Bbc, o-ringed block

Tweet

I recently bought a 496 c.i. motor, built with 14:1 pistons, Callies forged crank, Dart Pro 1 heads (310). Recently assembled, with no miles on it. I installed it, made a couple passes, and found the motor was blowing a little oil out of the intake, I decided to pull the heads off.....just to check things out. The motor is a 1969 427 4 bolt main....according to the research I've done on it. Everything looks o.k., but the deck of the block has 0-ring grooves with no o-rings in them. I never heard of this procedure before, but a lot of you may have. I talked to the guy I purchased this motor from, and he said it was an old race motor, and that was done years ago. I need some opinions. Should I just put it back together with the Felpro Blue head gaskets, or should I look for another block. I have 2 different engine builders telling me conflicting opinions. I figured I would try the really knowledgeable people on this forum. Any input will be appreciated. Thanks. Oh.... I should mention.......I found no noticeable head gasket leaks when I tore the motor apart, but keep in mind....there was very little running time on this motor.

a little oil out of the intake????can you maybe elaborate a little as to what you mean???

As for the oring grooves----are they maybe around 4
.040 wide and .030 deep??? and pics

Front and rear seal of the intake....I was getting a steady drip while the engine was running. That's why I took the heads off....to see if there was a noticeable problem with a piston / ring. It may be that it wasn't sealed that well when assembled....they just used the black silicone seal with no front or rear gasket. I know this is done a lot, but having had problems in the past, I always use the gasket. The oring grooves are about .040 wide, but I would say close to .020 deep.....probably not .030. I don't know how to post pics here, or I would do that. Thanks.

I would reseal the intake (not using the frt. and rear gaskets). I dont understand why you would not use the O-ring block .when you have 14:1 compression. I would install o-ring and put the heads on it and let that dog eat.

you do not need o rings at 14to1 with a felpro1027 or 1017 gasket or any of the plate fel-pro racing blue gasket do not use the oem blue felpros you will blow the fire rings out . if the fire ring is ahead of the old o ring grove or in back your ok if the head gaskets cross the fire ring and hangs in the o ring grove in the block you can use a bigger bore gasket like a 1057 .thats the only thing i would watch out for if this happens you could use copper wire in the deck.BUT if it hang the head up off the deck the heads will leak water .so you need to know the O ring groves are the right depth.then you could use your head gaskets or deck them out re work the pistons or use a thicker msl gasket like cometic

I bought the motor assembled, new heads, rotating assy., cam, etc.....unaware that the block had been oringed. I want to salvage the block as it's a good vintage block. Maybe my best option would be to just put a good set of multi layer gaskets on, and not worry about it.

Originally Posted by lodilobo

I bought the motor assembled, new heads, rotating assy., cam, etc.....unaware that the block had been oringed. I want to salvage the block as it's a good vintage block. Maybe my best option would be to just put a good set of multi layer gaskets on, and not worry about it.

you need to know that your sealing up good. if your ahead of the o ring grove or in back of it with a bigger bore gasket no need for the msl there not going to seal up any better if you cross the O ring grove in the deck if this happens you going to have to seal that up

Thanks for the info. on getting the right gasket....to make sure it's behind or in front of the oring groove. That seems to be the best option at this point.

Originally Posted by lodilobo

Thanks for the info. on getting the right gasket....to make sure it's behind or in front of the oring groove. That seems to be the best option at this point.

yep the head gaskets fire rings are not round like the o ring s in the block .so the head gasket can hang in it . sealing up the o ring groove fel pros will bite in the groove filling it some what .were the msl would not sealing it up this at all so you need to check that. i have seen guys get away with the fel pros like this .i do not care much for this as i like the gaskets to move on the deck so you want to say away from theO ring groove if you can

Just saying if the groove is the right depth why not install o-ring. Sure cant hurt