So I am putting the new intake on the '68 and the install instructions say not to use the end seals and use rtv. I have never used rtv instead of end seals and never had a sealing issue. Now I’m second guessing myself. Are any of you using end seals with an aluminum intake or rtv?
Go RTV, you’ll never look back (like me). Permatex Ultra Grey or Ultra Black. Put a good bead (a bit taller than the gap will end up being) and wipe the excess after the manifold is in place. Works great, it is the modern way to do it (and OEM’s do too).
Thanks. Will do.
Yes RTV only. I put a heavy bead on the block and a light bead on the corresponding surface of the bottom of the intake. Be sure it’s clean and dry. My personal preference is black and sometimes grey. Nothing looks more unprofessional than blue RTV or ever worse, copper RTV gooping out.
Good advice.
Another tip that has worked well for me-take a center punch to the 'China Walls" on both the block and intake surfaces and dimple those areas. Gives the sealer something to “bite into”.
Thanks guys. It’s been a while since I’ve built/warmed up an engine and it seems some things have changed. Like I said, back in the day everyone in my circles used the ends seals. I’m thinking that with an aluminum intake, decreased torque specs, that they don’t compress enough. I’m going black.
Done it both ways, I like using a cork gasket better if it fits properly. RTV can do the job but everything needs to be perfect or it can fail miserably.
If you use RTV only, you need to be sure all the surfaces are utterly free of oil or contaminants. You should scrub anywhere that RTV needs to stick with some scotch brite and MEK or Acetone. Let it dry and wipe it off a second time to make sure it is completely clean and dry.
For this type of application ordinary RTV is not recommended. You should use a reinforced gasket maker type RTV such as “The Right Stuff” if you want any likelihood of success.
Adhere the cork seals using Gasgacinch if it doesn’t have the peel-off strips, then a dab of RTV at each corner. Drop the manifold straight down. I’ve never had a leak using this method.
For this type of application ordinary RTV is not recommended. You should use a reinforced gasket maker type RTV such as “The Right Stuff” if you want any likelihood of success.
Not all RTV are the same and this is the Cats meow for sealing the ends of the Intake. Use Dow corning 9-1363 at work on OEM engines and I use it on all the old stuff as well. http://www.mcmaster.com/#dow-corning-9-1363-adhesives/sealants/=14ndheq
http://www.lentusllc.com/wp-content/uploads/2015/06/TDS-9-1363-Assembly-Sealant-Adhesive.pdf
Got everything spotlessly clean and did a test fit last night. No issues and all bolt holes lined up. So I’ll be torqueing it down tonight. Well, there was one issue. The driver’s side stud in the back would not come out and having dealt with that mess before I used the trusty old die grinder and took the back down about an 1/8 inch so that the nut would grab enough threads that I’m comfortable with it. It’ll also help to make sure I stay lined up when I drop it down. Tried a punch on the top of the bolt, heat, PB Blaster, and the list goes on with no success so it’s staying.
So I got the intake torqued down and test fit the carb (summit 600), and went and bought a 3/8 spacer today as the accelerator pump was laying on the port. I hope this gives me a little more clearance with the coil too as the dual feed line is right where the coil is. I’m also putting the throttle rod on the drill press and drilling a hole for a cotter pin as I don’t trust the crappy little aluminum holder. Not a lot of room on top of a 289. Come to think of it, not a lot of room between the carb and the hood either.
So everything is on and took it for a shakedown run. No leaks from end seals etc. I will say that an Eddy carb would make for more room on my tiny little small block, but I have had the carb for four years and got it for cheap from my nephew when he decided it was too much for a stock 304. I basically got a brand new carb for $75.
Putting this intake and carb on made me glad that I went back to the XE256 cam. They seem to work well together.
