Trying to ****on up the engine so I can drop it back in the truck (hopefully for the last time). The intake isn't seating right. Here's a picture of the intake where it meets the heads. Driver side - not sitting right. This is the back port. P***enger side - looks ok. I loosened up the bolts, but it doesn't drop into place. The gasket kit came with 2 different intake gasket sets. These are the ones I did NOT use. Water ports were a bit smaller and the ring around them looks like aluminum. The ones I used had a copper ring and the water ports were a bit larger. The ring sits on the mating surface..not inside the hole. Is that right? Which gaskets should I use? Which way is up on these? Am I supposed to use any silicone sealant or install them dry? Any ideas on why the intake isn't sitting flush? Should I try the other gasket? Here's a shot of the engine coming together.
The sealing rings should rest on the mating surfaces in order to seal the port. They compress when the bolts are tightened. I really don't think you have a problem. Are you gradually tightening the bolts side to side? If you tighten one side fully, or nearly so, before the other side, it won't seat correctly. What sort of head gaskets did you use? As for what side is up, it shouldn't matter if the gaskets are symetrical, which they appear to be. That said, just being picky about details, I would put them both the same way. p.s. where the locating dowels/rings in place to positively ensure the head is located spot on? If not, the heads could be out of place slightly due to clearance around the bolts. Just a thought, not likely the problem, but worth asking. Ray
Slightly off- topic, I think I'd lose the lock washers under the bolt heads if I were you. Use hard flat washers if you need washers, split lock washers can break and work their way out. Then you have a loose bolt and a vacuum leak.
This might be the problem. I did snug up the side that seated well first. I didn't think it would matter if I snugged them down a bit, then torqued them in the proper order. I'll take the bolts out and start over and see if it helps. Alignment dowels were in the block..but the engine was put back together by a local shop that seemed to do good work. Not sure on the head gaskets...I think they are FelPro (probably came out of the gasket kit I have...he gave me all the left-overs for me to use on the rest of the engine). Don't say warped intake...this one is in such good shape. I'm not mentally stable enough to accept that it's toast.
Dan if you still suspect the intake is warped, and need another to check let me know. Ive got access to a 354 intake. Ive got a 392 intake but it seems to me that it wont work.
Please see reply#2. That will tell you if it is a manifold or cylinder head problem. If you rotate the manifold and the gap is still in the same place on the head, it is not the manifold. If the gap stays in the same place under the manifold, it is the manifold.
If you torque the intake bolts down in the correct order, rather than one side at a time, you won't have any problem. That's not a big gap, and will disappear when everything is torqued down...
yes it would narrow, thats why you should put the manifold on without the gaskets, and try to line all of the bolt holes up , and check it that way.
Going to try again today during lunch. Do I use sealant or install the gasket dry? I did put a little sealant on it the other day just around the water port on the heads...more to hold the gasket in place while I was setting the intake on the engine.
I would try this first. I had the same issue along time ago and it was because I tightened one side down first. Just my .02 I never thought of rotating the manifold 180 degrees; it seems like a good idea to rule out a warped manifold.
If you like to use sealant then use something like Permatex red spray on both sides. Warped intake? It could happen, but highly unlikely... As noted, use the proper torque pattern. As noted, use a flat washer and a thread sealer. .
Went out during lunch and did the bolts in the right pattern. It looks better, but the gasket at the rear driver side is still just a bit loose. It doesn't move around at all...but I can wiggle the edge a bit. Not sure if that's normal or if the intake isn't seated flat enough. Torqued bolts to 30lbs (saw that spec on the hot-heads site). Any ideas on how to test the seal? I was thinking of putting my shop-vac at the carb base and then spraying some type of carb cleaner at the gasket and see if I can tell if the vac is pulling air through the gasket. Can't think of anything else I could put at the gasket end to try to check it out.
Flamable aerosol of somesort will tell you in a hurry. just spay a shot down the carb to check how engine reacts, then along the gasket.
anything under it, like between the bottom of the intake and valley cover? manifold should lay on both heads and not held off one, unless tightened only one side, or some thing holding it off, warped or not.
what about removing the intake and check sealing surfaces (heads & manifold) with straight edge to see if they are flat, seems the logical thing to do.
I don't think the bolts are bottoming out. What length should the intake bolts be? Or...how deep are the thread holes in the heads? I can use that to check all my bolt lengths. I know the intake isn't seated right...I can slide a .008 feeler between the intake flange and the gasket it most places. Only spots I can't is where the copper ring is around the water port.
Old snowmobiler's (Multiple cylinder) trick. On final ***embly, we'd just start the bolts holding the heads and jugs (cylinders) down. Then we'd put the manifold on, torque it down, and then torque the heads. Some times there'd be enough "slop" around the jug mounting bolts that if you torqued the heads and jugs down and THEN torqued the intake, the aluminum intake casting would crack. I don't know about car engines, but it was essential on them old two-strokes.
So, if I'm following this right, the intake wants to sit further down than the bolts are allowing it to? So when you place the intake on the engine with the bolts it (the manifold) ends up being too narrow correct? Since this is a used intake, I'll throw this out there. Someone may have had it machined to fit a set of heads that were milled down (to raise compression or correct for being warped). If that's the case, with your heads being uncut, the intake won't line up correctly... Take the bolts and gaskets out completely, and set the intake on the heads. Then check and see if the bolt holes line up. If they don't, either the intake, or the intake sides of the heads, may have been machined. This will also help tell you if its warped. If the intake sits down on the heads and you still have any gaps anywhere, it would indicate the intake may be warped (or the heads aren't square). Having an intake cut to match a set of heads that have been milled down isn't all that uncommon, especially for high performance applications. Since it looks like you're using a stock manifold, its had over 50 years to have been machined to match up with a set of heads that were milled for one reason or another.
You really gotta verify that the dowel pins are right. For instance, 331 heads had a larger hole than the 392 heads have. I run 331 heads on my 392 and made sleeves for the heads so they'd register correctly. Plus the aftermarket came up with stepped dowel pins to go from one way to another. And while certain combinations wouldn't normally make sense - it's really hard to rule them out without looking and making sure. So are you sure the dowel pins are right???? The pic you showed of the intake gasket...as far as I know there's 2 common gaskets - the difference is the opening on the heat riser - you have the "small" openings - my 392's run the bigger ones - I can't remember what the 331/354 heads use. In any event the only difference on those is that center opening - the thickness is the same - at least on every set I ever had. I just swapped intakes on a 392 last night. There's 3 different bolt lengths with the majority of them being 2-3/4" - p***enger side end bolts being longer (don't remember how long) and the drivers side front bolt being shorter. At least that's how it was for my 392 manifold. For mine - I set it in place - there was no gap - loosely install all the bolts - slowly snug down each bolt working from side to side in a circular pattern -usually I try to do it in 3 steps - 1/3 of the torque - 2/3 - then full torque. I always double check them all inline just to make sure I didn't have a brain fart. I can't remember the factory sequence - but I've done it this way on every intake I've ever done - never an issue. .008" is of course a country mile. You could try retorquing in the proper order, but I suspect your problem is much larger than that. I believe they are supposed to be installed dry, and on pristine surfaces that's probably fine. On my old heads (even though I've cleaned them) I put the thinnest smear of silicone I can muster just on the surface for the "crush washers". I have also used the permatex red spray like 73RR suggests - but I've only done that late on a friday when I was reusing gaskets - shhsh -don't tell anyone I was that cheap - I'll only deny it. Just thinking out loud here...IF the manifold was cut enough or the heads resurfaced enough to cause these problems - it would seem to me that the manifold would be bottoming out on the screws. If that's the case and it isn't a lot - you might try drilling out the manifold or even undercutting the screws. I mean if the manifold is junk otherwise - what do you have to lose? I realize the ports wouldn't necessarily line up perfectly - but stock intake suggest this ain't a race motor anyways. Don't shoot the messenger - just crazy thoughts...
This intake isn't the one that came with the engine. The engine looks like it had a rebuild at some point in its life...but it was in an aircraft tug, so performance was probably never a factor. I'm not 100% sure the dowel pins are right...but can't imagine they'd be wrong. The heads have the right casting number for the industrial motor, so I don't think they were swapped. Doubt there would have been a reason for the heads to be milled at a prior rebuild...not like this motor would have seen high RPMs. If I pull the heads - or loosen the bolts to see if they'll match up to the intake - will that mess up the head gaskets that are new? Tomorrow, I'll pull the bolts and the gaskets and set the intake down on the heads and see what that looks like. I'll also rotate the intake and see what's up. Will report back tomorrow. At least tonight I got some more of the wiring done...there's still a lot to do on my project, so this isn't killing me time wise (yet).
Is your block a 392 and are using 331 or 354 heads?I'm just curious,because I think I read somewhere you need to use a spacer.If I'm wrong somebody please correct me.Thanks.
You could use a straw or something to "measure" the depth of each hole to the bolt your trying to put in. You might put 2 intake gaskets on, glueing them to gether with spray on copper-coat, ect.
My block is a 354...the heads are 354 Industrial Heads (casting numbers confirmed that). Good idea on the straw...sometimes it the simple ideas that are genius.
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