F14CRAZY

Supercharging (this time, it's real)

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Philip, that is good news if you didn't get any bubbles up thru the cooling system during the leakdown tests. The little amount of air you heard escaping was probably that which was working its way past the piston ring end gaps.

Of course there is still a very small possibility that you might have a cracked cylinder. It wasn't clear exactly how you did your tests but if you did them with the piston at bottom dead center, that should check the whole cylinder bore for leaks.

At this point, like another person said earlier, it is far more likely you have a gasket or intake manifold failure that is letting coolant into the oil and induction stream. I would remove the lower intake and inspect all sealing surfaces carefully. DO NOT try to reuse the intake gaskets; it's not worth the risk. Also, if you use RTV on the end seals, apply the RTV, install the lower intake, start the bolts but do not tighten them down for about 30-60min. After that time has passed, torque the intake to specs. You don't want the RTV to fully cure before tightening down the intake because the RTV could prevent the proper gasket crush to take place. Also, allow the RTV to cure overnight before starting the engine.

Let us know what you find once you get the intake off.

-ryan

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All here in NWI are pulling for you in your quest to SC your Reatta.

Try not to view whats going on with the car as problems. What's really going on is that the car is <span style="font-style: italic"> <span style="font-weight: bold">talking</span> </span> to you. It's telling you what it needs. You just have to learn the language.

Good luck.

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Got the manifold off...

The manifold, mating surfaces, and gaskets have no visible flaws. I looked pretty closely but it looks normal to me. I did find a bit of coolant in the valley, indicating to me that the head-to-manifold gaskets were at fault. There is a little bit of spillage when actually taking the manifold off but not enough to have as much as I found in there. Below the ports, the gaskets were wet, and with a wipe of a finger, more coolant than oil.

So, there was coolant in the valley. With the round PCV ports dead-ending at the heads, are they under pressure? Could it have disrupted the nearby coolant port?

sc19.jpg

I'll see about some new gaskets

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I did go back out and re-inspect. No cracks or flaws. I also measured the front ports to back ports in the valley of both the LN3 and L67, and they're the same. Being both GM 60 degree V engines, the angle is the same. I obtained the funding for the gaskets so I can order tomorrow cool.gif

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The unused PCV port should not bother the coolant port, they are sealed independantly. I do not know exactly how the passengers side port ends at the manifold. I would imagine it is above the lower intake so it does not see boost pressure. It could end below the actual blower if they were expecting the PCV valve itself to act as a check valve, but I have not found them to seal perfectly all of the time. In any case, the coolant pressure can be approx. double what the maximum boost pressure will be.

I measured the TPI and stock vin C manifolds every which way I could think of and they appear to be identical regarding the sealing surfaces. The machined length of the valley ends is exactly the same, the distance between opposite ends of the valley are the same, all the bolt holes are in the same location, the distance between the upper edges of the sealing flange to the heads is the same and the angle the between the port flanges and the machined edge where the valley meets is the same, almost a dead perfect 45* on both manifolds. There is no apparent reason the two manifolds will not interchange. I have found that you need to tighten the intake manifold in small steps over and over as you torque it down. These gaskets are better than most since the silicone bead squashes very easily but the main body is very solid so they don't keep flattening over time. The flange of the manifold is relatively thin so it pays to sneak up on the final torque a little at a time. I don't recommend reusing the gaskets, but I did look at the gaskets I pulled from the junkyard engine that donated the TPI manifold and if it wasn't dirty from being used, the sealing beads of silicone are all above the surface and unmarked so they would look brand new if clean. This is a 90* V6, the Chebbie 2.8 and 3.1 are 60* grin.gif

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My bad on the degrees of the V tongue.gif

How exactly should I be torquing the intake manifold down? The manual lists 9 ft/lbs. Is this right? I'm pretty new to torque wrench use

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Think in terms of torquing the lug nuts on on a wheel, you stagger your tightening across/ around the pattern. You really should consult the service manual. Certainly the one I have for the S/C I'm certain lays out the torquing sequence for the intake dome.

Think of it like a clock face, only squarer. You start at 12 o'clock and just snug the bolt, go from there to 6 o'clock, then 3 o'clock, then 9 o'clock, then 4:30, then 1:30, then 10:30, then 7:30. Back to 12 o'clock and start all over again. You'd go around this pattern 3 or 4 times with a spanner or socket wrench before you ever got near the torque wrench. As Hal says, sneak up on it.I would use a half value on the torque wrench, in this case 4 and a half Ft Lbs and step it up a pound or two ber torque pattern. Brute force should be left in the Tool Box for when you need to bust stuff loose. Overtorquing any portion of any assembly is going to result in unbalanced stress-break off bolt flanges or result in leaks. I guess I forget you're just a Pup! Torquing correctly is vital to any mechanical assembly for reliability, etc, etc. Same would apply to cylinder heads, check a FSM and you're going to find a specific torqing pattern for this type assembly. But the same pre-torque approach must be applied, getting uniformly snug pull on each and every bolt to pull the faying surfaces together and compress that gasket evenly over its' entire surface.

Need to ask now, how exactly did you tighten down both the the manifold and the blower when you installed these on your 3.8L or had them off and reinstalled.

Hope this is coming across as helpful, don't mean to be critical but this is basic mechanics, also have to realize you have to learn it somewhere. And the School of Hard Knocks is definitely the best and enduring way to learn!

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Looked in both 88 and 92 manuals and the spec is 88 in-lb (actually about 7.3 lb-ft and that seems incredibly low for an intake manifold. I would have expected more like 15-20 lb-ft. Any idea why it is so low ?

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<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> I'm pretty new to torque wrench use </div></div>

Phil, let's go back to some basics. First of all get a good torque wrench. Get the kind where you dial in the torque at the handle, not the old "beam" type. Mine is a Craftsmen, got it for $75.00 on sale. Always zero the wrench after every use. I think the guy on the Bonne board suggested new bolts because some are designed to stretch when torqued. Make sure all threaded holes are clean. Like Greg said, use a criss-cross pattern when tightening, and arrive at your final torque value in steps, using the same pattern. I have done far less stripping and breaking since I figured out that using the torque values was the only way to go. This becomes very important for sealing some gaskets.

I hope this helps. cool.gif

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Frankly I am a bit puzzled. While I am used to torqueing in stages for head and wheel nuts, both are usually over 50 lb-ft. Your tighten to "snug" then alternate. I am not at all sure how to do that for a 7.3 lb-ft spec when "snug" is around 10 lb-ft.

Obviously the last time I put a manifold on a 3800, I must have done it wrong because I tightened like a spark plug which is more like 15 lb-ft. That was five years ago and it never leaked.

BTW I do have a Craftsman beam wrench in in-lbs. It is a 3/8" drive. Just put in a vice and went to 100 in-lb with my little finger.

Something just does not sound right but checked FSM for both "L" and "C" - same-same 88 in-lb

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I did find the bolt torqueing sequence on page 6A5E-8 of the FSM.

Advance had the head to intake gaskets in stock which I picked up, but have to wait until tomorrow or Saturday for the throttle body and supercharger gaskets. I did pick up some more RTV which I will be using as you guys described instead of using the two rubber strips that run bank to bank. That what you had in mind?

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You have the right idea on the RTV instead of the gaskets on the ends. Just form a small bead, let it sit to firm up a bit before installing the manifold. Frankly I did not remember the torque value on the intake being so low. I just did a 5 liter Ford this last weekend and it was 22 ft/lb, but that was a composition gasket that squashes down over the entire surface. The silicone bead requires very little force to flatten them but I would have though the torque value would be somewhat higher since the bolts pull the manifold down at a small angle to the actual surface and I would think sliding friction would require a little more force? With a torque value that low it is critical the surface is perfectly flat since there isn't enough force to move the flange. It would seem, as Padgett points out, that overtorquing a little didn't hurt anything as long as it was done in small steps and in the right sequence. The substrate of the gasket is very firm and should prevent the flange from warping.

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Before, I used my 1/2'' drive, 10-150 lbs or so clicking Ampro clicking torque wrench. I did just kinda set it under to do the 7.3 or so ft/lbs (88 in/lbs) but I'm learning quick, and that's not going to be accurate enough. Advance and Autozone didn't have a torque wrench that goes down that low (120 in'lbs was the starting) so we went to a hole in the wall auto parts dude thats been there for 30 years or so, and he'll have one in for me tomorrow morning (20-200 or so in/lbs). I guess when it comes to this, you can't really guess at things.

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There's a good chance I may have the gaskets tomorrow and can assemble. With the throttle body and the supercharger gaskets, should I use anything at all on them? I've used that brown permatex stuff but maybe I should use them as they are. I'll be sure to do a top notch prep job cuz I'm tired of pulling things apart frown.gif. Counter dude at Advance suggests blue RTV on the gaskets, but I don't know. Will be torquing everything though, and in sequence

Do know the intake manifold gaskets should not have anything though.

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Another little tip: anytime you use RTV or any other sealant, do not start the motor until the sealants have had plenty of time to cure. If the stuff migrates into oil galleries, you will fry the motor. frown.gif

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Ah yes. Have taken that precaution. Will let it sit at least overnight, just to be sure. Would not be nice for it to seal up my oil passages.

The page that Ryan emailed me for the manifold says to use thread lock on the intake manifold bolts...that necessary?

When putting the manifold together, I propose to start all the bolts and turn them with a socket and extension (no driver) until they stop, and then torque them to the 88 in/lbs in sequence according to the FSM. That sound good?

Holes and bolts will be near-sterile grin.gif

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<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">Ah yes. Have taken that precaution. Will let it sit at least overnight, just to be sure. Would not be nice for it to seal up my oil passages.

The page that Ryan emailed me for the manifold says to use thread lock on the intake manifold bolts...that necessary?

When putting the manifold together, I propose to start all the bolts and turn them with a socket and extension (no driver) until they stop, and then torque them to the 88 in/lbs in sequence according to the FSM. That sound good?

Holes and bolts will be near-sterile grin.gif </div></div>

I think the threadlock and low torquing of the bolts is necessary because the intake gaskets are constructed of plastic (IIRC). These gaskets are designed to seal great with low torque applications but will crack if overtightened. The blue loctite you are supposed to use on the intake bolts serves 2 purposes: 1) provide a positive seal against oil seepage and 2) lock the bolts in place so they don't loosen, due to the low-torque nature of the specs.

GM had huge problems on later engines using the plastic intake gaskets because it was so easy to overtighten them. I can't count high enough the number of engines I have seen in the core pile at the junkyard that failed because of these dumb plastic intake gaskets that were not installed/torqued properly.

Just so we are clear:

-Clean the threads in the heads and on the bolts (it is OK to reuse the lower intake bolts)

-Use blue loctite on the lower intake bolts

-Tighten to factory specs and sequence

-If you use a bead of RTV to seal up the end seals, make sure you let it set up overnight before starting the engine. Also, do NOT let it set up for more than about 30min (depends on type of RTV) before you torque down the intake. The reason why is because I had a friend let his fast-curing RTV set up for 1 hour on his Vortec 4.3 V6 before tightening down the intake and it was so hard at that point it wouldn't let the intake seal properly -- once he started the engine, coolant sprayed everywhere! Also, MAKE SURE anywhere you use RTV the sealing surfaces are completely clean and free of oil or solvents!

-ryan

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Thank you Ryan, I'm now sure of what I'm doing. I have to pickup the gaskets and torque wrench tomorrow, so I'll get some blue loctite too.

Didn't think about it much, but what's the best way to clean out the bolt holes?

I can let the bolts sit in Chem Dip (don't want stuff with a name like that on your skin) for a while and then do the rag and fingernail trick

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<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">

Didn't think about it much, but what's the best way to clean out the bolt holes?

</div></div>

Thread chaser. Kinda like a thread tap but a little different. Make sure you get out a vacuum cleaner and prevent any debris from falling in the engine while you are doing this.

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Advance didn't have my throttle body gasket yet, and the other store didn't have my torque wrench. Both will have to wait until monday. But I decided to do some prep work. I thought I had them pretty clean but still was able to get them cleaner.

Should I use a tiny bit of RTV on the supercharger/manifold O rings? I ask because there's a tiny bit of corrosion (really can't feel it with a fingernail).

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it would be a shame if you get this thing together again and the head gaskets are bad...just something to consider, maybe even the l67 heads

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I think my head gasket test was pretty effective. L67 heads would be an upgrade, but we gotta get this car on the road. Gotta get the calender done grin.gif

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Seems to be some discussion on the lower inake manifold to head torque values ( See here ). That 88 lb-in (7.3 lb-ft) value just sounds too low to me especially on a boosted engine.

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Honorable Padgett: Ryan sent me an Alldata page on the torque specs for the L67 and it came out to be the same 88 in/lbs.

Picked up my torque wrench and blue threadlock today (forgot the throttle body gasket). I've got the intake manifold and S/C mounted. I got all surfaces smooth and near sterile. As mentioned, I used blue RTV instead of the rubber seals in the valley. I did this installation as close to textbook, err, FSM, as possible. Getting tired of doing this over and over, and buying the same gaskets over and over tongue.gif. I followed the intake manifold torque sequence too.

Tomorrow I won't forget the TB gasket and will assemble everything else. Should be able to commence Initial Startup 2.0

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