Intake manifold gasket failed

[Donkeyteeth]

Does anyone know what could have caused my intake gasket to fail like this? All four of the runners I can see failed the same way, the gasket was sucked down and broken. Installed them about 1000 miles ago and it was probably leaking for some time but the Holley Sniper hid it well except for idle issues.

128355 128356

Engine is a stroked 393w Edelbrock Victor Jr. heads and Victor Jr. manifold. I installed as the instruction showed: gaskacinch the intake gaskets down, black RTV on bother valley ends, torqued outside-in to 18-20 ft. Lbs. per Edelbrock.

Also, heads recommend Felpro 1262, intake recommends equivalent to Felpro 1250. I used the 1262.

I ordered up the 1250s3 and 1262s3 and will install whichever fits better. Just want to make sure I don’t have the same failure. I’m pulling it apart this weekend.

Thanks!

[Norm B]

Did you re-torque the manifold bolts after a couple of heat cycles? If you did and they still failed like that, check your clearance at the China walls. If the clearance is too low there it won’t allow the manifold to move down enough to seat on the heads.

HTH

Norm

[Badfish]

I had the non-S3 version fail on me, no issues with the S3. I had the same problem as you. Car ran like crap after a very short while with the non-S3 version because the gasket broke apart.

Now, I didn’t put enough silicone in the valley, so I have an oil leak, but that’s another story! Good luck.

[Donkeyteeth]

Did you re-torque the manifold bolts after a couple of heat cycles? If you did and they still failed like that, check your clearance at the China walls. If the clearance is too low there it won’t allow the manifold to move down enough to seat on the heads.

I didn’t re-torque. I’m pretty sure it’s install error by me and not properly torquing the bolts. My search has shown a different torque sequence than what Edelbrock recommended. Edelbrock has you start with the outside boots and work inward. I’ve been reading most people torque from the middle out. Does it matter? I just don’t want to pull it apart again for another gasket failure.

I’ll make sure to do a dry fit this time and check my angles and gaps too. Thanks!

[Jeff Kleiner]

Be sure you use the steel core gaskets. I always run the torque sequence about 10 times, let it rest for 12-24 hours then run it a couple more times. With their low torque values these small block Fords don't do well with being torqued just one or two times.

Good luck,
Jeff

[CraigS]

Last time I had mine apart it took 6 re-torques before all of them stopped moving. I also upgraded to ARP studs and nut vs bolts. The feel of a steel nut tightening on a steel stud is so much better than steel into aluminum. I think that w/ studs/nuts you get more actual clamping force for any given torque.

[mike223]

I had the non-S3 version fail on me, no issues with the S3.


Be sure you use the steel core gaskets. I always run the torque sequence about 10 times, let it rest for 12-24 hours then run it a couple more times. With their low torque values these small block Fords don't do well with being torqued just one or two times.


+1 to all that.

The S3 is the steel laminate gasket.

One story I heard on the internet was the non S3 version is just for race engines that are soon coming back apart anyway.

Another story I heard was that Ford Motorsport had so much trouble out of the original gaskets (1250, 1262) that they specified a steel laminate to be added to that gasket (the S3 part).

[Avalanche325]

Here is the install sheet for Victor Jr on a 351 block.
https://www.jegs.com/InstallationInstructions/300/350/350-2981.pdf

As everyone says, do it several times, and then after a couple heat cycles, and then periodically for all eternity.

[GoDadGo]

If you are using ARP Stainless intake bolts, consider using BLUE Loctite on them.

Those bolts are so slippery that they can easily back out over several heat cycles.

[Donkeyteeth]

Thanks everyone! I have new ARP bolts and when the S3 arrives I’ll be sure to torque everything down multiple times. I was cringing last time because of the aluminum heads. Can’t wait to get it all back together so I can drive it again. I’ll have to decide if the Sniper is coming back eventually. I converted back to a carb before I found out about the failure.

[johnnybgoode]

When you have everything cleaned up I'd dry fit the manifold and check for any gap at the cylinder head. If the block was decked the manifold mating surface may be out of spec. The machine shop I used for my 408 build pointed out they had milled my manifold. Just my 2 cents for what is worth. Scott

[Bad Moose]

Times 2 on what Jeff Kleiner said.

The other thing is the torque sequence. Middle out cross pattern, finger tight, 1/4 tight, 1/2 tight, 3/4 tight and then finally full torque several passes. When the bolts stop torquing, 2 passes with 30 minutes in between passes and then the next day + 3 more passes. I have never had an issue with this from 4 cylinder to 3612 CAT engines with everything in between. When assembling PATIENCE, along with slow and steady is the key.

[Richard Oben]

We torque as many times as it takes for all bolts to be the magic 18 ft/lbs. 3 rounds, 10 rounds, 20 rounds. We then let is sit 24 hours and then check again. We silicone seal all of the ports with a little tiny bit of sealer. Seal the ends with Permatex gasket maker. We bought four long, six inch 5/16 bolts, cut the heads off and slotted the ends for install and removal. Always slide the intake straight down on the long bolts, put the other bolts in and then remove and replace the long ones. Then we fill with water and run to temp. Torque again. We have seen many, many leak but not after we do the job this way. One of the few times it would be nice if the bolts went straight into the head and not at an angle. JMHO, YMMV. Richard.

[Donkeyteeth]

Pulled it apart today. After reading everyone’s replies and looking at the gasket, I’m 100% sure I did a piss poor torque job on the manifold. I don’t think I’ll be using all that gaskacinch this time either. What a mess.

128437

I mocked it up with some Edelbrock gaskets I had, the deck height and angles all look good. I really appreciate all the help and advice. I’ll get it right this time. Thank you everyone!!

[Railroad]

Don't blame yourself, it was the cheap Felpros. The cardboard melts at the water passages.
The internet is full of reports of the same issue.

[Railroad]

Don't blame yourself, it was the cheap Felpros.
The internet is full of reports of the same issue.