Toyota Head Gasket Limitations?

[the t3d]

I have a couple questions. First, with the minor pitting in the block, it seems to be that a composite gasket is the way to go, preferably a Toyota gasket. I’m OK with this if I have to. I will be using ARP head studs to go with it, so I’m covered there. The issue I am having is my power goals are about 450rwhp. I’ve hit the 400 mark with my old metal gasket but the timing cover surface wasn’t perfect and eventually wouldn’t hold coolant pressure anymore. So, with a freshly rebuilt head with unknown ra’s, and a surface prepped block, would that gasket be sufficient for my goals? What are these gaskets rated at or capable of? I know head gasket thickness is important for the overall compression ratio, but with a compressed stock gasket that is only 1.37mm thick, I’m worried that if requires more to get back to the stock dimensions, what would the best thing to do? If you need more info lmk. I’ve read sooo much regarding my situation as a whole, so I’m really curious to know what you guys think…
Thanks!

 

[Nick M]

The Fel-Pro® PermaTorque® is a steel gasket with a composite facing specifically for repair. That is a much better choice than the standard composite gasket if you are pushing power. Especially when you have some detonation at that level.

 

[suprapilot]

I was also wounder about the latest Toyota gasket? Japan always makes the best! I'm scared of Fel-Pro but if people have tested it to be better then Toyota on 500+ HP? Would love to hear from them?

One thing I do know is that you must do the head bolt inserts to make it reliable permanently.

Here is a PDF from Fel-Pro

http://fme-cat.com/livedocs/PermaTorque.pdf

Seems like the PrintoSeal HG is the best they make? Does anyone know which of the 3 types of PermaTorque the 7m gasket is? Please reference the PDF for the 3 types.

PS Just saw on Amazon that part # for 7m is 9473 PT. It shows that country of origin is Japan? I wounder if this is also what Toyota is selling?

 

[Nick M]

I'm scared of Fel-Pro

Why? Is there something you know that automotive manufacturers don't know?

PS Just saw on Amazon that part # for 7m is 9473 PT. It shows that country of origin is Japan?

There is only one Perma-Torque by Fel Pro for the 7MGTE-7MGGE.

I wounder if this is also what Toyota is selling?

No. The Perma-Torque is a steel gasket. Not to be confused with a MLS. It has a composite face so it seals on an improper surface. I probably shouldn't say that on this forum.

 

[suprapilot]

Hi Nick,

Is Fel Pro an OEM supplier?

The fact that my search shows they do make gaskets in Japan is a HUGE plus!

Has anyone used the latest Toyota and Fel Pro gaskets to compare to each other?

 

[the t3d]

There is only one Perma-Torque by Fel Pro for the 7MGTE-7MGGE.



No. The Perma-Torque is a steel gasket. Not to be confused with a MLS. It has a composite face so it seals on an improper surface. I probably shouldn't say that on this forum.

Oh man. I appreciate you bringing this up. I'm gonna look into that. I promise you, I went through sooo many posts trying to find what's gonna work the best for my situation. No one has mentioned this one yet, but I knew there had to be a middle ground between the two. I would trust Fel-Pro over most others, so I am OK with that. Now, to source one...

suprapilot, what do you mean by door the head bolt inserts?

 

[the t3d]

So with a little digging, I found AutoPartsWarehouse.com has them, but in a kit form. I already have a gasket kit, but it looks like I might have to get another one. BUT then I just googled the part # and found a few options! I think that's the best route to go! Thanks, Nick.

 

[suprapilot]

Oh man. I appreciate you bringing this up. I'm gonna look into that. I promise you, I went through sooo many posts trying to find what's gonna work the best for my situation. No one has mentioned this one yet, but I knew there had to be a middle ground between the two. I would trust Fel-Pro over most others, so I am OK with that. Now, to source one...

suprapilot, what do you mean by door the head bolt inserts?

Oh sorry I mean do the head bolt inserts. I read so much info on the latest on 7m stuff since I was out of the loop since the 90s lol.

One of the members figured out that the head needs inserts put into the bolts to stop the head from de torquing.

Oh it's on Supra Forum.

http://www.supraforums.com/forum/showthread.php?683040-finally-an-answer-to-the-7m-head-gasket-issue

I spoke with the member on the phone. Real nice guy. Anyhow read that link. This is the final answer to head problems on the 7m.

 

[suprarx7nut]

Oh sorry I mean do the head bolt inserts. I read so much info on the latest on 7m stuff since I was out of the loop since the 90s lol.

One of the members figured out that the head needs inserts put into the bolts to stop the head from de torquing.

Oh it's on Supra Forum.

http://www.supraforums.com/forum/showthread.php?683040-finally-an-answer-to-the-7m-head-gasket-issue

I spoke with the member on the phone. Real nice guy. Anyhow read that link. This is the final answer to head problems on the 7m.

Thanks for the link. I've seen the thread, but hadn't read through everything. I can see how that would help, especially with annealed heads (most all 7Ms by now...). I think that's a bigger issue above 500 whp, but may still be beneficial for lower power builds.

I guess OP here is near that threshold so it's pretty relevant. The inserts make sense, but if the head is soft I think it will still deform and lose its seal. To know if that fix is actually a "fix" would require a lot more controlled empirical data than we have now.

 

[Nick M]

Fel-Pro makes many gaskets for automotive manufacturers. I should say Federal-Mogul. I have opened AC Delco and Motorcraft packages in the past and on one side is say...a Blue Oval, and on the other side is the Fel-Pro stamp.

If you get Toyota Motor Corp out of Japan to comment then do share. Toyota Motor Sales the division out of California is one of the worst places to learn anything in that line of thinking. But think about all the parts stamps on your car under the hood. NipponDenso, Fuji (high dollar), Mitsubish, Toyoda....

 

[JDMMA70]

Stone | Ishino is the OE supplier for gaskets/seals to Toyota for the 7M.

 

[suprapilot]

Thanks for the link. I've seen the thread, but hadn't read through everything. I can see how that would help, especially with annealed heads (most all 7Ms by now...). I think that's a bigger issue above 500 whp, but may still be beneficial for lower power builds.

I guess OP here is near that threshold so it's pretty relevant. The inserts make sense, but if the head is soft I think it will still deform and lose its seal. To know if that fix is actually a "fix" would require a lot more controlled empirical data than we have now.

According to Quake, He has logged A LOT of use with 700+RWHP and still holds bolt torque. Even if your engine is stock this will still benefit. They start to loosen as the bolt ever so slightly sinks into the head.

 

[suprapilot]

Stone | Ishino is the OE supplier for gaskets/seals to Toyota for the 7M.

Nice to know thanks!

I wounder who the supplier is to Fel Pro because the HG they sell is made in Japan from my research so far? It could also be that they have a factory in Japan??? I doubt it though?

 

[the t3d]

That link is quite interesting. I can totally seeing this make sense. I'm gonna have to look at the one I'm about to put on. It's complete but not installed so that might help a little the examining it. I'm really curious as to how many people actually have done/did this. I mean, if you think about it, this can happen to literally any aluminum head so this should be a pretty well-known problem, right?

 

[suprarx7nut]

I have 2 heads in my garage I can check. They both suffered a BHG at some point, one was very soft. I expect you'd see a big difference in the diameter of the hole at the top and bottom if this was a significant source of the BHG phenomenon.

As IJ has said though.. once the head is soft it's just done. Anything you do aside from hardening it again is just a band-aid for cancer.

 

[Nick M]

That link is quite interesting. I can totally seeing this make sense.

Good because it is a real problem for any engine. If the engine is not over heated, it is likely that won't happen. Annealing is the correct term, IJ likes to use it as he blazed some impressive trails with the 7M and found strengths and weakness.

 

[suprapilot]

That link is quite interesting. I can totally seeing this make sense. I'm gonna have to look at the one I'm about to put on. It's complete but not installed so that might help a little the examining it. I'm really curious as to how many people actually have done/did this. I mean, if you think about it, this can happen to literally any aluminum head so this should be a pretty well-known problem, right?

Your right. This is why ARP makes those inserts for heads. I'm sure they know high clamping forces and metal fatigue plagues heads.

Quite a few people have done them from my searcher. There is NO WAY I won't do them once I get a head off. Guys that do them report that the head keeps torque. If you don't do it. Even with the block and head decked with a MHG. It will lose torque with head studs. Good luck clamping down head bolts 90+ ftlbs and not sink in.

 

[suprapilot]

I have 2 heads in my garage I can check. They both suffered a BHG at some point, one was very soft. I expect you'd see a big difference in the diameter of the hole at the top and bottom if this was a significant source of the BHG phenomenon.

As IJ has said though.. once the head is soft it's just done. Anything you do aside from hardening it again is just a band-aid for cancer.

I did read posts that mentioned that they used inserts in soft heads. It worked! Kept torque under high boost. It was stated that after 6 months that it was re torqued and a few studs move a tiny bit but still kept torque. Then after another 6 months it didn't budge at all. Still kept torque with an otherwise junk head that would have been trashed. Heads are going to be hard to come by and most will be soft so this is good news.

 

[the t3d]

Thanks a lot for posting that up. I did a lot of reading and whatnot. Since my head is off and the block is out, I'm gonna be a little more patient and snag these sleeves, get my head checked out and install these, and then snag the Fel-Pro Pertatorque gasket. I will feel SOOO much better with my goals and being durable with that power. I'm also getting the turbo rebuilt. The block has new pistons, Eagle rods, and ARP everything. The tranny has been rebuilt as well. I am finally starting to believe I can get this done, and get this done right. I love this forum. You guys are awesome.

-Ted

 

[suprapilot]

Thanks a lot for posting that up. I did a lot of reading and whatnot. Since my head is off and the block is out, I'm gonna be a little more patient and snag these sleeves, get my head checked out and install these, and then snag the Fel-Pro Pertatorque gasket. I will feel SOOO much better with my goals and being durable with that power. I'm also getting the turbo rebuilt. The block has new pistons, Eagle rods, and ARP everything. The tranny has been rebuilt as well. I am finally starting to believe I can get this done, and get this done right. I love this forum. You guys are awesome.

-Ted

I plan to do the same if I need to. I don't want to pull the engine and have it stripped down to resurface the block. Id do studs and inserts after like you are with the possibly Perma Torque HG. I wounder how the latest Toyota HG seals?