I put my Topspeed header and RT cat on today. The install was not without its troubles but overall it's a very straight-forward process.

Here's the deal: no matter what I did, I could not get the bottom center bolt to thread in properly. In fact, the bottom center bolt would only go in crooked - from under the car, that bolt is sloping down towards you. I tried all three of the OEM header bolts, and none of them would go past a certain point. I don't think it's Topspeed fitment as an issue, either, because even threading the bolts straight in to the block with no header or gasket, I encountered the same resistance.

I tried doing the bottom-center bolt first, I tried evenly tightening the other 4 bolts first, I tried everything I could think of.
So as it stands, I have 4/5 of the header to block bolts tightened fully and flush, but the bottom-center bolt has easily 1/2" of thread exposed. So far the car runs well and pulls harder than before, and beyond the standard Topspeed hiss, I hear no abnormal noises.

Any suggestions here? I'm thinking I will have to take it to a shop with air tools to get the damn bolt all the way in! I'm worried about it breaking or something due to me driving around with it not all the way flush.

 

Try to loosen the other 4 bolts to possibly allow for more play in the final bolt, then tighten all the the proper torque specs. Did you notice any threads stripped on the bolt you are having trouble with? Did you try to put that bolt in any of the other 4 holes? If it won't go all the way in, then you have your problem and a quick solution, you may need to replace one of the bolts. Try cleaning up the thread, and trying another one of the bolts. Good luck on this one. I know those stubborn bolts can be a beyyyyoch sometimes.

 

I'll probably end up playing with this on the weekend. On the header, two of the bolts are actually mounting studs - that is, they're coming right out of the engine, so you don't screw those in. The other three are bolts, and I tried all three of those bolts in the lower center hole, and no dice on any of them, so I dunno if the bolts are the problem.

As for loosening the other four to allow more play, I tried that. I imagine I'll be trying it again, though... thanks for the post.

 

Have you tried looking at it using a small hand held mirror to confirm that the alignment of the holes is not a problem? Otherwise, I'm stumped.

 

That's actually a good idea - thanks Jan. I just need to find a mirror small enough. I think I'll give that a shot this weekend (I'll have the car jacked up to swap my OEM wheels back on anyway).

 

maybe trying screwing the bolt in with the header off of the car, just to test and make sure it will fit?

 

^^i think he tried that. I would definitely take it to a shop and let them handle it.

 

How did the removal of that bolt in the first place go? I'd suspect perhaps the threads in the block were damaged when the original bolt was installed (when the car was built). When you removed it, you may have further damaged the threads. That bolt hole probably need to have the threads chased and hopefully that's all (unfortunately your continued attempts to install a bolt may have left the bolt hole in need of more than that though). I'd say time to consult the pros. Seems like it always something..........

 

Removal of the bolt was straight-forward - I broke it loose with my 18" breaker bar without any more trouble than the other four bolts. I don't remember if it was any harder to unthread than the other two bolts on the lower side of the flange, it doesn't stick out in my mind as being difficult.

 

Check the length of the bolt you took out of that hole, if you can remember which one is which... compared to the other bolts. If its a different length then it might have stretched the threads and you might be in a big mess.

 

I already checked acuraoemparts.com, all three of those bolts are the same (10x30) size. Thanks for the suggestion though. I consulted with a trusted mechanic and he thinks I may have cross-threaded that hole and if that's the case, I will need to have the hole re-threaded (not a happy prospect I imagine. )

I'm going to give it one last look on the weekend and if I can't make any progress, I'll be giving Acura a shout to have a look at it (luckily I'm in good with the service managers there, who are mod-friendly and know me and my car).

 

Def sounds like you cross-threaded it. Before you do anything else, simply go to a hardware store with the BOLT and have them get you a correctly sized tap. Tap the hole with the header off, and you should be okay. You may have just junked up the first thread, so after you clean it up with the tap, you should be okay