General Pulled EXHAUST threads out of the head???
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General Pulled EXHAUST threads out of the head???
the hobbler
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Sadly, a common problem with the 500/126 heads. There is only 1 proper way to repair this problem (fairly permanently). That is by putting steel inserts into the head and using studs instead of bolts. I always use the "Self-tapping steel inserts" marketed in the UK by either:---"MEMFAST" or, "THE STEEL INSERT COMPANY". Their products are practically identical to each other, and coincidentally, almost identical to the original ABARTH items that we fitted at Radbourne Racing---even on the new engines. If you are having a problem finding these inserts, contact me direct and I will put some into the post to you (and, yes, I am aware that you are in the USA).
If you contact me direct ([email protected]) I will put a copy of my thoughts on how to tune the 500 engine through to you---one of the sections in the article describes how to get round your problem
If you contact me direct ([email protected]) I will put a copy of my thoughts on how to tune the 500 engine through to you---one of the sections in the article describes how to get round your problem
the hobbler
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Did a quick bit of research for you after my last posting. MEMFAST have a US distributor------"Hanson Rivet and Supply Company
13241 Weidner Street
Pacoima
CA 91331
800-777-4838 www.hansonrivet.com
The part number that you will probably require is:---STTIMB--CR3. These inserts have in INTERNAL thread of 8 x 1.25mm--the correct and original size. If you still have problems obtaining the inserts, my offer still stands. Instead of bolts, use long studs--long enough that they can lock up against the fins of the head, and long enough where they go through the manifold that you can use 2 PLAIN nuts--1 to secure the manifold and the 2nd to 'lock' the first nut. Do NOT use 'locking' nuts. If the head is damaged to the point that you have to go up a size in insert, make 'stepped' studs--10mm into the head and still 8mm through the manifold. If you drill out the manifold to take 10mm studs you will end up with very thin walls on the manifold.
13241 Weidner Street
Pacoima
CA 91331
800-777-4838 www.hansonrivet.com
The part number that you will probably require is:---STTIMB--CR3. These inserts have in INTERNAL thread of 8 x 1.25mm--the correct and original size. If you still have problems obtaining the inserts, my offer still stands. Instead of bolts, use long studs--long enough that they can lock up against the fins of the head, and long enough where they go through the manifold that you can use 2 PLAIN nuts--1 to secure the manifold and the 2nd to 'lock' the first nut. Do NOT use 'locking' nuts. If the head is damaged to the point that you have to go up a size in insert, make 'stepped' studs--10mm into the head and still 8mm through the manifold. If you drill out the manifold to take 10mm studs you will end up with very thin walls on the manifold.
Thank you for the reply!!
Waiting to hear from Hanson Rivot.
Found these on amazon, is stainless steel a good option? link below.
[ame]https://www.amazon.com/Stainless-SUS303-Tapping-Slotted-Helical/dp/B07C6PWFGH/ref=sr_1_3?keywords=M8+Self+Tapping+Threaded+Inserts&qid=1553102252&s=industrial&sr=1-3[/ame]
Unfortunately its the hard to reach front side. Is it possible with the head in place.... any chance the hole is sized for the self tapping inserts? Or is head removal the sound choice?
On the lower one, the threads are sticking out a bit, do I remove it or try to sink it in place then install stud?
Stud length, is 60mm ish a good length? seems like a little too long is not a big deal.
Again thank you for the great advice
Waiting to hear from Hanson Rivot.
Found these on amazon, is stainless steel a good option? link below.
[ame]https://www.amazon.com/Stainless-SUS303-Tapping-Slotted-Helical/dp/B07C6PWFGH/ref=sr_1_3?keywords=M8+Self+Tapping+Threaded+Inserts&qid=1553102252&s=industrial&sr=1-3[/ame]
Unfortunately its the hard to reach front side. Is it possible with the head in place.... any chance the hole is sized for the self tapping inserts? Or is head removal the sound choice?
On the lower one, the threads are sticking out a bit, do I remove it or try to sink it in place then install stud?
Stud length, is 60mm ish a good length? seems like a little too long is not a big deal.
Again thank you for the great advice
I can see from the picture that the thread has been helicoiled before and then pulled out from the head which is not surprising when you see how short the helicoil is. It looks like someone has tried to glue the thread back in looking at the deposits present. I assume that the engine is still in the car and the pictures show the most awkward exhaust port at the back of the engine. In theory it should be possible to fit a longer helicoil deeper into the head. It is not easy but I have managed to fit helicoils to stripped threads in that same position. You are in effect working blindfolded and probably best done by someone who has fitted helicoils before.
Yes the engine is still in the car and its the blind side
Here is the helicoil I pulled off the bolt in the above pic.
It measures 10mm wide x 12mm long
Yes the helicoil would be 10mm outside diameter and when installed the head has to be tapped out to M10 X 1.25 (M10 fine) so that with a helicoil installed it restores the original M8 X 1.25 thread size. If the other hole has part of the helicoil protruding then that could be pulling out also or it may have been badly fitted or even have unscrewed a little. Best to pull that out if possible a fit a new longer helicoil deeper in in both cases then use longer studs instead of bolts.
