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Manifold stud positions


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Colleagues

I have a high port head with both lower outer exhaust manifold studs sheared off below the surface. I plan to drill them out but could benefit by making up a, reusable, drill guide jig to drill them as centrally as possible. Can any body help with accurate dimension for the inlet and exhaust manifold stud centres ? 
Any help appreciated

Regards

Rog

 

 

 

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11 hours ago, Icarus60 said:

Colleagues

I have a high port head with both lower outer exhaust manifold studs sheared off below the surface. I plan to drill them out but could benefit by making up a, reusable, drill guide jig to drill them as centrally as possible. Can any body help with accurate dimension for the inlet and exhaust manifold stud centres ? 
Any help appreciated

Regards

Rog

 

 

 

Don't bother, bang a centre punch about central into the stud and use a fluted stud extractor tapped knocked into a drilled hole (that's what the centre punch mark is for) and using a suitable fluted extractor with slip over hex nut just undo the sheared off stud. The extractors look like this

Available on Amazon for under £30, comes as a complete kit with drills and centralising bush to drill through and the tap the fluted extractor into the hole. (Amazon now out of stock, just checked and this Neilsen set https://www.ebay.co.uk/itm/172279869503 is what I've got and is fine and does the job, cheaper here on e bay than Amazon ).

This is important, these extractors have fluted drive faces that go end to end, there is no stress raiser which is the problem with so called "easy outs" the left hand thread on these where it runs out at the top is weak and will shatter as soon as you put any torque on it. These fluted extractors do not have this problem and you can use a torque wrench on them, I've used 80 lbs on a 3/8th sheared bolt...it came out, no problem.

Mick Richards.

 

 

 

 

Stud extractor.jpg

Flange extractor set.jpg

Slide flanged nut over stud.jpg

Stud extractor finish.jpg

Edited by Motorsport Mickey
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8 hours ago, rcreweread said:

Mick - the best I could find was this link at £95 not £30 : 

https://www.amazon.co.uk/s?k=Hazet+841%2F25&crid=30F8AM77PT1MS&sprefix=hazet+841%2F25%2Caps%2C73&ref=nb_sb_noss

Have you got a better link/source?

Cheers Rich

Here you go Rich, there's a variety on e bay just make sure you pick a fluted set, this one is from US Pro at just under £20.

https://www.ebay.co.uk/itm/263601363424?hash=item3d5fdd99e0:g:rJ8AAOSwupRazk77

I have a Neilson set which I bought at just under the £30 from Amazon but the offerings vary as to when you go on. Looks like I waz robbed here on e bay for under £20...it works fine.

https://www.ebay.co.uk/itm/172279869503

regards Mick

Edited by Motorsport Mickey
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Thank you Mick but I will still appreciate knowing the stud positions if anybody has the dimensions available.

regards

Rog

 

 

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Ive got the Snapon version of those and they work well though be careful with the smallest one.

Stuart.

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2 hours ago, Icarus60 said:

Thank you Mick but I will still appreciate knowing the stud positions if anybody has the dimensions available.

regards

Rog

 

 

Hi Rog,

What about using a new inlet manifold gasket for the hole centres ? they have to fit everybodies head so will be made on a jig themselves, and the hole centre should be consistent even if the holes are slightly oversized. Crab the dimensions off there to turn into your jig ?

Micky 

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I didn’t know these things existed!.

I’ve never succeeded with the “Easy out” type you mentioned. I’ve always chickened out when I put a bit of pressure on them. It never seems to feel right.

What I have done is used TORX bits (and Allen bits) in a similar manner to the fluted items you describe. They work to a degree, but it’s still a bit hit and miss, not really knowing what diameter to drill the hole.

Charlie.

Edited by Charlie D
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Yes I would use the gasket for a high port head as the template.  Pt no 113122   Just locate it on the existing studs and dowels and scribe through the hole with the missing stud.   The original studs are 3/8” unc steel with a copper plating.

You will need a couple of gaskets anyway when you come to assemble the engine, so not wasted.

 

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Yes I have a couple of gaskets and I’ll give it a go and report back.

Thanks and regards

Rog

 

 

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Mick

Just a thought. Why are the two studs broken. I have found that some times these studs are screwed in very tight. As the threaded hole in the head goes through to the cylinder head studs, this brings the stud in contact to them. When you try and extract them, this contact may make it harder to extract. I certainly have came across this issue.

Brian Richards

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1 hour ago, Trumpy3 said:

Mick

Just a thought. Why are the two studs broken. I have found that some times these studs are screwed in very tight. As the threaded hole in the head goes through to the cylinder head studs, this brings the stud in contact to them. When you try and extract them, this contact may make it harder to extract. I certainly have came across this issue.

Brian Richards

Brian, the studs are often used for the engine hook for engine removal complete (certainly the rear one), and are suitable if you hang engine and gearbox off them combined but only if you carefully space the under hook spacer distance. If you just stick any old bigger nut over the the stud it will tighten the lifting hook onto it but also put a bending moment through the stud, which fractures.

As for the corner stud holes being drilled deep enough to allow the stud to contact the side of the cylinder head stud, I've seen enough of this "gotcha"  to ensure inlet manifold stud removal are my first operations for head removal. On refitting I take 3mm off the stud bottom thread length on the corner fittings to ensure they don't "snub out" against the head studs, the studs are all lubed with a smear of copperslip and wound fully into the head by hand until the thread is used which stops their progress. After this is done there are no further problems with strip downs.

One of the benefits of building race engines, you strip down an engine you rebuilt yourself only 7 or 8 months ago and as you find fails or problems starting to occur you can change methods or items to eliminate. It's far harder rebuilding unknown units that were last built when the Beatles were in the charts, some can be a right battle.

Mick Richards

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Mick

Sorry, my input was meant for Rog. You obviously are aware of the pitfalls. The issue of manifold stud/cylinder stud interference has been found on other members engines I have worked on. There are a lot of non spec studs out there.

Brian

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No problem Brian, we tend to forget that the hardwon experiences need passing on so it's good to sometimes restate how these wrinkles work.

Mick Richards

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Thanks Brian and Mick

I was not aware that the two outer manifold studs are drilled through into the outer head stud bores and I suspect I’m far from being alone on this.  I can confirm that this is the case on the head I’m working on but with the correct depth studs fitted they are well short of contacting the head studs. It looks to me therefore that it will only be a problem if incorrect, excessively long, manifold  studs are used. I wonder however how many reluctant to move cylinder heads have been caused by over long manifold studs?   

Onwards and sideways

Rog

 


 


 

 

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  • 1 month later...
On 2/28/2022 at 11:10 PM, Motorsport Mickey said:

Here you go Rich, there's a variety on e bay just make sure you pick a fluted set, this one is from US Pro at just under £20.

https://www.ebay.co.uk/itm/263601363424?hash=item3d5fdd99e0:g:rJ8AAOSwupRazk77

I have a Neilson set which I bought at just under the £30 from Amazon but the offerings vary as to when you go on. Looks like I waz robbed here on e bay for under £20...it works fine.

https://www.ebay.co.uk/itm/172279869503

regards Mick

Hi Mick, I have a head stud sheared off at the block face. Do you think one of these kits would be up to the job? They state they go up to a 16mm stud.

Thanks, Brian

Edited by Brian Eldred
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5 hours ago, Brian Eldred said:

Hi Mick, I have a head stud sheared off at the block face. Do you think one of these kits would be up to the job? They state they go up to a 16mm stud.

Thanks, Brian

Hi Brian,

There are 2 ways of the stud removal, drill out using a drill stand to keep the hand drill square in both planes (assuming it's a short stud) from a dead centre mark increasing drill size until it reaches just below the stud thread root at which point the stud just collapses and a correct tap gently entered into the hole should pick up the thread and clean the remaining material out leaving an unmarked thread.

Or if it's a long stud (or even a short stud) use a set like these pictured, when you drill the core dia ready for the flute drive decide upon what torque you think can be applied for the dia used. For example I've used a flute in a 3/8th sheared bolt and set a torque wrench at 80 lb ft and after leaning on the wrench (without it clicking off) the bolt let out a scream (my heart sank !) and started undoing finally winding out after a little toing and froing. Give it a dowsing in a superior unseizing fluid first for a day or two, I think it's your best chance of removing the stud without having to retap.

 

Mick Richards

 

Edited by Motorsport Mickey
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Thanks Mick,

I've ordered the US Pro set from eBay, though at £19.35 including postage I don't think it comes from the US...I like the idea of a drill stand if I can find a way of clamping it - would probably have to remove some more studs.

The studs are 1/2 in. so can probably take a bit more torque. I also have a centre stud sheared at the top - the one sheared at the block is the rear one that hides behind the heater valve, and I didn't know this was gone until taking the head off. I've been thinking of leaving the centre one but just as well I didn't....

I've made a little well of blu-tac around the two studs and filled with plus gas. I'm away for a few days so will be attacking it next weekend.

Brian

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11 hours ago, Brian Eldred said:

the one sheared at the block is the rear one that hides behind the heater valve, and I didn't know this was gone until taking the head off. 

I've made a little well of blu-tac around the two studs and filled with plus gas. I'm away for a few days so will be attacking it next weekend.

Brian

I had huge problems getting my cylinder head off early 2020 see below:

It was stuck on the stud nearest the heater tap. Eventually it came off, but I could not remove the stud, so left that one in.

Later that year I stripped the engine for a re-build, & so had to remove it (out of the car now) it took three head nuts wound on as tightly together as I could

& a ring spanner on the lowest one with a scaffold pipe approx 4 ft long over the spanner. I was convinced the stud would break, but it eventually unscrewed. I hate to thing what torque I was putting on it.  so for yours to have sheared it must have had some abuse !, also given the above, I don't rate much chance of getting it out with an extractor, even the fluted type, I suspect you will end up drilling it out.

IMG-20201105-WA0005.thumb.jpeg.9235e7f07388717f605cf58d5e2db6f7.jpeg

Bob

 

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Thanks Bob, that's filled me with confidence :(

I do wonder what caused one stud to shear at the block face and another at the head face? I've bought another tool with a serrated cam to hopefully shift that one.

As it happens the engine was running fine, but for how long is anyone's guess....

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