02GF74
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| posted on 26/3/07 at 09:04 AM |
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manifold studs vs bolts
some cars use studs (e.g. crossflow) to hold inlet and exhaust manifolds to the head whereas others use bolts e.g. Rover v8.
Are the two interchangeable, i.e. can I use bolts on the crossflow? What is advantage of one over the other?
(I already have bolts for the inlet - not fitted by me) that seem to give no problem as yet.
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will121
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| posted on 26/3/07 at 09:21 AM |
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think from an engineering point of view and especially on the exhaust manifolds on a cast iron head that studs are best with brass nuts as a result of
the temperatures and possible ceasing up and potential for ringing off when trying to remove a bolt with the knock on problems of drilling it out.
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turbodisplay
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| posted on 26/3/07 at 09:26 AM |
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With studs i can think of two advantages:
There are two thread areas (stud and nut, stud and head) that can release so if one gets siezed there is still another to release.
Less likely to snap with a stud.
Darren
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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smart51
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| posted on 26/3/07 at 09:37 AM |
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I replaced the studs on my R1 engine with bolts (following advice from MNR) largely because the original studs were just slightly too short. It
turned out that the old exhaust rings were so corroded onto the cylinder head that I thought they were part of it and so added new rings on top.
I've had no problems with it and the bolts have been easy enough to remove.
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muzchap
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| posted on 26/3/07 at 09:44 AM |
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If it's an ALLOY block - then studs are considered safer.
TBH for the amount of miles/maintenance a kitcar has the arguments for/against are probably somewhat diminished. Cars are expected to last 200,000
miles + with longish service intervals.
Kitcars typically do around 3,000 year (if lucky)
I personally use STUDS as I have a Zetec - which is alloy block and I do a few trackdays where the under bonnet temps get quite high.
HTH
Cheers,
Murray
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If you believe you're not crazy, whilst everybody is telling you, you are - then they are definitely wrong!
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bimbleuk
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| posted on 26/3/07 at 10:31 AM |
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Apart from the engineering advantages of studs its much simpler to hang the manifold on the studs then bung on the nuts than fiddling about with
lining up bolt holes. At least with the limited space in my engine bay its much easier.
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DIY Si
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| posted on 26/3/07 at 11:07 AM |
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I always use studs, if nothing else they are so much easier to use, as ^^^ said, you can just hang the manifold on then add the (in my preference)
brass nuts. Mush easier than trying to hold a large mainfold in place with one hand whilst trying to line a bolt or two up. Also, brass nuts look
better IMO, although some nice cap headed bolts come a close second.
“Let your plans be dark and as impenetratable as night, and when you move, fall like a thunderbolt.”
Sun Tzu, The Art of War
My new blog: http://spritecave.blogspot.co.uk/
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Dave J
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| posted on 26/3/07 at 12:30 PM |
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On my RV8 I've used studs with brass nuts to good effect. Been running for 12 months with no probs.
As the other guys have said, with ally heads, studs are the way to go. If a bolt seizes in the head or heaven forbid cross threads, then you have
problems.
Cheers
Dave
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JB
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| posted on 26/3/07 at 06:51 PM |
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The advantage of studs is its easier to slide the manifold over them than line up holes for bolts.
However sometimes there isnt room to slide a manifold over studs so bolts are required.
If you remove your manifold a lot you will eventually strip the threads in an alloy head if you use bolts. Unless of course you Helicoil them which
you should for any thread into alloy.
My head originally had studs but I now use stainless 12 point ARP bolts for installation reasons.
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WIMMERA
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| posted on 27/3/07 at 02:40 AM |
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Another method is to use a longer fully threaded bolt and a nut, run the nut up the bolt till it's just under the head, install bolt through
manifold and into the head to the required depth then tighten the nut onto the manifold while holding the bolt head with a second spanner to prevent
it turning, when dismantling hold bolt head with one spanner and loosen nut with another then remove bolt .The threads in alloy heads will love you
for it.
Wimmera
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