Big end bolts

[v8ivor]

Are these nuts the correct way around because the bolts don't finish flush and cover the shake proof part of the nut ?

[chaterlea25]

Hi, V8
That aint right 
What engine is that?
The nuts look too big to accomodate a socket to tighten them??
Are the bolts seated properly in the rods?? as they look short ???
Also judging from the punch marks (heathen PO*eek* ) the bolts have been reused several times ???
Not too clever looking at this point in time

John

[v8ivor]

It's a 52 A10 plunger and I cant get even a 3/8" drive socket on them, so I wouldn't be able to torque them up after, and may damage the threads if I undo them past the punch marks.

[chaterlea25]

Hi, V8,
So you have found it like that ??

ON the early engines the nuts were smaller hex castellated ones with a built in shoulder if I remember correctly

I would remove the bolts and bin the lot 
You may need to enlarge the spotfaces where the nuts sit to accomodate the new bolts
I would not run an engine with bolts/nuts  like that
New ARP bolts are really the only solution

John

[Rocket Racer]

I largely agree with John, the bolts and nuts need to come off, even if you could fit a socket you cannot trust a torque setting on threads that have been punched and they are too short...
So whoever assembled it cannot have torqued it up and the shells should typically be replaced as a matter of good practice even if they are not as mickey mouse as those big end bolts.
Pull it down, flush the sludge trap, and sort out as a minimum new bolts and nuts (yes ARP a good option)
When you start seeing bad practice like that it suggests treating everything with question. ie get the rods checked for straightness and consider shot peening them to relieve stress - or get fresh rods...

[RichardL]

Assuming you go with ARP bolts, you will see in their instructions that they are more interested in bolt stretch when tightening than in torque. They offer a specialized measuring tool for this, though I measured mine with a micrometer. If, after used and removed, the bolts return to the specified length then they are OK to reuse.

Richard L.

[bsa-bill]

Sorry to disagree folks but I think the nuts are correct, If they didn't have the corners taken off the bottom of the nut they would risk catching the crankcase

[v8ivor]

There are plain washers under the nuts (The same thickness as the bolts are recessed ) And the end of the bolts are machine finished as opposed to cut off .

[v8ivor]

I just looked at what you said Bill, and the outer edge of the nuts are in line ( Or a few thou past ) With the flywheel.

[RichardL]

Sorry to disagree folks but I think the nuts are correct, If they didn't have the corners taken off the bottom of the nut they would risk catching the crankcase

Well, Bill is correct that those are rod nuts, but they are not correct for those rods. As John mentioned, the castellated nuts have a shoulder that fits the landing and a smaller hex that clears the case. There are some other twists (maybe the wrong word) on this, but inability to securely use a socket and engage all the threads in the nut are not among them.

Richard L.

[bsa-bill]

they are not correct for those rods

yes there are several types, I've had the castellated ones before also, not that it helps V8ivor except to point out the machined bit is correct at the bottom.

two other types here one self locking the other not but looks like made from a nut with a pin,

[v8ivor]

Did you mean the nut to go this way on or up the other way Bill ? These bolts haven't got a hole for a split pin.

[bsa-bill]

Yep that the right way.

The nut with the hole for a pin is (I think cause it's a while ago) one of a set came with bolts from Mike Cheyne (dont know if your in here Mike), mike asked for them back as someone had found they caught the crankcase, so he kindly sent another set with a bit more machined off

[RichardL]

Ivor,

I think one dfference between the nut in your picture and the picture from Bill, as well as the picture from deGroot (below), is that the points on your nut are not chamfered where they come against the rod cap as are the other two. The unchamfered points seem to contact the recess in the cap. I will, and should be, corrected if I'm wrong, but I think washers are not used under the type nuts we're showing here (Triumph type?).

Richard L.

[chaterlea25]

Hi All,
Whatever has happened ????? V8's setup is clearly wrong
maybe the bolts are from something else????
Some years ago there were a lot of poor quality big end bolts on the market, these were machined not forged head
At the time C&D had the correct forged bolts, presumably these sold out and were not replaced??
After that the only properly made bolts available are ARP (as far as I know)

Another issue came to light a couple of years ago the replacement  Triumph type nuts that were commonly sold were made of cheese !!! WTF

HTH
John