Are You Using Sub Standard Bolts In Your Engine ?
#1
Posted 31 October 2010 - 07:35 AM
Bolts
We have noticed an increasing trend for certain suppliers to sell a centre main strap with "high tensile" bolts..... however these HT bolts are not of a sufficient tensile level to even be close to the original items used to hold your crank in to the block.
You should be using an SAE grade 8 bolt not an ISO 8.8 bolt
A rough guide is ISO 8.8 is SAE 5 which is about as low as it goes in HT bolts.....
The main cap bolts as supplied by Austin, Morris, Leyland, Rover, etc are SAE 8 which is about the same as ISO 13.9
The SAE 8 bolt is recognised by the 6 lines formed in to the top of the head of the bolt, these bolts would also come with a certificate of conformity, ask your supplier for a copy, if they can't supply one then is it worth using the bolts ?
How much did your engine cost you ? don't be forced to use substandard parts just because your supplier hasn't the knowledge or experience to know the difference yo uwill be risking your engine and possibly your gearbox if it all goes wrong.
#2
Posted 31 October 2010 - 07:52 AM
#3
Posted 31 October 2010 - 07:59 AM
#4
Posted 31 October 2010 - 08:03 AM
When I started building the engine, I torqued up the first bolt on the centre main and it stripped the thread out of the block. It wasn't until afterwards when I inspected the bolts that I realised they only went into about 5mm of thread!
The hassle this caused me was just unreal and I ended up buying some super strong, longer bolts from America. I had to have the block machined, the bolts machined and the strap itself slimmed down!
Heres the thread on problem. You'll see how much trouble it caused me: Link
#5
Posted 31 October 2010 - 08:15 AM
Would these bolts, if incorrect, Have caused any damage??? Im off to the garage to check the throwout on the crank!!!
#6
Posted 31 October 2010 - 08:53 AM
http://www.americanf...kings_steel.asp
Personally I always use studs for the mains, but thats just me,
There is a chap in the US that does really high grade mains bolts (including the long ones for centre main straps) for the A series at a really good price, also hos high grade gearbox to block fastening kits. He can be contacted through Turbominis or minimania on username Turbodave.
#7
Posted 31 October 2010 - 10:23 AM
Ive just had to strip my engine ,AGAIN, for other reasons. but the bolts that were supplied with my center main strap(Jonspeed) dont have these lines on them. I phoned them up at the time and asked and they said they were fine and to the correct tensile strength.. Im not so sure now?? Is this something you could supply Martin??? Er sorry for the blatent shopping on the forum!!!
Yes Andy we have the correct SAE grade 8 bolts in stock and at the correct length. However this topic was to raise awareness of the situation.
#8
Posted 31 October 2010 - 12:38 PM
Ok Martin, Ill call you tomorrow.Ive just had to strip my engine ,AGAIN, for other reasons. but the bolts that were supplied with my center main strap(Jonspeed) dont have these lines on them. I phoned them up at the time and asked and they said they were fine and to the correct tensile strength.. Im not so sure now?? Is this something you could supply Martin??? Er sorry for the blatent shopping on the forum!!!
Yes Andy we have the correct SAE grade 8 bolts in stock and at the correct length. However this topic was to raise awareness of the situation.
Im really pleased you started this topic today. Perfect timing..I hope many other people find it as usefull as I have.
#9
Posted 31 October 2010 - 01:33 PM
#10
Posted 31 October 2010 - 02:59 PM
The closest i could find on the chart posted by Mini13 is the grade 5 bolt. Im guessing this is not strong enough so will speak to Martin tomorow.
#11
Posted 05 November 2010 - 10:06 PM
#12
Posted 05 November 2010 - 10:22 PM
#13
Posted 05 November 2010 - 10:26 PM
#14
Posted 05 November 2010 - 10:29 PM
#15
Posted 05 November 2010 - 10:31 PM
Edited by danrock101, 05 November 2010 - 10:32 PM.
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