Uprated Bottom End

[luke1987 5]

Hi all just wondering if any one has any info on the best route to follow for upgrading XU9JAZ bottom end conrod snapped on the last one and just before cylinder head swop new head has piper ultimate road cam double valve springs piper followers and spring caps all info would be much appreciated dont fancy another hole in block oh and before i forget its running twin 45 webbers cheers Luke.

Edited October 24, 2009 by luke1987

[Tom Fenton 1,542]

Was it tapping before it let go? I have had a con rod fail, but the little end was tapping it turned out so I think this contributed to it.

[j_turnell 137 3 Cars]

I would imagine a rebuilt lightened and balanced bottom end with ARP rod bolts should suffice. Depending on what the cars used for and how high your revving, could go steel bottom end, but that is ££££££££

[luke1987 5]

Was it tapping before it let go? I have had a con rod fail, but the little end was tapping it turned out so I think this contributed to it.

 

No just on motorway slight bang and lots of oil and smoke engine was fully rebuilt 9 months ago by me and was fine rac guy reckoned it could have been down to oil surge/starvation.

[luke1987 5]

I would imagine a rebuilt lightened and balanced bottom end with ARP rod bolts should suffice. Depending on what the cars used for and how high your revving, could go steel bottom end, but that is ££££££££

 

Was gonna go steel bottom end (if the bank allows) seen some rods and pistons on ebay so was thinking the works.

[projectpug 0]

iirc the piper ultimate road cam is a 285 degree duration you won't need a steel bottom end for that. I wouldn't rev that past 7500 as it won't make much power up there anyway.Just used a lightened,balanced, bottom end(balanced rods etc) and arp bolts. In mine it took 8200rpm, untill the camblet slipped a tooth that is.

[luke1987 5]

iirc the piper ultimate road cam is a 285 degree duration you won't need a steel bottom end for that. I wouldn't rev that past 7500 as it won't make much power up there anyway.Just used a lightened,balanced, bottom end(balanced rods etc) and arp bolts. In mine it took 8200rpm, untill the camblet slipped a tooth that is.

 

Thanks who did you use to source parts found a few places but allways good to here recomendations.

[projectpug 0]

I got my ARP bolts online. You would be best off using someone specialist to balance the crank/rods, skip browns etc would be able to do a competent job.

[luke1987 5]

The Damage

[Tom Fenton 1,542]

So that looks like the rod bolts have broken, not the rod itself. When mine broke the big end of the rod was still attached to the crank. So really what you need is some ARP rod bolts.

[Miles 331 1 Cars]

As std the std rods and pistons are fine within that spec, Get some 1.6 pistons next thou as this will up the compression and doesn;t have a one sided dish (Pond) on the piston, Some ARP bolt's, even shot peened rods will help if you are worried and doesn;t cost allot either.

[luke1987 5]

So that looks like the rod bolts have broken, not the rod itself. When mine broke the big end of the rod was still attached to the crank. So really what you need is some ARP rod bolts.

 

Cant find the rod to show you but 1 of the bolts had snapped and the rod was broken just above the other bolt must have let go at crank end to smash piston and bend valves but arp bolts got to be a must next time.

[Tom Fenton 1,542]

OK, so the rod ended up broken. But the root cause was the rod bolts failed. If the rod bolts had not have failed then the rod would probably be Ok still.