Joe91

Just wondering if its worth getting these or not, Ive just brought some Arp head bolts and have no been advised by a friend to get Arp conrod bolts aswell, Im on a very tight budget and want to know if its really really worth getting them or not? Im trying to find some standard rings on the cheap so id want to find these on the cheap aswell although they arent as much as headbolts thankgod...

Joe.

chaffe

for a cvh? not really required on a modest build TBH, just build it correctly and cleanly and it will be fine

Joe91

yeah s2, It will be running about 270bhp when its done so its not your average standard rs. I have stage 3 head but keeping the bottom end standard for now till i can afford forge.

chaffe

how tight is tight?
what spec are you planning on running to achieve this?

Joe91

urm like Ł50/60 for rings and the same again for bolts, The bolts are Ł55 odd on ebay..

Stage 3 head, Omex 600, T34, FMIC etc etc.

chaffe

etc,etc,etc,etc,etc

Joe91

Its slightly off subject so i dont want to write loads up then have people start talking about it.

Rob_DOHC

iTrader: (4)

I would use ARP conrod bolts every time, even on a standard(ish) build. I've seen pics of rods after the bolt snapped at moderate power.

I think really the max RPM of your engine will dictate how necessary they are, but for the sake of Ł60 its really not worth not....

Rob,

Rob_DOHC

iTrader: (4)

PS, do your reading first, then buy.

ARP head bolts are commonly considered to be a waste of money.

Rob,

Joe91

Mmm, i only brought them because they seemed highly recommended for putting the head on nice and tight, theres so many opinions flying around though..

haz87

I took out a bottom end when a rod bolt stretched and killed a bearing/crank (and made a big mess due to the metal contamination) but then i was doing 7500rpm+ alot (n/a not turbo). Fitted ARP's when i rebuilt and touch wood, not had a problem. Tho i don't think it will be the bolts that will go this time round if anything does anyway,lol

Rob_DOHC

iTrader: (4)

Ford standard head bolts are proven to over 300bhp, the con rod bolts are not.


Ford use stretch bolts for several reasons, as far as i know the main reason is to accommodate the different rate of expansion of iron and aluminium when heated.... your block is cast iron and your head is ali.

Non stretch bolts, not only need the all important re-tighten after a thermal cycle, but will not allow for this differential expansion.

Ie, send em back and get some more money to build a decent engine, have a look at my project page for tips (haven't updated it in a while though!).

Good luck

Rob,

chaffe

note, ALL bolts are stretch bolts, its how they work. I have always re-used all my head bolts on many cars (ford, VW, peugeot, honda and many more) and have never once had a HG failure yet. Assuming the bolts are free from damage and corrosion they will go again.

Rob_DOHC

iTrader: (4)

I disagree mate,

All bolts stretch, not all bolts are designed to stretch.

Stretch bolts are torqued to a point where a certain part of the bolt experiences plastic deformation. In essence the bolt is always stretched when installed and torqued properly.

A normal high tensile bolt, can and does stretch BUT it isn't in a plastic state deliberately.

Rob,

Rob_DOHC

iTrader: (4)

PS, lots of the cars you mention won't use proper stretch bolts as standard like the cvh. Most of the above will probably have ali blocks and ali heads... no need for stretch bolts to account for different expansion rates.... they could use them to negate automated machine intolerance (over tightening to a degree won't effect clamping forges as the bolt stretches by a predetermined amount).

After a bolt has gone plastic (a perminent change to shape) its next to useless.

Stretch bolts are used for numerous reasons, differential expansion, tightening tolerances, but essentially the are used to maintain a certain clamping force, regardless of gasket 'squish', material expansion/contraction etcetc.

If you don't use the stretch bolts a re-torque is essential.

Rob,

chaffe

All the cars mentioned have stretch bolts, and recomend new bolts, having re-used the bolts on all of them and had no problems i dont see what the problem is. Most of the above is iron blocks/alloy heads.
And as for "going plastic" if you say they do this when torqued down originally the surley they are "next to usless" after the first torquing?
All i base my info on is the 20 or so engines ive built using the same bolts that were on it when i took the head off, some even used three times to change pistons/valves. And ive never had a HG failure yet on one of these. Another point is that on a ZVH (no different to a cvh) i used 12.9 n/mm2 allen bolts, and the general concensis is that these can be re-used indefinatly.
Have you ever re-used head bolts?

luke19790_3

i've reused head bolts, even reused a cometic headgasket with no issues

chaffe

its one of those things, everybody is a hater unless they have done it.

Canada1

Reusing stretch to yield head bolts is certainly a risky practice. Every factory Ford manual suggests new head bolts when replacing the headgasket. If a shop was not following factory recommendations I would go elsewhere for service work.
Why not follow factory procedures? To save a few pounds? This is just silly.

Using ARP head studs - nothing wrong using race type fasteners - IF the retorquing procedure after a heat cycle is followed.
For the very low power output of the cvh engine the standard Ford fasteners are well up to the task. (Even turbocharged out cvh engines are typically well below 75 hp per cylinder)

Cheers

Rob_DOHC

iTrader: (4)

No i don't re use my head bolts, all i can say is im glad nothings ever failed with you

But i did re use my arp rod bolts (non stretch).

Yes in theory they are useless after they have gone plastic, however this is what the original torque stage is for, then the angle stages. The bolts in theory sit there stretched slightly past their plastic point a bit like a rubber band (but not lol).

The bolt designer will include a safety margin, all your re-used bolts haven't failed because of this safety margin, the more you tighten/reuse/stretch a bolt the closer you get to its yield point, the point at which tightening the bolt more has little effect on clamping force... before it breaks.

Its all good tho buddy, if you've had a lot of experience doing it then fair play, but manufacturers don't use and advice their dealerships to change them to be difficult.

Rob,

Rob_DOHC

iTrader: (4)

Mate read my above post... not a hater here, just have a differing opinion to yours, doesn't mean i have to get shitty about it.

chaffe

Sometimes you just need to get the job done, and there is no time to fuck about buying new bolts. All very well and good if its a five year restoration project and you have all the time and money in the world, but if its a sat afternoon and you need the car for work on monday....

Some manufacturers quote two torque settings- one for new bolts, one for used bolts
No shittyness intended as always

Rob_DOHC

iTrader: (4)

Cool cool,

PS, i agree with your comment re getting the car done, if you don't have the luxury of time and need a car for work the next day i would do the same.

chaffe

The problem is for most people an oil change is a mission, let alone a HG, thas a major strip down and major 10 page re-build thread then breaking thread GET IT DONE!

little bram

chaffe for the cost of bolts mate why put the old in and as for time if you are doing anything to an engine you are going to need parts ie shells or HG unless you have a stock of them so when you are there why not pay the little bit more and do the job right.
the OP is rebuilding his car and sound like he wants a good job doing so for the cost of some bolts i would just put them in.
i put arp stud and nut kit on mine and had a HG fail running about 30psi so put ford bolts back in and never had a problem
so imo ford head bolts and i would put arp rod bolts in mate

Joe91

Looks like its time to sell the head bolts then and buy some con rod bolts instead!!

Putting them on ebay if anyone is interested..

chaffe

I think for the cost of a zetec and Megasquirt i would use one of those instead TBH, but then i can build, wire, get running and map an engine so there is no probs there

Rob_DOHC

iTrader: (4)

Not to stir things up lol but have a look at brams build thread before making the above comment.

Rob,

chaffe

Read the OP mate

BRAM

iTrader: (1)

Don't understand mate why are you talking about zetecs and megasquirt? The lad only wants to know if he should use arp bolts.

In my opinion I think you should use arp rod bolts but get rid of the arp head bolts just use ford head bolts.

Canada1

Hello Bram,

Did you retorque the ARP head studs after a few heat cycles?
Most don't do this critical step.

Cheers

Perry

little bram

yes mate retorque them

chaffe

Because he is looking for nearly 300 bhp on the cheap

Karlos G

iTrader: (4)

ARP rods bolts are a must IMO, there have been plenty of failures on stock bolts.
Re-using CVH head bolts is a joke, I did it years ago before I knew any different and one snapped when doing it up the last 90 degree's! lol For Ł8 why risk it?!
ARP stud and nut conversions have seen many HG failures too, there is a reason everyone uses stock bolts even upto and over 350bhp... again why risk anything else?!
To the OP if your aiming for 270bhp then you MUST upgrade your rods as they will bend/snap at that power, pistons are good for around 300bhp but rods have been known to break as low as 200bhp if used hard (high rpm), if your careful then 240bhp'ish is about the limit for them.

chaffe

some sort of aftermarket management will be required for 270bhp