12 replies to this topic

[SIR]

Hi Guys

 

Up to yesterday I was running the stock 12mm 6bolt head bolts on vr4 motor, and it has started to push a fair amount of coolant out under boost (1L for 10 hot laps at Mallala).  We checked the head bolts and about half had relaxed so we re-torqued the bolts and it was good for about 30more laps of racing then it started again, so we suspect either the head bolts have stretched or the head has gone soft.

 

I am taking the head off this weekend for a look and have started to look for some head studs. I see that over in the states you can purchase "L19" spec ARP head studs for the 6bolt https://www.extremep...productid=21008  they are a lot more expensive especially once shipped, I couldn't find them locally.

 

Question is are people getting away with the standard ARP studs?  My engine is in a race car so it is constantly being flogged, boost peaks at 22psi before being choked by a restrictor and it is very high comp motor on E85, been using a felpro permatorque MLS gasket.  I have read on other forums that the standard ARP studs are not much stronger than the stock 6bolt 12mm bolts??

 

Also any issues with the VR4 heads going soft?  It is an issue that the Toyota guys seem to have with keep clamp on the head gasket never heard of it for the 4g63.

 

[EV0300]

no such thing as "overkill" 

only futureproofing

[ENGINR]

I'm running standard ARP studs in my setup and putting 26psi through the engine.  Blew the headgasket once but we think that was the MLS gasket giving out.

[Cranked]

Yeah I'm running arp on a permaseal. Yet to have a problem at 25psi

[jack be nimble]

You are already some 15% stronger than the 7bolts from the bigger bolts. May as well press the advantage all the way.

[Evo-00x]

Get the best head studs/bolts you can afford. There is no pleasure in looking back on saving a few dollars on head studs after you've experienced lifting the head and pressurising the cooling system on the dyno.

It only ends up costing you more money in the long run. Don't skimp on headbolts or good headgaskets on turbo cars boosting over 20 psi ever!

[Ross Cox]

G'day .

If you go studs, whichever you want to use, when you have the head off, take the power steering bracket off the block and grind/trim it so you can remove and replace the head without removing the power steering pump bracket. With studs the head moves vertically when it is taken off or replaced, with bolts you can manoeuvre the head out from under it.

Cheers

Ross

[SIR]

L19 Studs have been ordered hopefully this sorts it out.

 

Ross - I don't have Power Steering or a top engine mount to clear (RWD setup) but I will still have to install the studs once the head is on the block thanks to the CAS needing to go under a lip on the firewall.

 

[caged]

Check your tune if you're lifting the head on regular 12mm arps which are similar strength to the l19 11mm 7 bolt head studs. You shouldnt have a problem at all on your setup especially since you run a restrictor.

[Ross Cox]

L19 Studs have been ordered hopefully this sorts it out.

 

Ross - I don't have Power Steering or a top engine mount to clear (RWD setup) but I will still have to install the studs once the head is on the block thanks to the CAS needing to go under a lip on the firewall.

 

Cool. That must be fun to drive!!

[OLDIE]

Better late than never.

I have ARP studs in the head,mains and flywheel on my7200RPM rev limited 2.3 no balance shaft stroker with zero problems to date.

[bazeng]

Another late post....

Amg is on standard arps. No issues to date. At 24psi. Street car. I have been told they stretch...

Vr4 is on L19s. Haven't tested them yet. Only done 30psi. No head lifting issues. But do have a leaking head gasket (cometic) most likely gasket related.

[CLuTZ]

I would use OEM flywheel bolts instead of ARP, as there's been a bunch of guys in the US who have had them back out on them. Not cool.