Head Bolts question... 300bhp+ (18 - 25psi td05)

[goldenvtr]

im currently running 18psi on my forged 5e on a td05. the bottom end should be able to take whatever i can throw at it, but the head (4efte) is stock bar a 2mm headgasket,
Now i think its possable the head is lifting as i seem to get small amount of oil in my breather after a spirited drive.

just wondering what the stock headbolts are good for, and what ARP bolts are good for. i dont really want to have to take the engine out anytime soon to fit a stud kit but i do want to keep it reliable ( i was running 25psi but after this possable issue ive turned the boost down)

ive had this engine running 17/18psi on various turbos for about 5 years now but only recnelty started running 20psi as base boost and 25psi for giggles lol

any input appreciated

 

[BallıGee]

wıth a 2mm gasket you should not have any head lıft as the c/r should be v.low what dısh are the pıstons
my old set up had stock head bolts any never had any worrys at 2bar

 

[buckets]

arps run 400 odd so ive been told

 

[Murray]

Your issue could just be the gasket is pretty thick. 2mm is huge
Ive always thought the thinner the better, for sealing.
Also what breather setup do you have?

Murray

 

[weeJohn]

The oil in the breather is more likely to come past the rings due to flutter rather than past the head gasket. ARP bolts should handle what you want to put into it, I dont think you need to go to the 4AGE studs with a 2mm gasket.

 

[AdamB]

Thought Aze had his head lift at 1.6 bar? If you want to build a bullet proof engine go for the stud route.

 

[Nick@TD.co.uk]

We've ran 1.7bar through ARP headbolts and had no issues.

We stretched stock bolts at 1.5bar...

Cheers

Mike Jones
Tuning Developments Ltd

 

[goldenvtr]

wıth a 2mm gasket you should not have any head lıft as the c/r should be v.low what dısh are the pıstons
my old set up had stock head bolts any never had any worrys at 2bar

my CR is 7.5.1 ish, -10cc wiseco pistons 74.5mm and im sure i got a 2mm HG might of been 1.8 but so long ago i cant rememeber to sure lol

arps run 400 odd so ive been told

thats pretty good, i might change for peice of mind

Your issue could just be the gasket is pretty thick. 2mm is huge
Ive always thought the thinner the better, for sealing.
Also what breather setup do you have?

Murray

surly a seal is a seal the same pressure will be applied via the headbolts, qould have though quality and as long as the head is flush/ not warped HG size shouldnt matter, i just have the stock breather setup both breathers (pvc and breather go into a catch tank with a filter on the top)

The oil in the breather is more likely to come past the rings due to flutter rather than past the head gasket. ARP bolts should handle what you want to put into it, I dont think you need to go to the 4AGE studs with a 2mm gasket.

i did think about piston rings but compression is spoton, might of been becasue they had not fully heated up and expanded on first hard accelartion.

We've ran 1.7bar through ARP headbolts and had no issues.

We stretched stock bolts at 1.5bar...

Cheers

Mike Jones
Tuning Developments Ltd

thanks mike that good info, i like to hear proper input instead of guesswork,
how did you diagnose the headbolts had streched, and what boost CR was the engine running if you know?

 

[weeJohn]

i did think about piston rings but compression is spoton, might of been becasue they had not fully heated up and expanded on first hard accelartion.

You would only see flutter when on full tilt or high engine loads.

 

[GP82]

ARP claim there headbolts have 30 - 40 % more clamping force then the stock bolts, depending on how precisely and equally they have been torqued.

I know this is going off the topic slightly, but was curious if anyone had a answer to my query. When using headbolts which are torque to yield and you overcome the stretch on the bolt with high boost, the head will lift and the motor will probably eventually blow the headgasket, but say you are using a stud kit where the head will not lift with high boost, would the pressure or energy go elsewhere in the engine and possibly damage another part of the motor?

 

[weeJohn]

Studs can be stretched and cause the head to lift as well, the stud kits people use are heavier (12mm I think) than the 9mm bolts in the stock EP engine, thats why they give a performance upgrade.

 

[AdamB]

The pressure would stay in the cylinder, just like it would if you was running stock/arp bolts under their limit.
There is a few things we do in the motorsport industry to eliminate the headgasket failing

 

[Murray]

surly a seal is a seal the same pressure will be applied via the headbolts, qould have though quality and as long as the head is flush/ not warped HG size shouldnt matter, i just have the stock breather setup both breathers (pvc and breather go into a catch tank with a filter on the top)

The thicker the gasket the more likly it is to fail. Also get rid of the PCV its doing your engine no favours. Look to getting bigger breather lines aswell, the 5e needs to breathe.