eyefi Posted August 23, 2002 Share Posted August 23, 2002 does anyone bpu (18psi) use a non stock (ie competition) head gasket, or do any of the big power guys use anything other than the stock head gasket. Quote Link to comment Share on other sites More sharing options...
GavinL Posted August 23, 2002 Share Posted August 23, 2002 Originally posted by eyefi does anyone bpu (18psi) use a non stock (ie competition) head gasket, or do any of the big power guys use anything other than the stock head gasket. I don't and I'm not aware of anyone else either. The stock item is metal so I guess not much point unless you want a thicker one to lower the compression ratio. Quote Link to comment Share on other sites More sharing options...
Alex Posted August 24, 2002 Share Posted August 24, 2002 Which is a dodgy way of lowering the compression ratio...you'd be better off using forged piston with a slightly concave head...or just using tougher internal to take the strain at the higher boost pressures at normal compression ratio's. What is the stock HG thickness????? The HKS ones are 1.2 1.6 and 2mm If i remember correctly....long time since I last looked. Quote Link to comment Share on other sites More sharing options...
MONKEYmark Posted August 24, 2002 Share Posted August 24, 2002 Originally posted by Alex Holdroyd Which is a dodgy way of lowering the compression ratio...you'd be better off using forged piston with a slightly concave head...or just using tougher internal to take the strain at the higher boost pressures at normal compression ratio's. What is the stock HG thickness????? The HKS ones are 1.2 1.6 and 2mm If i remember correctly....long time since I last looked. hi whats the pros and cons of hks metal head gaskets i was thinking about them last night at work it lowers the compression ratio to allow you to run more boost? its stronger than stock ones and can be re used? also i have seen somewhere that you can get copper ones that supposed to be better than hks ones would it be worth buying one as a spare if the stock one ever goes, as in an upgrade to stock item could a novice change or would it be too much of a job thanks just curious Quote Link to comment Share on other sites More sharing options...
tDR Posted August 24, 2002 Share Posted August 24, 2002 Head Gasket isn't too hard to do so long as you have the right tools (including torque wrench) and someone to help with locating the head onto the block once you've cleaned it up and fitted the new gasket into position. It's always best to use new stretch bolts when you re-torque the head down and depending on how the head assembly comes apart on the Supe you'll prolly need new inlet and exhaust manifold gaskets. A head gasket is a bigger job to do if you have blown the gasket as you really have to take the head off and give it to a decent machine shop to skim and pressure test because it'll likely be warped. Quote Link to comment Share on other sites More sharing options...
eyefi Posted August 24, 2002 Author Share Posted August 24, 2002 the reason im asking this is, while talking to my toyota mechanic friend about my upcoming work (which involves head off), he suggested an aftermarket head gasket due to the increase in boost. he belives the stock item is over engineerd for the stock boost (toyota learned from the mk3), but believes it may be a potential weak point at 18psi (a 60% increase over stock), so as i need to buy a new one anyway (stock head gasket £75) it would b worth upgrading (hks £170+). ive not read of many mkiv's with blown head gaskets and alot of folk r running bpu now, so im just checking my own observed stats and looking for other opinions on this. my friend is working on theory, not practical experience with this engine in this situation. Quote Link to comment Share on other sites More sharing options...
GavinL Posted August 24, 2002 Share Posted August 24, 2002 Originally posted by eyefi the reason im asking this is, while talking to my toyota mechanic friend about my upcoming work (which involves head off), he suggested an aftermarket head gasket due to the increase in boost. he belives the stock item is over engineerd for the stock boost (toyota learned from the mk3), but believes it may be a potential weak point at 18psi (a 60% increase over stock), so as i need to buy a new one anyway (stock head gasket £75) it would b worth upgrading (hks £170+). ive not read of many mkiv's with blown head gaskets and alot of folk r running bpu now, so im just checking my own observed stats and looking for other opinions on this. my friend is working on theory, not practical experience with this engine in this situation. over caution in my opinion. Lots of BPU cars are running with the stock head gasket without issue. Quote Link to comment Share on other sites More sharing options...
Alex Posted August 24, 2002 Share Posted August 24, 2002 Well if the car is being stripped down then yes indeed do it. I would presume that the 1.2mm version is the one closest to stock. The PHR reusable copper one is 1.3mm's. 1.6mm HKS next on the scale. Then the 2mm one...this is too thick 1.6mm max but ask CW or Darren Blake first as they know about the implications more than I. For a stock ish system the 1.2 should suffice. I would also get some ARP 190,000psi Head Studs. These like the PHR HG are reusable. And whilst your at it you might as well do the job fully. So what are you removing the head for? New pistons? Rods? Or just getting the head ported/flowed? Quote Link to comment Share on other sites More sharing options...
Alex Posted August 24, 2002 Share Posted August 24, 2002 Originally posted by GavinL over caution in my opinion. Lots of BPU cars are running with the stock head gasket without issue. Yeah but if the head is coming off its got to be replaced anyway....AFAIK So why not put one in that is a bit stronger?? Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted August 24, 2002 Share Posted August 24, 2002 The stock MKIV head gasket is an MLS gasket and just like the aftermarket HKS ones used on the MKIII. I am CONVINCED HKS don't make these gaskets and believe i may have sourced them from source, so if anyone wants MLS gaskets for the MKIII, or any other engine in fact, e-mail me privately at : [email protected] I have just sourced one for my Opel engine in my race car and it was incredibly similar in all detail to the HKS MKIII one :-) (MLS = Multi Layer Steel, a stack of stainless shims, the outer leaves being flourine rubber plasma sprayed to seal the oil and water ways properly) Quote Link to comment Share on other sites More sharing options...
GavinL Posted August 24, 2002 Share Posted August 24, 2002 Originally posted by Alex Holdroyd Yeah but if the head is coming off its got to be replaced anyway....AFAIK So why not put one in that is a bit stronger?? About £100 + it's a dodgy way of lowering the compression ratio I'm advised Quote Link to comment Share on other sites More sharing options...
Gordon F Posted August 24, 2002 Share Posted August 24, 2002 How does a re-usable head gasket work then, and how many times can you re-use it??? Quote Link to comment Share on other sites More sharing options...
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