Heads are lifting from boost. What should I do now? (Photos)

[Tippy]

Appears my heads are lifting from 1.4 bar of boost. Did not see this at 1.2 bar on 1st rebuild.

Been reading that flame rings aren't a guarantee??

If flame rings aren't a cure, what is?

Also, what is happening around the piston crowns?

[faapgar]

Hi,does this have twin plug?Piston crowns look like it is being washed with oil from blowby.It is black around the piston from the crown down to the top of the 1st ring land.The flame rings always sweat around the seal anyway.I recommend the 3.2 repair head gasket 930 104 381 01.It is 0.05mm thick metal gasket with a silicone type coating.Only buy from Porsche at $120.00 a set.Lap the cylinders to the heads for a perfect fit.I have never run these at more than 1.2 bar for a customer but they did not leak or sweat.Better head studs than the fully threaded would help.1 .4 bar without race gas is foolish & expensive.Fred

[racing97]

Nothing will seal a vertical fan engine at 1.4

[faapgar]

Agreed for sure.

[Tippy]

Originally Posted by racing97

Nothing will seal a vertical fan engine at 1.4

I was planning on 2 bar with race gas.

Juan Ruiz is over that with the same engine.

[Tippy]

Originally Posted by faapgar

Hi,does this have twin plug?Piston crowns look like it is being washed with oil from blowby.It is black around the piston from the crown down to the top of the 1st ring land.The flame rings always sweat around the seal anyway.I recommend the 3.2 repair head gasket 930 104 381 01.It is 0.05mm thick metal gasket with a silicone type coating.Only buy from Porsche at $120.00 a set.Lap the cylinders to the heads for a perfect fit.I have never run these at more than 1.2 bar for a customer but they did not leak or sweat.Better head studs than the fully threaded would help.1 .4 bar without race gas is foolish & expensive.Fred

What studs are you thinking?

I ran the barrel nuts dry, which probably lowered overall torque resulting this we see here?

[Henry Schmidt]

Supertec head studs have been used in professionally built Porsche flat six turbos in excess of 1200 hp.
Two East coast builders of both air-cooled and water cooled turbos use Supertec studs exclusively.

Will they "cure your issue completely? who knows. What I do know is that you will see better results than with Dilivar nonsense.

[racing97]

If it's in excess of 1200 HP why not just say 1500...........

[Henry Schmidt]

Originally Posted by racing97

If it's in excess of 1200 HP why not just say 1500...........

If I built them I could quote accurate numbers but I am just relaying the general sense of the levels to which our studs have been tested. These engine builders are known world wide for producing incredible numbers so why would I need to question their integrity.
If I decide to produce that kind of horse power, I guarantee you I'll have a deeper conversation.
When I last spoke to them about producing an air cooled "high" horse power turbo my goal was 650 and both of these builders suggested that was "child's play".
I originally hoped to put an air-cooled turbo in my Riley Daytona Prototype.
650 would have been plenty.

[nocarrier]

Flame rings don't cure the heads from lifting. Think of them more like a large shuffle pin.

It just assures the head returns back to the same location after it lifts. The combustion gasses go right around them.

I think what you really need to be looking at is cylinder head efficiency. Get some flow data. Have a cam made to match...

I see you're running carrera heads. Any port work done? How much hp were you at at 1.4?

How much hp do you want?

We play with 2.0 bar from time to time.......

I'm running supertec headstuds. I personally feel they are a better choice for a few important reasons.

Oh and e85.....

[Lapkritis]

Supertec or ARP head studs will expand less with heat than dilavar and hold the head tighter to the jug. Everything else being equal, the strength of the seal will then be higher.

Sent from my SM-T580 using Tapatalk

[Tippy]

Originally Posted by nocarrier

Flame rings don't cure the heads from lifting. Think of them more like a large shuffle pin.

It just assures the head returns back to the same location after it lifts. The combustion gasses go right around them.

I think what you really need to be looking at is cylinder head efficiency. Get some flow data. Have a cam made to match...

I see you're running carrera heads. Any port work done? How much hp were you at at 1.4?

How much hp do you want?

We play with 2.0 bar from time to time.......

I'm running supertec headstuds. I personally feel they are a better choice for a few important reasons.

Oh and e85.....

Stock port 3.2's, yes. Steve Weiner said to not touch them, so I didnt.

Chris at TK said it should have been over 600hp, was hoping for 700 with 993SS cams or GT2 Evo's.

Not sure if possible, but the 3.2 profile is very weak.

[Tippy]

Originally Posted by Lapkritis

Supertec or ARP head studs will expand less with heat than dilavar and hold the head tighter to the jug. Everything else being equal, the strength of the seal will then be higher.

Sent from my SM-T580 using Tapatalk

Yeah, I'd go Supertec. They are a great price.

I'm a huge fan of ARP, but Henry's are priced better from quick searches.

Nothing in stone and weighing options now.

[chris_seven]

You really need to torque them tighter than the standard setting as you need enough preload to overcome the peak cylinder pressure and to stop the head lifting even when cold.

You can easily calculate the lifting force and compare this to the preload to see how much extra torque you may need.

The fact that the reduced coefficient of expansion compared to Dilavar will add clamping due the expansion doesn't help when the engine is cold and the damage occurring whilst the engine warms will be cumulative.

If the 'lift' of the head is small then a Wills Ring will help to maintain a seal.

An internally pressurised O Type Ring will seal to around 5800psi and in a Inconel material will withstand operating temperatures of around 1500degF. They have reasonably good resilience and deal quite well for varying pressure applications.

We have used them in Coventry Climax based race engines that blow head gaskets for a pastime for more than 30 years with good success.

If you used an internally vented O Type Ring will seal at up to 145000 psi but this uses the internal pressure to help seal and is more suited to 'static' pressure applications.

You could also use a C section but again using an internal C section which uses internal pressure to aid sealing will allow around 29000psi.

I am not sure what peak cylinder pressures you will see but 200bar (3000psi) seems a fair estimate and should be within the capability of an internally pressured O Ring design which is designated as an MOT Type.

I would use Stainless Steel or Inconel with a Nickel Coating. Some care in terms of groove dimensions is needed but it is not difficult and the Trelleborg Manual will provide all required details.

[KNIGHTRACE]

I have built a motor than ran 2.1 bar for short amount of times with an air to water intercooler, On an air cooled motor once the heads heat soak your HP falls. However I have many hours on race tracks running 1.4 bar. The ARP head studs don't work well in turbo or high HP motors in my opinion because they don't expand enough and crush base gaskets. The ones used in this motor look like 993 twin turbo.. There great but $1300 now. most likely the reason the heads lifted were too much timing, lean spot in fuel curve or under torqued studs. The apr torque lube is the best lube to torque bolts. I would say there is a good chance this is an under torqued problem, hard to say without knowing more variables. On the 1.4 bar motors I have the cylinders and heads cut and a 935 style ring installed. Hope this helps in some way. William Knight

[KNIGHTRACE]

Supertech studs are much better than ARP as well for an air cooled motor in my opinion.
William Knight Preformance or knightrace@mac.com

[chris_seven]

I am surprised by your comments about lack of expansion as this doesn't really fit in with the detail of the design of these studs,

The ARP and Supertec Stud have virtually identical Corefficients of Expansion and the Supertec Stud is stiffer due to its greater shank diameter.

This should mean that it is more likely to crush base gaskets than the ARP Stud as it will generate more load for a given Delta T, but there are far too many Supertec Studs being used successfully for this to be a problem.

I would have thought that the Supertec stud could allow more preload which should benefit the lift of the head when the engine is cold.

At a standard torque setting of 24 lbsft the preload produced by an M10 stud is not enough to hold the heads down if peak cylinder pressure is 2000psi or above so lift is not surprising if they have been torqued to this value.

You should be able to tighten the Dilavar studs to a torque of 36 lbsft without causing and issues to the stud and this will increase the preload to a value that should hold the head adequately clamped.

If you are worried about scatter in the preload then tightening the nuts to a small preload and then an angle would help to eliminate issues of undertightening.

If you torque the nuts to around 12lbsft + 90 degrees + 90 degrees you will be well within the capacity of the stud and should have enough preload.

I would torque initially to 12lbsft in the correct sequence and then 90 degrees in the correct sequence and then the final 90 degrees.

[Tippy]

Originally Posted by KNIGHTRACE

I have built a motor than ran 2.1 bar for short amount of times with an air to water intercooler, On an air cooled motor once the heads heat soak your HP falls. However I have many hours on race tracks running 1.4 bar. The ARP head studs don't work well in turbo or high HP motors in my opinion because they don't expand enough and crush base gaskets. The ones used in this motor look like 993 twin turbo.. There great but $1300 now. most likely the reason the heads lifted were too much timing, lean spot in fuel curve or under torqued studs. The apr torque lube is the best lube to torque bolts. I would say there is a good chance this is an under torqued problem, hard to say without knowing more variables. On the 1.4 bar motors I have the cylinders and heads cut and a 935 style ring installed. Hope this helps in some way. William Knight

I was thinking I'm simply undertorqued, as I did the torquing with the barrel nuts DRY, as I never found anywhere in the Bentley nor Wayne's book to put lube on them.

When I was a mechanic, I was trained that lubricants have a huge impact on overall torque.

I used the 3.2 specs, and now realized I probably should have used the 993TT specs........not sure if different? Will look up shortly.

Anyways, if it's 12ft/lbs for initial, that could mean a big difference in angle depending on dry or lube!!!

Clearly, I have LESS torque using dry method than lube.

This might be the whole root cause.

[Tippy]

Originally Posted by chris_seven

You really need to torque them tighter than the standard setting as you need enough preload to overcome the peak cylinder pressure and to stop the head lifting even when cold.

You can easily calculate the lifting force and compare this to the preload to see how much extra torque you may need.

The fact that the reduced coefficient of expansion compared to Dilavar will add clamping due the expansion doesn't help when the engine is cold and the damage occurring whilst the engine warms will be cumulative.

If the 'lift' of the head is small then a Wills Ring will help to maintain a seal.

An internally pressurised O Type Ring will seal to around 5800psi and in a Inconel material will withstand operating temperatures of around 1500degF. They have reasonably good resilience and deal quite well for varying pressure applications.

We have used them in Coventry Climax based race engines that blow head gaskets for a pastime for more than 30 years with good success.

If you used an internally vented O Type Ring will seal at up to 145000 psi but this uses the internal pressure to help seal and is more suited to 'static' pressure applications.

You could also use a C section but again using an internal C section which uses internal pressure to aid sealing will allow around 29000psi.

I am not sure what peak cylinder pressures you will see but 200bar (3000psi) seems a fair estimate and should be within the capability of an internally pressured O Ring design which is designated as an MOT Type.

I would use Stainless Steel or Inconel with a Nickel Coating. Some care in terms of groove dimensions is needed but it is not difficult and the Trelleborg Manual will provide all required details.

Salivating at your data! HA. Thank you, Chris. Informative as always.

Thank you for your input

[Tippy]

Originally Posted by KNIGHTRACE

Supertech studs are much better than ARP as well for an air cooled motor in my opinion.
William Knight Preformance or knightrace@mac.com

Thanks for your massively awesome input too.

I feel I can make a better decision along with xbmwguys info too.