2.7 cylinder heads
- Thread starter ukmastiff
- Start date
Well, the main use which you have overlooked for a 2.7 head is to mend a broken 2.7.
That apart, there don't have to be loads of people building big-capacity Turbos to make 2.7 heads scarce. They have always been scarce. The 2.5 head was produced in (by Porsche standards) massive numbers in 924s and 944s over many years. The 2.7 was only made for a short time, and in years when the S2 and Turbo were also available, and only was only built in small numbers.
George Elliott
New member
Are there not two of them on a 5.4 litre 928?
Pete, they dont have ceramic seats, but then what proportion of turbo engines do have them.
I have one on the shelf "just in case" and as S2's and 968's slide in value under the weight of massive 996 and 986 availability, maybe one day I will need it[8|]
George
944t
Pete, they dont have ceramic seats, but then what proportion of turbo engines do have them.
I have one on the shelf "just in case" and as S2's and 968's slide in value under the weight of massive 996 and 986 availability, maybe one day I will need it[8|]
George
944t
PSH
PCGB Member
I can't remember the full spec of my Stage 2 head but I did add a number of options, so besides the normal ceramic linning and sodium valves it also has high velocity exhaust ports , at the this time only Lindsey have this option. I also ordered a new coating for the chambers but during my head build Lindsey had discovered some issues with the coating material used and decided not to risk the coating for my head. However the head made a big improvement in performance so i was happy.
Pete
edit: forgot to add the larger inlets with 5 angle seats
Pete
edit: forgot to add the larger inlets with 5 angle seats
944 man
Active member
My post about the ceramic coating breaking down seems to have disappeared... The real purpose of the ceramic lining, I believe, was to try to keep the heat/speed/power in the exhaust, because having the turbo on the end of a very long up-pipe was a big compromise.
Much of the benefit (and perhaps more) can be retained now by wrapping he manifold and up pipe.
Much of the benefit (and perhaps more) can be retained now by wrapping he manifold and up pipe.
Diver944
Active member
My 3.2L was built using a 2.7 head without ceramic liners or sodium valves. The advice was they were actually bit of an overkill on the 2.5 by Porsche because they did not really know at the time how things would turn out and wanted the extra exotica as an extra safety net. Indeed the weak point in mine was the piston getting damaged by heat and caused a bottom end rebuild, the valves and head were fine.
I would be surprised if there are more than ten 3L Turbo cars in the UK and the actual rarity of the 2.7 head is purely because so few were made in 1989, the only year they were manufactured. It took me less than a week to find a complete 2.7 engine for my build back in 2005 and IIRC it cost around £500 for the whole thing (bought from one of the PalmerSport mechanics at Bedford Autodrome who'd put his 2.7 into a ditch over winter)
I would be surprised if there are more than ten 3L Turbo cars in the UK and the actual rarity of the 2.7 head is purely because so few were made in 1989, the only year they were manufactured. It took me less than a week to find a complete 2.7 engine for my build back in 2005 and IIRC it cost around £500 for the whole thing (bought from one of the PalmerSport mechanics at Bedford Autodrome who'd put his 2.7 into a ditch over winter)
TTM
Well-known member
Ceramic linings are probably worth having on extremely powerful engines (say 500+bhp) where heat may begin to boil coolant and the resulting vapour may get trapped into the upper cavities on the 8V head and ultimately lead to headgasket failure.
As Simon said, ceramic linings were added to help the turbo spool because it being so far away from exhaust headers means a severe decrease in exhaust gas temperature all through the cross pipe. This and the humble profile in ignition timing contributing to high exhaust gas temperature.
As Simon said, ceramic linings were added to help the turbo spool because it being so far away from exhaust headers means a severe decrease in exhaust gas temperature all through the cross pipe. This and the humble profile in ignition timing contributing to high exhaust gas temperature.
PSH
PCGB Member
The standard Turbo head has both good and bad points in it's design... the Ceramic linings are a good point and as Simon and Thom have said it helps greatly with spool up times but it also has it's Achilles heal which is it's exhaust velocity which is very low at 390 FPS. Normally you can not port the Turbo exhaust ports due to the ceramic lining but Lindsey have found a way around this that means they can greatly increase the FPS while retaining the full benefits of the ceramic liner. My head has an exhaust speed of 566 FPS so you can imagine how this extra 176 FPS, over a standard head at 390 FPS and possibly any other modified head not using Lindsey's High Velocity ports, helps my car achieve it's power output while retaining a very good spool-up speed, I doubt that the lag on my car is any more than a standard 220 using a K26/6 turbo, in fact it may even be less. I have no figures to prove this but can say how the car feels when compared to it's standard set-up. The other good thing about Lindsey HV ports is they don't get carbon'd up like standard ports do so are able to maintain that velocity.
Pete
Pete
Posts made and opinions expressed are those of the individual forum members
Use of the Forum is subject to the Terms and Conditions
