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Another 2.7 rebuild +ITB&EFI
This is my first porsche engine rebuild, so I bought all the books and read up and down on the pelican forum in advance.
it's a 74' engine 150bhp with the small 30/32mm head ports. It's been running on Zenith 40's the last year. car/engine has only 52000miles. Engine runs good, some small oil leaks. 7:31 R&P 915 transmission I've installed MS2 in the car but I have just used it to monitor WB02, Air&oil temp, Ignition angle and rpm when i was tuning the carbs. Plan is to open head ports to 35/35mm and go with EFI&ITB's JE 9.5 pistons and maybe DC-30camshaft? Any recommondations on camshafts are appreciated BHP with this setup? Anything out of the ordinary on these pictures? Engine out, took 3hours http://i380.photobucket.com/albums/o...psccc57010.jpg Rear engined Audi :p http://i380.photobucket.com/albums/o...pse805408b.jpg Before cleaning, the gaskets around the "triangle of death" was changed half a year ago, so its just old oil spill http://i380.photobucket.com/albums/o...ps7ba9f4d6.jpg Appears to be leaking oil from this bolt? http://i380.photobucket.com/albums/o...psbd557e57.jpg http://i380.photobucket.com/albums/o...psa4c4eb3e.jpg Cleaning engine before dissasembly http://i380.photobucket.com/albums/o...psb09f6790.jpg Steel bolts with timserts or casesavers? http://i380.photobucket.com/albums/o...pse0da59ad.jpg http://i380.photobucket.com/albums/o...psc5cde0f1.jpg Teflon seals http://i380.photobucket.com/albums/o...ps85c8a7ef.jpg |
Woho, Nikasils right? magnetic!
http://i380.photobucket.com/albums/o...psfd0f7577.jpg http://i380.photobucket.com/albums/o...psb21e336b.jpg http://i380.photobucket.com/albums/o...ps6b36d2f7.jpg Just a quick test fit gsxr600 throttle bodys http://i380.photobucket.com/albums/o...psee5b6d32.jpg |
I also weighed the engine (kg)346lbs including heat exchangers, flywheel zeniths, and alternator/fan.
So basically complete engine minus muffler/cluth disc and pressure plate. My car is 1020kg /2249lbs full tank and as delivered from factory with spare wheels etc. Nothing removed http://i380.photobucket.com/albums/o...ps485afe00.jpg |
Our 2.7 race engine is setup nice with stock 90mm cylinders but used the 9.5 J&E pistons and weber 40's along with the DC-40 cam Very nice setup for what we do on the track.
That bolt/stud thats leaking holds the IS is known to pull much like the head studs, make sure they put a 8mm case saver in there too. |
cool, any bhp figures on that engine?
My car is for street use so i think maybe the Dc30 is enough? I dont want to loose to much at low rpm. |
Another 2.7 rebuild +ITB&EFI
We don't have hp numbers yet but it was originally built as a street motor we set the overlap around 4mm for more low end and for the track set it closer to 5mm so it would continue to pull at higher rpm's. It stays with my 3.4 Carrera @ 2400# 260hp but weighs in at 1900# in the straights, naturally can out corner the piss out if me. :)
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overhauled the starter, the solenoid did not kick in after a long hot drive, so i guess it's time to have a look at it.
http://i380.photobucket.com/albums/o...psff6c3522.jpg think i found the problem with the solenoid http://i380.photobucket.com/albums/o...ps5a6b5eb6.jpg http://i380.photobucket.com/albums/o...ps85f8d2f1.jpg |
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Today I made a jig to use in the mill for the cylinder heads that needs to be ported
I have I/E , 30/32mm Thinking of going to 36/35? http://i380.photobucket.com/albums/o...psdc1de811.jpg |
So the big question is, how deep to mill??
It's 35mm to where the valve guide starts to protrude. After milling i will need to use hand tools to smooth the edges, I don't have a flow bench, so they will have to do without. The port also appears to increase in diameter from the top surface going down towards the valve guide http://i380.photobucket.com/albums/o...ps405bc439.jpg |
Here is a 2.7 head cut to 37mm kind of gives you an idea?
http://img.tapatalk.com/d/14/01/19/5ypa5ybu.jpg |
Ah, perfect! Thanks :)
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Like your ITB' setup.
Where did you get the intake adapters and velocity stacks? |
#cgarr
do you have a picture of the exhaust port as well? #totle I made them myself :) |
Nice build! And with properly tuned MS it will be a hoot to drive I bet :)
Here are some photos of my porting job prior to finishing the head work: http://forums.pelicanparts.com/911-engine-rebuilding-forum/644958-my-2-5ss-turbo-engine-build.html |
Quote:
Going the same route |
Quote:
Here it is but did nothing with them just stock 35mm http://img.tapatalk.com/d/14/01/21/juguhu9y.jpg |
I did some work yesterday, intakes are done, exhaust I will do later today.
I found half of the valve stem seals torn in half. http://i380.photobucket.com/albums/o...pse4c43487.jpg |
My clutch was stock from 1973 with the rubber dampened clutch disc.
It had to be resurfaced , was 9.43mm is now 8.83mm, had to go that deep to get rid of some localized hardened spots. http://i380.photobucket.com/albums/o...ps52f2ccdb.jpg |
So now all the exhaust sides are done, and i drilled out all of the exhaust studs since they were stuck (tried heating, welding a nut to the stud etc), new threads in all, waiting for new studs.
Next will be to smoothen all the edges from the milling and clean the heads. http://i380.photobucket.com/albums/o...ps82bb9721.jpg |
Now with some spare time I started to measure all the P/C's
http://i380.photobucket.com/albums/o...ps3cafc2a0.jpg |
And hmmmm, I have the largest cyl/pist combo (group2), and small JE's...
I've read other posts here that ideal p/c clearance to be 0.0381mm/ 0.0015" And I'm at 0.11mm / 0.004" if I mix large piston with large cyl etc. Ovalness is within 1 hundreth of a millimeter so that part is good. So what to do with the P/C clearance? get custom JE's? http://i380.photobucket.com/albums/o...ps44b768e4.jpg http://i380.photobucket.com/albums/o...ps4a7ad264.jpg |
I went to measure again but this time with a scale that reads 1 thousanth of a millimeter,
and then I found this ... So now they will go to us chrome to be coated&honed with nikasil 0.04mm larger then my JE's. I measured my cylinders to 4 RA where the piston rings move and the bottom of the cylinder is 7.2 RA US Chrome says they will hone to between 4-8 RA, and two weeks turn around time. http://i380.photobucket.com/albums/o...ps6e71dc30.jpg |
In the mean time I've smoothened the transitions in the cyl head ports after I milled them.
And then glass blasted, next will be to fly cut the head. http://i380.photobucket.com/albums/o...ps6c559c48.jpg http://i380.photobucket.com/albums/o...ps119fc9c2.jpg |
Cyl heads need fly cutting
http://i380.photobucket.com/albums/o...psaff7efda.jpg http://i380.photobucket.com/albums/o...psb77fcb9b.jpg All done :) http://i380.photobucket.com/albums/o...ps97c82850.jpg |
All cyl heads are now within 0.02mm in height differnece, same goes for cylinders
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How much did you have to take of the heads to clean them up?
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0,35mm, I read somewhere that there is a max to how much one can take of, but I can't find it.I guess I will add a 0.25 extra copper shim in addition to the 0.5mm i have underneath the cylinders.
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Yea .25mm is the max that's to keep within the limits of the chain tensioners and chain box centering without modifications to them. Stock measurement from the cam carrier top of the head to the sealing surface is 84.5mm
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Awesome thread. Your not interested in selling the carb setup are you?
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So today I checked the torque on my case throug bolts and the M8's, they were all to loose, the through bolts are supposed to be 35Nm, they were around 20nm. Torqued all to spec, and checked crankshaft end play to be 0.22mm
Max is 0.3mm, new I think i read something between 0.12-0.19mm Then looking at the valves for my cylinder heads, alle the exhaust guides are shoot, measured 0,6mm radial play.... Intakes are good. took out the guides using the method in this thread, worked as a charm. http://forums.pelicanparts.com/911-engine-rebuilding-forum/552404-valve-guide-removal.html http://i380.photobucket.com/albums/o...psa9f7b2e0.jpg http://i380.photobucket.com/albums/o...ps110c3b0f.jpg |
So now I need to order new valve guides, and then cut the seats.
I borrowed a set from a friend, I see in Bruce's book that the seat angles are 30-45-75 degrees. The valve seats at 45 degrees. Are both the valve and the seat 45 degrees? The tool I borrowed is 46 degrees? http://i380.photobucket.com/albums/o...ps4b905b32.jpg |
Your talking Interference Angle or "pinch" cut the seat and lightly lap the valve and you will see the benefits mostly with air cooled engines. Nice cutters, I have 12 different ones. You have a Valve Concentricity Gauge?
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hm not sure I got that, do I use the 46degree tool or do I need a 45?
What is a Valve Concentricity Gauge? I have tools to measure the roundness of the valve seat. And I have the cutting tool to straighten the valve sealing surface. this engine needs more and more parts every day, and I hate waiting for parts :p |
The neway kit for Porsche uses cutter 642 and 272 are those the ones you have?
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I have 203/212/217/622
The 622&217 will do the job on the exhaust valves. They are too small for the intake. Found this as well 203 Cutter- 1-1/4" dia. 31° x 46° 212 Cutter- 1-1/4"dia. 15° x 75° 217 Cutter-1-1/2"dia. 15° x75° 622 Cutter- 1-1/2"dia. 31° x 46° 619 Cutter- 1-1/2"dia. 15° x 60° 216 Cutter- 1-1/2"dia. 75° 642 Cutter- 1-3/4" dia. 31° x 46° 272 Cutter- 1-3/4"dia. 75° |
Another 2.7 rebuild +ITB&EFI
Oh that's right your doing 2.7 heads, that 622 is too small for those intakes? Might have to get the 642 for that? You can extend those cutters to their limits?
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