How to build a 2.7?
 

I've been plugging along restoring/restomodding a 77 911 Targa. It is a budget build, being done in less than optimal work conditions (a rough garage / good shed). The goal is a cool 911, reliable, that is used for spirited drives, possibly a track day or two. As far as I know, the engine is original, with the thermal reactors having long ago been removed. Car was parked 25 years ago, supposedly in good running condition.

Well, fast forward, I finally got the 2.7 to fire up. It's not humming like it was in 1977, but it does start and run.


Theres a nasty oil leak somewhere behind the airbox, and a clean and rebuild of the injectors and fuel distributor is needed. So, at this stage I'm debating about whether to continue the spot repairs, or to go ahead and pull the engine.

Looking to y'all for input and guidance. Do you pull the motor and look at a top end rebuild, or continue with it in the car? If you go rebuild at this time, would it be 964 cams and 2.7 Nikasail cylinders with the CIS, or some other configuration?

Here's how we did my 2.7 and it pulls strong.

JE Lightweight pistons
Dimon Eligin SC Cam
SC air filter box
SSI heat exchangers
Dansk two in one out muffler

This was 12 years ago. It leaks a little but runs great!

One consideration is whether you need to have emissions checks on the engine. If not, eventually going with RS pistons/cylinders, S cams, and Weber carb’s really wake these engines up. Need to machine the case for CaseSavers as well. These mods are far from cheap, so I’d chase the leaks and drive it until funds are available todo it right.

Start here...no need to jump straight to rebuilding the thing.

https://www.pelicanparts.com/techarticles/101_Projects_Porsche_911/21-Oil_Leak_Fixes/21-Oil_Leak_Fixes.htm

C,

the bit of work involved in removing the engine/trans to be able to easily inspect and resolve the leaking issues will be well worth the time and trouble.

There are many old hoses and wires between you and the source of those leaks....it'll be MUCH easier with engine out, and most likely you'll solve most, if not all of the running issues by replacing hoses & cleaning connections encountered along the way.

PD

I'd do a leak down test (or at least a compression test) to find out the condition of the valves and rings. If they are good, fix the ancillary things, tune it, drive it, and save money for when you want to do a rebuild in the future. I built the 2.7L in my '69 with longevity and dependability in mind. I has: JE 9.5:1 pistons; Nikasil cyliinders; E cams; Webers, balanced (not really a necessity); thermal barrier coated piston tops, valve faces, combustion chambers; dry film coated main & rod bearings, cam lobes & bearing faces, valve stems, oil pump, & some other things. This was some years ago, and a proper rebuild on a 2.7L now would be very expensive, especially with case machining (which mine needed).

I appreciate the input! In SC we dont have to worry about emissions, but who knows how long we will be located there, so I'd rather keep emissions in line if possible.

The idea of dropping the engine to access the hoses, etc. isnt something I had considered. but I can see the merit in that.

A compression test and leak down will not give an accurate diagnosis on an engine that has not been run for awhile, rusty valve seats and valves will cause false readings. Get the leaks fixed replace rubber bits tune it up and drive it. Once you have 500 miles on it and knock the crud off the valves do the tests and see what is up.

If you want a build like Overlander 80 mentioned, I have a set of SC grind cams I was going to use on mine....before I found out it was bad enough to need a full rebuild.
I initially intended to do a CIS with the SC grind.

Cough....cheap ITB and EFI setup....cough

pampadori, mind elaborating?

For reference, I have a 76 Targa S that was a garage find and had been sitting so I can sympathize with the while you’re in there mentality. I would also prioritize changing your 42 yr old fuel lines while the engine is out. This guy makes fuel line replacement kits, he’s on Pelican forum too.

Mason_paul@yahoo.com

Have you heard of triangle of death? Likely oil leak locations.

Exactly this is the triangle...
- breather oval seal
- sensor plug or it's seal
- oil thermostat O-ring

and since you have the oilcooler off, it's your chance to adress the spot behind it according to tech Bulletin:

I will frwd tech bulletin via email.

Thanks Frog76S! Fuel lines have been replaced, though I'm running the front fronts into a plastic gas jug until I'm ready to buy a new tank!

Yes, please forward that article when you can.

+1, I don't think a cheap ITB/EFI system exists, aren't they all $4k+
If someone has one that's only a little bit more than my good Weber 40s I'd be all over it :D no better time to upgrade than when the engine is out of the car being rebuilt.

Triumph ITBs is what Pampadori means. They are about 150-200 each side. Clay makes a great linkage kit for them. But yes, by the time the harness is done, crank triggers, sensors, COPs, injectors, pump, fuel lines and all the fabrication, and an AEM Infinity 506 ECU running it all it is indeed still a good more more than a set of carbs but very worth it once set up IMO. I can’t say enough about the flexibility and overall drivability when done right.

This.
The CIS will be easier to rebuild/get running well than any of the mentioned projects. Get it running well, then decide. In the meantime there are plenty of things to do to get it running well. There are plenty CIS primers available, buy/acquire them all, keep them near the toilet and read until you understand completely. If you start dicking around with changing the intake system, you will ultimately sell the entire mess on Bring a Trailer. Fix what you got, run it.

Update on this... after pulling the CIS, and going through it to get decent fuel flow, replacing injectors and cleaning the CIS, we decided to do a pressure test on the cylinders. All looked pretty good, considering, four of the cylinders at 150-155. One at 143. All held the pressure well. The exception is #2, which got zero. Ran it several times and got the same result.

We are in the middle of the snowball effect here. Alternator was fired too.

Looks like once I figure out to clean out the fuel distributor and get the CIS back together, how to it's time to drop the engine.

Is it reasonable to spot replace cylinders?

I wouldn't just assume that you need to change a cylinder/piston. I'm thinking more like a valve stuck open. A leak down test should help pinpoint. You should actually be able to hear the leakage.

Wow! That hadnt occurred to me. maybe because I'm learning as I go! :)

Ya know, when we were doing the compression test, we had 4 done, and I was getting excited by the results we were getting, and then the zero. I was baffled how we could get 4 at 150-155, and then the goose egg. It would be awesome to avoid a rebuild!

Dont know how I'd do a leakdown test, but I have the CIS and runners off. Would putting some blaster and marvel mystery oil in through the injection port and letting it soak be a good option for releasing a likely stuck valve?

Here's an "order of magnitude" leakdown test you can do:

- Crank that suspect cylinder to top-dead-center where both intake and exhaust valve should be closed (distributor rotor pointing toward the corresponding plug wire).

- Lock the engine so it won't turn.

- Connect compressed air to the spark plug port.

If you hear air leaking from the intake port, you've got an intake valve problem (won't close, burned valve, eroded seat, etc).

If you hear air leaking from the exhaust, you've got an exhaust valve problem.

If you hear air leaking from the case breather, you've got issues with rings/piston.

If you hear air leaking from around the cylinder head, you may have a blown head gasket or enough broken head studs that things are trying to separate (rare to get zero compression from this).

If you find it's a valve, I'd start by removing the rocker covers and determining if the valve is stuck open (might be able to see directly with the intake runners off on the inlet valve). Having the covers off will let you verify valve clearances and see the back side of the valve stem move (or not) as well as find any broken head studs.

Hope that helps.

Your realistic options are to fix what you have, which means diagnosing (leakdown) your existing problems and trying to fix it on the cheap, or drop about $10k rebuilding the engine. Leakdown testers are fairly cheap, and well worth it. Pull the valve covers off and see if any valves are stuck open.

the 2.7L has a Mg case - add the thermal reactors and you are looking at a lot of specialty machine work

get it align bored (or checked); aka line bored - the machinist will know what else it needs

you can roll the dice and skip this, but if you do start saving for a 3L motor

The guidance has been very helpful, and much appreciated!

On the thermal reactors, fortunately they were long gone before this car was parked. Not sure what else the PO did, but this is a positive, and the head studs, at least the top ones held up to 20 lbs with the wrench. knock on wood!

The lower head studs are the ones that will give you problems.

Doh! I'll be getting at those shortly.

I asked a similar question here, my 71 has a 77 engine in it.

Honestly, the engine itself is strong and runs nice. But it has webers on it, not CIS.

https://forums.pelicanparts.com/911-engine-rebuilding-forum/1031100-engine-build-advice-71t.html

225 HP would be awesome. What did you end up doing with it?

the thermal reactors are long gone, but warping of the "congealed butter" the case is made from may still be an issue

so, you can pay for machining & inspection now or risk paying a lot more later - your choice

Bruce Anderson quote

25 year inactivity: a few thoughts..
 

A lot can go wrong in 25 years.
I like clickclick's advice, just get it running before jumping to efi. My car has been down for 6 years, while I am doing suspension, brakes, a few upgrades plus family health issues, moving, etc, etc.
At 25 years of being parked, I'd make sure I replaced every single fuel related hose, including the tunnel and evap lines, next, before diving into an engine overhaul, it might be good to know if you have any catastrophic problems, like serious rust, rat chewed wiring, big trans problems, so you can prioritize and plan for the work ahead.
You can live with loose shocks and tired suspension, but the brakes need to be right.
Not trying to dampen your enthusiasm, but a lot of small stuff is going to need to be checked/serviced, wheel bearings, CVs, boots, brake lines, lights.etc.
I'm doing a new fuel tank, due to rust through, upgrading to front, new pump and late ffuel lines, hope to be cleaning, testing the CIS soon, after the rear suspension/brakes.
Good luck with the dead hole

Just driving the piss out of it! The car goes great.

Problem seems to have been confirmed. Verified that #2 intake valve is well sealed. Exhaust valve seems to be stuck open. lot of play between the rocketr arm and valve stem. Sprayed the port down with Blaster and did some tapping on the valve and top of the arm. No luck yet. Back at it toward the end of the week. hopefully.

Back at it... After mush tapping on the valve stem and oil sprays, I decided to put the valve cover back on, finish up the fuel system and see if #2 would free by letting the engine run. Though I would let this happen and adjust valves and oil after some engine run time. So, long story short I did that, and this is a video of the engine running now.

https://m.youtube.com/watch?v=g-6ju6PqJT0&feature=youtu.be

I checked compression after this run, and still have zero compression in number 2. I was alarmed by the engine noise, so haven’t let it run much. Any thoughts on what you hear or see in the video?

cfassett, did you ever get around to a leakdown test on that engine? The audio from the youtube video did not seem consistent to me for a stuck valve. I would expect a lot of popping. What I hear is a very rhythmic tapping noise. I do not blame you at all for being hesitant to run it.

BTW, that seems to have a nasty vibration. Is the rocker arm depressing the valve continuously, or is it free to bang on top of the valve? That would explain the vibration a bit.

https://www.bing.com/videos/search?q=automotive+engine+valve+traing+in+motion& &view=detail&mid=479C4968DDB0370F8C6E479C4968DDB03 70F8C6E&&FORM=VRDGAR

I haven’t yet. Since I don’t have the equipment and that one cylinder had no compression, I was planning to let it run a while and let some of the kinks work themselves out.

Patkeefe, on the vibration, yes, with the assumption that the valve is stuck open, I didn’t bother to adjust valve gaps while I was in there, but set a ballpark gap on number 2 after tapping on it... wanted to allow it to move out and seat. It was set at about .010from the position it was in.

I ran it again last night before hitting the sack and didn’t hear as much of the tapping, but there was still the vibration.

The vibration could be from uneven running of the motor. I would take something like a wooden dowel with a hammer to tap on the lifter of your stuck valve. That may loosen it up.

There is a chance that some carbon from the combustion chamber broke off and is stuck on the valve face, preventing it from closing.

Also, you may want to confirm all the other cylinders are actually firing. Perhaps pull each plug wire to confirm.

I did a fair amount of tapping with a small hammer with the end wrapped in electrical tape... not sure if it helped or not.

Today, tried to adjust valve gaps, which were all tight against the lifters to begin with. Loosened all to start. Adjusted 1 and 6 no problem. Then when it gets to 2, the crank binds at this same spot on the pulley, every single time. About 1/2” short of TDC for #2.

I bump the ignition key and it moves past without issue, but I can’t seem to move it past there by hand to set # 2.http://forums.pelicanparts.com/uploa...1567369305.jpg

That sounds like a more serious problem. I would get in there with a bore scope and try and see what is going on. It almost sounds like the valve stem is bent and the valve is touching the piston....

I would also want to make sure the chain tensioners are still doing their job. After sitting they could have gone soft.

I agree with Gordon, look in through the spark plug hole with a borescope. Sounds like something is on top of the piston and hitting the head. It sounded pretty ratty in the video. I guess you now know why it was parked. Ugh.

Thanks for the advice. I did look in there before with the scope and saw nothing of concern. Will do so again shortly, maybe run a magnet in there as well. I've had some local friends helping out as well. We've been adjusting the valves, which has been a challenge as noted above. While the valve covers were still off and some most of the valves still loose, we fired it up. Local VW expert was on hand and wanted to evaluate it. Interesting in that the tapping noise was not there this time. Valves appear to all be moving fine at this point. I'll do as suggested and let you know what happens next.

Thanks for all the input and guidance! Any other thoughts, please let me know.