2.7 Hot Rod Engine Build (Advice Needed)

[SiracHaile]

Hello Fellow Pelicans,
I’ve been lurking and searching through the forum ever since I purchased my first porsche.
I’m currently in the process of planning my engine rebuild (terrible leak down numbers) and I need some advice.

Here are the current engine specs.
2.7 7R Magnesium Engine Case
RS Spec pistons
S spec Cams
Already Time Sert or Case Savers

Here are my plans
Surface case and align back to standard
Shuffle pin
Insert all threads
LN Nickies
Mahle 10.3:1 Pistons (or 10.5 JE)
Keep S cams
Clewett ITB
Dual plug coil on plug ignition
Link Stand alone ECU and custom harness


I’m looking for a streetable car that I can enjoy in the canyons and the track(occasionally). Is my build over the top(in a bad way) or is it well suited for a fun street car. I will be assembling the engine myself but will be taking the engine to get machined by either Ollie’s or Competition Engineering.


Looking for advice or someone who has experience with the specs above and can provide feedback or recommendations.

Thanks
-Sirac Haile

[chrismorse]

Hi Sirac,

ARP or Raceware rod bolts.
Factory thermostat and lines to an 85 front cooler, or front valence cooler, depending on how hard you use it and ambient conditions.
Oil bypass mod, perhaps a "massaged" carrera oil cooler for a bit better flow.
Talk to John Dougherty to see if the S cam is right for your intended use.
Have Craig Garrett port and do a valve job on your heads + machine for 2nd plug.
You might need stronger valve springs.
KEP all aluminum clutch and RSR flywheel.

My good friend Gordon, is guiding me through the above work. We are going with JE 10.5 pistons in 92 mm replated Mahle cylinders. I went with Al Kosmal's Megasquirt EFI, with PMO ITB's and running EDIS twin plug, For exhaust, i got SSI's and a Scart Riva.

My use is very close to what you are planning, If you are going for more zoom, you might want to consider headers - talk to your head work guy and a good engine builder for cam specs.

How is your suspension/brakes/wheels/tires??

Have fun,
chris

[SiracHaile]

Thanks for the information Chris,
I do plan on doing the oil bypass mods along with the other items you mentioned, so I’m glad to hear that.

I was planning to take my heads to either of the two machine shops I listed, but I’m having trouble finding more information about Craig and his pricing. Could you share his information?

The engine is on my first list of to dos, I’ll be tackling the other aspects of the car later but I do have stiffer TBs front and rear with plans of using the KW shocks. Brakes are still in the air, but the boxer calipers and adapters seem like a good affordable option. But I’m taking it one step at a time.

[Neven911]

Consider Pauter rods - a lot lighter than standard

[targa72e]

Having recently built an engine very similar to your existing engine for a friend and dynoed in the same car with a different engines I would offer these thoughts.
You can read build details for engine similar to your build here.
911 Engine for sale

Having recently dynoed a 2.4 engine with similar head port sizes (36I 35E) but smaller cam (stock E) and compared to friends 2.7 I would suggest the following: Higher compression should be good, I would also consider a more efficient cam like MOD S cam or maybe even step up to next more aggressive with your higher compression plans. I would also consider some mild porting.

The dyno below compares a 2.4 with E cams and 2.7 with MOD S cams. 2.4 was 9.5 comp and 2.7 was 8.5. Same size ports on heads.



Knowing the the MOD S cams are much more aggressive than E cams and seeing how the power is falling off on 2.7 at higher RPM would see what I could do to get the ports to flow better.

I also compared this 2.4 to previous 2.4 I built. The previous engine had lower compression 8.5 and smaller ports 33mm., but had the advantage of MFI compared to carbs with 30mm venturi. With a little more compression and larger ports power and torque was better everywhere with current engine.



I am planning my own engine for my 914-6 conversion (car all the above engines were tested in) very similar to your plans. 10.5 JE pistons, twin plug, MOD S (or more) ITB, programable EFI, ported heads. Should be fun.

john


john

[Mixed76]

Suggestion: Consider just doing rings, valves, valve guides, and valve seals to fix the poor leakdown result?

Then drive it?

Seems like tackling everything all at once is a really hard way to go, so many things to get exactly right, so many potential mishaps and delays.

Add itbs and efi after the top end. If that doesn't get you where you want, you can change pistons and cams without cracking the case.

Not sure there's any reason to buy Nickies before inspecting the cylinders you have.

Baby steps will get you there just as fast and let you enjoy the car as you go?

Edit- I just read your introductory post- why not keep the carbs on there?

Sent from my Nokia 7.1 using Tapatalk

[SiracHaile]

Thanks for the information John. I’ll be reading into that and I’ll check to see if the Cam will work well for my goals.

The heads do appear to look to be ported and I did get some confirmation from Craig that ok looks like light porting.




As far as just doing a top end, I did consider that and that’s was an option. But since I never heard the engine run nor do I have any history on it I think it would be wise to tear it apart and inspect it.

The nickies are my preference since I wanted to start fresh. I’ll be inspecting the RS pistons and cylinders and posting them for sale to recover some costs.

The car needs a lot of work and I’m working on systems and the goal is to have a complete car when I’m done. I enjoy the journey and driving it at the end would make it so worth it.

But I appreciate the advice and feedback. There are a lot of very knowledgeable people in the forum so as a Newbie I’d like to absorb as much as possible.

More pictures of the engine as it sits




Thanks
-Sirac

[Neil Harvey]

Originally Posted by SiracHaile

Hello Fellow Pelicans,
I’ve been lurking and searching through the forum ever since I purchased my first porsche.
I’m currently in the process of planning my engine rebuild (terrible leak down numbers) and I need some advice.

Here are the current engine specs.
2.7 7R Magnesium Engine Case
RS Spec pistons
S spec Cams
Already Time Sert or Case Savers

Here are my plans
Surface case and align back to standard
Shuffle pin
Insert all threads
LN Nickies
Mahle 10.3:1 Pistons (or 10.5 JE)
Keep S cams
Clewett ITB
Dual plug coil on plug ignition
Link Stand alone ECU and custom harness


I’m looking for a streetable car that I can enjoy in the canyons and the track(occasionally). Is my build over the top(in a bad way) or is it well suited for a fun street car. I will be assembling the engine myself but will be taking the engine to get machined by either Ollie’s or Competition Engineering.


Looking for advice or someone who has experience with the specs above and can provide feedback or recommendations.

Thanks
-Sirac Haile

These kinds of posts bring a smile to my face. You asked and you will get a multitude of opinions. The only opinion that is important is yours.

What is streetable and occasionally track? This has always baffled me. Do you mean the engine will not be built particularly for the track , therefore when you are at the track you will drive it like you do on the street? I would bet every dollar for every doughnut that is never the case. Its the same as "boost fever" people get often. Some is OK, more will be better.

I used to ask 2 questions of my customers. The budget and performance goal. Now I have 4. The other 2 are, do you want to build the best engine or the cheapest?

Decide on a performance (including engine size) you want, then decide on the budget and see if they both fit. Then start making compromises (least first) to see if it all comes together. Then you know the costs, and then start buying.

Your list shows some work. Until you have disassembled, cleaned and measured, some may not be required. Be careful of some parts that may be required. Some have very long lead times now.

The performance level required will dictate the build. Any head work, port sizes, valves sizes, etc, along with dual spark plugs etc. Dual plugs changes the Ignition as well. My advice is to stick with CDI for these engines. Before you make any decisions, you should decide upon the Intake and have the heads and Intake flow tested as is. Then this will tell you what to build and what parts may be required. The air flow numbers will tell you the how much restriction is in the Intake system, how much the heads flow, what camshaft to chose etc.

Plan this, engineer this, don't rely upon what others have done.

nh

[SiracHaile]

Thanks everyone for the input and the contacts. I have been been planning and seeing what worked for others to try not to reinvent the wheel. These engines and combinations have been around for along time so I would think there is a recipe that would work.

I’ve been in contact with the people mentioned here and I have a good plan on what I will be doing and I am thankful for those who provided the information.

I did tear the top end apart and the valves and seats were rusted from water that leaked past the carbs when the car sat under it’s previous ownership. So I was able to clear that up. It did have Web cams 149 grind that’s an s spec cam. And RS pistons too. The cylinders look in good condition with the exception of one that looks to have some spalling from the coating I think. So I think I have to replate or just get new cylinders.

I’ll update as I progress and let you all know the final recipe

Thanks
Sirac

[SiracHaile]

For those who even care here is what I came up with.

So I’ve did enough research to start ordering parts.
Heads were sent off to Craig for his magic. They were mildly ported/smoothed
Twin plug
Aasco Springs and Ti retainers
Cams are Dougherty DC43x
Pistons Mahle Motorsport 2.7 10.3:1
Cylinders Nickies
Refreshed bottom end with all the reliability updates
40mm Clewett ITBs
Link ECU
SSI heat exchanger (maybe upgrade to bursch)
Muffler still pending.

Hopefully will see it running before the end of the year lol.

[911 SLANT]

I would just drop off with Henry at Supertech in Fallbrook California. He will setup your 2.7 better than anyone. Good luck!

[75 911s]

Sirac,

Great to meet you before Luft8 and thanks again for bringing me those ignition parts. Following your build with interest. Keep us updated on how progress goes. Pics too!

[SiracHaile]

Small update! Got my case and parts from Ollie’s took a while but worth the wait.

[SiracHaile]

A little update for those who care.
Got a lot of parts WPC treated, bearings rockers and shafts, cams, pistons and cylinders. It’s a surface treatment that adds micro dimples onto the surface to reduce friction and wear.




Measured the Carillo Rods and the crankshaft to verify clearances.








CC’d the heads and they came within spec and equal at 67cc. Heads machined by Craig Garret with Aasco valves and minor port to s spec.





Sorted all the parts to start the assembly



Getting ready to finish up and seal up the case soon.

[Mixed76]

Rods look nice and light

Sent from my Pixel 7 using Tapatalk

[SiracHaile]

Continued on the assembly this weekend.
Forgot to add the photo of ccing the head



Added Driven assembly grease to main bearings. Assembled the case and sealed it up.

[Buckman]

I like your post I have the same engine I will be rebuilding in the future I will be keeping up with you post.
I want to see a cost break down on your build if you can show that and maybe what options you looked at before you pulled the trigger on parts ?
Looks Good look forward to progress

[SiracHaile]

I do have a spreadsheet that I was keeping track of that needs to be updated. But I’m way over budget with all the unforeseen upgrades and impulse purchases.

I’ll be updating it soon and can share. But I’m over $30k in the build so far. Without the intake and exhaust system

[SiracHaile]

More progress with the engine. Working on the top end now.

Installed ARP studs





Brand new Mahle Nickies set from LN Engineering

WPC treatment on the pistons, cylinders, rings and pins.






Measured deck height to 1.4mm for an effective 10:1 compression




Assembled the updated idlers with new sprockets and Supertec idlers


Next up measure piston to valve clearance

[Black 993]

Great thread, keep the updates coming