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-   -   A few 1911 questions. (http://forums.pelicanparts.com/porsche-914-914-6-technical-forum/1062357-few-1911-questions.html)

JaredM 05-27-2020 07:38 AM

A few 1911 questions.
 
Hey guys. I'm going to rebuild my 1.7.

I am on a budget and want to get my '71 on the road for the mid to late summer.
I've done some solid research on the world and some older threads here.

I have a 1.7 to rebuild I want to make sure I am planning this out right.

-Old NPR Japan 96mm P&C or the Keith Black P&C Kit
-Fly cut my 1.7 Heads to 105mm.
-Hastings Rings
-66mm stock crank
-Victor Reinz seal kit 1.7
-New Oil cooler
-Dual 36 Webers.

Questions:

-I'm going to send my heads out for a refresh, besides the fly cut, do I need any more work done, do I need bigger valves?
-Can I use a stock cam with the carbs? If not, what would be good for dual webers?
-If no cam, than the block stays the same, besides a refesh?
-Do I need to relocate spark plugs?

Looking for a solid motor, decent MPG, not power hungry. I've decided against a 2056 for this motor, I'd rather build a 2.0 for that, and use this 1911 to cruise around with until then.

Thanks so much for any info.

ppeters914 05-27-2020 09:31 AM

It depends on what Decent MPG means to you. My understanding is Decent MPG = FI plus easier tuning, etc., etc.

Why carbs if you're not power hungry?


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JaredM 05-27-2020 11:23 AM

Quote:

Originally Posted by ppeters914 (Post 10881196)
It depends on what Decent MPG means to you. My understanding is Decent MPG = FI plus easier tuning, etc., etc.

Why carbs if you're not power hungry?


Sent from my LM-G710 using Tapatalk

I donít have FI stuff. Two 1.7s with 3 sets of carbs here. Iíd like to utilize what I have.

Low to mid 20ís would be acceptable and I suppose expected. Not planning on getting 35+ mpg... thatís what the TDI daily is for. ;)

Jared

Dave at Pelican Parts 05-27-2020 12:18 PM

Your recipe should work fine. Get comfortable messing with carbs; there is a decent chance you'll do it a lot.

You do not have to go with larger valves, but it should help things flow a bit better. Be careful of not taking too much material out of the area between the valve seats in particular, and on the short radius of the port. There isn't a lot of extra material in that area.

You don't need to relocate the spark plug hole, and it's a lot simpler if you don't. But evidently the 2.0 location is good for some power and torque.

Going with 2-liter heads gives you larger valves and the better plug location, but they do tend to be on the fragile side. Throwing money at the problem can get you some LN heads; new AMC castings modified by Len Hoffman at HAM to be equivalent to the 2-liter heads and which are sold through the "type 4 store" (Google it). Not cheap, though.

The cam is going to be a significant limitation on what you can get from the engine. It is very mild in order to not confuse the D-jet EFI. That leaves a significant amount of potential power on the table, and pretty much kills the power at 5000 RPM.

The mild cam also won't really let you increase compression over the stock 1.7 levels of over 8:1 without starting to run the risk of detonation. (I forget the stock figure now, it may have been 8.6:1 or 8.2:1?) You might even think about dropping it a bit to five the larger bore cylinders a bit more time for a complete burn.

That said, the bottom end of the motor will work fine for a 1911. No changes are required other than pistons and cylinders.

--DD

JaredM 05-27-2020 03:21 PM

Quote:

Originally Posted by Dave at Pelican Parts (Post 10881389)
The cam is going to be a significant limitation on what you can get from the engine. It is very mild in order to not confuse the D-jet EFI. That leaves a significant amount of potential power on the table, and pretty much kills the power at 5000 RPM.

The mild cam also won't really let you increase compression over the stock 1.7 levels of over 8:1 without starting to run the risk of detonation. (I forget the stock figure now, it may have been 8.6:1 or 8.2:1?) You might even think about dropping it a bit to five the larger bore cylinders a bit more time for a complete burn.

That said, the bottom end of the motor will work fine for a 1911. No changes are required other than pistons and cylinders.

--DD

Thanks for the response. (Ignore my PM)

Iím moderately familiar with carbs, done a bunch of Harley, while single and small. I can tune it. Duals will be a new experience.

Iím familiar with the LN heads. Nice but out of the budget.

Back to the cam quickly: forgive my confusion, would it be beneficial with this set up to throw in an 86 grind cam? Limiting the motor not doing it? D. Elgin, scat, Eagle, etc.

This is a budget build, but not El Cheapo. I have no problem running a mild cam if it will make a day and... evening difference.
With hopes it will not grenade.


Thanks Dave!

Dave at Pelican Parts 05-27-2020 04:55 PM

To change the cam, you're splitting the case. Might as well do the whole bottom end at that point--at least all of the bearings.

One of the Web 86 grinds should make a noticeable difference. Make sure to get the lifters to match; a mis-match in hardness can lead quickly to the cam going flat which will make nobody happy.

--DD

jess p 06-03-2020 07:35 PM

I’m on my 5th 914 but, way back in the day when I bought my first 914, I rebuilt the engine on a budget, it cost me $45.00. Yes, that’s not a misprint. The car had over 100,000 miles on it. I took the engine apart and used all the original parts. I hand sanded the bores and put new rings and with new gaskets put the engine back in the car and drove it another 90,000 miles. The car eventually broke in half from rust. A testament to how good those type 4 engines are. Now thats on a budget.


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