Home  |  Forums  |  914 Info  |  Blogs
 
914World.com - The fastest growing online 914 community!
 
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG. This site is not affiliated with Porsche in any way.
Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners.
 

Welcome Guest ( Log In | Register )

2 Pages V  1 2 >  
Reply to this topicStart new topic
> Six cylinder engine rebuild
mate914
post Jan 17 2020, 10:44 AM
Post #1


Matt
***

Group: Members
Posts: 721
Joined: 27-February 09
From: Eagles mere, PA
Member No.: 10,102
Region Association: North East States



My father and I are starting the process of restoring a 9146 that he picked up 15 years ago. We are about to dive into the motor rebuild and I have a few questions, a few as in 1000 or so. We have both done a lot of research and are confident enough to be dangerous. He is keeping the numbers matching motor to sit on a shelf. We will be building off of a 69 magnesium case. We plan on going with the short stroke crank and either 86 or 90 mm J&E pistons and cylinders. Engine will have 40 weber carbs with chokes sized accordingly. Camshaft will be ordered specifically for engine.
Can any of the informed engine builders advise whether this is a good set up or not? Car will be a garage queen and occasionally autocross and driver’s ed. He is looking for 150+ horsepower.
Thank Matt
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
brant
post Jan 17 2020, 10:49 AM
Post #2


914 Wizard
**********

Group: Members
Posts: 11,584
Joined: 30-December 02
From: Colorado
Member No.: 47
Region Association: Rocky Mountains



The 69 mag case is the weakest of all of the cases and as a result is not a good choice for high HP
the stock motor was at least 110hp... and can easily be jetted and tuned to 135hp

if your looking for 150hp you will likely be fine
you won't need big pistons though
the case spigots will not likely support those big pistons

you would be better off with a 7R case if you intend to have a High RPM or larger bore/piston motor

the factory found a Need to update to a 7R case when they went with 90mm pistons

additionally I don't think the 69 case has the piston squirters you would need with larger displacement

the small spigot 73.5 case is a 7R that was made for half of year

its the strongest of the small spigot cases... but you ideally would look for a large spigot case for those large cylinders. Aluminum cases cost more, but require much less machine work to bring back to correct specs (may not cost more once you add the machining)
User is online!Profile CardPM
Go to the top of the page
+Quote Post
roblav1
post Jan 17 2020, 10:54 AM
Post #3


Senior Member
***

Group: Members
Posts: 528
Joined: 18-September 12
From: KY
Member No.: 14,943
Region Association: MidAtlantic Region



That's the last case I'd spend money on.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Johny Blackstain
post Jan 17 2020, 10:57 AM
Post #4


Walnut Elite Stratocaster player
****

Group: Members
Posts: 3,434
Joined: 5-December 06
From: The Shenandoah River
Member No.: 7,318
Region Association: MidAtlantic Region



Slightly off topic... when did they stop making mag cases for street use?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
mate914
post Jan 17 2020, 11:00 AM
Post #5


Matt
***

Group: Members
Posts: 721
Joined: 27-February 09
From: Eagles mere, PA
Member No.: 10,102
Region Association: North East States



OK, how about making it a 2.2 S? Engine will be sent to Ollies for machining and prep work. Oil squirter’s will be installed if they need to be, dowel pins will be installed.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
brant
post Jan 17 2020, 11:06 AM
Post #6


914 Wizard
**********

Group: Members
Posts: 11,584
Joined: 30-December 02
From: Colorado
Member No.: 47
Region Association: Rocky Mountains



QUOTE(Johny Blackstain @ Jan 17 2020, 09:57 AM) *

Slightly off topic... when did they stop making mag cases for street use?



the cases were

early aluminum, small spigot motors 1965 -1968

then magnesium small spigot 1969 1973.5

magnesium large spigot motors 1974-1977

then aluminum cases came back with large spigots in 1978
(1977 on the euro only 3.0 cars)

oh... and the turbos were the later aluminum cases also in 1975-1976
User is online!Profile CardPM
Go to the top of the page
+Quote Post
brant
post Jan 17 2020, 11:16 AM
Post #7


914 Wizard
**********

Group: Members
Posts: 11,584
Joined: 30-December 02
From: Colorado
Member No.: 47
Region Association: Rocky Mountains



Matt,

I failed to add that this sounds like a very cool project !
I restored a 914 with my dad and will always treasure him, the experience, and the car...


hey motors are super expensive to build.
why not use the correct number matching block
build it above stock HP... the same machining and the same cost exactly as the 1969 case-builder...

it will look stock from the engine bay
you can achieve the 150hp you want
and you only have to pay to build one motor instead of eventually 2

plus the one motor you spend the money on is going to be much more valuable to the car and much more valuable than an old 69 motor that has little value when you pull the car (a big $ looser eventually)

where the number matching motor becomes a money maker... in that the huge investment you spent on building it will all come back to you in the sale or eventual sale
User is online!Profile CardPM
Go to the top of the page
+Quote Post
mate914
post Jan 17 2020, 11:46 AM
Post #8


Matt
***

Group: Members
Posts: 721
Joined: 27-February 09
From: Eagles mere, PA
Member No.: 10,102
Region Association: North East States



I agree with the logic in value of the original 9146 engine. My father on the other hand thinks that that case should be saved. He wants a motor that he can run hard in the six and if it donates it won’t break his heart. We looked around for other engines, but then you have 4K invested in something that still needs just about the same machining.
It’s a tough decision, is the 69 magnesium case so lousy that you would spend 4000 on something else?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
mate914
post Jan 17 2020, 11:47 AM
Post #9


Matt
***

Group: Members
Posts: 721
Joined: 27-February 09
From: Eagles mere, PA
Member No.: 10,102
Region Association: North East States



The $4000 that I’m referencing is about the average 2.7 in our area obviously that would need rebuilt
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
brant
post Jan 17 2020, 11:56 AM
Post #10


914 Wizard
**********

Group: Members
Posts: 11,584
Joined: 30-December 02
From: Colorado
Member No.: 47
Region Association: Rocky Mountains



I know my builder was really disappointed with me when I brought my 73.5 mag case in for maching and rebuilding.

he told me the machining work would cost more than if I had rebuild my prior 66 aluminum race motor that wouldn't need the maching
(I did it to save 20lbs in a race car)

the maching difference was thousands...
I think it depends on the evaluation of the actual case condition of the one you are trying to use.

maybe send the 69 case out and have it evaluated?
a good, trust worthy, builder can answer the dollar and cent question based on your exact parts and your exact situation


both of your examples... the 69T and the 914/6 case... have steel cylinders.
bad for shedding heat and normally the first things that is junked to build hp over stock...

so either of those starting points will require new Pistons and also new Cylinders
not cheap....


but these are the details that keep people up at night
a biral or other cylinder on a different motor might be reusable saving thousands..
so its hard to really say which is cheaper..
depends a lot, on which parts you put into it.
but because of the steel cylinders your going to need more parts than others already

and thus the reason the "affordable" cores often cost just as much as an aluminum 3.0 when all is said and done.
User is online!Profile CardPM
Go to the top of the page
+Quote Post
mepstein
post Jan 17 2020, 12:00 PM
Post #11


914-6 GT in waiting
***************

Group: Members
Posts: 19,142
Joined: 19-September 09
From: Landenberg, PA/Wilmington, DE
Member No.: 10,825
Region Association: MidAtlantic Region



If you build it right, you should be able to run it hard and not damage the engine. That’s what these engines were designed for. Letting them sit is just as abusive to the engine.

Below is a mag case that was sitting for years. Not worth putting the money into fixing it.


Attached thumbnail(s)
Attached Image
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
mate914
post Jan 17 2020, 12:05 PM
Post #12


Matt
***

Group: Members
Posts: 721
Joined: 27-February 09
From: Eagles mere, PA
Member No.: 10,102
Region Association: North East States



QUOTE(mepstein @ Jan 17 2020, 01:00 PM) *

If you build it right, you should be able to run it hard and not damage the engine. That’s what these engines were designed for. Letting them sit is just as abusive to the engine.

Below is a mag case that was sitting for years. Not worth putting the money into fixing it.


Are you saying that this happens to all the magnesium cases while they sit? Did those deteriorating holes underneath the bearings happen with the bearings installed, or the races dry?
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
brant
post Jan 17 2020, 12:07 PM
Post #13


914 Wizard
**********

Group: Members
Posts: 11,584
Joined: 30-December 02
From: Colorado
Member No.: 47
Region Association: Rocky Mountains



maybe show this thread to your dad..

a good motor build.. even when trying to maintain costs...
is still going to end up at 10K


10K into a 1969 case becomes a crappy/cheap/undesireable core 10 years down the road... one that you sell for 3k

10 into the correct matching number block for the 914/6
after rebuild, will add 20K to the value of the car

you are not likely to blow or hurt either motor once rebuilt
or if you miss a shift... yes you can hurt either motor
but both will put out good hp and run a long life...

If you were going for 180 hp or more, I wouldn't try it with the stock block or the 69

but if your going for 140hp... it makes no sense to put 10K into that 69 block

User is online!Profile CardPM
Go to the top of the page
+Quote Post
mate914
post Jan 17 2020, 12:10 PM
Post #14


Matt
***

Group: Members
Posts: 721
Joined: 27-February 09
From: Eagles mere, PA
Member No.: 10,102
Region Association: North East States



Attached Image this is the factory motor.....
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
brant
post Jan 17 2020, 12:13 PM
Post #15


914 Wizard
**********

Group: Members
Posts: 11,584
Joined: 30-December 02
From: Colorado
Member No.: 47
Region Association: Rocky Mountains



QUOTE(mate914 @ Jan 17 2020, 11:10 AM) *

Attached Image this is the factory motor.....



yeah.. but if its number matching to the chassis..
it ads value to the finished product
and anything can be repaired….

its just not worth repairing things that don't have the matching COA/ engine numbers

mag can be welded and machined
User is online!Profile CardPM
Go to the top of the page
+Quote Post
mb911
post Jan 17 2020, 12:15 PM
Post #16


914 Guru
*****

Group: Members
Posts: 6,750
Joined: 2-January 09
From: Burlington wi
Member No.: 9,892
Region Association: Upper MidWest



I have a 73.5 case 7r with 2.4 steel cylinders with nikisal plating done by millennium then S pistons coated both top and skirts.. Using solex cams.. I expect to be north of 150hp very easily.. In fact the parts package came from supertec and Henry said it would a great combo..

I have not driven the car yet but have run the engine and it runs nicely.

User is offlineProfile CardPM
Go to the top of the page
+Quote Post
brant
post Jan 17 2020, 12:19 PM
Post #17


914 Wizard
**********

Group: Members
Posts: 11,584
Joined: 30-December 02
From: Colorado
Member No.: 47
Region Association: Rocky Mountains



QUOTE(mb911 @ Jan 17 2020, 11:15 AM) *

I have a 73.5 case 7r with 2.4 steel cylinders with nikisal plating done by millennium then S pistons coated both top and skirts.. Using solex cams.. I expect to be north of 150hp very easily.. In fact the parts package came from supertec and Henry said it would a great combo..

I have not driven the car yet but have run the engine and it runs nicely.



killer combo!
and I would expect 170hp or more

(I don't have that case... but wanted to build the same motor for a street car)

you should pick up some 2.2 E or S pistons... bump it another half compression point with the long stroke... up to 180-190
User is online!Profile CardPM
Go to the top of the page
+Quote Post
TomE
post Jan 17 2020, 12:42 PM
Post #18


Member
**

Group: Members
Posts: 88
Joined: 17-January 20
From: Sonestown, Pennsylvania
Member No.: 23,839
Region Association: None



This is Tom, father of mate914
. Everyone I spoke to or have read said put the original 6 engine on a shelf. Cover it in oil and put it up because the engine with the car will add a lot of bucks to a resale. The 69T engine and the 914-6 engine is the same engine? That is why we are looking at the 2.0T. With that said we are in no big hurry to do anything. We are just weighing our options at this time.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
mepstein
post Jan 17 2020, 12:46 PM
Post #19


914-6 GT in waiting
***************

Group: Members
Posts: 19,142
Joined: 19-September 09
From: Landenberg, PA/Wilmington, DE
Member No.: 10,825
Region Association: MidAtlantic Region



QUOTE(mate914 @ Jan 17 2020, 01:10 PM) *

Attached Image this is the factory motor.....

It might be toast regardless of what you do to it. When mag gets to the point that it crumbles away, there isn't any way to fix it. It's a fairly reactive metal. We have mag minilites that you can break apart by hand.

That's one reason why aluminum case engines are going up in price (especially early 2.0) and mag isn't.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
mepstein
post Jan 17 2020, 12:49 PM
Post #20


914-6 GT in waiting
***************

Group: Members
Posts: 19,142
Joined: 19-September 09
From: Landenberg, PA/Wilmington, DE
Member No.: 10,825
Region Association: MidAtlantic Region



QUOTE(TomE @ Jan 17 2020, 01:42 PM) *

This is Tom, father of mate914
. Everyone I spoke to or have read said put the original 6 engine on a shelf. Cover it in oil and put it up because the engine with the car will add a lot of bucks to a resale. The 69T engine and the 914-6 engine is the same engine? That is why we are looking at the 2.0T. With that said we are in no big hurry to do anything. We are just weighing our options at this time.

It will add money to resale to have the number matching case but less sitting by the car than running in the car. I would talk to a good machine shop to see if the case can be saved. It won't get better with age, even covered with oil.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post

2 Pages V  1 2 >
Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



- Lo-Fi Version Time is now: 29th March 2024 - 07:32 AM