2.5 S/S questions

[gandalf_025]

I'll try to keep this as short as possible....
In the late 70's, my mechanic found a write up about making a 2.5 out of an early 2.0 case and 2.7 p/c's.. Sounded pretty interesting, so he took an early 65 engine I had and sent the case and heads out to be machined to hold the 2.7 cylinders.
The engine was built with everything from the 65 engine except for a set of 2.7 Euro S pistons and cylinders. A set of Webers were used that had the venturis machined larger. . Engine did not get case savers, oil squirters or any other oil mods.

Engine ran great, but seemed to run hot, according to the gauge.. But I'm not sure the sending unit on the engine matched the gauge in the dash.... It was in a 914-6 with no external oil cooler.. I parked the car in 86 and am thinking of putting the car back together with that engine back in it in the future...

Questions are... I'm considering replacing the 65 heads with a set of 2.7 twin plug heads.. Figuring a better combustion chamber shape and bigger valves.? I'd like to keep the solex cams.. Any advantage to changing out the cam boxes and not run the oil through the cams.? A larger oil pump... and how late a pump can it go without case mods.? Maybe swap out the pistons for JE pistons?
And should I bite the bullet and do the oil squirters and oil mods to the case.. and if so, anyone know someone in the North East, as in Boston Area to do the case work.
I'd hate to ship it.
Looking for opinions.... thanks

[Raceboy]

If it really is a '65 case then it is an early sandcast aluminium case and it does not need case savers or other stud mods that are usually necessary with magnesium case.

Updating to later heads is definitely a plus but you will lose some of the compression ratio.

[Henry Schmidt]

Using the 2.7 RS pistons on a 66mm crank will yield compression ratio of
less than 8:1
Twin plug at that point is a waste of time.
The oil pump to use in that engine would be an aluminum SC or Carrera pump.
The SC is better in that it uses a flat sump plate/ cover that is interchangeable with the early cover. Remember to use the late venturi screen with all early pickups that have no screen.
JE pistons in a serviceable cylinder is a nice option. At that point you can select the compression ratio you desire and twin plug if you choose.
We are building twin plug engines with lower compression (9.5:1) which allows for poor fuel quality and a veritable smorgasbord of ignition timing and cam options.
As for the 2.7 heads: you get bigger valves and improved valve angle vastly improving volumetric efficiency (read MORE POWER!!!)

[gandalf_025]

Engine is an early 65.. As I remember the # is 901552. It did have solex carbs and the mechanical fuel pumps on the cam chain cover when I first got it.

As far as I remember, the pistons were fairly flat topped. I figured a set of JE's might be in order. A magnet doesn't stick to the cylinders... The engine still turns over by hand, so hopefully the cylinders are still useable..

A few years ago, I picked up a set of 2.7 heads that needed a valve job... They were already twin plugged. After I got them home, I noticed they looked like they had been flycut. The number .070 was stamped on each head.. That seems to be a fairly deep cut.. I don't know if they are useable, or are they too cut to use.?

[SWS911]

For the nikasil cylinders I would think that you would need the squirters. Henry?

[Henry Schmidt]

Originally Posted by SWS911

For the nikasil cylinders I would think that you would need the squirters. Henry?

It's all about the heat.
Squirters are a good idea but not necessary unless you're making 160 hp.

[gandalf_025]

Given the factory claimed 130 hp from the stock 65, 2.0, I would hope the 2.5 should get to 160 hp. Otherwise it isn't much bang for the buck..

Does anyone know a shop near Boston that could do the oil squirter mod ?

[Walt Fricke]

For sure do the squirters and the oil mod. You can do the oil mod yourself with a drill and a tap and some ingenuity (tricky to get a drill hole started on a sloping surface, basically), but duck soup for a shop.

It isn't hard to clearance the case for an even larger oil pump than those Henry mentions, but I have concluded that is overkill.

[Matt Monson]

Not to take things too far afield but have you considered selling that case and getting another one? I ask the question because a '65 is pretty damn rare and the market on that really early stuff has exploded as cars that previously were left to rot get put back together.

I would bet someone who owns a '65 missing its engine would pay as much for that case as it would cost you to find a replacement, have all your machine work done, and then some. Might be worth considering if your project is financially limited because that case could provide a real nice bump of cash to the build.

[gandalf_025]

I had thought of the engine possibly having value for someone with a very early car, But since it has already been cut to hold the 2.7 cylinders Not so sure now.

I would never modify such an early case now, but in the late 70's it really wasn't worth much....

I really liked this combination. but now that I'm going to take it apart to put in a larger oil pump, I'm starting to get into the "while I'm in there" mode.

Does anyone have experience with heads being flycut .070 They certainly look well used so someone had them in an engine the way they are ?? Just seems like a lot
taken off.. and wondering what that would do for compression??

[Walt Fricke]

You are going to have to do some measuring and test fitting to see what you have. The good news is that you can compensate for the flycutting by raising the cylinders up at their base by using thicker copper gaskets/spacers. EBS, among others, stocks some oversizes (1mm, for instance, which I bought from them for one of my motors).

You will want to be familiar with, and able to do, volume measurements to calculate compression. And the measurements with solder or clay to determine piston to head clearances.

One benefit of the J&Es you have cut for you is you can specify their volume. They will pocket for your larger 2.7 valves, and cut their forgings top to achieve the piston dome volume you want.

Before you disassemble the motor, with the heads off you can measure the distance below the cylinder tops that the top perimeter of your pistons is. With the pistons out, you can measure and compute what the distance from that top perimeter down to the center of the wrist pin bore is. This is typically called deck height. It enters into calculations of compression ratios, and also into the needed clearances.

I kind of doubt that someone can tell you what that deck height distance is in a standard engine of this sort, because there isn't such a motor. I'm supposing you have 2 liter or 2.2 liter rods with pistons designed for 2.7 rods for the shorter stroke. As the strokes got longer, the rods got shorter. So measuring is the key.

If I understand the dome of the heads, it normally comes over to the edge of the cylinder ID, then goes flat for the seal. When you cut the seal surface, you also widen it? Now you have a flat area projecting over the cylinder top. At some point, this may need to be champfered for clearance, or the piston edge needs this, or both.

All doable - you have Wayne's book I assume, and Anderson's also? They will have about all you need by way of explaining how to measure and calcuate things.

[gandalf_025]

I just posted this engine in the for sale section, as a "Want to trade" ad.

Just in case someone really has need for this early an engine. Everything internal except for the P/C's are still the 1965 parts...
I would trade for something with comparable performance.. So, someone is really going to have to want this engine pretty badly.
If not, when the time comes, it will get the mods and a bigger oil pump, new pistons and heads.

Still wondering if someone knows a shop near Boston to do the case mods ??

[bumble]

"I had thought of the engine possibly having value for someone with a very early car, But since it has already been cut to hold the 2.7 cylinders Not so sure now."

Some years back there was a discussion on returning AL cases to the smaller spigots here:

Henry - Supertec spigot adapter? - Pelican Parts Technical BBS

[Henry Schmidt]

Originally Posted by bumble

"I had thought of the engine possibly having value for someone with a very early car, But since it has already been cut to hold the 2.7 cylinders Not so sure now."

Some years back there was a discussion on returning AL cases to the smaller spigots here:

Henry - Supertec spigot adapter? - Pelican Parts Technical BBS

The spigots can be returned to original, creating even better than new cylinder stability.
The '65 case has it's most value as an FIA vintage race engine. They have classes that are limited to 1965 and earlier.

[Lapkritis]

Boston metro: just North is Exotech near Haverhill. Drop your parts and then have a pint at the Barking Dog downtown.