Alfa Romeo Forums banner

1 - 20 of 31 Posts

·
Registered
Joined
·
17 Posts
Discussion Starter #1
Will a 1300 101 head fit and function correctly on a 750 block?
 

·
Registered
Joined
·
289 Posts
The 101 head is higher than the 750. Guess you will need longer studs.
Think Gordon told.me that factory racers used to have 101 heads on 750 blocks as it gave more stability, so I guess it will be possible
 

·
Super Moderator
Joined
·
11,781 Posts
Alfa did this with the Monoposto Spiders in racing to stiffen the 750 blocks. Some of those had 101 heads, 40DCOE2 Webers (maybe 40 or 38 DCOE1's as built) and aluminum Veloce sumps.
There are 2 ways to do this, and I did not look closely at the last Alfa built example seen to remember how that one was done.
The best way would be replacing the 10 studs with 10 new 1300 101 studs. This allows full thickness at the boss where the hardened washer and head nut live. The other version avoids stud R & R, by making mill cuts around each stud hole in the top of the head for use of the shorter 750 studs. This would negate some of the stiffening offered by the head swap.
This was done by Alfa when they discovered in racing, that the 750 engine became somewhat jello like with continual high rpm use, resulting in crank and bearing issues. It obviously lead to the 101 1300 transition.
I participated in a race 750 engine build in Europe, some years ago where the car owner applied these modifications along with a custom crankshaft, Carello rods, a 101 sump that allowed him to use a race version of one of my 101-1600 oil pumps, as well as the 101-1300 head and 40DCOE2 Webers. Head was left full height at stud holes. Not an inexpensive engine build, but VERY durable.
 

·
Premium Member
Joined
·
1,657 Posts
I ran a 101 head and front cover on a 750 block.
Machined the head around the 10 stud holes for the shorter 750 studs.
1500 cc with full Veloce Bits. Never any issues. SCCA drivers school and LOTS of autocrossing.
Back in late 60's
 

·
Super Moderator
Joined
·
11,781 Posts
It WORKS FINE!
 

·
Premium Member
Joined
·
834 Posts
I can provide pictures of the head milling if that would be of value. I have the head/block combination which I took out of a 750 Spider. No idea who or where the modifications arose.
 

·
Super Moderator
Joined
·
11,781 Posts
If you can post a photo it will help those interested notice how it was / is done. BB members LIKE pictures!
Thanks!
 

·
Premium Member
Joined
·
834 Posts
I think that I have a photo in the archives otherwise I'll take new ones. Most likely it will be tomorrow before this is done.
 

·
Super Moderator
Joined
·
11,781 Posts
There is no hurry. Builders have done this since 1959!
 

·
Administrator
Joined
·
3,904 Posts
Jim there is an alternative and that is to find one of the 4299 engines built in late '59 early '60 - these were actually 101 engine but the first ones still had the old 1315 numbering, easily recogniseable as they have the block mounted fuel pump on the side under the dizzy and 4 rectangular black plates on the head, although any 101/105 1300cc head will fit as they are 101 engines. These engines are numbered from 1315*10001 to 1315*104299. I have one for our 11 Jan '60 Sprint & I know of another one possibly 2 for sale in the USA

This gives you an old numbered block (1315) while being a modern 101/105 style so parts are readily available & cheaper than the early pure 750 engines. Wrap & oil your original 750 engine & keep it under the bench.

Ciao
Greig
 

·
Super Moderator
Joined
·
11,781 Posts
Greig, any idea how many of these were made? In 50+ years here in the USA I've only actually worked on 2 in transitional spiders.
 

·
Premium Member
Joined
·
834 Posts
Here's the pictures I promised. Let me explain a little about the car. It was shipped from the factory to Thailand. I suspect that it was purchased by a US airman who took it with him when transferred to Beale AFB near Marysville, CA. I bought the car from a junk yard in Yuba City, CA ten or so years ago. It had spent years under a tree in the junk yard. The floors were completely gone as was the frame joint behind the driver's seat. I salvaged what I wanted then gave the hulk to a local Alfa vintage racer. That sort of explains the appearance of the motor.

IMG_5656.JPG IMG_5658.JPG

I suspect that there are specs available covering this operation but I will supply measurements if needed. I also have pictures of the block and head numbers.
 

·
Super Moderator
Joined
·
11,781 Posts
PERFECT. This shows the typical conversion. This is like those I've seen that used stock 750 studs. Thanks!
 

·
Premium Member
Joined
·
834 Posts
Promises, promises. OK, here's the block and head numbers. Interesting that on the head the number is upside down. Must be a 'stand on your head' joke in their somewhere.
PICT4876.JPG

The other picture won't upload. The block is AR1315*95208*
 

·
Super Moderator
Joined
·
11,781 Posts
I've already forwarded your photos to one 750 builder. Thanks!
 

·
Administrator
Joined
·
3,904 Posts
Greig, any idea how many of these were made? In 50+ years here in the USA I've only actually worked on 2 in transitional spiders.
Hi Gordon 4299 engines in total, they are numbered from 1315*10001 to 1315*104299 in Fusi hence 4299 made

It's just an early 101 engine but with a 1315 designation, so works really well for a car where you want the nicety of a 1315 numbered engine but the simplicity of a 101 engine that uses readily available 105 parts. They don't have the head mounted fuel pump so visually are a give away in an early car for those that do know what they are looking for.

Ciao
G
 

·
Super Moderator
Joined
·
11,781 Posts
I am pleasantly surprised. It seems few of these came to the USA. The 101 block was a sturdier piece than the 750's and the 1315 designation makes these a good find for restorers that like to drive.
 

·
Administrator
Joined
·
3,904 Posts
1959 & some slipped into very early '60

Fusi page 839 for Sprints - 2 lines of them, check the engine numbers
Page 840 for Spiders, again check the engine numbers

The irony is they are surrounded by Sprint & Spider Veloce's with 1315*3xxxx numbers which were still pure 750 engines as the Veloce 750 engine lasted longer than the Normale 750 engine which was replaced by the Normale Interim 101 engine carrying the 1315 number

I found out about this by chance when we bought 1493*21726, an 11 January '60 Normale with a 1315 engine which was a 101 spec. It's all in Fusi, the trick has been learning how to read the durn thing... Mine is full of pencil annotation and corrections from the past 25 years or so, the clerk who compiled the lists made more than a few mistakes.

Ciao
Greig
 

Attachments

·
Super Moderator
Joined
·
11,781 Posts
My '60 Spider Veloce race car, bought as a nice driver in '62 was a pure 101 everywhere. I did not note it's serial number as that was unimportant at that point in time. I raced it until early 66 when I started again with my '65 Spider Veloce still owned. Both excellent drivers cars.
 

·
Registered
Joined
·
441 Posts
Greig,
A small correction on the engine numbers you quoted, they should be *010001 to *014299, giving a total of 4299 engines as you stated.
However, looking at the Fusi chassis numbers for the sprints and spiders these would have been used in, they only add up to about 2000 vehicles.
I’ve always thought that the *014299 Serial is too high.
What is the highest serial numbers of the two engines you have, or have seen?
My own (extra) engine is 1315*011692.
Joe
 
1 - 20 of 31 Posts
Top