1969 Lotus 61 Engine

[Rick Iverson]

Gents;

Is there a definative source on the 681F 6015 and 2737 blocks as they relate to the 1969 Type 61? As I understand, both have an 8.21" block height to accommodate the 3.056 stroke for the 1600 crossflow. My car is currently equipped with a 711, but I desire authenticity.

Comments are welcomed.

V/r

Iverson

[SEComposites]

I think have a stock 2737 motor of that's any use to you?

[LFFR]

Rick,

Are you trying to recreate a period correct Holbay engine for the 61. Is this going to be a museum piece or are you actually planning on racing it?

The basis for the Holbay @ 1969 will be the 67 Cortina GT motor; 681 block, chambered head, Cortina intake (no throttle linkage bosses on manifold), a DFM carb, .030 over Cortina pistons without the valve reliefs (just about un-obtainable), small diameter lifters (hard to find) and a front mount Holbay oil pump (also un-obtainable). Rings will be a problem. I have Total Seal numbers if you want.

I talked to CP about making +.030 Cortina based pistons, years ago. I think they were quoting me about $600 a set w/o rings and pins.

Then it will only produce about 105 HP.

I ran Cortina motors for years. Parts availability has pushed me to the 711 based motors. The new Ford Motorsports blocks are far superior to any of the 681 blocks.

John Mihalich, Jr.
Lotus Formula Ford Register
Lotus 61/FF28; RMVR #61
Lotus 61/FF108; in pieces

[scorp997]

If you are going the original route, I have a front mounted Holbay pump. PM me if interested

[lotus51a]

Rick,

Are you trying to recreate a period correct Holbay engine for the 61. Is this going to be a museum piece or are you actually planning on racing it?

The basis for the Holbay @ 1969 will be the 67 Cortina GT motor; 681 block, chambered head, Cortina intake (no throttle linkage bosses on manifold), a DFM carb, .030 over Cortina pistons without the valve reliefs (just about un-obtainable), small diameter lifters (hard to find) and a front mount Holbay oil pump (also un-obtainable). Rings will be a problem. I have Total Seal numbers if you want.

I talked to CP about making +.030 Cortina based pistons, years ago. I think they were quoting me about $600 a set w/o rings and pins.

Then it will only produce about 105 HP.

I ran Cortina motors for years. Parts availability has pushed me to the 711 based motors. The new Ford Motorsports blocks are far superior to any of the 681 blocks.

John Mihalich, Jr.
Lotus Formula Ford Register
Lotus 61/FF28; RMVR #61
Lotus 61/FF108; in pieces

Wow you just described my motor I think John , sounds like I will have to go easy if so much of it is hard to replace ????

[LFFR]

John,

You may find it easier to get pistons, valves and bits "down under", than we do up here. I have seen pistons pop up occasionally on the Ebay.AU. Getting them here is another matter. AFA the Holbay front mounted pumps, they do take standard pump internals, just don't mess up the housings. I recommend cow magnets down in the oil pan to collect the big iron bits.

John M.

[cortinalodi]

I have several complete motors, boxes of cortina manifolds ect. But I'm on the left coast.
remember the cortina block motor mounts are about 3/4" less than the 711 block. Often a set of spacers are bolted in line to orginal mounts. If it has refabricaled for 711 you will have have one made.( all space is on one side)

i like seeing the cars returned to orginal condition, let me know if you get stuck finding something.....I'm sure I have several.
cortinalodi@yahoo.com

[Lotus61J]

Rick,

I had a 681 block long ago that broke. They were weaker, esp. the main caps than the 711 block. The 2737 might have come with a 51 but not likely with a 61 I think. Also the crank that came with the 681 was also different and not as robust as the later units. I would suggest building it with the block you have and make the search for the 681 block a long term project. Also, I may have a set of Cortina pistons 30 over, but not sure.

Jay

[Earley Motorsports]

I have a set of very low mileage stock bore pistons (no valve reliefs) with pins and rings if you are interested.

[Robert J. Cavanaugh]

Gents;

Is there a definative source on the 681F 6015 and 2737 blocks as they relate to the 1969 Type 61? As I understand, both have an 8.21" block height to accommodate the 3.056 stroke for the 1600 crossflow. My car is currently equipped with a 711, but I desire authenticity.

Comments are welcomed.

V/r

Iverson

Hello Ric, I have a original Charles Lucas Cortina as installed in my Titan Mk6 in Dec 1969. This 681F 6015 block dated May 1969. Engine has new bearings/rings/valve job. All original ready to install in your Lotus. $5000 and its yours. regards Bob Ps the input shaft is excellent.

[Robert J. Cavanaugh]

If you are going the original route, I have a front mounted Holbay pump. PM me if interested

Hello, condition and price on the pump. Photos. Thanks

[scorp997]

Hello, condition and price on the pump. Photos. Thanks

Rick took me up on my offer, so I no longer have it.