Home 
Home Search search Menu menu Not logged in - Login | Register

 Moderated by: Greg Fletcher
New Topic Reply Printer Friendly
engine questions  Rate Topic 
AuthorPost
 Posted: 11-20-2013 03:52 pm
  PM Quote Reply
1st Post
Barthol
Member
 

Joined: 10-31-2013
Location: Denmark
Posts: 67
Status: 
Offline
Hi,

This summer I bought my first JH. it is a black 1974 model with a 2.0 lotus 907.
just a few weeks ago I found a 2,2 ptr 907 lotus engine, I thought what the h… and bought it.

My question is now which ways to go.

The original engine has strombergs ( it´s a us model) and it starts , idles , and runs very clean without any hasitation. ( It works well). only it does not feel like 140 BHP.

Is there anything i can do to this engine in terms of ignition setting / valve timing that would improve it?

I guess I will use this winter to build the 2.2 engine, bottom end is done.
cylinderhead is done , at least valve springs looks brand new.

How can I tell which cams are in there, they have no numbers stamped.
The timing wheels have 6 holes each and the only marking is "inl end EXH" on both sides of them. And there is a dot in the casting but only one one side of the cam wheel.
What about carbs. It came with a set of strombergs, 2 sets of 40 mm webers and one set of 40 mm Dellortoes( they all need to be refurbished.

Would 40 mm carbs be enough or should i go for 45mm.
Which cams should I put in there , and should I do something about the ignition.

I measured the stroke to 76mm and the comp ratio to 9,35.

I would like to end up with a drivable engine with tourqe and some power:-)

I know this is a lot of questions, but I hope some of you can point me in the right direction .

BR
Kim

Back To Top PM Quote Reply  

 Posted: 11-20-2013 05:56 pm
  PM Quote Reply
2nd Post
Jensen Healey
Super Moderator


Joined: 03-11-2005
Location: San Anselmo, California USA
Posts: 976
Status: 
Offline
Nice find! The best bang for the buck on a stock federal engine is to replace the Strombergs with the Dellorto 40's that you have. The accelerator jets alone make the engine feel more alive. If they are off of a JH it could be an easy conversion.

How did you calculate the compression ratio?

The 2.2 liter is usually setup for street with 104 intake and 107 exhaust cams to retain the torque. Measure the cams to the tip of the lobe and then measure the base perpendicular to the first measurement. Subtract the second reading from the first. If the result is .340 then they are stock cams.

Then worry about the brakes!

Kurt

Back To Top PM Quote Reply

 Posted: 11-21-2013 04:50 am
  PM Quote Reply
3rd Post
Barthol
Member
 

Joined: 10-31-2013
Location: Denmark
Posts: 67
Status: 
Offline
HI Kurt,

Thanks a lot.

For the 2 .0 I will properly as you say fit the Dellortoes. I do not know which car they come from. But they do com with a intake manifold that fits the engine.

All my 4 cams measures .340" meaning standard. Does that mean 107 or 104 cams?

The 2.2 engine is properly not born as 2.2 as the lot also included a 2 .o crank shaft , and 4 con rods.

<compression rate I calculated by deciding the compression space into the displacement of the cylinder.
Compression space I found by tilting the engine ( spark plug hole must be the highest point). Then measuring how much light oil i could pour into the cylinder with the piston in TDC. I my case it was between 59-60 ml.

questions to the 2 .0 engine :
In the WSM I can see that north american engines runs with a valve timing of
IO 36 BTDC
IC 56 ABDC this gives an opening time of 272deg
EO 66 BBDC
EC 21 ATDC gives opening time of 267 deg

the other option is 272 dye on both inlet and exh with two diff timings
1: IO 26 BTDC EO 66 BBDC
2: IO 21 BTDC EO 71 BBDC

Looks like that in 2 the cams have been moved forward 1 tooth.

There is also different Ignition timings specified for stromberges and Dellortoes
For the static timing.
What would be the timing figures using a strobe?

Would 45 dellortoes on the 2.2 engine be significantly better than 40 mm.

Best regards
Kim

Back To Top PM Quote Reply  

 Posted: 11-21-2013 03:02 pm
  PM Quote Reply
4th Post
Jensen Healey
Super Moderator


Joined: 03-11-2005
Location: San Anselmo, California USA
Posts: 976
Status: 
Offline
The standard cam is the "c" cam. The intake and exhaust are the same, the manual contains an error concerning cam timing. 272 deg is correct.

The 107 and 104 cams are from later iterations of the 907 engine.

One tooth on the cam pulley is 18 crankshaft degrees IIRC.

Back To Top PM Quote Reply

 Posted: 11-22-2013 12:27 am
  PM Quote Reply
5th Post
Jensen Healey
Super Moderator


Joined: 03-11-2005
Location: San Anselmo, California USA
Posts: 976
Status: 
Offline
10 to 12 deg advance with the distributor vacuum line capped. Leave it capped off due to the capsule being vacuum retard, not advance. Emissions stuff you know!

The Dellorto 45 would be optimal for a hot street setup. You can certainly make the car drive well with the 40's, either will take a bit of jetting to get right.

Kurt

Back To Top PM Quote Reply  

Current time is 02:36 pm  
> Jensen Healey & Jensen GT Tech > Engine & Transmission > engine questions Top




UltraBB 1.172 Copyright © 2007-2011 Data 1 Systems