Do I need new valve Springs?

[Beantown]

I am rebuilding a e21 block and a 1.8 head for my 1973 2002,  and converting it into a 2.0 with maybe a mild cam, 284 or 292.  Most of my parts are used but in very good shape,  and this is a shade tree mechanic build.  below are the specs...

•2.0 crank

•Piano top pistons 89.47

•Mild cam regrind 292 or 284

•Either dual 40's or 38/38 carb. or 32/36

•Electronic ignition

•Stock valves and rockers

I'm getting ready to build the head,  and was wondering if I need to replace the valve springs in the head.  The block and head have been machined and cleaned and I think they look pretty good.

 

Thanks

Jamie

Edited May 26, 2020 by Beantown

[rcf925]

I would do the valve springs because of the extra lift on either .284 or .292 cam. IE sells some that are made for .292 cam which is what I used doing my build. Stock springs really not stiff enough

[Henning]

Hm...

If you've lost all of them, then: yes.

If not: not.

While rcf's post isn't out of reason but you may think about how often you're going to kick the engine above 5Krpm.

wdik.

 

h

 

[tech71]

I myself would spend another $120 and get the new billet cam from IE, not a regrind.

No need for lash caps (hate them) or oversize rockers.

Match it up with the HD springs.... sweet. Good at higher RPMs

However, The stock ones would be fine as well for most road driving conditions.

I have inspected a lot of valve springs, found a broken one occasionally but never one that was sacked.

I would have no issues reusing stock springs with stock cam or mild performance.

 

 

Edited May 26, 2020 by tech71

[jireland2002]

It looks like you have a 1.8i head and E12 pistons. 

[kbmb02]

2 hours ago, rcf925 said:

I would do the valve springs because of the extra lift on either .284 or .292 cam. IE sells some that are made for .292 cam which is what I used doing my build. Stock springs really not stiff enough

 

Depending on desired RPM’s and valve to piston clearance, I’ve found stock springs are sufficient for a 292. With any aftermarket spring(s), I’d suggest testing the rates at installed height and at the cam lift. (In my experience, more valve spring than necessary sucks some life out of an engine .... you want ‘just enough’.)

 

25 minutes ago, jireland2002 said:

It looks like you have a 1.8i head and E12 pistons. 

 

Good catch, J Ireland. See this:

 

5 hours ago, Beantown said:

.... and this is a shade tree mechanic build.

 

 

 

 

 

 

 

[tech71]

2 hours ago, jireland2002 said:

It looks like you have a 1.8i head and E12 pistons. 

I missed that, oh my.

 

 

[Beantown]

Great,  thanks all.

 

I wasn’t sure what kind of piano top pistons they were,  but I guess they are e12,  and yes my head is a 1.8. Is that a problem?  It doesn’t seem like I have clearance issues yet,  but I have some flat top pistons I could install if needed.

 

This will not be a race engine,  I’m just learning as I go...  thanks again.

[tech71]

The general consensus on the Faq is there will be valve clearance issues mating a 1.8 liter head to piano top pistons. The valves may impact the piano top pistons. even more likely with higher lift cam.

 Has to do with the difference in combustion chamber dimensions I believe.

I have not confirmed this my self but think others here have.

If you have decent flat tops from a 2 liter engine you should use them with the 1.8L head. They must be from a 2 liter engine. 1.8 liter flat top pistons with stick out several millimeters.

 

 

Edited May 27, 2020 by tech71

[Schnellvintage]

Need to know the Compression ratio for the E12 pistons,  I have used 9.3 to 1 for a 1.8i head, however, you need to clay the head to piston clearance,  I have equally ground away the combustion chamber  in the past and haven not had any issues.  The build was for a 320i and a stock cam, though.  proceed cautiously if you pursue this setup.

my 2 worthless cents.

[Beantown]

I knew of this clearance issue after I acquired the parts.  But I heard that some had issues,  but others did not.  From what I understood,  it was a clearance issue with the pistons and the compression chamber,  not the valves.  I didn't think I would have problems with the valves,  we will see.  And if I do,  then I will have to move to plan #2.  I probably did a NO NO as far as the professionals go,  but I cleaned some material out of the chamber to account for the pistons.  In the pictures,  you can see the really smooth part,  that was me.  The shop said I did a great job.  I have had the head on the block and checked with clay and did NOT have issues,  but I did NOT have the valves in.  What is the process of checking the valve clearance with the valves in?  Do you bolt everything up?  For now I will proceed with the stock cam...

 

Thanks for all the help!

[rcf925]

Getting back to valve springs, If your spending all the money to rebuild and putting in higher lift cam I'm assuming you want to rev motor more than stock or whats the point, Valve springs are cheap and why not match to cam, You will be happy you did

[TobyB]

Stock springs manage go to 6500 with more cam than a wussy 292.  

 

If you want to wind it past that, yes, upgrade spring pressures.

 

further to the head clearance issues, the 1.8 came from a late E21, so

you'll want to plug the injector holes someway...

 

t