Replacing springs and retainers

[KenH]

Replacing valve springs and retainers

I am curious if anyone bothers to replace the stock springs and retainers when upgrading to 1.7 RRs?

You are suppose to be able to do this with the heads on the engine using compressed air. I'm just wondering if it there is much benefit in doing it with a stock cam. You could reduce the valvetrain weight some and there may be some benefit in increasing the spring pressure a bit to help the engine pull strong to redline.

My engine has 40K on it, so although it pulls hard right to redline, it might benefit from freshening the valve springs.

As a secondary thought, the SCT allows you to increase the rev limiter. Anyone know if it is safe to increase the redline a bit on these engines?

--- Ken

 

[plumcrazy]

i would think the faster you wanna spin, the more important it is to do

Great idea because the factory Gen 2 retainers are bricks. The basic problem is there isn't much installed height on a Gen 2 head.

You can use Gen 3 factory spring locators (.060" thick), factory locks, Comp Cams 774 retainers, and you'll end up with 1.700" installed height. That doesn't leave you much choices in 1.290" beehive springs. Comp has a 26995 that will work. It has 137 pounds of seat pressure at 1.700", 305 pounds of open pressure, and with a 708 cam with 1.7 rockers you'll be ~ .070" from coil bind. Do-able.

The Gen 3 heads have 1.760" installed height from Dodge, and if you swap in a 774 retainer you can get it up to 1.830". So those guys have lots more options for springs and can run the comp 26918.

 

[Greg Good Cylinder Heads]

Great idea because the factory Gen 2 retainers are bricks. The basic problem is there isn't much installed height on a Gen 2 head.

You can use Gen 3 factory spring locators (.060" thick), factory locks, Comp Cams 774 retainers, and you'll end up with 1.700" installed height. That doesn't leave you much choices in 1.290" beehive springs. Comp has a 26995 that will work. It has 137 pounds of seat pressure at 1.700", 305 pounds of open pressure, and with a 708 cam with 1.7 rockers you'll be ~ .070" from coil bind. Do-able.

The Gen 3 heads have 1.760" installed height from Dodge, and if you swap in a 774 retainer you can get it up to 1.830". So those guys have lots more options for springs and can run the comp 26918.

 

[plumcrazy]

now greg, thats EXACTLY what i said....sheesh...some people...

 

[KenH]

I was REALLY impressed with your response Plum.... until I scrolled down

 

[Greg Good Cylinder Heads]

 

[plumcrazy]

gregs been riding my coat tails long enough, its about time he comes clean....lol

 

[KenH]

Hi Greg,
In your opinion is it worth upgrading to Titanium retainers for the weight reduction? I think the 788's will fit those springs per the Comp Cams website, but the price goes up significantly (they are more than the springs).

Wondering if you think they are worth the extra expense.

--- Ken

 

[Greg Good Cylinder Heads]

Not on such a small diameter retainer. The 774's are already within a few grams of a 1.550" diameter Ti retainer.

I'd stay with the 774's.

 

[KenH]

Hi Greg,
I have started to assembly the parts for this project. One thing I noticed is that the Gen 3 valve seat is quite a bit smaller than the base diameter of the26995 valve springs (approx 1.2" vs 1.415").

This doesn't seem right to me, but perhaps it is, so I thought I'd better check. I ordered the 5004031AB valve seats for the 8.3L Viper engine. They are .060" thick.

--- Ken

 

[dave6666]

I stayed at a Holiday Inn Express last night, but it was emergency orthopedic surgery training night, and nothing on automotive valve train design and engineering.

SORRY.

 

[KenH]

Thanks for the bump Dave. Now if we could just get you to start doing some performance work on your motor and documenting those instead of all those poser mods, we'd be in good shape.

Here are some pics of what I am talking about. Any input is welcome. Sure seems to me that the valve seat should be bigger. Unfortunately I can find no info on valve seat dimensions.

 

[Greg Good Cylinder Heads]

I was thinking the 995 spring was a 1.290" spring and would work with the Gen 3 locators.

But it is 1.425" and needs a Comp 4696 locator.

 

[dave6666]

Thanks for the bump Dave. Now if we could just get you to start doing some performance work on your motor and documenting those instead of all those poser mods, we'd be in good shape.

Sneak preview of my upcoming Winter write-ups:

-> Checking the air in your tires; for the DIY performance in you.

-> Got bugs? Windex and a soft towel - follow this performance tip for driving safety.

-> Radio button cleaning for flu season - how to stay healthy.

Those are looking to be the feature ones. I'll post more as they come up.

 

[KenH]

I was thinking the 995 spring was a 1.290" spring and would work with the Gen 3 locators.

But it is 1.425" and needs a Comp 4696 locator.

Thanks Greg,
I was eye-balling the 4694s, but will go with the 4696 as you suggest.

If anyone can use a set of 20 stock Gen III spring seats/locators, let me know. Free to good home.

--- Ken