L31 Timing Chain Cover

Performance modifications, tips & tricks

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s10mods
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L31 Timing Chain Cover

Post by s10mods »

Any one know if there is an aftermarket cover that has the crank sensor so we dont have to use the plastic crap?

James B.
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Post by James B. »

Funny you should mention that, I was just thinking about it this weekend. The timing cover is the last piece of plastic on my engine. There's not one available unfortunately, you'd have to make one.

s10mods
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Post by s10mods »

I was thinking about making one but getting the crank sensor in the right place would be key. I wish some aftermarket company would make a nice aluminum pice.

hquick
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Thanks for the info...

Post by hquick »

Also been looking for one!
Surprised Summit or equivalent performance suppliers don't make one?

Hog
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Location: 1997 Chev ECSB L31 350 1997 GMC Sierra SLE RCSB, Ontario

Post by Hog »

I have heard of someone actually moving the crank sensor into the distributor, thus eliminating the need for the special plastic front timing cover to hold the crank position sensor. Then you can just run any normal 12 bolt metal front timing cover, using only 8 bolts of course.


I dont really think you would need to put the crank sensor in the EXACT position as it is stock. If it was that critical, the CASE relearn wouldnt be necessary.

peace
Hog

Stealth97
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Post by Stealth97 »

Moving the crank sensor into the distributor?

s10mods
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Post by s10mods »

Will the PCM pick up an aftermarket signal like from a MSD flying magnet trigger? like this one

http://store.summitracing.com/partdetai ... toview=sku[/url]

Hog
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Post by Hog »

s10mods wrote:Will the PCM pick up an aftermarket signal like from a MSD flying magnet trigger? like this one

http://store.summitracing.com/partdetai ... toview=sku[/url]
IIRC the L31 engine uses a 4x reluctor wheel, I beleive this means that 4 pulses will be generated per revolution. You may need to add 4 more magnets because the cam spins at 1/2 the crank speed. I dont remember EXACTY what was changed during the reluctor wheel relocation to the distributor.



I am pretty sure that it was an MSD setup that was used by this guy I know to move the crank sensor reluctor wheel into the distributor.


This post has a pic of both a GEn 1e and a GEN 3 crank and reluctor wheels.
http://www.pacificp.com/forum/viewtopic.php?t=2342

peace
Hog
Last edited by Hog on Thu Nov 30, 2006 7:32 pm, edited 1 time in total.

Hog
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Post by Hog »

Stealth97 wrote:Moving the crank sensor into the distributor?
Yes, since the distributor spins with a specific relation to the crank, you can move the crank position sensor into the distributor assembly. Then you can use a much cheaper conventional stamped front timing cover WITHOUT the mount for the CKP sensor.

I am wondering if play between the camshaft gear and the distributor gear would reduce misfire detection effectiveness?

peace
Hog

350SS
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Post by 350SS »

One thing you would have to overcome by moving the crank sensor to the cam is that the cam/dist turns at half the speed of the crank; 2 crank rev = one cam rev. So since the crank sensor on the crank uses a 4x reluctor you would need a 8x reluctor if it was put on the distributor. I believe the biggest problem comes from variances between crank and cam timing due to timing chain stretch rather than distributor/cam gear slack. There's definitely a reason to mound the rpm sensor on the crank. Much more accurate.

350SS
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Post by 350SS »

I was looking into this a few weeks ago when I was trying to figure out how to put a Dart Little M shorblock in my truck and retain all the sensors and the roller cam setup since this is an older style 2pc rear seal non roller cam type block. This would require a sturdy timing cover so that I could run a cam thrust button with a retrofit roller cam and lifters since the block does not have a provisition for a roller cam retainer. Since it would require using something other than the factory timing cover I was considering maybe going with one of Accel's Dual Sync distributors that they manufacture for use with their sequential efi systems:
http://go.mrgasket.com/pdf/DFIDistributorsCamshafts.pdf

I don't know if these use the same voltage or frequence of sensors/reluctor wheels but if you guys are serious abou this, it might be worth looking into. Still you run into the problem of timing variances due to timing chain slack, but it may be an option.

Max

hquick
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A pic please?

Post by hquick »

Can someone post a pic of the insides of the two different types of covers?
Just want to see the differences and how the prox is mounted?
Thanks
Howard

Hog
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Re: A pic please?

Post by Hog »

hquick wrote:Can someone post a pic of the insides of the two different types of covers?
Just want to see the differences and how the prox is mounted?
Thanks
Howard
Whats a Prox??

peace
Hog

hquick
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Sorry....

Post by hquick »

Electrician coming out in me....Proximity switch!

Howard

350SS
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Post by 350SS »

BTW, I don't believe the MSD flying magnet crank trigger would work since it produces a different signal than the stock pcm uses. But if there is a crank/balancer mounted hall effect sensor that produces a 4x 12volt square wave signal, you're money baby.

350SS
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Post by 350SS »

I'll handle this...What's a proximity switch?

hquick
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Joined: Thu Aug 10, 2006 1:56 pm
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Mmmm!

Post by hquick »

An electronic sensor!
We use alot of them at work for sensing positions or movement of things such as rotary feeders, flywheels etc.
We get a signal of varying types (depending on the application) which we can use as an input for a PLC (programmable Logic Control) unit to tell us things like rpm etc!

350SS
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Post by 350SS »


hquick
Posts: 4689
Joined: Thu Aug 10, 2006 1:56 pm
Location: Melbourne, Oz-----98 K1500 LT Suburban. RHD, 0411, Whipple, Marine, 4L80E, Trutrac, H/boost,E-Fans

Reference..

Post by hquick »

I know they are not the same identicle item but they do the exact same job. Different application!

http://web5.automationdirect.com/adc/Ov ... ype=search

Thanks for the info!

Howard

Hog
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Location: 1997 Chev ECSB L31 350 1997 GMC Sierra SLE RCSB, Ontario

Re: A pic please?

Post by Hog »

hquick wrote:Can someone post a pic of the insides of the two different types of covers?
Just want to see the differences and how the prox is mounted?
Thanks
Howard
There is a plastic timing cover that comes of the GM crate engines that DOESNT have the "mount"CKP sensor, the front timing cover that comes stock on teh L30 and L30 is exactly teh same except there is a spot where the CKP sensor is installed, it sits on the bottom passenger side of the engine, just behind the harmonic balancer. You cans ee the wires.
Both of these covers have 8 bolts.

Then tehre is the conventional 12 bolt front timing covers which also CAN be used except that there will be 8 bolt holes in teh cover which will be unused due to the L31 block only having 8 bolt holes for attaching the plastic front timing covers.

pics of teh sensor
http://www.autopart.com/CrankSensor/Cra ... PICKUP.htm

The connector
http://www.autopart.com/EngineControl.htm

If you scroll down in this link, just after about 1/2 the way down the page is a pic of teh palstic Vortec front timing cover.
http://www.suburbanimports.com.au/otherparts.htm

peace
Hog

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