will62085

I'm looking for a dimensioned drawing of the front side of an LT1 block, or the timing cover. Can anyone help?

jraney

Try this. It may be what you are looking for. Let me know if it is.

http://www.enginefactory.com/chevdimensions.htm

will62085

Thanks for the reply, but not what I am looking for.

I'm looking for locations of the dowel pin holes, bolt holes, and seals on the timing cover when viewed from the front.

96capricemgr

What are you trying to do? Maybe we can come up with some ideas to help you or maybe someone would have a spare cover to send you.

Stl94LT1

will62085

I've got a few spare covers, but they are boxed away about 150 miles from here...haha.

I can take measurements easy enough from a cover once in hand, just curious if anyone has them already, or original GM drawings??

I need the dimensions so I can make an inner and outer front cover to run a standard SBC Jesel belt drive on my new setup. As we all know, the LT1 and Gen 1 SBC have a different timing cover bolt pattern and dowel location...

will62085

Thanks for the reply, but I'm looking for an engineering drawing...

cnorton

Will, you won't have much of a problem putting a standard Jesel small block belt drive on the LT1. I've been running that exact set-up for the last six years. The Jesel front cover bolts directly to the LT1 block with NO issues. You will need to fabricate a small piece of aluminum plate to block off the top of the LT1 front cover opening. I've done a couple of them for my own motors. The block-off plate can stay on the motor when you do a freshen up and it seals off against the top of the Jesel cover with a a little silicone. It's a very uncomplicated process.

c

will62085

Okay, I'm a little confused. The LT1 uses 11 bolts to hold the front cover on, standard SBC uses only 10. Are you simply leaving one bolt out?

cnorton

The standard SB cover matches all but three of the bolt holes in the LT1 cover. The lower dowels also line up with no problem. Following is a description of the process as I outlined it to another person who inquired:

================================

Adapting the belt-drive timing belt system was a relatively simple, straightforward matter. The addition of a belt-drive distributor was something else altogether. I’ll be glad to describe the process to you but I’ve never taken any pictures of the timing belt set-up when the motor was out of the car. Because of the complicated nature of all the plumbing and wiring around the front of the motor related to fuel delivery and ignition, taking a picture with the motor in the car is pretty much a waste of time. The good news is that putting on the timing belt is such a simple process that I think I can describe it well enough for you to get the idea.

The challenge to my situation was the need to use an LT1 block and water pump housing, a front-loading Hogan FI manifold, a stock throttle body, a generation I crank, and generation I oil pan. The timing belt installation required nothing extra beyond fabricating a small aluminum plate to fit over the top of the Jesel front cover to block off the extra-tall LT1 timing cover opening. I cut it out of a piece of 1/4” aluminum plate, shaped the contour to match the top edge of the front cover, and drilled the holes to fit the LT1 bolt pattern. It seals against the top of the Jesel cover with a thin coating of silicone. Once that plate is cut and fit, the installation is exactly like the installation on a traditional small block although the Jesel cover needed some minor trimming on the outside edge in the area of the water pump in order to clear the LT1 GM pump housing. I used the basic 31000 small block Jesel kit. I used a Gen I small block camshaft with a short pin and the early nose configuration instead of the later roller cam design that uses a retainer plate. The Jesel system incorporates a cam-thrust control. As you know, the bolt pattern in the end of the factory roller cam configuration is different. I have since learned that Jesel makes a unit that will fit the factory roller cam bolt pattern configuration. Because you will be ditching the original LT1 timing cover you’ll need a damper (I recommend ATI) and timing pointer for a generation I small block also.
==============================

The better news is that I now have done another front cover change-over for a bracket motor that's on the engine stand and I can take pictures of that for you. Believe me, if you buy the right parts, this is a one-day project.

c

Lcvette

I am also currently planning this conversion and was curious about the cam thrust control portion of the project. I figured I could find a belt drive kit for a roller cam, but wasn't sure if the factory cam retention plate would still be used or if the new belt drive kits would be used instead.

Can you shed some light on that for us? Also when you say we will need a damper because the front cover is no longer used, I don't quite follow the meaning. Are you referring to the seal in the front cover no longer being there and a new damper/hub type being required. Thanks in advance! I haven't put my hands on a belt drive system before so from pictures I have found it is kind of difficult to make out what I will need to put on the list of required parts.

Chris

cnorton

Chris, in my installation of the Jesel belt-drive, I used a traditional (not an LT1 core) roller cam, I omitted the cam retention plate, and everything worked just fine. Use loctite on the cam bolts.

Check out: <http://jesel.com/index.php?categoryid=9>

That page illustrates the issue of the cam thrust control.

The STOCK front cover and the Optispark are not used so you don't need the extra length of the LT1 damper hub. When the Jesel cover is substituted (see same page of Jesel website), you will, instead, use a traditional small block damper assembly. In my case, I used an ATI damper which is also a two piece unit. Press the hub onto your crank in the usual manner and bolt the damper ring to the hub. I used a traditional timing pointer assembly such as sold by Summit or Jeg's AFTER choosing the diameter of the preferred damper diameter.

I hope this explanation answers your questions.

c

Lcvette

I currently run DFI Gen 7 with a dual synch distributor in the gen 1 traditional location so opti isn't an issue and I also run an electric waterpump so no issue there. problem is I just bought a new custom ground $400 solid roller cam setup for the LT1 cam retention plate so I imagine I need to use that. not too familiar with the gen 1 thrust bearing design and wasn't sure if they had the belt drive for a roller style setup. were you able to snap some pictures of yours? that would be awesome! I am pretty well sold on the belt system from everything I have researched and read about. just want to make sure I order the right stuff the first time!

Chris

cnorton

Chris, I don't blame you for not wanting to dump the $400 camshaft. I still have a similar $400 cam ground on an LT1 roller billet sitting on my shelf. I believe that, before you order any parts, you would benefit from placing a direct call to Jesel Valvetrain Innovation (M-F 8:30 am - 4:30 pm EST - 732-901-1800) to describe your needs. It has been several years since I did precisely that same thing to come up with the combination that worked for me. Perhaps since that time, they have produced an LT1-specific front cover and even more probably, they will be able to provide you with the "zero-thrust cam adaptor" that will accommodate the later-style camshaft using the cam retention plate. In 2002 they didn't have that option.

I can provide you with pictures of the block-off plate that I fabricated to seal the area that was left exposed when the gen 1 small-block front cover was bolted to the LT1 block but that's the last piece of the puzzle. If you PM your e-mail address to me, I'll be able to forward a picture of the plate.

Good luck with your project.

c