Hello all,
My son and I found a '94 S10 Blazer at an estate sale. It has the 4.3 MFI V6 engine. My son has overhauled the transmission (he's in an automotive trade school right now.) His friend helped him with the engine. We've had the crank machined, and replaced all the bearings. We are looking to replace the plastic timing chain cover with a metal one. All the metal ones seem to have a lot more bolt holes than the plastic one and we are trying to figure out if they are compatible or if there is an identical fit replacement for the plastic cover. My son seems really concerned that the metal one will leak with only 6 bolts holding it on like the plastic one used. However, his block only has holes for 6 bolts. Is there anyone here who has done this, can recommend a good metal replacement for the plastic timing chain cover, and help us know what to expect? He's already had the engine out twice and can never seem to get rid of the oil leaks.

 

Could he drill and tap new holes to match those on the metal cover? Is there not some sealant that could be applied? Are you sure the timing chain cover is the culprit?

 

Hi and thank you for the prompt response. We might be able to drill and tap more holes, but I was just having hard time believing someone doesn't make a billet aluminum replacement. There are some seriously professional and really good mechanics in the extended family. They both say these plastic timing covers are infamous for leaking so it's far less about finding the source of the leak and fixing it than it is about trying to prevent a future leak. While we have the engine out, we thought we'd upgrade/mod it to put a metal cover on. Yeah, we could use RTV and seal it up fine even with the extra holes but we were hoping someone on the forum with experience doing that can tell us if additional holes are needed or if the 6 bolts from the plastic cover will work fine with the metal one. The design differences I'm finding between the plastic one and the metal ones seams pretty significant.

 

Athe plastic ones are for the balance shaft motors and the metal ones for the older standard small block design. Or at least all that I have found anyway. Having been thru this a couple times now I think I would RTV all rubber to plastic points in the cover and then a light coat from cover to block. Make sure all surfaces are clean clean clean. Clean is very important in maintaining a bond

Shawn

 

Did yall reuse the plastic one during the rebuild? I usually replace them as it is suggested to.

 

Here is what the engine rebuild article says:

There have been three front covers used on the 262. The first one came on the ’85 to ’94 non-balancer engines. It’s the same one that was used on the small block Chevy. The second one was a tall, metal cover with 10 bolt holes that was used from ’92 through the ’95 “first design” balancer motors. See photo.

The latest version is a unitized plastic cover that is held on with only six bolts. It came out mid-year in ’95 and was installed on the “second design” engines that had the wide flange with only six bolt holes drilled in it. The plastic cover fits on the earlier balance shaft blocks, but it shouldn’t be used on them because it leaks around the bolt holes. It comes with or without a large hole drilled in the bottom corner for the crank position sensor that was installed on the engines that came with OBD II.

https://www.enginebuildermag.com/200...new-chevy-262/

 

Wow, I can't thank you enough! This was super helpful information. I really appreciate you posting this info! Based on your reference to that article and the information you summarized, we were able to determine that the engine in this vehicle has likely been replaced and is not the one that shipped with the chassis. That had to have taken some time to both read and write. Please know that your time was well spent and much appreciated by both my son and me. Thank you! This gave us what we needed in order to put together a plan that will likely work now.