composite timing cover

[yourownself]

has anyone used a composite timing cover on there SBC out of a later gen I engine such as a late 90's van or suburban?
i'm wondering if i can run my double roller underneath this cover...

any advice?

 

[ibanezfxer]

I would think it should be fine. I'm an aircraft mechanic at night and have worked with composites alot and you may be surprised how robust and strong they are. Plus, with a double roller you have more surface area to spread the stress over. Oh yeah, they're much lighter too.

 

[85 Cutlass Brougham]

The biggest issue with composites is that they do not age well. Ask anyone who has had a plastic intake manifold fail on them. On an aircraft, this is not as big an issue as they tend to get far better maintenance than cars do. On a car though, it can be a real PITA when they dry out and warp or crack. Comp Cams used to sell composite valve covers, intakes, etc., until they had the same issues with theirs. Ford Modular V8's are notorious for bad intake manifolds, as are Chevy Malibus and a number of other makes and models. I am a big fan of weight reduction wherever possible on the front end of these cars, but I would not sacrifice reliability to do so.

 

[85GPLef41]

I've worked on at least 4 Vortec 305/350 engines with the composite intake and have had to replace the intakes and gaskets as they seem to leak quite a bit around the coolant ports. If you catch it in time its a easy fix but I've done 2 cylinder head swaps on 2 different Tahoe's. i have found that the rear of the block tends to leak coolant. and with them not checking the coolant, they overheat and ruin the heads.

 

[ibanezfxer]

The biggest issue with composites is that they do not age well. Ask anyone who has had a plastic intake manifold fail on them. On an aircraft, this is not as big an issue as they tend to get far better maintenance than cars do. On a car though, it can be a real PITA when they dry out and warp or crack. Comp Cams used to sell composite valve covers, intakes, etc., until they had the same issues with theirs. Ford Modular V8's are notorious for bad intake manifolds, as are Chevy Malibus and a number of other makes and models. I am a big fan of weight reduction wherever possible on the front end of these cars, but I would not sacrifice reliability to do so.

This is very true. I didn't even think about that. Guess we get so complacent about what we work with we don't always remember the little things like that. Funny, I now remember my instructor told us our very first day at the acadamy " you car mechanics need to forget everything you ever learned."

 

[yourownself]

hey, good to know! i figured the added rigidity and improved leak resistance would be a bonus, but it sounds like i'd be sacrificing a lot more.
thanks guys.

 

[megaladon6]

the gm plastic intakes leak for 2 main reasons. they are improperly installed at the factory where people making 80K a year are too lazy to read a torque wrench, and in the case of the buick 3.8l they ran the egr through steel tubes in the plastic and has incredible inadequate cooling. plastic doesn't like 750* temps and eventually melts out at the coolant/plenum interface creating the fun of hydrolock.
the composite covers actually do quite well. the biggest problem is that some have the crank sensor in them which occasionally gets overtightened. however the best thing is a decent 2 pc so that you don't have to go nuts to change the cam/timing.

 

[85 Cutlass Brougham]

I just worked on a Ford 4.6 Modular that had the rear heater hose bung break off. The plastic had dried out and was crumbling in my hands. Evidently, it did not like the heat of that particular part of the engine, which was NOT the typical failure point. They normally fail at the front, where the new factory replacement manifold replaces the plastic with aluminum in this section.