OHV Aluminum Intake Manifold Differences

[DPDISXR4Ti]

I had been under the impression that only the '90 - '94 engines got Aluminum intake manifolds and then starting with the EEC-V engines in '95 they were all plastic. But today I noticed an eBay listing for 1995-2000 Aluminum intake manifold, part# 96TF9424AB (also indicated as 96TF9424AA).

A couple questions...
1) What's the difference between the early lower manifold (p/n 90TF9424AA) and this one?
2) Did the '95 - 2000 engines perhaps only get a plastic UPPER and the LOWER manifold was still AL?

 

[JoshT]

I'm about 90% certain that #2 is the correct answer. It's been a while since I looked at the 4.0L that was in my 99, but I'm almost certain that the lower was aluminum.

As for #1, I have no idea what the differences are.

 

[SenorNoob]

I see no visible difference in those pictures.

 

[Shran]

The newest OHV 4.0 I’ve worked on was a 98 and it had an aluminum lower and a plastic upper.

 

[gaz]

@DPDISXR4Ti

- The OHV plastic upper intake manifold should offer potential lower intake temperature as the plastic does not really absorb heat...although the Al can work as a heat sink, actually dissipating heat.
- I vote for the Al version as it will have bosses for all features, should be more durable and the inlet can be bored to match a larger throttle body.

 

[rhekman]

I had been under the impression that only the '90 - '94 engines got Aluminum intake manifolds and then starting with the EEC-V engines in '95 they were all plastic. But today I noticed an eBay listing for 1995-2000 Aluminum intake manifold, part# 96TF9424AB (also indicated as 96TF9424AA).

A couple questions...
1) What's the difference between the early lower manifold (p/n 90TF9424AA) and this one?
2) Did the '95 - 2000 engines perhaps only get a plastic UPPER and the LOWER manifold was still AL?

My '95 has a plastic upper intake and aluminum lower, with the cast aluminum injector distribution plate sandwiched in between. I don't have a 94 or earlier to compare, but the pictures on ebay are similar. The pressure regulator, fuel supply line, etc. are all in the same place. If there are subtle differences in port geometry, sensor positioning, etc, I couldn't tell you.

 

[DPDISXR4Ti]

The newest OHV 4.0 I’ve worked on was a 98 and it had an aluminum lower and a plastic upper.

Thanks - first-hand experience always beats out guesswork. But it's always nice when the two match! There's probably some small difference between the two lowers. Didn't the intake port shape change some small amount maybe starting in '95 with the higher compression?

 

[JoshT]

There's an article in the tech library that covers differences.

 

[DPDISXR4Ti]

There's an article in the tech library that covers differences.

Hmm, I just checked but didn't find. Could you perhaps provide a link?

 

[JoshT]

@DPDISXR4Ti sorry looks like I was thinking about heads, which are in a tech article and have been subject of discussion in a few recent threads. Intake port in the heads is mentioned in the article, but that doesn't mean anything about the intake itself.

 

[SenorNoob]

That's the only logical reason I can think of for it to have a different part number for the 96 model year. I'm pretty sure they didn't use the same lower on the SOHC...

 

[DPDISXR4Ti]

Thanks for the input. Sometimes it's a very small, insignificant change that requires a new part#. At the end of the day, it's best to just use the part that's designed for your engine. My question was more out of curiosity as I know some people like to use the '90-94 AL intake on their '95+ engine, but I wasn't sure if that required the '90-94 lower as well.

 

[gaz]

@DPDISXR4Ti
The 91 through 98+ lower intakes and their intake ports are the same; only the exhaust port was changed on the 98+ heads.

 

[DPDISXR4Ti]

@DPDISXR4Ti
The 91 through 98+ lower intakes and their intake ports are the same; only the exhaust port was changed on the 98+ heads.

Thanks for the data-point. So basically you're saying the '90 - '94 and '95- 2000 lower intake manifolds are essentially the same? That would be good news for someone wanting to put a '90 - '94 upper on a '95+ lower if they wanted an all-AL intake.

 

[RussAdams]

My '99 4.0L has a plastic upper and an aluminum lower. I'd also be interested in knowing if the '90-'94 aluminum upper would fit on my '99 aluminum lower.