Matt's '88 780

Very nice project, love the attention to detail. Excellent work.

Matt Dupuis said:

Since they've got the helical gear for the distributor drive, I assume they're B27/B28 cams. Any good?

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I have no idea, thought of your project and maybe it could a useful cam. Didn't notice the distributor drive type

It's okay, I appreciate the thought!

Matt Dupuis said:

Some new pix:
Whipped up a heat shield/mount for the cone filter

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Does this make any difference (performance/sound/mileage)? I have now the flat panel K&N in the original airbox, and I am seriously considering this mod...

tomasss said:

Does this make any difference (performance/sound/mileage)? I have now the flat panel K&N in the original airbox, and I am seriously considering this mod...

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Cutting the airbox would make more difference then that.

However headers help more!

Matt Dupuis said:

An M46 swap could be in the cards for next winter. I needed to get it on the road for this summer, and I'm nowhere near as productive in the garage that I used to be before the kid. I've got the bell, flywheel, and most everything else, but I need to mod the flywheel for crank triggers & mod the bell for the CPS mount. Not deal breakers, but they weren't going to get done before this summer.

Besides, the automatic works very well behind the V6, and it suits the car well.

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Don't bother with an M46, they aren't worth putting behind a V6, I killed one with a stock b28E....

tomasss said:

Does this make any difference (performance/sound/mileage)? I have now the flat panel K&N in the original airbox, and I am seriously considering this mod...

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I can't hear the damn thing over the noise from the exhaust, so I don't know how much noise it added. I doubt there's any performance or mileage improvement, but I haven't driven this combination with the stock filter to put that to rest.

VQ said:

Don't bother with an M46, they aren't worth putting behind a V6, I killed one with a stock b28E....

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That was probably an old needle bearing M46, as equipped behind a B27/B28, correct? It seems that you can break one behind just about anything, but the one I'd install has been behind a pair of improved turbo motors, and even though they weren't hot rods I'm sure this thing ain't making that kind of power.

But if I can find a Getrag before then, I'd be tempted to go that way.

Awesome 780!

Matt Dupuis said:

I can't hear the damn thing over the noise from the exhaust, so I don't know how much noise it added. I doubt there's any performance or mileage improvement, but I haven't driven this combination with the stock filter to put that to rest.



That was probably an old needle bearing M46, as equipped behind a B27/B28, correct? It seems that you can break one behind just about anything, but the one I'd install has been behind a pair of improved turbo motors, and even though they weren't hot rods I'm sure this thing ain't making that kind of power.

But if I can find a Getrag before then, I'd be tempted to go that way.

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Probably, but m46's still aren't a strong box and they will have less torque then a worked PRV makes, if you go to all the hassle, might as well do it right with a T5 or W58 box that will handle the power and low down torque you make now and more later on. Don't even bother with a getrag as they aren't that good for a daily without a overdrive 5th...

I've started pulling apart my 760 to do the head gaskets, finally...

I know the M46 is less than ideal, but I'm not crazy about using my T5 in this car, especially as I don't plan on keeping it. And I'm pretty sure that I wouldn't be able to find a Getrag with a 1:1 5th if I tried, and I'm well aware that any I DO find are probably in need of a rather expensive overhaul anyway. Not many choices available...

I've had pretty good luck with the getrags... An unknown condition ebay unit went into my 740 and eventually ended up in Bergen's 245 putting down over 500whp, and bought one from a guy parting out an e30 m3 that had been run through a puddle locally for Vurbo, also was a great trans. Sure is an easier swap for the 7/9 than a T5 just cause of the shifter.

I would love to see (and hear ) the video with fitted mufflers...Matt, do you plan something like this?

Not sure, tomass. I pulled the headers 'cause they made such a racket, and I mean it was really irritating. Once I fitted the EP manifolds and some custom downpipes it got a lot quieter, but that just showed up a massive leak in the Y pipe. It was at about that time that it started snowing, so I haven't driven it since then.

In the next couple of weeks I'm pulling the exhaust to work on that Y pipe and we'll see if I put the headers back in or not. I doubt it, at least this year. If all goes well with the car and I don't decide to sell it off, I'll maybe pick up some DMC-CA cams and toss the headers back on, & maybe do a tranny swap. This year it's all about fixing the little things that need to get taken care of, and starting work on my 123GT, and having some fun this summer.

FWIW, the removal of the headers didn't kill off the top end power much. It suffered more in the bottom-midrange, but the new torque curve could just be fooling me into thinking that the top end power is the same. What's more likely is that the 1 3/8" primaries choked off the top end just a little, which really perked up the bottom end. The manifolds gave it a really nice gurgle too - the headers are all equal length so it's smoooooth, while the manifolds make it sound a bit burblier. Honestly I like the sound of the manifolds better, but all bets are off until I get that Y pipe welded up.

Ok, video with fitted EP manifolds will be perfect, because I am planning the same setup - EP headers and two straight mufflers - and I would like how noisy it will approximately be...

How is it going?

You should swap the slow AW71 for an AW72 incl the converter, i did it to my 760 88? and i also changed endgear/final gear ratio to 3:54 from an 94 960. (with diffbrake)

This made the car go 0-100km/h from 12sec to 7.9sec. And it made the car wake up BIG TIME..I could do donoughts easy after it..

They say that the 24valves heads should fit to. But hard to find maybee...

you're the ****ing man, man!

Matt Dupuis said:

Disassembled the B280F heads to check 'em out. This is the "Swirl" intake port

Compared to the EP and B280E intake port

Close up:

Interesting: check out the position of the spark plug. It's deeper inside the combustion chamber in the B280 (shown here)

Compared to the EP head. I don't know what the B280E head looks like.

Then I cleaned up the rocker assemblies. Before:

After. I blasted the stanchions but only cleaned up the shaft and rockers with scotchbrite and brakleen.

Nice shaft! Again, 200,000 miles.

This little oiling hole is the cause of the B27/B28 failures... or one of them. Extended oil change intervals would create sludge which would clog these little jets, and these little jets were the only lubrication of the camshafts. In the B280, OCIs were reduced, oils were improved, these jets were enlarged (I believe) and there was a dam added to keep the camshaft sitting in a puddle of lube, much like in the B21/B23/B230.

Here's one I prepared earlier:

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Just an addition to your post here.

I ported out the intake of my b280F heads and decked .35 thou off them, as well as cleaning up the exhaust side to be a bit better flowing. It's all solid material and I think the heads have a lot of room to make more flow. There are some companies that make or regrind PRV even fire cams due to them being used in Renault Alpines as well...

Just wondering as well what you did for heat shielding on your fuel lines? I'm planning on some elaborate things and I'll be running a hot dog on each pipe to quieten down the car as well.

Then, seven years after the last post in it, this thread is alive again!



Matt's former car has had a change of ownership (to me) and a change of address (to Australia).



Seen here in Canberra....


... and at the Volvo National Rally with all the 780s in Australia (i.e. the other one)


... and seen again in Coolah, in outback NSW....


She's also had a change of address within Australia, which dictated a need to change plates.


The car is on full Tasmanian registration, made possible thanks to an engineer's report, plus the change to Japan-spec headlights. That's needed here due to Oz being a left-hand-traffic (i.e right hand drive) country. Having US or EU spec headlights would mean it would be restricted to daytime use only and thus placed on restricted registration. The engineer also had to add child-restraint anchor points in the back seat parcel shelf. Why, when we don't have kids? Well, it's a mandatory Australian Design Rule that all 1988-spec cars had to have these things. So it was either fit them, or no rego.

Next thing on the To-Do-List is get that bonnet - or hood, as some say - repainted. The clear coat has seen better days, like, about 30 years ago. The aircon also needs to be setup for R134A, as Duracool isn't available in Oz.

Did they make the 780 right hand drive?

Post pics. None of the original links work.

Ursan said:

Did they make the 780 right hand drive?

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Nope; they didn't. I thought about converting this one over to RHD using a 740 firewall, etc, and gathered all the bits. Then LT told me it it was possible to register it as LHD since it's over 30 years old now, so I took his advice and did that instead, and saved myself a LOT of hassle.

Post pics. None of the original links work.

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I'd like to, but the older photos are all Matt's pics, which were on ExtortionBucket.

The bonnet ... errr, hood, is looking a lot nicer now.



A trip to Gary Presnell Bodyworks here in town set that right.

The next things to deal with are the air conditioning and heater fan fuse, which appears to have melted in the fusebox, and to re-run a new piece of hose to the cruise control. Since there's no local replacement for what Matt was using as R12 replacement refrigerant over here, I have to convert the system to R134A.