Supercharged V6 into 740

PeteWA · 2023-12-25T02:15:36+00:00

This project is already well under way. Originally this was to be a small block chev swap however that engine was moved to another project and I have opted t...

PeteWA

Three (3) word post/replies do not explain anything. I started this as a build discussion to see if there was any interest or perhaps find someone else who has attempted this engine swap. Maybe I have this in the wrong place. And I get random messages/posts that have nothing to do with my build ……….. Go figure.

Ex850R

PeteWA

No man, you’re good, he hijacked your post to get acceptance perhaps.

Stay here, your work is beautiful

ramrod

What I meant was, johan is a scammer and is trying to suck money from people gullible enough to fall for it

He’s been banned from this site

PeteWA

OK got it. Thanks for clarifying what was happening. I see enough scammers when I'm selling parts to be wise to them. Cheers

PeteWA

A bit of an update on my build progress. D2 suspension.

The 740 was exceptionally comfortable ride with the standard suspension with the exception that cornering was more like riding in a boat. I spent a considerable amount of time researching and trying to find the standard 740 spring rates and, I found no credible information. In the end I went with D2 Street Kit because the D2 front and rear spring rates where similar, the kit was reasonably priced for a entry level full spring and adjustable shock absorber set. Time will tell if the quality is there.

The D2 Pro Series Street Kit has advertised spring rates of Front 8.7 kgf/mm and Rear 4.4 kgf/mm. Motion ratio correction has the Fronts at 7.395 kgf/mm and the Rears at 6.468 kgf/mm

I measured the 740 corner heights (top of the wheel opening to floor as a base measurement so as to gauge how much I was lowering the car when it came to setting it up.

I have finished re-installing rear axle, brakes and the front and rear suspension. The D2 kit was reasonably trouble free with the exception of a few modifications to have it all bolt up properly.

To be able to access the camber plate adjusters, the top of the strut tower opening has to be relieved slightly. Apart from that modification which was not mentioned, the cutting of the strut tube and welding the D2 tube to the spindle was straight forward.

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The rear set up (pictured below) was also pretty straight forward. The kit instructions (which are pretty vague) says that OEM spring perch has to be re-uesd. This is incorrect. The supplied adjustable perch has to be used. The retaining bolt in the kit is the incorrect size, it is to big (diameter). The captive nut in the chassis is not big enough to re-tap to the size of the bolt supplied in the kit. I made a threaded sleeve to screw into D2 perch and bought 2 x longer 10.8 bolts to secure the spring perch.

The kit instructions made to mention of re-using the spring insulators. To reduce 'spring creak' or noise that could be transmitted into the car I re-used the top insulator and the lower spring seat insulator. This reduces the amount that the car can be lowered if the intention was to drop it as low as possible. Thats not my aim so the insulation is of more importance.

The only other issue not mentioned is that there are 2 'nibs' inside the chassis where the top shock absorber mount bolt hole is located. These need to be removed so the mount hole can be aligned and bolt can be inserted.

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To date. The rear axle, front and rear suspension has all reinstalled. I have resealed the calipers and installed those, fitted new brake hoses and bled the brakes. The suspension height has been set at 30mm lower than the original measurements taken. The new steering rack has been fitted along with all the front end suspension components.

I have cut the engine sump to have it fit and made wings to weld to regain the volume capacity plus an extra liter.

I will post some pictures of the sump a little later.

Ex850R

I have seen others cut the top of strut tower off and weld a thicker bit of sheel on there for the larger hole , 3.0mm would do fine , a 10.0mm high bit of SCH 5 pipe around the hole maybe , but really , 3.0mm is plenty there over a small area and triple the thickness of the sheetmetal.

PeteWA

I can see that what you say could be beneficial for a drift car where the loads are substantially increased. Compared with the standard top spring plate the D2 top plate has substantially more contact with the underside of the spring tower which should reduce flex and transfer the load more evenly.

This is a street sleeper for cruising and some 'straight line racing'. The change of suspension was more to bring the cars handling in line with the engine modification, give me the ability to set the suspension height and adjust the shock absorber rate. After I have the engine back in the car I will look at making a tower brace, if it will fit over the top of the supercharger.

PeteWA

The Oil Pan.

As the L67 (Commodore V6) has a cast alloy pan with bowl forward, this would not work in the 740. In fact this has proved to be the biggest hurdle in fitting this engine. I managed to find a steel pan that was used when these engines were fitted into 2000 -2002 Chevrolet Camaros. So, I purchased this and the oil pickup from the US. What I didn't realiase was that the pan is actually pressed with 2 sheets of metal, the result is this has made the welding all that more difficult.

Removing the front section of the oil pan (for crossmember clearance) decreased the volume by 1 liter, the wings on the rear gives me back almost 2 liters, increasing the pan to almost 6 liter volume. I drilled and tapped a piece of 13mm steel plate to bolt the pan to for welding.

Now all I have to do is leak test it again and then its ready to fit.

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Forg

Very interesting you needed to custom a sump for this … my recollection from the 90’s was dozens of ads in Unique Cars for 760’s that’d been converted to moo-mangs when their PRV’s had inevitably given up the ghost.

760 doesn’t do something different to 740 crossmember-wise, somehow?
Unlikely, you’d have researched that!
Ah wait … if you’ve looked at 2000 Camaros this is an Ecomoo, mebbe that’s the difference, those conversions I was talking about were the ancient original moo-mangs.

PeteWA

Hi Forg. Yep its a ecotec and believe me I looked far and wide for a oil pan before I started this and nothing turned up. V6 conversions do make a few oil pans to retro fit the V6 non eco and ecotec into holdens, hiluxs and a few others but they are a bit pricey and there was no guarantee any of these would bolt straight on without having to modify them. CRS, Marks 4WD, CAE do oil pans for holdens and a few others but nothing Volvo..

JTR Engineering in California still make a adapter kit (I know because I purchased one) to bolt a small block chev to 740/760, same kit, same crossmember.

Originally the plan was to bolt a SBC into the sedan. That project went south when the DOT here in WA would not allow me to fit the 377 that I built because of the cubes, 350 only. I had everything ready to go including, purpose built bottom end for a blower, AFR heads, Holley stealth injection, a procharger and TKX 5 speed. I've put that aside for my next build, 1987 Camaro.

So, I already had the L67 and that's where it is at now.

The 90's where 30 plus years ago and I was not looking at anything Volvo back then :-) If there where that many running around then they must all have gone to god by now because I have not been able to find any reference of anyone doing a V6 swap. I found a few holden V8's, same with SBC's and a few LS swaps here in WA. If there where that many floating around (most likely some are stuffed in back of people's sheds) there must be a few at least still on the road. It would have made my life easier if one had turned up so I could have got some info.

Forg

They were all non-enthusiast cars, just 760’s that weren’t rooted enough to scrap except for the dead engine, and the moo-mang was cheap & plentiful. So yeah, can believe they were all done on a one-off basis with SFA care for repeatability or longevity.

Ex850R

Forg

And done in era of the internet not used by these people as well.

It’s not something Volvo enthusiasts would document either. “Not the done thing” .

Philthy

Hi Pete WA. I need to do as you did and clean the rust proofing and red dirt from the underbody of my 240. What did you use to get that black shit off it's everywhere on my car? In the process of trying to clean my rear axle. As with your car been beating down a country dirt road and covered with red dirt. I'm still not sure what engine I'm going to use. I have an VS Ecotec V6, a Honda J30A4 v6 and a 5.0 Ford to choose from.

PeteWA

Hi Philthy,

My 740 had factory sound deadner applied in places, not the whole under body and I would guess just the areas where they could see that there may be debris impact and then it was sprayed with rust proofing most likely before delivery from the dealer.

Getting it off took about a week. To make the job easier I removed everything, suspension, rear axle, fuel tank, fuel and brake lines and obviously the engine and gearbox where out. That way I was not working around or damaging other parts. To remove the rust proofing I used a heat gun to soften it and a variety of different shaped scrapers and I got to work. After I had scraped the majority of it off I used a solvent to mop it clean. Extreme care must be taken if you do this, use the appropriate breathing gear and eye protection, in a well ventilated area and only do a small area at a time.

Once it was cleaned I primed the entire under body, reapplied the sound deadner and then 2 coats of black paint.

If you look back at the photos you can see that I had all the small parts sand blasted. I made plates to seal the axle tubes and masked the pinion seal area.

As far as your choice of engines, well that is a call for you. The V6 that I used was not a good choice, mostly due to the fact that the oil pan bowl is forward on these engines and that created a lot of issues. I have a engine mount conversion kit to a small block chev into Volvo if you are interested.

Philthy

Hi thanks for the reply. All these engines need a sump rehash unfortunately there is no other way to get them low enough in the engine bay. I've sanded all of my suspension parts down to bare metal and resprayed in epoxy enamel and I might pull the axles and do as you did and get the casing sandblasted. The rust coating is all over the underside of this car must have been a dealer option when sold. Its protected the floor pans but not anywhere else. Anyway thanks for letting me know what you did. I had been using the heat gun. Cheers and good luck with the rest of you project.

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