Wedge TR7-Saab Conversion

[DanNagy]

Is it possible to swap a TR7 engine with a Saab engine? I remembered that older Saabs and Triumphs shared the same engine block, and so I tried to find something on the internet but didn't see that anyone had done it.

The reason why I am thinking about this is a discussion I had with my mechanic about the aluminum head sitting on the iron block. I never had this happen, but I guess many of the heads warp if the car is used too hard. I seem to remember something about taking it every so often to have the head torqued. So, now I am thinking that if a latter model turbo Saab engine could be dropped in, that could be cheaply done without a lot of fuss, and would be a hoot. This will help me to decide to keep it or not. Thanks.

 

[BryanC]

I don't know about the TR7 in particular but there are a bazillion Chevy and Ford motors out there with cast iron blocks and aluminum heads that seem to be OK. I think that if you overheat the engine (that is, boil over the radiator) then the aluminum heads may be easier to warp. Otherwise I don't know that there is anything wrong with aluminum on iron unless the TR7 has a particularly bad head design.

Bryan

 

[billspit]

The engine was actually used by Saab before Triumph used it. Saab later did so many improvments, it became a different engine. I vaquely remember this has been considiered by others and seems there is a problem, probably with the bellhousing bolt pattern or something. I'm sure it could be done with enough time and money.

 

[70herald]

The engine was actually used by Saab before Triumph used it.

It was designed by Triumph for Saab. Saab had initial rights to its exclusive use.

 

[TR3driver]

Story I've heard is that it was originally a joint development effort between SAAB and Leyland/Triumph. I rather suspect that the Triumph engineers were so [irritated] at having to work with/for the Swedes that they deliberately sabotaged the design in ways that the Swedes (who had not done a motor before) did not realize. That screwball water pump, for example.

Anyway, there are a lot of problems with the Triumph version. Things like the aluminum alloy not being very good (corrodes easily), while the clearance for the head studs is very tight. Add to that the studs being at an angle and it makes a real mess. Very common to find engines where the head cannot be removed or that have been damaged by excessive force to remove the head.

Triumph also had severe problems with the head casting, apparently some core shift happened to almost every head and they weren't particularly careful about pulling the bad ones and remelting them. Essentially no allowance for skimming the head; no bearing inserts for the cam; the list goes on. On top of that, they had a LOT of problems with the labor unions at the time. So bad in fact that one of the TR7 factories was eventually shut down (and the workers fired).

The GM/Rover aluminum V8 is a popular swap; you can even buy kits to turn your TR7 into a faux TR8 ...

 

[Roger]

There are a bazillian cars with alloy heads on iron blocks - like the Twink and all those Mazdas for example. That's not the problem as long as you use good anti-freeze or other corrosion resistor.
TR3driver nailed the Triumph issue!

 

[billspit]

But the question remains, will the later true Saab motor work in a TR7?

Also, there are pretty darn good V6 conversions that are pretty easy to do.

 

[tr8todd]

I think the real early Saab 99s would be a direct replacement. I seem to remember I used a head off of one once. The later 2.2 motors were similar enough to recognize their origins, but a very different motor. The real problem with the TR7 heads is removing them. You can skim 20 thousands off. The aluminum heads seize to the steel head studs. Sometimes you can double nut them and unscrew the studs with a deep socket. If you maintain the car, torque the head studs every time you change the oil, and don't let them overheat, you have a pretty reliable motor. The timing chains do tend to get a little sloppy thou. And oh yea the water pumps start to weep. And the carbs/chokes are difficult to keep at a nice idle. Adjusting the valves is alot of fun. I guess what I am saying is throw away the 4 banger and drop in a Rover V8. Problems gone!

 

[gjh2007]

I ran a 71 SAAB 99 EMS clone back in the late 70's. It had the 1.71 slant 4 in backwards, as saab ran a transfer case down the front of the engine to drive the wheels. Actually made a clutch job pretty easy, just pull the rad & remove a cover & C clip & you could pull the drive shaft through the clutch & unbolt the cover. I did blow an oil ring at 100k, but was able to get it 150 miles home from college. Did a valve job somethime thereafter also. I believe the 2.0 SAAB motor was a bit more stout.

Now, for whether the later 2.0 SAAB boxes work I don;t know, I may be able to get some info as a good friend of mine used to be in charge of SAAB R&D back then.

I'll keep you posted.

 

[DanNagy]

Hey, thanks Gary. Yeah, that 2.0 turbo would be a hot replacement. I did see the V8 packages, but they look a little overwhelming to me.

 

[Andrew Mace]

In the "swap" category, another possibility is to get the home market's Dolomite Sprint engine: 16v, 127 +/- horsepower. Not a cheap alternative, but something to consider. I believe Rimmer Bros. offers bits for same.

 

[glemon]

As far as aluminum heads, I would agree that modern motors are for the most part pretty reliable, but aluminum heads are prone to warpage, I talked to a machine shop guy earlier this year when I was rebuilding my motor, he said he does not do many rebuilds on modern car motors anymore, but does skim a LOT of heads, in fact that he said is what keep him in business.

He does some rebuild work for the collector car trade, but the bread and butter is skimming heads.

Might be easier to go high compression pistons and better cam in the 7 than the engine swap, my brother has done this in his and is getting a good increase in power, not as much as a SAAB turbo though. I think GM V-6 conversions are pretty popular in the 7 as well.

 

[DanNagy]

Yeah, thanks. I just need to do some more research on it. When I looked at the original 0-60 of the TR7 vs the TR8, there isn't that much difference. It's like the turbo 4 GTI vs. the VR6 - engine/tranny weight of the 6 vs. a turbo 4 - not much difference in 0-60. I am sure there is a lot of add-ons to make them quicker now, but it's a little overwhelming for me.

I am hoping to do some of the work myself so I can learn something, and the V8 conversion looks like it is way out of the possibility. I have never torn an engine apart, so I was hoping to buy one an drop it in... just do bolt on kind of stuff to get my feet wet.

The answer does seem to be to go high compression and change of cam. I need to think about puling the engine apart, what tools I'll need, what can I read about doing it, and the probability of putting it back together once it is apart. I see stuff on eBay all the time where guys ripped their cars apart and never got them back together. That could be me not because of lack of interest, but shear stupidity.

I am also going to look into Andy's suggestion. when I log off from here.

 

[swift6]

When I looked at the original 0-60 of the TR7 vs the TR8, there isn't that much difference.

Depends on whose data you look at. There was an English test that compared a TR8 to a home model TR7 that showed very similar performance data but the majority of tests by most of the car magazines show close to a second and a half to two second difference for 0-60. Torque does make a difference, a big difference. /bcforum/images/%%GRAEMLIN_URL%%/computer.gif

The V8 in the TR8 only weighs 28lbs more than the four cylinder and the TR8's move the battery to the trunk. Its no where near as nose heavy as some would have you believe. /bcforum/images/%%GRAEMLIN_URL%%/nonod.gif

Even if you add the weight of the power steering in, there really isn't that great of a difference in real world front to rear weight between the two. A/C cars are a bit more nose heavy but the same penalty applies to TR7's with A/C. /bcforum/images/%%GRAEMLIN_URL%%/wall.gif

Even though I have a TR8, I still believe that TR7's can be fun. The peppy four cylinder likes to be revved and they are very fun to drive. When you add the V8 and its extra torque the car becomes a bit of a hoodlum car and makes you grin like an idiot with the extra torque thrust. /bcforum/images/%%GRAEMLIN_URL%%/thumbsup.gif

 

[DanNagy]

Well, Shawn, yes, I see that there are different numbers for the 0-60. The additional 35 HP I am sure made some difference, as well as the torque. Too bad they didn't develop a "federal" "sprint" engine from the Dolomite.

I looked at the Sprint conversion at Rimmer and it looks interesting. The entire kit for a rebuilt engine, exhaust, and brakes is about $3800. However, they want the old engine as a trade. I am not sure how that would work sending it to the U.K. I also read some interesting stuff about the TR7 Sprint, a model that was never really introduced but 25 were made. I had no idea about these. That led me to read some stuff about TR8 coupes that were sent to the US without any badges. The article mentioned that some of them were shipped during a strike, and may have been built by management! I need to find a book about Triumph history... this little bit leads me to believe that it is very colorful.

 

[swift6]

For the 0-60 sprint you can bet its the 170+ lbft of torque instead of the extra 35 horses. Especially on such a low revving engine.

The coupes built without badging and are known in wedge circles as the "ACN" cars as that is the prefix to their chassis numbers. Some of the paperwork for these cars identify them both as TR7-V8's and as TR8's. The "ACN" cars are 'PRE-production' and were not built by management but were built for management. They were built at the Speke plant but not by the regular production line but a special team instead. Management used them as company 'test' cars. Most of the ACN cars were also automatics.

There are two series of 'Production' coupes. Both of these series have the TCN prefix. The first group was built in late 1978/early 1979 and have TCN150### as their designations. The second series are TCN160### and were built in late 1979. After that they were all DHC's. My FHC is TCN150015, making it the 15th production TR8 coupe. It is fully optioned with A/C and sliding sunroof (Which seems to be a Leonia N.J. thing and not a Canley assembly plant thing). Supposedly, there are less than 500 factory V8 coupes in total (ACN and both series of TCN's). The records from BMC in that time frame are really very poor.

/bcforum/images/%%GRAEMLIN_URL%%/wall.gif Make that the JRT division of BL.