Triumph V8

[ozyfordman]

Has anyone on this forum done any port development on the 3 litre Triumph OHC V8 heads and manifold. Playing with one at the moment, just like to gauge my progress. Not a race engine, just looking for improvements. The intake is a shocker. Hope to hear from someone with experience.

[chimpvalet]

If i recall correctly the Triumph was derived from the SAAB 45 degree slant OHC 4 banger. Can't be certain as this is from memory of reading car mags 45+ years ago in my teens. Might broaden the chance of a response, if true.
Cheers
Steve

[hoffman900]

Pretty sure all the Triumph TR8’s have the 3.5l OHV engine. The 3L OHC engine is for a Triumph Stag.

[ozyfordman]

The engine in question is from a Stag. Have researched the web without luck. There is a site for Stag owners but is very light on tech detail.
Intake valve is 1.44 and exhaust 1.29. Currently have 89 cfm at .37 which is cam max lift. Have 81 percent exhaust to intake flow with very little work. MCS is about 1.25” square. Main issue is the manifold. Flow drops to 71.5 cfm even after reworking plenum. Stock head with stock manifold and carbs went 59.5 cfm@ 10”. Short of cutting the manifold apart and reworking the internal passages I think I’m just about done.
Any comments on these figures? The manifold is crap but the owner doesn’t want to go to the expense of a sheet metal one. This is a job I’m doing for a mate, so not a big earner for me.

[Protech Racing]

Those had issues when new and stock. Oil pressure to the cams , water pump failures and warped heads . Continual exhaust manifold gaskets. Nothing good .
Yeah the SAAB gave TR the rights and design for the TR7 engine and the Stag is twice the SAAB.
Thank goodness the Stag usually rotted away soon enough.
For today, using some sort of EFI through the carb bodies would be a huge improvement IMHO . Along with the controls to go into a safe mode or shut down due to lack of water pressure . A 3PSI oil pressure switch into the water system, etc. Overheating is the biggest problem area . Using an electric water pump might help.
I have never seen one hot rodded other than some sort of exhaust . They can sound OK. "Web cams" can grind a cam set for it .
The SBFord or Rover TR8 goes in easy.

[PackardV8]

This is a job I’m doing for a mate, so not a big earner for me.

Those had issues when new and stock. Oil pressure to the cams , water pump failures and warped heads . Continual exhaust manifold gaskets. Nothing good . Yeah the SAAB gave TR the rights and design for the TR7 engine and the Stag is twice the SAAB.
Thank goodness the Stag usually rotted away soon enough.

We wrestle with obsolete engines every day, but they usually have some strengths. Your mate has chosen one of the worst V8s ever designed and built. There's literally nothing good about that engine; it was both weak and unreliable. As for the Saab connection, this POS is all on Triumph. Saab only had the bad judgement to buy it from Triumph for about three years. The four-cylinder half of it Triumph was building for Saab was so problematical Saab had to cancel the contract, redesign the problem areas and begin building their own engines.

jack vines

[hoffman900]

Usually when I meet a cheeky Brit, I'll point out what a disaster their cars were.

I'm pretty (was more) clued into the Triumph racing scene in the States, and there isn't a single Stag racing, here. I don't think you'll find much on those heads and if someone has ported them, I doubt it was at a high level (even most Spitfire and TR heads aren't).

[Protech Racing]

Jack has the time line correct. Tr sold the POS to SAAB.

[ozyfordman]

Thanks for the responses guys. I know this thing is a POS. He has had the car for like 30 years and is just now putting an original engine in it. It had a 202 Holden when he bought it. It’s been in his shed for about 20 years in pieces. Currently has a 3.5 Rover in it but never got it running. I would have stuck with the Rover as it looks like a decently designed engine. Not my choice with selection, just helping a mate. I’ll play with it a little longer and call it done. If I make 200hp I’ll be happy.

[Krooser]

Triumph designed the slant 4 and Saab bought the rights to it after British Leyland went bust. They did a lot of improvements on the engine but it still was a Triumph design.

I used to buy and sell TR's... only had two TR7's. Sold both to a soon to be retired college professor who was one of those folks who always knew better than anyone else.

Makes me wonder why he bought TWO TR7's from me.

[Pett]

Saab had a few prototypes with the Stag V8.The V8 and the slant four got the same bolt pattern.

[BCjohnny]

Any comments on these figures?

If I make 200hp I’ll be happy.

I almost replied earlier on in the thread, but I guessed most of what I'd written would also be said by others, regardless ......

You're not going to get anywhere near 200 bhp without cams & valves, being almost 40% more than stock, and that would be a bigger mistake than what you're currently attempting

If you're determined to pursue this ........ clean up the ports, get the valves & seats in properly, and put it back together with the best of your ability ....... if you get to a 'crisp' 165 bhp or so I'd call it quits

Don't be tempted to take too much off the head face or you might rum into timing chain issues

Get the biggest rad you possibly can in it, as in purpose built, and a stat controlled oil cooler too ...... I'm assuming you're in Oz and it's not exactly cold over there

Personally I'd leave the Rover in it, and keep the Stag V8 on one side until the value of having an 'original' car makes it worth putting back, in fairly stock trim

This is a job I’m doing for a mate, so not a big earner for me.

I don't think you'll ever come closer to the saying "no good deed ever goes unpunished" than this ......

[Edit: Grammar]

[benno318]

when in high school in the mid 90's a senior had a stag, i always thought they were 2.5L - sounded magic, but went nowhere

[BCjohnny]

i always thought they were 2.5L

A lot of people retrofitted the Triumph saloon straight six ...... a straightforward enough conversion as the Stag was a essentially a short wheelbase 2.5 saloon

With the standard 132 bhp 'injection' cam and simple head mods they would give more than the V8, on SUs ...... and be a thousand times more reliable

The rest that were converted usually got Rover V8s ...... nuff said

[Kevin Johnson]

...
Makes me wonder why he bought TWO TR7's from me.

Probably a geometry teacher. It just feels right.

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