Triumph Sports Cars

engine swaps and other performance upgrades, plus "factory" V8s (Stag and TR8)

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Greg55_99
Greg Williams

(102 posts)

Registered:
11/01/2007 07:12PM

Main British Car:
Hey! That could almost work!
Posted by: Greg55_99
Date: April 21, 2009 12:07AM

Ever have one of those moments when something you'd swear would work.... but... in the end you find out it won't? I had one of those moments a few years back when I found that Mopar made two different versions of the same DOHC head. One, a mirror image of the other, for the 2.4L 4 cylinder engine. And I thought "Y'know, that just like a DOHC V8 setup". So, IF they COULD be bolted to a block, what block would that be? Well... after looking at the bore spacing of several different blocks, I found that they could ALMOST work on a Triumph Stag V8. ALMOST.... It turned out the bore spacing of Stag blocks is not symmetric...

But hey, it almost worked!

Greg
2.2_heads11.JPG
Stag_block28_1.JPG


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6470 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Hey! That could almost work!
Posted by: BlownMGB-V8
Date: April 21, 2009 12:34PM

Keep looking I guess. The Stag also has those damnable angled studs to deal with IIRC so that would have been a fairly major PITA to sort out. There are some web sites that list bore spacings of common engines. Good luck, it'd be a really cool motor if you can find the right block.

Jim


djw090
David Witham
Warwick UK
(115 posts)

Registered:
06/12/2008 11:20AM

Main British Car:
MGB 1974 and MG ZT 160 turbo 2005

Re: Hey! That could almost work!
Posted by: djw090
Date: November 18, 2009 03:36AM

If you want 4 valve heads on a stag block the place to start would be the Triumph Dolimite Sprint head. The Triumph slant 4 was in effect half the V8. On the Sprint they used a single cam but 4 valve head. You will have the problem that you need a mirror image as well unless you mess around with the end of the head or have one banks exhaust in the valley! However as the head is from the same family the spacing should be correct and it used angled bolts.

With the stags short throw crank you could end up with a very revy engine.
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roverman
Art Gertz
Winchester, CA.
(3188 posts)

Registered:
04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

Re: Hey! That could almost work!
Posted by: roverman
Date: November 18, 2009 11:39AM

Greg, your pic's are probably how the Volvo B230/234-end cylinders would look on a Rover. Considerable labors aside, the 907 appears to be a lot of bang-for-$. Fortunately there's other engines with very close bore spacing to BOPR. roverman.


roverman
Art Gertz
Winchester, CA.
(3188 posts)

Registered:
04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

Re: Hey! That could almost work!
Posted by: roverman
Date: November 20, 2009 11:48AM

Greg, What are those BC's for Stag? Maybe 4.25" and 4.125"? If so, Maybe easier to get Volvo B234's? roverman.


V8WEDG
Robert Carter
Fremont, CA
(24 posts)

Registered:
11/20/2009 06:03PM

Main British Car:
Poseidon Green '80 TR8 5spd conv, '05 Lotus Elise 6spd SC'd, '91 Volvo 240 wagon

authors avatar
Re: Hey! That could almost work!
Posted by: V8WEDG
Date: November 22, 2009 08:50PM

The Triumph Dolimite Sprint head would certainly be the easiest and most straight forward option but next in line would certainly be the 1986-199x Saab 2.0L, 2.1L, or 2.3L 16 valve DOHC head. The classic Saab 99/900/9000 block theses heads were used on was derived from the same 2.0L triumph block the that the stag engine was derived from, only Saab engineers fixed all the problems with it like the angled head studs, etc. This of course would make fitting them to the stag more difficult, but given their heritage the cylinder spacing, etc should be right on!
In fact I always wanted to build up a TR7 with a saab 9000 2.3L 16V DOHC turbo motor. In therory it should fit like it was meant to be there!


Krusty
Tom Burke
Maryland
(2 posts)

Registered:
12/03/2009 10:18PM

Main British Car:
1980 Triumph TR8 3.5 V8

Re: Hey! That could almost work!
Posted by: Krusty
Date: December 04, 2009 09:15AM

Gents,

I'm a new guy here, so hello and excuse me if this is all ready well-known info.

Somewhere on the internets (can't find it now), I read a story that Triumph once somehow fitted a pair of Dolomite Sprint heads into a Stag and had great fun bombing around the test track for a day until it exploded "spectacularly". There was no mention of how they dealt with the left/right manifold issue, but I guess you could say it almost worked?

Krusty



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