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Dan Jones
Dan Jones
St. Louis, Missouri
(280 posts)

Registered:
07/21/2008 03:32PM

Main British Car:
1980 Triumph TR8 3.5L Rover V8

I hurt my TR8's engine today
Posted by: Dan Jones
Date: September 29, 2010 11:21PM

I ran to FedEx over lunch. On the way home, the
engine felt funny. I ran it up through the gears
to see if it was down on power or not. It felt
decent in 1st and 2nd (chirped the tires on the
shift) but seemed a little down on power in 3rd
and 4th. As I backed out of the throttle, I heard
a tapping noise coming from the engine. I made it
back to work but the engine was popping (through
the exhaust) and down on power besides, besides
the tapping noise. Temperature gauge and voltmeter
looked fine. Oil pressure and level were good.
I had a few hand tools in the boot so I pulled
a valve cover and found the bolt retaining the
rocker stand closest to the driver was loose.
I unscrewed the bolt and a spiral of aluminum
came out with the bolt. Probably a bent rocker
shaft too. I know D&D also make end stands to
prevent such things from happening.

I could probably use an insert or helicoil to
repair the head without pulling it apart but
I'll probably take it as a sign to build a
stroker engine over the winter.

I've got most of the parts on hand to build three
strokers:

1. 4.3L: Buick 300 crank, Eagle H-beam rods, forged
flat top pistons (3.530" bore size), aluminum flywheel.
Just bore the block and drop in the rotating assembly.
Without porting, the Rover cylinder heads would be the
limiting factor in this build. Maybe port a Rover 3.9L
EFI manifold set...

2. 4.2L: Rover with cross-bolted mains, Carrillo H-beam
rods, Wiseco pistons (10.75:1), GM race cylinder heads
(developed for Mickey Thompson's Indy car effort),
stud mount roller rockers, Huffaker intake (or GM 2x4 bll
but I don't think that will fit under the sloping hood),
solid lifter cam. I have one of the heads at the shop
to be flow bench tested.

3. 4.9L: Rover cross-bolted block, ported Buick 300 heads,
roller rockers, Buick 300 crank, Willpower fuel injection
single plane intake, solid lifter cam, aluminum flywheel.
Still need to order the pistons and rods. This one would
make the most power but the other two would probably make
enough power for the convertible and I could save this one
for the coupe.

Time to fire up Dynomation and see how the engines compare.

Dan Jones


mbhnm
Mark Howard
Maryville, Tennessee
(7 posts)

Registered:
08/15/2010 07:02PM

Main British Car:
1972 Spitfire, 1969 GT6

Re: I hurt my TR8's engine today
Posted by: mbhnm
Date: September 29, 2010 11:31PM

Hi Dan ,

Been reading your posts with interest, lot's of good information. Sorry to hear about the engine. The rocker shaft supports are on my build list, seems with good reason.

I would vote for the 4.9, mainly because that is what I am working on but with the 4.6 offset ground crank and Rover heads.

Keep up the good work and best wishes. Keep everyone posted. I'm sure I'm not the only one who is interested.

Mark Howard


pcmenten
Paul Menten

(242 posts)

Registered:
10/08/2009 10:40AM

Main British Car:


Re: I hurt my TR8's engine today
Posted by: pcmenten
Date: September 30, 2010 12:12AM

Curious to hear more about the 4.2 x-bolted configuration. Did the original 4.2 come with x-bolted mains or is that a 4.0 with offset ground rod journals? I think that's the one I'd go with.

I got a 4.2 crank off of eBay and was considering using it in my Olds 3.5 engine. If I recall correctly, that makes right around 4 liters.


Dan Jones
Dan Jones
St. Louis, Missouri
(280 posts)

Registered:
07/21/2008 03:32PM

Main British Car:
1980 Triumph TR8 3.5L Rover V8

Re: I hurt my TR8's engine today
Posted by: Dan Jones
Date: September 30, 2010 08:19PM

> Curious to hear more about the 4.2 x-bolted configuration.

It's a 4.2L small journal block that was fitted with
cross-bolted mains. It came from the factory with
provisions for cross-bolting on the block but had
standard main caps. Cross-bolted caps were fitted
and it was align bored.

Dan Jones


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