Subject: Re: [6pack] 72" TR6 Engine Rebuild

From: David Friedlander <[email-masked]>
Date: Sun, 3 Nov 2013 17:58:02 -0500

Bob;

I just completed a rebuild of my '74 after blowing the head gasket on a
road trip a hundred miles from home... I got the car towed and began work
immediately. I went with a Goodparts GP2 cam -- a little spicier than a
stock cam but very useable for the street. Had my head milled to flat (.009
shaved by the local machine shop). CR is now 9.75:1. Replaced the thrust
washers (+0.005), connecting rod bearings, pushrods (one was bent from "the
event"), tappets (one shattered) and +0.020 piston rings (last item from
BPNW). My compression was pretty low beforehand, too, so I felt this was
the time to re-ring. Be careful with your bore measurements and compression
ring gaps (Bentley's specifies the gaps for each ring on pg. 101). Measure
the gaps of top and second rings carefully (pg. 99). Cam bearings may be a
good idea though not really necessary -- but you'll need to pull the engine
to line bore the block for them to do that. I have no cam bearings and did
all my work with the block still in the car. Bentley's has some good
instructions but patience and a sense of humor make the job easier. You'll
need a piston ring compressor and perhaps a cylinder hone attachment for
your drill if your cylinder walls are "glazed."  Timing the crank with the
cam you'll also need a degree wheel and a dial indicator. Good luck, Bob!
Keep us posted on your progress.

I'd heartily recommend Rick Patton's Throttle Body Injection (TBI) so you
won't have to ever worry about those carbs and diaphragms again (
http://www.pattonmachine.com). NFI.... Just a very satisfied customer

Dave Friedlander
'74 Six with TBI and A-type OD

On Sun, Nov 3, 2013 at 5:08 PM, Bob Rochlin <[email-masked]> wrote:

> Hi List,   I'm contemplating rebuilding the engine of my 72' TR6 this
> winter.  I am hoping the collective experience of the list can give me some
> guidance as to some of the decisions I'll have to make.   I'm thinking of
> getting a cam just a little hotter then stock and shaving the head just a
> bit.
> I've been very happy with the performance of the original ZS carburetors
> and
> wonder of they are  able to supply the increased fuel demands of the new
> set
> up. As far as I understand the jets are fixed.   Speaking of cams, how
> necessary are cam bearings?  Should I have them installed while I'm doing
> the
> rebuild?  The engine runs very well, but bit doggie.  I don't think that
> it's
> ever had any machine shop work done.  I did a compression test about a year
> ago.  The results were low of 85, hight of 120.  A leak down test confirmed
> that almost all the lost compression was through  the rings.  The car burns
> almost no oil (it just leaks out a little)  what other components should I
> replace as a matter of course during the rebuild?  Anything I should look
> out
> for?  I am long forward to hearing your advice.  Take care.  Bob

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From: "Alex&Janet Thomson" <[email-masked]>
Date: Sun, 3 Nov 2013 17:58:56 -0500

Bob - I lost several lobes of a cam several years ago and replaced the
camshaft with a GoodParts GP2. Lots of low end torque (like my farm
tractors) and seems just right for our type of driving. I can't remember how
much we had the head shaved but the shop that did the work gave me figures
for actual volume of the combustion chamber contained in the head. I never
did get around to doing the math. I think I bought the cam and followers
from TRF along with a new oil pump. The new oil pump made a big difference
in hot pressure.

Alex Thomson

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On
Behalf Of Bob Rochlin
Sent: Sunday, November 03, 2013 5:08 PM
To: [email-masked]; Truiumphs
Subject: [6pack] 72" TR6 Engine Rebuild

Hi List,   I'm contemplating rebuilding the engine of my 72' TR6 this
winter.  I am hoping the collective experience of the list can give me some
guidance as to some of the decisions I'll have to make.   I'm thinking of
getting a cam just a little hotter then stock and shaving the head just a
bit.
I've been very happy with the performance of the original ZS carburetors and
wonder of they are  able to supply the increased fuel demands of the new set
up. As far as I understand the jets are fixed.   Speaking of cams, how
necessary are cam bearings?  Should I have them installed while I'm doing
the rebuild?  The engine runs very well, but bit doggie.  I don't think that
it's ever had any machine shop work done.  I did a compression test about a
year ago.  The results were low of 85, hight of 120.  A leak down test
confirmed that almost all the lost compression was through  the rings.  The
car burns almost no oil (it just leaks out a little)  what other components
should I replace as a matter of course during the rebuild?  Anything I
should look out for?  I am long forward to hearing your advice.  Take care.
Bob

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---

From: Richard Seaton <[email-masked]>
Date: Sun, 3 Nov 2013 18:30:26 -0600

you can get away with out cam bearings if you go with a GP2 cam, Piper 270, or
Kia's middle cam (WBC518v2). Replace cam tappets with quality replacements!!!.
I would want to line bore the mains to get them within spec as they may be out
of round same with the rods. A lightened flywheel is a worthwhile modification
and Wishbone ($229) can turn your stock one down and loose some weight. The
motor will spool up quicker with no ill effects. I had mine turned down and
ballanced for $75 10 years ago at Race Engine Designs in Georgia (do a
search). Do use the better thrust washers (Custom Thrust Washers). Raising the
compression to 9:1 and still use pump gas. Follow correct cam break in
procedures and use ZZDP in your oils or Dello Diesel oil. The use of 3 ZS
carbs isn't of any benefit except for the bling factor. Mild port matching of
the intake and exhaust is easy to do. Rebuild/ recurve the dist for the engine
mods, which ins't too exspensive. Jeff's Advance Distributors.

Of course new valves, springs, guides and a hardened rocker shaft.

> From: [email-masked]
> To: [email-masked]; [email-masked]
> Date: Sun, 3 Nov 2013 17:01:39 -0600
> Subject: Re: [6pack] 72" TR6 Engine Rebuild
>
> I recommend, and did:
>
> aluminum fan base
> electric fan
> lightened flywheel
> shaved, ported and polished head
> decked block
> pistons 30 over
> balanced engine
> goodparts gp2 cam
> goodparts triple carb setup (uses the zs carbs)
> goodparts lowered suspension springs
> upgraded goodparts front sway bar
> goodparts rear swaybar
> goodparts adjustable camber rear trailing arm mounts
> heavy duty rear lever arm shocks
> http://www.ranteer.com/davescars/tr6/ShockRec.jpg
> replacement lug nuts (hated that flakey chrome look)
> http://www.ranteer.com/davescars/tr6/LugNuts.jpg
> brass gas tank sending unit float
> http://www.ranteer.com/davescars/tr6/fordfloat.jpg
> litezupp L.E.D stop and rear blinkers
> http://www.ranteer.com/davescars/tr6/LIteZupp.jpg
> digital flasher unit  http://www.ranteer.com/davescars/tr6/BlinkerEL12.jpg
> 215/60R15 yokohama tires  http://www.ranteer.com/davescars/tr6/scan0008.jpg
> high torque starter from ted schumacher
>
> do all this and you won't recognize the car.  but YOU WILL LOVE IT!!!!!
> this car is competitive with a tr6 with a rover v8 in autocross
>
>
> all pretty well documented at www.ranteer.com/davescars/tr6
>
> contact me offline if you have any questions.
>
> From: Bob Rochlin
> Sent: Sunday, November 03, 2013 4:08 PM
> To: [email-masked] ; Truiumphs
and
set
> Donate: http://www.team.net/donate.html
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---

From: "Robert M. Lang" <[email-masked]>
Date: Mon, 4 Nov 2013 10:15:37 -0500 (EST)

Hi,

You already did the most important part - test the engine health prior to 
the teardown!

Building on what others have said:

I would spend the money on installing cam bearings. It's a lot of $$$ to 
align bore the block and install the bearings, but it's totally worth it 
because the block is almost always worn in the cam journals, and this can 
be a cause for low oil pressure. BUT, before you commit to getting the 
block bored out and everything - MEASURE WHAT YOU HAVE. If you get a new 
cam and it fits and you have reasonable clearances, then you can skip the 
cam bearings.

I guess the overall point here is that you shouldn't "just do" various 
operations on the block because you have the motor apart. Do the work 
because the block needs it, or you need it for longevity, or, or or. 
Nobody can answer the core question but you.

Regarding compression, I'm a big fan of 9.5:1 or so. You can do that and 
still run regular gas as long as you don't go crazy with the timing. I run 
9.67:1 on my street car and I have no problem with pinging. I do get 
"run-on" sometimes but only when I've been lugging the engine. To the 
point, though - get the head "cc'd" when you get it milled. There are 
charts on the web, like goodpart.com, that explain the relationship of the 
combustion chamber, the bore and so forth. Don't assume that beacuse you 
remove a certain amount from the casting that you'll be at a certain 
compression ratio - MEASURE IT. There's enough variances in the head that 
you can be off quite a bit just assuming a certain "skim" will up the c/r.

As far as the cam goes, you can get bigger lifts with less duration to 
make the cam more streetable. Just use this point to decide: If you drive 
the car in 3rd or 4th, can you drive the way YOU drive at 2500 RPM... if 
the answer is "yes, I always do this" then stay away from the cams with 
seat to seat duration of more than 280 degrees. If you tend to be more in 
the 3k rpm or more, than you can get away with the more hairy cams. 
Actually, the thing to look for is the lobe centers... and you want to 
have l.c.s in the 110-108 range. Lobe centers in the 103-104 range are 
hairy and they will not pull at low RPM.

Of course, nothing is ever simple and there are newer grinds out that that 
have assyimetrical profiles... FWIW, I run a GP3 cam in my street car and 
it is not that hairy in terms of drivability. BUT, the idle vacuum is very 
low, so idle timing / mixture etc. is very sensitive. So, once in a while, 
I'll try to accelerate in 3rd at say 2000 rpm - the motor won't pull at 
all. But, you just drop a gear and off you go.

Everything else is personal preference. For example, I wouldn't just bore 
.030 over. Why? If the holes are round, but the taper is only a couple of 
thou', why remove ALL the material in the block? Maybe an .010 or .020 
bore is called for. You might also base your choice on parts 
availability... I have a couple of motors that are .020 because that's 
what I had on hand AND the bores were pretty good to start with.

I'd also strongly suggest getting a GOOD header and exhaust system. This 
makes a huge difference in the available power. Money well spent. I would 
NOT go crazy with induction unless you're going for max. power. If you are 
building a street car, you are NOT going for max. power. Trust me on that. 
Your stock ZS175's are good for about 170 to 175 flywheel HP. THAT'S A LOT 
OF POWER and you won't get there without going to at least 12:1 
compression - so there's nothing to be gained by changing that aspect of 
the system. Well, there is the ooooh - aaaahhhh factor. But there's no 
mechanical reason to get nuts with the carbs.

Oh well, enough blabbering....if you have questions, fire away.

c ya,
rml
---------------------------------------------------------------------------
Bob Lang              Triumph TR6!!            |  This space for rent
Former NER Solo Chair                          |
Voice:617-253-7438                             |  Cell: 339-927-4489
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