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RichardSIA Dork
5/22/22 6:57 p.m.

Dio Tipo track/street toy build.
Wanting to build a Dio Tipo for resell faster and less expensively than will happen for a pure street car.
Seems a decent track car sells for as much or more than a street car without the registration hassles.
May just build it for Track/Hill-Climb and let the buyer make it street legal if desired.

The big question becomes, who's rules do I build to?
Lots of "Vintage Racing" and "Track Day" organizations around the country now.
Building to current SCCA Sports Racer rules means an ugly full cage that might hinder enthusiasm for the vintage body style build.
Vintage racing is generally a bit more tolerant of fewer bars.
Do I concentrate on somewhat local NV/AZ/CA/OR clubs or is there a national club other than SCCA?

I have a nice strait TR6 chassis and a TR6 engine that was built for some sort of road racing, with zero miles on it.
Been sitting so I've torn it down for a refresh.
Old assembly lube had petrified so it did not spin over.
Some very nice pieces included in the build, ported head, Arias flat-top .040" over forged pistons, trick aluminum dual-disc flywheel setup, polished beam stock rods, new 25225 cam ("125 HP"), new lifters, etc.
Going to get to play with that burette I have hoarded all these years in order to CC the head for compression calculation. 
Hoping I can use the Weber intake I bought, not sure with the enlarged ports as the intake is thin where it joins the head. 
Pretty sure this engine will make significantly more than the stock 100 HP even with Stromberg's.
The light pistons and flywheel should let it rev quick too.
Hoping to identify the dual-disk clutch and flywheel.

So this is the build thread for my current "I need to get this done ASAP" build.
I have all the major mechanical pieces in hand so it should mostly be about configuring to meet likely rules, finding time to bend tubes, and fitting up the body.

Yah, I know, worthless without pics.

TR6 race head

Aluminum flywheel and dual-disc clutch, Brand?

Just thinking out loud...

Is it possible to find/secure your buyer in advance and offer a custom build to their preferred specs?

RichardSIA Dork
5/23/22 1:23 a.m.

Been there, done that, professionally at one time. 
Major PITA, if you think kids are annoying when they begin asking "Are we there yet" before you are out of the driveway, they have nothing on car build customers!

Custom build buyers have almost no patience for any sort of delay no matter the reason.
"Hey the build is going to be late because the French dock workers are on strike, so those bespoke German made parts for your English kit car are delayed".
Actually had that happen, I should have a degree in international supply chain and finance. wink

So, as far as I may go is more like running car in primer, buyer can choose the paint color.
Needs to be running before I even offer it up for sale, I'm not as fast as I used to be and was never fast enough to keep everyone happy. (See above)

Going to research Vintage Race Org's and their rules.
TR6 based may be difficult.
But this engine is probably a bit much for a regular street car, that 18 Lb. flywheel and clutch combo certainly is. I would hate to have to discard the trick parts.

Got the engine the rest of the way apart.
Trying to decide how much to spend double checking prior work.
It is clear that someone tried to balance the rods, but who and how well?
Same for the rest of the rotating assembly.
Light NLA Arias forged pistons, but I do not see any sign of crankshaft mods for balance.
Clean up of all parts is the next chore.
Then I will be able to get a better look at what I have.

Once again, mostly talking out my ass here, but I'd think that a hot-rod/cruise-in type car guy would be a hell of a lot more likely to say, "that looks cool; I've got some money, I'll take it!" and the racer type car guy would be much more likely to be sorta interested, but take issue with the roll bar design, the engine spec, the wheel size, etc, etc, not to mention the asking price. wink

RichardSIA Dork
5/23/22 2:34 a.m.

Vintage Race or Track Day toy type build.

Want to use the parts I have on hand as much as possible.
Hoping to not have to deal with street title.
Once it is a runner a buyer may request reasonable changes they are willing to pay for.
So it can have a DOT legal windshield if they like, or different wheels.

RichardSIA Dork
5/24/22 3:08 a.m.

With the engine fully apart and some on-line references I have been making notes.
Not sure it will be usable as the head has been skimmed very heavily.
But if the chambers were opened up sufficiently when they were CC'ed and polished it may be OK.
Time to drag out the Burette!

JoeTR6 Dork
5/24/22 8:22 a.m.

I have run a TR6 with up to a 10.5 compression ratio on the street.  This was with triple Webers and 91 octane gas, but ignition timing was via a crank trigger wheel and more precise than stock.  If the shop doing the head work went by Kastner's book, they would have removed some material to eliminate ridges near the spark plugs.

RichardSIA Dork
5/24/22 3:54 p.m.

As near as I can measure without a proper glass plate the chambers are 38cc and completely deburred.

So call it 11-1 compression.
Might be OK at my 4,000' but not so sure about sea level in CA.

oppositelocksmith Reader
5/24/22 5:41 p.m.

Will be following this closely. 

Not a lot of TR6's racing in autocross, SCCA, or vintage racing organizations.

I run mine (not very competitively) in either FSP or HCS in SCCA autocross. 

Trying to get one right for a varying sanctioning body ruleset seems a bit like trying to hit a moving target. Case in point- I looked a few weeks ago at a Spitfire for vintage racing on my end of the country. It was competitive 30 years ago in SCCA. Now it's so modified, it is no where remotely legal for the 2 vintage sanctioning bodies. I did not buy the car.

RichardSIA Dork
5/24/22 11:44 p.m.

Any cage I build will be heavier than the new body.
If it does not sell right away I may get it street legal and play with it myself.
Best way to get an offer is to decide to keep something, voice of experience.

Smooth 38cc chambers

vwcorvette (Forum Supporter)
vwcorvette (Forum Supporter) GRM+ Memberand UberDork
5/25/22 9:42 p.m.

Don Dingman runs his Ambro (name before the Tipo) with VRG and VSCCA. It however is powered by a 327 SBC.

Since this pic was taken he has since flared the wheel openings for more rubber and changed the color to a darker blue metallic and silver scheme. No pics at the moment. I might have a video somewhere.

vwcorvette (Forum Supporter)
vwcorvette (Forum Supporter) GRM+ Memberand UberDork
5/25/22 9:50 p.m.

Grainy cellphone video. Test following steering and suspension upgrades.


APEowner GRM+ Memberand SuperDork
5/25/22 9:56 p.m.

If you build it to SVRA rules it should be legal with pretty much any vintage organization.

Stampie GRM+ Memberand MegaDork
5/25/22 10:23 p.m.

In reply to vwcorvette (Forum Supporter) :

RichardSIA Dork
5/25/22 11:01 p.m.

SVRA rules make it Group 5.

Going to read them later.

EDIT: 4/DM since it is a 2.5L six.

vwcorvette (Forum Supporter)
vwcorvette (Forum Supporter) GRM+ Memberand UberDork
5/26/22 8:30 p.m.

In reply to Stampie :

I agree. I did an autocross with it. Couldn't keep it straight ahead. The throttle pedal simply made it go sideways! That was on narrow vintage spec tires however. Haven't tried the new version.

Richard SIA, if you like I can see if Don can help answer some of your questions. He only runs vintage events (mostly with his 1959 Formula Junior OSCA) but has used the Ambro.

RichardSIA Dork
5/26/22 11:58 p.m.

Seems TR4 would be easier to fit into class but TR6 is what I have to work with.

If I cannot make this work out I suppose I could part out the engine, but I would keep the Arias forged pistons in any case for one of my other engines. 

Going to take a hard look at the possibility of moving the engine back for better weight balance, it's a bit on the heavy side for the power it makes.

Any insights may be helpful.


RichardSIA Dork
5/29/22 11:23 p.m.

Okay guys, I chickened out on using the super-trick flywheel/clutch combo on my street toy build. :(

Have not found the maker but it appears to be a very high quality piece in excellent condition.

Now posted to the for sale forum.


RichardSIA Dork
2/15/23 10:51 p.m.

Well, I am back into the Dio Tipo/TR6 build.
Got the crank re-polished and the head checked over.
Since I have to keep this as budget friendly as possible I will be using the aluminum flywheel and dual disc clutch this engine came with.
I am keeping a stock flywheel on hand in case the low mass setup is too hard  to use on the street.
I have most of the needed parts on hand, just need to order some bearings and rebuild a set of stock carbs since I do not have three matched DCOE 40's on hand.
Compression will be a little high but I am at over 4,000' and the car will be very light.
Plan is to make it a runner before fitting up the body.

clshore Reader
2/16/23 8:27 p.m.

You could always order a copper head gasket made in greater than stock thickness to reduce the Compression Ratio.

Not horribly expensive.


RichardSIA Dork
2/16/23 9:34 p.m.

Need to check my quench.
Too much promotes detonation.

RichardSIA Dork
3/20/23 1:05 a.m.

Got to work on the Dio Tipo a bit this week.

The best progress was getting the cylinders honed and the block/head painted.
I can actually begin assembly as soon as the bearing arrive.

The bummer was finding that my trick head is "Narrow Port" so I have to find a different intake.
But I did confirm that I have a good pair of Zenith's if I chicken out and just get a stock (To be port matched and ported) intake.
I would like to run triple HS6's. Much cheaper than Webers and still supports a vintage vibe while improving flow.
HS6 also has much more adjustment than the Zenith.

Also found that my custom oil pan has a built in crank scraper. Wish I knew who made it.
And the front cover has been modified to take the tach drive directly from the end of the cam.
Checked the rod bolts via part number , not ARP but 200 KSI which I think is a bit better than stock.
I may still get ARP if I can find them before May.


RichardSIA Dork
3/20/23 1:52 a.m.

Perused the SVRA rules again.
Mainly interested in their roll-bar requirements.
Seems simple enough and they really are what I would be doing anyway.
Original Ambro/Dio chassis design provides side impact beyond requirements.

Not certain where I would fall for classification, by displacement and type 4DM seems right but the TR6 chassis did not exist in 1960.
TR6 came out in 1968 as a 1969 model, and this one does use the early type head, body is Ambro/Dio Tipo so it may be a "Continuation" car.

I note that many of the Ambro's out there have strayed a long way from their TR origins, in some ways my car will be more authentic as it still has a Triumph engine and transmission.
The chassis and drive train I am using are from an unfinished So-Cal TR6 SCCA? effort that I think may have begun construction sometime in the late 70's or early 80's.
This body came to me loosely fitted to a TR4 chassis that featured the old school Blue-Streak treaded racing rubber.
As I see it this is just completing a long unfinished build with parts from a couple of sources. 
So I will try to build to SVRA rules and hope the car will be accepted for Track Days/Exhibition events even if not actual vintage racing.


RichardSIA Dork
3/20/23 12:17 p.m.

Response from SVRA.
I sent them the basic history and build details.

Hi Richard,

This sounds like an interesting build. This car may qualify as a continuation to run in Group 4 as a DM. It can certainly run with us in some group. Please continue your build and keep me abreast of the progress you are making. We will find a place to run the car.

A few  semi-local tracks have "Test and Tune" days for reasonable money as well.
So it will be able to see track time.

californiamilleghia UberDork
3/20/23 1:04 p.m.

where did the fiberglass body come from ?

and what wheelbase and  width is it set up for ?


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