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What did you do with your TR7/TR8 today?

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POW Peter Wirth
HEBRON, NH - New Hampshire, USA   USA
Bob and William
Thing is I don't feel like I have a problem any more. I've been chasing my tail for a few seasons now but always knowing when to stop. I've been through two other carbs, A Holley 600 CFM and an Edlebrock 500 CFM. Meticulously keeping notes on both until realizing both were at their tunability limits and not good enough for me. Both are too big. I have a friend who bought "the pre jetted and set up bolt on kit" for a 3.5. What a load of BS. Drivability stinks but once all the initial flats, hesitation, surging and general poor response is past the car finally picks up and runs OK...And he's happy with that. All carbs in the CFM that works for a 3.5 are limited in tunability by design. Drilling or filling air bleeds or opening PVCR is a whole other dimension in Holley tuning and that rabbit holes is full of expensive dead ends with or without an air/fuel meter. Just got back from a hundred or so mile run of mixed steady 75 MPH 5th gear interstate and 3rd - 4th gear back roads. A fill-up showed 21 MPG and at home a tail pipe check showed nothing in the way of deposits. I don't think I can do better than that. Oh, and no cats on mine to mask tail pipe color. Oh and Bob, Squirter is .25 and pump cam is white in position #2.

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parrisw William P
Victoria, BC, Canada   CAN
My old 7V8 had Holley 390 and it ran perfect.

Though now. My TR7 and TR8 are injected running megasquirt and highly modified.



Edited 1 time(s). Last edit at 2017-10-22 08:44 PM by parrisw.

davmach1 Avatar
davmach1 Dave Leininger
Andover, Minnesota, USA   USA
1980 Triumph TR8 "The 8"
The oversize carb issue is one reason I am sticking with the original carbs on mine. If I were to switch over I would rather have a 2bbl Rochester. I used this carb for years on my stock cars and you can't find a more reliable easy to find carb. I think if you could match up the CFM correctly it would do as good or better than any Holley. Never seen a 2 bbl manifold for a 3.5 though so I guess I'l stick with what I got.

DaveL

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kevphill Kevin Phillips
Oxford, Michigan, USA   USA
My wife and I put this heavy thing in the car today. There are many wires and hoses involved.
kp


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POW Peter Wirth
HEBRON, NH - New Hampshire, USA   USA
In reply to # 1493341 by davmach1 The oversize carb issue is one reason I am sticking with the original carbs on mine. If I were to switch over I would rather have a 2bbl Rochester. I used this carb for years on my stock cars and you can't find a more reliable easy to find carb. I think if you could match up the CFM correctly it would do as good or better than any Holley. Never seen a 2 bbl manifold for a 3.5 though so I guess I'l stick with what I got.

DaveL

The 390 isn't oversized for a stock or lightly massaged 3.5.but it's the only readily available one that isn't. I think the only 3.5 2 bbl manifold that will fit a 3.5 is an old stock Buick 215 c.i. and that had, I believe a Rochester carb. I'm not sure how easy it is to get both a manifold and carb though, and not sure if that package will fit under a Triumph's bonnet either. Though I'm happy with 390's behavior now, in hindsight, with the same modification I've done to my engine's mechanicals, higher compression pistons and a hotter cam, I believe I could have achieved similar performance with Zenith-Stomberg carburetors with less hassle and expense.

TR8todd Avatar
TR8todd Todd Kishbach
Mass, USA   USA
1977 Triumph TR7 "Rally Fraud"
1978 Triumph TR8
1979 Triumph TR7
1980 Triumph TR8    & more
The Buick 215 2 bbl manifolds are fairly common and unwanted. I have at least one and probably three or four of them if anybody wants one. Over the last couple of summers 5 or 6 Buick/Olds engines found there way into my garage and I can't bring myself to throw them away. The 2 bbl would make a good base for a blow thru turbo. Top looks relatively flat and thick. If one was inclined to do so, it appears that the manifold could be easily machined to accept any number of different bolt on adapters. Easily could be opened up for a 4 barrel, or just about anything else. I'd venture that there is at least one original 2 bbl carb out there as well.

racing1549 Avatar
racing1549 Brad Williams
Harrisonburg, Virginia, USA   USA
What size are they? . Wheels and tires?? Brad

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POW Peter Wirth
HEBRON, NH - New Hampshire, USA   USA
I know 2bbl's and 4bbl's are rated differently to arrive at their CFM rate and I have no idea what the original Rochester may have flowed, probably 320-340 CFM? So how that number compares to a 390 Holley I don't know. An interesting trouble shooting session last year, which turned out to be distributor caused actually, involved wiring the vacuum secondaries shut. Under full throttle I was getting carburetor back-fire consistently starting at 3000-3500 RPM, and surging along with lesser 'pop-backs' under lesser throttle but at the same RPM. With the secondaries inop the car still felt the same until the point when the secondaries would have opened. Here, obviously, the acceleration rate eased off a lot. I could not tell how much lazier the performance would be overall though because the carb back-firing was still there preventing me from keeping my foot in it. I'm assuming an original Buick manifold along with it's Rochester would feel similar. - Pete

Bergie Bob Berg
Powell, Ohio, USA   USA
pete ..classic lean carb condition causing backfire........

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POW Peter Wirth
HEBRON, NH - New Hampshire, USA   USA
In reply to # 1493448 by Bergie pete ..classic lean carb condition causing backfire........

Yes it can, and that's what I was chasing, but the issue proved to be a bad distributor cap. It wasn't cracked or otherwise tracking but the center carbon button had eroded flat and even with it's brass housing. On further investigation I found the TR8 'expert' ( we know who that may be, Todd) who made up the wires failed capture the actual wire core in the terminals of 3 the wires plus the coil wire. I think the ignition had enough energy to initially jump this gap and actually fire all 8 plugs but I think the cost was a rapidly eroding center carbon button. Interestingly enough the cap terminals that where badly crimped were tarnished while the OK ones were still bright and shiny.

carltr7 Avatar
carltr7 carl g
halifax, ns, Canada   CAN
Today I started gathering up the bits for this winter's upgrades.

Definitely doing an Accord disc brake upgrade on the back, since the front one went so well.

And I've been reading about some of the MGB guys putting FWD GM 3.4 V6s into their cars (185bhp).
And since I already have a GM 2.8 V6 in mine(140bhp) ....
And a WC T5.
With a dual pocket bell housing.
And a megasquirt....
And a friend who's scrapping a 2004 grand am...

mwahahahahaaaaaaaaaacoughcoughcough

Darth V8R Avatar
Darth V8R Vance Navarrette
Beaverton, Oregon, USA   USA
1980 Triumph TR8 "Wedgie"
In reply to # 1493353 by kevphill My wife and I put this heavy thing in the car today. There are many wires and hoses involved.
kp

Kevin:

Your wife helps you wrench on the car? OMG, I think I am in love! smiling bouncing smiley

Does she have a twin sister that's single?

Vance



1980 Platinum Metallic TR8, navy blue interior
Bare metal respray, Crower cam, raised compression
ported heads, modified Zenith carbs, 0.060" overbore

Darth V8R Avatar
Darth V8R Vance Navarrette
Beaverton, Oregon, USA   USA
1980 Triumph TR8 "Wedgie"
In reply to # 1493087 by POW In the on going battle to dial in my carb (Holley 390 CFM, list # 8007) I can say I am 95% there. That may well be where it'll stay. Could not get rid of an off idle flat spot no matter what combination of accelerator pump cams and squirters I used. I could make it worse OK, but never better. In addition there was a jerkiness while coasting down hill and at other times with light throttle often as not. Apparently I was chasing 2 problems but expecting one solution. On the recommendation of Holley tech I went up in main jet size from the original fitment of 51 to 54 then to 57. Off idle hesitation and between shifts went away but off throttle jerkiness remained. On a lark I disconnected vacuum advance and now that's gone too. Economy seems about the same so it's all good. Mallory magnetic pick-up distributor is all in at 3000 RPM with a crankshaft timing of 28°, so with my initial at 10° My total advance is 38°. My secondary metering plate has equivalent to 56 jets. That's smaller than my primary for sure. I may go up with the these.

POW:

Any chance the vacuum advance was connected to the wrong vacuum port on the carb? I am not familiar with the 390, but normally carbs come with several different ported and unported vacuum nipples, so it would be easy to get the dizzy hooked up to the wrong one. See it all the time on the TR6 - the vacuum pot on the distributor gets connected to some random nipple somewhere in the engine compartment. Makes for some weird symptoms.

Vance



1980 Platinum Metallic TR8, navy blue interior
Bare metal respray, Crower cam, raised compression
ported heads, modified Zenith carbs, 0.060" overbore

POW Peter Wirth
HEBRON, NH - New Hampshire, USA   USA
In reply to # 1494057 by Darth V8R

POW:

Any chance the vacuum advance was connected to the wrong vacuum port on the carb? I am not familiar with the 390, but normally carbs come with several different ported and unported vacuum nipples, so it would be easy to get the dizzy hooked up to the wrong one. See it all the time on the TR6 - the vacuum pot on the distributor gets connected to some random nipple somewhere in the engine compartment. Makes for some weird symptoms.

Vance

No, none at all. There is an ongoing battle on all the Chevy, Ford, Mopar, Hot Rod, etc,etc forums as to just where the vacuum advance should be connected with everyone absolutely, positively knowing that ported, in one camp, and full (manifold), in the other camp, is best. It's as bad as the infamous oil thread that pop up now and then. At any rate I was connected to ported vacuum (none @ idle) but now no vacuum advance at all. Sounds counter-intuitive for economy but has not effected it one bit. Interesting to me since you mentioned TR6's is that my '71 had a retard at idle but nothing for advance while my '70 TR6 had both.

TR3barton Avatar
TR3barton John Taylor
Greenfield, MA, USA   USA
Today on my DHC I removed both rear light housings and cleaned/polished same while replacing all the gaskets. I had the gaskets in stock for 2/3 years so it was about time to use them.

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