TR7 Sprint conversion - engine rebuild help

moodyblue · Postby **moodyblue** » 27 Apr 2014 11:20

Sprint engine rebuild - year 14-take 2.
Following a search on this site, I found an old post which suggests that you should use the Sprint flywheel as its lighter. The Roger Williams book (How to Improve Triumph TR7) states that the TR7 flywheel should be used, although the author doesnâ€™t tell us why. Would it not be better to use the one that was factory fitted, and balanced, to the Sprint engine? And if itâ€™s also lighter, then it would be a simple choice.
Using a lathe Iâ€™ve skimmed the flywheel, just to remove some corrosion/pitting although it would probably have been fine and cleaned up in use. However, this engine rebuild has taken so long that Iâ€™m not 100% sure if this flywheel came off the Sprint or the TR7; does anyone know how to tell them apart? I also have the same problem with the crank pulley.
Weâ€™re also told to use the TR7 oil pick-up, but I couldnâ€™t spot any difference between the oil pick-up for the Sprint and the TR7 which have the same part number (156859).
Any advice would be appreciated as Iâ€™d like to get this engine rebuilt this decade.

Graham.Fountain · Postby **Graham.Fountain** » 27 Apr 2014 11:43

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by moodyblue
I also have the same problem with the crank pulley.
<hr height="1" noshade id="quote"></blockquote id="quote">

The problem with the crank pulley is only that you can't match the pulley and timing quadrant on the block from the two cars. So unless you know which quadrant you have, it probaly doesn't matter if you don't know which pulley it is.[:)]

I would recommend the TR7 pulley and plate, as they're easier to see.

TR7 Sprint VVC 697S (some of)
TR7 DHC Sprint A TR7 16V (fake, rusty):
B&Y '73 Doly Sprint (kids!)

moodyblue · Postby **moodyblue** » 27 Apr 2014 14:31

Thanks for the info Graham, I'll mix and match to see which quadrant and pulley fit together best. I would think it would be clear to see if it's wrong.

jeffremj · Postby **jeffremj** » 27 Apr 2014 15:59

<blockquote id="quote">quote:<hr height="1" noshade id="quote">I would recommend the TR7 pulley and plate, as they're easier to see.<hr height="1" noshade id="quote"></blockquote id="quote">From my old website:

http://mjjfar.servehttp.com/triumph/geocities/16vconv.htm

it says that the TR7 and 16V pulleys are different. As the timing chain is duplex, I am not surprised - although I can't do a physical check. Note that all 3 pulleys (Dolly Sprint, 1850 and the TR7) have different part numbers. At an educated guess, I would imagine that the 8V pulley will stick out further by the extra thickness of the 16V crankshaft sprocket. You would then have to adjust the position of the alternator so that the 'fan' belt is aligned. If you definitely have both, then the difference should be apparent.

As regards the flywheel, I used the TR7 version. There are very few differences between the all 3 versions, indeed the 1850 and 16V are the same except for the clutch locating pins - the TR7 shares the 16V items. My guess is that clutch locating pin positions would be the only differences (if any) between the TR7 and 16V.

Graham.Fountain · Postby **Graham.Fountain** » 27 Apr 2014 18:59

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by moodyblueI would think it would be clear to see if it's wrong.<hr height="1" noshade id="quote"></blockquote id="quote">
If you check if the indicated TDC timing is actually at TDC it will.

It's been some (20+) years, but, as I remember, they both fit. But if you mix the two sets, the timing is way, way off. Other than that, I don't remember any other difference. I don't think the timing cover actually makes a difference, despite being deeper, as pointed out, for the duplex chain. If it did, the fan would be further forward on a TR7 Sprint, and it's not - neither factory built nor homebrewed. And if the fan pulley's no further forward, the crank pulley better hadn't be, either.

WRT flywheel, I looked on Rimmer's website. They list the doly sprint and TR7 flywheel under the same part number TKC411. Mind you, they still list inlet rocker arms for the Sprint engine!

Graham.

TR7 Sprint VVC 697S (some of)
TR7 DHC Sprint A TR7 16V (fake, rusty):
B&Y '73 Doly Sprint (kids!)

moodyblue · Postby **moodyblue** » 27 Apr 2014 20:06

Thanks guys, I remember having to make a spacer plate between the fan pulley and the timing cover on my 8v engine so it would lign up with the crank pulley, so now I know that I mixed some of the parts up, but it runs very well. I've been doing 30 miles a day for the past 7 months with no issues other than having to undo pointless upgrades to the suspension and steering. As for the flywheel I removed the locating pins prior to skimming the whole face, I think it's the Sprint one so I'll probably fit that one.

jeffremj · Postby **jeffremj** » 27 Apr 2014 20:13

<blockquote id="quote">quote:<hr height="1" noshade id="quote">It's been some (20+) years, <hr height="1" noshade id="quote"></blockquote id="quote">Same here.<blockquote id="quote">quote:<hr height="1" noshade id="quote">
but, as I remember, they both fit. But if you mix the two sets, the timing is way, way off. Other than that, I don't remember any other difference. I don't think the timing cover actually makes a difference, despite being deeper, as pointed out, for the duplex chain. If it did, the fan would be further forward on a TR7 Sprint, and it's not - neither factory built nor homebrewed. And if the fan pulley's no further forward, the crank pulley better hadn't be, either.<hr height="1" noshade id="quote"></blockquote id="quote">But the thing is that the 16V fan pulley is 'closer' to the timing cover than the TR7's. Precisely why you need the 16V pulley. If you use the TR7 pulley it will be further out by the extra width of the sprocket, but this might be OK if you are using the TR7 fan system - you will then have to move forward the alternator. Note that I only used kenlowe fans. I have done a quick measure, and both the TR7 and 16V pulley are 6cm out from the sump - thus the 16V pulley is shorter than the TR7's.
<blockquote id="quote">quote:<hr height="1" noshade id="quote">WRT flywheel, I looked on Rimmer's website. They list the dolly sprint and TR7 flywheel under the same part number TKC411. <hr height="1" noshade id="quote"></blockquote id="quote">I look at my 1978 Dolomite parts list and TR7 parts list for my details.

Here are some pictures of the pulleys and timing positions

TR7

16V

moodyblue · Postby **moodyblue** » 27 Apr 2014 20:31

Thanks, for the pics. I'll measure next week and see what's what. I have to remove the pulley off the Sprint engine in any case as the timing chain is too tight so I'll find out for sure then. I'll also compare flywheels to see if I can spot the difference, now that they are both cleaned up.

dursleyman · Postby **dursleyman** » 28 Apr 2014 14:16

Just compared a Sprint pulley against the standard TR7 one. The TR7 one is approx 1/4" longer than the Sprint to take account of the extra width of the twin-row Sprint chain sprocket.

Russ

1980 TR7 Sprint DHC, 1981 TR7 Sprint DHC
Dursley
UK

http://tr7russ.blogspot.co.uk/

[img]http://i1040.photobucket.com/albums/b410/dursleyman/TR7%20web%20picture/IMG_0479-Optimized.jpg[img]

Graham.Fountain · Postby **Graham.Fountain** » 28 Apr 2014 15:18

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by jeffremjBut the thing is that the 16V fan pulley is 'closer' to the timing cover than the TR7's.<hr height="1" noshade id="quote"></blockquote id="quote">
But the thing is that's offset by the sprint timing cover being deeper.

The question is, what's the offset between the end of the crank (which is def. in the same place for both) and the line of the belt. Looking at the pics, it looks the same to me, though I admit it's a bit hard to see.

But my current 7 Sprint, ATR 716V, has got a quadrant the same as my early (73) doly sprint and a 7's fan. And ATR's is truly shit to see when timing up (the doly's not better). I'm only guessing that it's a doly quadrant means it's necessarily a doly pulley too. But...

Don't know if you can use a doly fan assembly in a 7 sprint - never tried.

Graham

TR7 Sprint VVC 697S (some of)
TR7 DHC Sprint A TR7 16V (fake, rusty):
B&Y '73 Doly Sprint (kids!)

Graham.Fountain · Postby **Graham.Fountain** » 28 Apr 2014 16:44

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by dursleyman

The TR7 one is approx 1/4" longer than the Sprint...<hr height="1" noshade id="quote"></blockquote id="quote">
Okay, but if the offset between the end of the crank and the line of the belt is right, it's an easy fix to machine 1/4" of the chainwheel end. It may be possible that the "TR7" one I compared to was already so modded, and may even have been the factory TR7 Sprint one. If so, that make another unique part to the factory sprints.

However, I stand by saying the doly quadrant is in a B.S. place. Even the doly forum's Jon (If I haven't done it in or to a dolomite, I know somebody who has...) Tilson admits I'm "right about the difficulty with seeing the timing". So if you've the wherewithal to lop a bit off the end, and a pulley to spare, I would do it, if I were you.

I suppose the alt. would be to mark the Sprint pully with a TDC mark the same as the TR7's, and use the 7's quadrant. Might be easier.

TR7 Sprint VVC 697S (some of)
TR7 DHC Sprint A TR7 16V (fake, rusty):
B&Y '73 Doly Sprint (kids!)

jeffremj · Postby **jeffremj** » 28 Apr 2014 18:38

I don't understand the problem. Here is a picture where you can see the timing mark from 10ft or so!! Another reason for an electric fan:

moodyblue · Postby **moodyblue** » 28 Apr 2014 19:19

Strange, with the deeper timing cover on the Sprint I would have thought that the Sprint pulley would be the long one.

Stag76 · Postby **Stag76** » 28 Apr 2014 19:43

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Strange, with the deeper timing cover on the Sprint I would have thought that the Sprint pulley would be the long one<hr height="1" noshade id="quote"></blockquote id="quote">

The Sprint has a wider sprocket (Dual Row) on the crankshaft, hence the narrower pulley.

TR7 Convertible
Sprint Motor
MegaSquirt EFI

moodyblue · Postby **moodyblue** » 28 Apr 2014 20:12

Yes, my poor brain on overload, thinking about my job and the restoration at the same time[:p]. It would be a narrower on the Sprint for obvious reasons. Thanks.

Anonymous

TR7 Sprint conversion - engine rebuild help

TR7 Sprint conversion - engine rebuild help

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