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PostPosted: Sat Jan 30, 2021 11:48 pm 
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Can anyone explain what the two machined grooves are designed to do on the crankshaft pulley of the 1850 Dolomite and the Dolomite Sprint engine. Each pulley is different but the grooves sit about where the front crankshaft seal runs on the two different engines.

On the Sprint engine which I am currently working on, the crankshaft seal needs replacing. I have removed the pulley and if you look very closely at the photo of this pulley you will see that there is a polish mark just outside the right hand groove which is about where the lip of the seal was running but as the lip wore I suspect it moved into the groove.

The polished centre between those two grooves was probably where the bulk of the outer seal face rubbed.

I shall fit a double lipped seal and position it slightly proud of the timing cover so that both lips of the seal run in that polished area.

That is unless somebody tells me that my thinking is all wrong and that those two grooves have a particular function.

Robert


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PostPosted: Sun Jan 31, 2021 8:47 am 
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Hi Robert,

Both of the grooves are due to wear. The whole of the surface should be smooth, that is polished.
You need to polish up the surface and reposition the seal or preferably find a better replacement.

BobM


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PostPosted: Sun Jan 31, 2021 9:29 am 
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If finding a new pulley is difficult, look at a Speedi-Sleeve to repair it with.


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PostPosted: Sun Jan 31, 2021 10:24 am 
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Option
1) Find a other pulley that’s hadn’t got wear marks.
2) Sprint Speed do a modified Pulley boss that takes a BMW dampened pulley.
3) weld up grooves and machined back smooth.
4) Machined down to remove grooves and fit a sleeve over the top.
5) Don’t fit the seal all the way home leaving it proud.
So the seal sits elsewhere on the pulley.


Personally I’ll go for either 1-3 or 4.

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2005 Mercedes C Class V6 Diesel Turbo Daily Driver.
1980 Dolomite Sprint with a touch of BLTS
Balanced Lightened and Tweaked 13B Rotary and SuperCharged.
Rebuilding the Sprint time taken so far, 111Hrs@15/12/2020

Member TDC no 0471

Project 13B Sprint now on hold.
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PostPosted: Sun Jan 31, 2021 2:54 pm 
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If you go for option 1, be careful of TR7 pully wheels. They fit the Sprint, but have the timing marks at a different position relative to the keyway. Though you can correct by fitting the TR7 timing quadrant to the front chain cover. I don't know what the situation with the 1850 is, but assume they are like the Sprint's.

Graham

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The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).


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PostPosted: Sun Jan 31, 2021 7:13 pm 
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Both Tr7 and 1850 crank pulleys are different to the Sprint one; they have a different length as the timing cover on a Sprint is deeper.


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PostPosted: Sun Jan 31, 2021 8:11 pm 
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Thanks for the comments, folk.

I shall fit a speedi sleeve and new seal for that will be the easiest and quickest option.

I had already noted that the TR7 and 1850 pulleys were different for I found a couple of those in my 'reluctant to scrap' bin and checked them out.

Robert


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PostPosted: Sun Jan 31, 2021 11:09 pm 
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Quote:
Both Tr7 and 1850 crank pulleys are different to the Sprint one; they have a different length as the timing cover on a Sprint is deeper.
There was a previous discussion on this: https://forum.triumphdolomite.co.uk/vie ... hp?t=34774

That discussion reminded me that there was also an issue with using the Dolomite Sprint pully on one of the fake the TR7 Sprints, that the pullies on the TR7 fan boss and otherwayup alternator mounting didn't line up well and it ate belts.

So I was wrong, and it's not just the timing quadrant that corrects.

Graham

_________________
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).


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PostPosted: Mon Feb 01, 2021 2:22 pm 
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Quote:

That discussion reminded me that there was also an issue with using the Dolomite Sprint pully on one of the fake the TR7 Sprints, that the pullies on the TR7 fan boss and otherwayup alternator mounting didn't line up well and it ate belts.

So I was wrong, and it's not just the timing quadrant that corrects.

Graham
I don't understand about the Sprint pulley issue, could you explain further please Graham?

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PostPosted: Mon Feb 01, 2021 6:50 pm 
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Quote:
Quote:

That discussion reminded me that there was also an issue with using the Dolomite Sprint pully on one of the fake the TR7 Sprints, that the pullies on the TR7 fan boss and otherwayup alternator mounting didn't line up well and it ate belts.

So I was wrong, and it's not just the timing quadrant that corrects.

Graham
I don't understand about the Sprint pulley issue, could you explain further please Graham?
As I said and you've confirmed, the timing marks on the Sprint and TR7 pullies are in different positions relative to the woodruff keyway, i.e. rotated round by different amounts relative to TDC #1. So, if you use the TR7 pully with the timing quadrant (the sawtooth thingy fixed to the chain cover) from the Dolomite Sprint and do the ignition timing, it will be well out. The same is true with the Dolomite Sprint pully and the TR7 timing quadrant - though the timing error will be the other way around.

Image

But, as both you and Alun pointed out, the lengths of the pully shanks are also different. And, from what's been written here and as I remember, you can fit the TR7 pully on the Sprint engine (with the TR7 quadrant), that upsets the alignment with the fan and alternator pullies. So, if that's true, it will eat fan belts. I'm not so certain you can use a Sprint pully on the TR7 and get a seal, but if you can, I think that may eat belts too.

Image

The TR7 Sprint is special, because it takes the TR7 fan and alternator and mountings, but the Dolomite Sprint chain cover. So, as the different chain covers do not move the fan and alternator pullies relative to the end of the crank, if the different crank pullies do move wheel forward and back relative to the end of the crank, it will need the TR7 pully and so the TR7 timing quadrant on the front of the chain cover.

I don't know anything about the 1850. So what's what there is a mystery to me.

_________________
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).


Last edited by GrahamFountain on Tue Feb 02, 2021 12:50 pm, edited 1 time in total.

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PostPosted: Tue Feb 02, 2021 8:46 am 
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Quote:
Quote:
I alway's found that an ideal situation. Machining an 1850 pulley to sprint size. A nice clean surface for the seal.

Jeroen

That sounds an excellent idea, but after Graham's comment I just compared the timing marks of an 8v pulley with a Sprint one and they are completely different. I couldn't dig out an 8v timing cover to compare them at the moment but it must be more than just the depth so I think Graham is correct.
Graham - Apologies for doubting you!

Jeroen - Do you make your own new timing mark?





Image
Having thought about this post from the other thread, I wonder if the TR7 Sprint has a 4th type of pully, which has the timing mark where the TR7's is, but the boss is shortened, as Jeroen suggested doing to an 1850 to fit it to the Sprint. In that way, it can use the TR7 timing quadrant, which is more visible with the TR7's different alternator mounting than the Dolomite one, and the pully will align with the fan and alternator pullies. I'll see what I can find out.

Graham

_________________
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).


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PostPosted: Wed Feb 03, 2021 1:34 pm 
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I am a bit confused by this, if you have to fit the duplex chain to fit a Sprint head to a TR7. How do you fit the pulley? Surely the Sprint crank must be different to take into account the greater depth of the Sprint timing chain cover? Meaning you have to change the crank to me it work, yet that doesn't appear to be the case.


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PostPosted: Wed Feb 03, 2021 3:53 pm 
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I am a bit confused by this, if you have to fit the duplex chain to fit a Sprint head to a TR7. How do you fit the pulley? Surely the Sprint crank must be different to take into account the greater depth of the Sprint timing chain cover? Meaning you have to change the crank to me it work, yet that doesn't appear to be the case.
No, the cranks are largely the same - the Sprint crank is cross drilled. So, the deeper duplex drive crank sprocket should move the TR7 pulley forward relative to the end of the crank, so there's less of the setscrew thread in the hole - but probably still enough to hold it. But the boss on the Sprint Pulley is shorter to compensate for the deeper sprocket. And while the chain cover is also different to allow for the duplex chain and drive, etc., if I remember correctly, the mountings for the fan boss and alternator are the same depth, i.e. stick out in front of the block by the same amount, on both covers.

I think that where I've used the TR7 pulley on the Sprint engine, and so the TR7 quadrant, that's been with an electric fan, and the alternator has been washererd forward a bit to line up enough. I admit I've wondered about why the alternator position needed adjustment now and again. But I usually use alternatives to the proper Lucas ones, and never thought of the crank pulley as the cause.

However, I haven't got a Sprint or a TR7 sprocket or either pulley to hand to compare, and I'm not exactly certain the TR7 and Sprint pulleys have the line of the belt the same distance from the end of the crank when used with the relevant cam chain sprocket. So I realize I'm making some assumptions in the above.

Graham

_________________
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).


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PostPosted: Wed Feb 03, 2021 10:02 pm 
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Early sprint cranckshafts are crossdrilled and with no effect as these bores are plugged. From mid 1974 all crankshafts are the same. All are interchangeable through the whole range and year of build.

Jeroen

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PostPosted: Thu Feb 04, 2021 3:31 pm 
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Quote:
Early sprint cranckshafts are crossdrilled and with no effect as these bores are plugged. From mid 1974 all crankshafts are the same. All are interchangeable through the whole range and year of build.

Jeroen
Is the cross drilling of the cranks really just cosmetic? I'm a little surprised no one has noted that before.

That it was only the early engines that had cross drilled cranks is interesting because the crank on my 1978 year model TR7 Sprint (engine number CG 62 HE) was cross drilled when it was first reconditioned. And I'm fairly sure it hadn't been touched internally from new. However, I believe a number of engine set parts for the TR7 Sprints were made well before the car was built, while there was still funding for the 16-valve slant-4 Triumph SD2 Dolomite replacement, which was cancelled in 1975.

However, as the TR7 Sprint engines - which have a TR7 block not a Dolomite Sprint one - were delivered for production at Canley and Speke as full sets, I wonder if their having cross drilled cranks mean the full engines were assembled much earlier and sat round till 1977, when the need for the TR7 Sprints to re-homologate the head for the Group-4 TR7 became obvious as the production of FHC TR8 homologation specials was getting delayed again and again.

Graham

_________________
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).


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