sprint engine

[chilly]

Hi

 

After years of TR6 ownership I'm toying with the idea of getting a 7 but know very little about them. I've just discovered that the later ones had the dolomite sprint engine (or so the owner told me!). Is this motor preferable to the earlier engines or are they worse (told you I didn't know much)?

Any Pro's / cons would be appreciated.

 

Cheers

Chris

Edited December 3, 2008 by chilly

[chilly]

This is engine in question...

[Guest Wayne S]

Hi Chris,

 

TR7's never really came out of the factory with the Sprint conversion. There were a handful of prototypes made which fetch very big prices now and judging by this car I'd very much doubt this was one of them, (besides I might be right in saying the genuine Sprints were all fixed heads not convertibles like this?).

 

This car has obviously had many modifications, the door handles and bonnet support strut are different for a start so you need to make sure that these mods have been done with a good quality of workmanship and not botched halfords style. The Sprint lump will be an aftermarket conversion, so check the receipts and/or quality of the mechanics.

 

The Sprint engine is essentially the same bottom end as the standard TR7 2 litre, but with the more advanced engineered 16 vlave head instead. It come with many of the same problems associated with the standard slant 4 regarding overheating and water pumps but does have the improvement of a duplex (double thickness) timing chain for extra reliability on that front.

 

A properly tuned 16V dolomite engine is a great lump and in standard trim like that is capable of about 135BHP, about the same as a factory TR8. You will have much more scope for tuning up to 180+ with the addition of webers , flowed head etc so can be very pokey if tweaked. The engine is probably better in the 7 than it ever was in the dolomite sprint as its a lighter car with engine bay space for extractor manifolds and the like.

 

More important with this car is to check the usual things.

 

Rot - how are the sills and a-posts. Check the rear trailing arm mounts where they meet the back of the floor. Floorpans and in parlticular, the suspension turrets in the engine bay.

Engine - Coolant levels correct, coolant clean no oil etc. No mayonaise on the oil filler cap. No rattles form timing chain or bottom end.

Check the slot under the front carb on the engine block for any coolant weeps, this indicates a leaky water pump. Not a major issue but a good haggling point. Take it for a run and make sure it doesnt overheat etc all the usual stuff.

 

Dont worry if theres some wheel shimmy at 50 - 60 mph its a common and solvable problem on 7s. Also if when cold the gearbox is baulky into 2nd, its the old LT77 5 speed and it always suffers from this - it should be slick when warm though.

 

Hope that helps a little. If you dont end up buying it, then I know of a decent 2 litre grinnall for sale soon after it comes back from a respray to front nose cone

Edited December 3, 2008 by Wayne S

[chilly]

Hi Chris,

 

TR7's never really came out of the factory with the Sprint conversion. There were a handful of prototypes made which fetch very big prices now and judging by this car I'd very much doubt this was one of them, (besides I might be right in saying the genuine Sprints were all fixed heads not convertibles like this?).

 

This car has obviously had many modifications, the door handles and bonnet support strut are different for a start so you need to make sure that these mods have been done with a good quality of workmanship and not botched halfords style. The Sprint lump will be an aftermarket conversion, so check the receipts and/or quality of the mechanics.

 

The Sprint engine is essentially the same bottom end as the standard TR7 2 litre, but with the more advanced engineered 16 vlave head instead. It come with many of the same problems associated with the standard slant 4 regarding overheating and water pumps but does have the improvement of a duplex (double thickness) timing chain for extra reliability on that front.

 

A properly tuned 16V dolomite engine is a great lump and in standard trim like that is capable of about 135BHP, about the same as a factory TR8. You will have much more scope for tuning up to 180+ with the addition of webers , flowed head etc so can be very pokey if tweaked. The engine is probably better in the 7 than it ever was in the dolomite sprint as its a lighter car with engine bay space for extractor manifolds and the like.

 

More important with this car is to check the usual things.

 

Rot - how are the sills and a-posts. Check the rear trailing arm mounts where they meet the back of the floor. Floorpans and in parlticular, the suspension turrets in the engine bay.

Engine - Coolant levels correct, coolant clean no oil etc. No mayonaise on the oil filler cap. No rattles form timing chain or bottom end.

Check the slot under the front carb on the engine block for any coolant weeps, this indicates a leaky water pump. Not a major issue but a good haggling point. Take it for a run and make sure it doesnt overheat etc all the usual stuff.

 

Dont worry if theres some wheel shimmy at 50 - 60 mph its a common and solvable problem on 7s. Also if when cold the gearbox is baulky into 2nd, its the old LT77 5 speed and it always suffers from this - it should be slick when warm though.

 

Hope that helps a little. If you dont end up buying it, then I know of a decent 2 litre grinnall for sale soon after it comes back from a respray to front nose cone

 

Wow thanks Wayne. You found the other pictures then I noticed the door handles and wondered how well they'd been done. Did make me think that, with them and the recent(ish) non-standard paint, what else had been filled/painted over The gas strut could be a good improvement? Thanks for all advice, I will certainly check it out properly.

Got any pics of the Grinnall

[Guest Wayne S]

Hi Chris,

 

My car is currently being resprayed at the front end to remove some of the stone chips and bubbles it had sustained in everyday use, but as soon as its finished it may well go on sale again.

 

Pictures are here http://www.djwaynes.com/tr7forsale/tr7.htm

[Alec Pringle]

Hi Chilly,

 

if you're in the market for an interesting TR7 you could do a lot worse than look at Wayne's Grinnall. It's one heck of a nice car, and there are very very few 2 litre Grinnalls around now - most were V8s.

 

Rather more exclusive than the relatively common Sprint conversions, too many of which have not been adequately upgraded to cope with the power of the 16 valve engine.

 

Incidentally, the 16 valve is a great engine when it's going well, but it doesn't have the reliability of the 8 valve 2 litre or the V8, and it's often regarded as the most expensive and difficult to rebuild.

 

Cheers,

 

Alec

[Andy Brady]

Hi Chilly,

 

if you're in the market for an interesting TR7 you could do a lot worse than look at Wayne's Grinnall. It's one heck of a nice car, and there are very very few 2 litre Grinnalls around now - most were V8s.

 

Rather more exclusive than the relatively common Sprint conversions, too many of which have not been adequately upgraded to cope with the power of the 16 valve engine.

 

Incidentally, the 16 valve is a great engine when it's going well, but it doesn't have the reliability of the 8 valve 2 litre or the V8, and it's often regarded as the most expensive and difficult to rebuild.

 

Cheers,

 

Alec

 

 

Indeed Alec,

 

I ran a Sprint for many years.

 

When they're good, they're very, very good, but when they're bad you want to reach for a box of matches.

 

They need very careful assembly and very regular and thorough maintenance, let it slip and you will get bitten badly. I did get my 2nd engine to run very reliably with help from Broadspeed and HRS.

 

The tolerences from the factory were truly aweful. Anything from 120-135hp depending on how the tolerences fell. A well put together engine with matched and smoothed ports and manifolds, (steps of 1/16-1/8" were commonplace), electronic ignition and well set up carbs was good for 150. Cooling was always problematic on a Sprint, the 12 vane pump certainly helped.

Edited December 26, 2008 by Andy Brady