Buying a sprint engine

[Guest offroading.net]

Just found a sprint engine in a TR7 at a local scrappy, the car has had it but the engine looks okay.

Now as I will not be able to run it prior to buying it I will be doing a basic strip down and rebuilt (inc balancing and lightening it up). What bits should I deffo buy new for it?

My thinking at the mo is high pressure oil pump, water pump, rings, big end shells, new head gasget, valve oil seals.

Anything else I should do???

 

Also are there any bits I will need off the donor to fit in my TR7 (when I find one!)

 

cheers

 

Steve

[Andy Moltu]

The bit you have to hope for is the pistons/bores being OK as they are reputed to be very rare.

[BryanD]

Make sure you get the heater connection pipework - this has to be fabricated for a 16V conversion.  

 

Also the rocker pedestal threads into the head are usually stripped to some extent. Suggest you get these helicoiled while the head is off the car.

 

Ps - getting the water pump out is an absolute B****r.  The special tool sold for the job is useless too...

[CraigAddison]

As Andy says the pistons are as rare as rocking horse doo, so if these are in good condition, keep them, having said that the standard 2 litre TR7 pistons fit and are ok, there are surprisingly no clearance problems even with the standard thickness head gasket, I have been running mine for 2 years now with this set up and no problems to report. I would always replace the timing chain & tensioner, and carefully check the chain guides for wear, as it is bent valve time if anything slips (I've had this happen!!). The heads arent as much fuss and trouble as the cynics say, just be careful and ultra clean on the rebuild and use plenty of lube, do regular oil & filter changes (every 3-6K miles) once up and running and you should have no problems with it.

Not had a problem pulling a water pump out myself but have heard others having major difficulties. Not sure about the high pressure oil pump, don't even know if there is one available, I know there is or used to be a different relief spring available but never used it myself, I've run modded sprints on the standard pump with no probs, it's quite often the water pump that lets go under excessive revs.

[Guest JGG]

12 vane water pump and quality radiator and coolant are a must,lighten and balance only if you intend to race car,if not balance crank and match pistons and rods only,std oil pump is adequate.Contact Brian Kitley for sound advice,he is the best there is.

 

John

 

Ps to get the water pump out use a slide hammer.

[Guest dolomiteman]

12 vane water pump and ........ are a must

 

Why is a 12v pump a must? It puts more stress on the jackshaft and cavitates the coolant. It was thought a good idea for a while but then the works cars had a 12v with every other vane milled off fitted to get the best result. Contemporary thought is now the 6v is better than an unmodded 12v.

 

Sprintparts in NSW Australia supply o/s sprint pistons and ship to the UK very reasonably. To contradict an earlier thread Mark and Phil Larmour who run Sprintparts as an offshoot of their very successful racing campaign are more highly thought of in Dolomite circles than other 'specialists' who could be mentioned.

 

www.sprintparts.triumphowners.com.au

 

sprint@netspace.net.au

 

If you use TR7 pistons in a Sprint engine the valves will either form their own cutouts in the crown (!!) or if you use dished pistons they will cause lower compressions.

 

I would do a compression test off the starter, if OK, would then inspect the mains and big ends and then change the timing chain and tensioners checking the jackshaft/waterpump/dizzy drives for wear as I went, replacing the seals on the wp whilst its out (these are expensive finite items [incidentally exactly the same part as a TR7] so why oh why oh why do you guys continue to advocate changing them for no apparent reasons whatsoever??.

[simon]

I've got a rebuilt standard short block and spare heads as well as a tubular manifold if you need some spares.

[CraigAddison]

If you use TR7 pistons in a Sprint engine the valves will either form their own cutouts in the crown (!!) or if you use dished pistons they will cause lower compressions.

Must amit I haven't pulled the head off to check the pistons, but no problems & engine seems as quick as it should be, I'll have to get another head gasket & have a look for you!!

[CraigAddison]

Just remebered, I've got a 2litre block in my Dads garage, that had a sprint head on it, I'll have a look at the pistons, it covered 12000 miles before I stripped it, thought it was a crank problem, turned out to be loose timing gears, already bought a recon block, so used the new one, will reoprt back.