Advice for Sprint engine rebuild.

[sprintchris]

Hi,

I'm in the process of a Sprint engine rebuild and would be very grateful for some tips and advice.
Currently the head is away being gas flowed and ported, it's also had an 8 thou skim to the face - am I ok to use a standard gasket with this?

Hopefully this week the block and crank are going to a specialist for rebore and regrind. Are there any particular running clearances to adhere to? Or is it stick to the Leyland factory manual and the engineering company to decide. When built it will have Kent fast road cam and 45 Delortos but road use only. The chap doing the head has chemically dipped the block and seems to think the bores at 116,000 miles aren't that bad, very glazed but little wear lip.

Also I see chain tensioners are a big issue, I'm ditching the Rolon one bought a long time ago, however I noticed the Renold one that was on there when stripped, and had been on since the early 80s when the head was removed has no dowel but a flat back with oil feed hole.

I have noticed looking around some have a locating dowel with oil feed, is this the best way to go? I'm imagining the oil seal and alignment would be better?? Also I'm aware these tensioners where fitted to many Leyland cars, and other makes but with all different part numbers. Does anyone have a list of vehicles that used the same tensioner as a Sprint?

If anyone who's been there and done all these things can advise it would be very much appreciated.

Thanks in advance,

Chris.

[gmsclassics]

I trust you got the company spending all your money on the head to do a hardness test (drop ball) across the head surface first and that it is okay? That level of skim is fine with standard Payen gasket, but is that all it has had taken off over its life? The important measure is from the head surface to the bottom of the semi-circular cut out (cam journal to mating face). The manufacturing tolerance for thickness of new heads was a minimum of 120.5mm. There are posts on here of people still using standard head gaskets with 2mm skimmed off (ie 118.5mm). Compression will go up and you'd need premium octane and perhaps even play with timing a little. I've used 3mm off on a race engine with high lift cam, but the piston cutouts had to be machined deeper and checked for contact by trial fitting. I doubt you'll be even close to any of that.

If you've picked a good specialist to do the block and crank, then they will know best so just explain what you are using it for and leave it to them (race and road are different). He will tell you if you can just hone and new rings or rebore with new pistons. Someone who knows their stuff will not rebore until he has the new pistons so each one will be individually matched.

There is a lot written here about chain tensioners, I think consensus is there is a Jag version that is the best substitute. Do a search and you should find it.

I suggest when finished you get the carbs jetted and tuned by an expert with the car on a dyno. A starting point is the jetting used on the Lotus 2.2L engine (I think in the Excel).

Geoff

[AlanH]

There is a lot written here about chain tensioners, I think consensus is there is a Jag version that is the best substitute. Do a search and you should find it.

Seen this one
http://www.ebay.co.uk/itm/Triumph-DOLOM ... Sw~oFXDj22

[Hobo]

Be very careful about where you get an alleged Part number C36617A Tensioner from, not all are what they seem to be packaged as...

Another choice I believe is Part number EAC3629 ( Jaguar ).

[SprintMWU773V]

Or try and find someone who has a dyno to test the engine before you fit it!

[xvivalve]

The problem is if you order under that Jag number from some suppliers, they will send you the inferior Rolon part that has superseded in their supply chain.

[mahony]

http://www.sngbarratt.com/ProductDetail ... dcb06&b=GB

[James467]

Get all your timing bits from Robsport, Simon will send you the correct quality tensioner.

https://www.robsport.co.uk/

TDC Members get a discount

[IncaDolly78]

Going directly on the Robsport website is cheaper than the eBay link above too for the same tensioner (numpty9 is Robsport's account on eBay), the different cost is something I only learned after ordering from eBay. Impulsive purchase while under the influence haha! I guess the difference in postage cost is to cover PayPal charges. Plus I didn't know about the members' discount until after I bought the tensioner. Oh well, I don't mind as I'd prefer to support Robsport than another supplier beginning with R!

[trackerjack]

Me too regarding Robsport, I buy all my stuff from him however I am rebuilding a sprint engine that had an as new Renold tensioner already fitted so have not bought one of his tensioners yet.

[sprintchris]

I trust you got the company spending all your money on the head to do a hardness test (drop ball) across the head surface first and that it is okay? That level of skim is fine with standard Payen gasket, but is that all it has had taken off over its life? The important measure is from the head surface to the bottom of the semi-circular cut out (cam journal to mating face). The manufacturing tolerance for thickness of new heads was a minimum of 120.5mm. There are posts on here of people still using standard head gaskets with 2mm skimmed off (ie 118.5mm). Compression will go up and you'd need premium octane and perhaps even play with timing a little. I've used 3mm off on a race engine with high lift cam, but the piston cutouts had to be machined deeper and checked for contact by trial fitting. I doubt you'll be even close to any of that.

If you've picked a good specialist to do the block and crank, then they will know best so just explain what you are using it for and leave it to them (race and road are different). He will tell you if you can just hone and new rings or rebore with new pistons. Someone who knows their stuff will not rebore until he has the new pistons so each one will be individually matched.

There is a lot written here about chain tensioners, I think consensus is there is a Jag version that is the best substitute. Do a search and you should find it.

I suggest when finished you get the carbs jetted and tuned by an expert with the car on a dyno. A starting point is the jetting used on the Lotus 2.2L engine (I think in the Excel).

Geoff

Hi Geoff,

Thanks for the info, I'm not sure if a hardness test was done or not.... However I did ask for a crack test, 8 thou has been skimmed, and I will check that measurement you explained about, I don't think it's been done before as I have the complete history of the car. I do know the timing cover was cracked around the crank sprocket area and do know it suffered some kind of failure in the early 80s so would need to read the receipts again! Apparently the head flows extremely well, and a lot better than the Lotus Cortina head this chap was doing too.
Regarding the tensioners, should the proper set up be with a dowel? Also, do you know of any issues with after market chain guides?

Best regards,

Chris.

[sprintchris]

There is a lot written here about chain tensioners, I think consensus is there is a Jag version that is the best substitute. Do a search and you should find it.

Seen this one
http://www.ebay.co.uk/itm/Triumph-DOLOM ... Sw~oFXDj22

Hi, thanks for that, I did see that, I wonder what brand it is?? I've a couple of new old stock tensioners, but not sure about the part numbers....they look identical to one that came off!

[xvivalve]

If you have old stock, look to see if it has 'ROLON' stamped into the side of the housing; if it has, put it in the bin!

[Mad Mart]

So is the one from the Jag site, that mahoney posted, the same as the one Robsport are selling? Only it seems a tad cheaper?

[mahony]

So is the one from the Jag site, that mahoney posted, the same as the one Robsport are selling? Only it seems a tad cheaper?

Im pretty sure it's the same as the one robsport sells Mart, the link i posted was from another topic on here regarding tensioners and was recommended, i ordered one and the quality looks very good, if you look at the bottom of the link i posted he does a cheaper one for £11.79 plus vat and another very expensive one at £187 plus the vat