Dolomite based Robin Hood Kit Car
Dolomite based Robin Hood Kit Car
Hi
I have a Robin Hood based on the 2l Dolomite Sprint the slant 4 engine.
Bought it some years ago and in that time it's only done maybe a 100m. Wasn't completely happy with the build quality so put it in the garage where it was used by the wife as a shelf.
Anyway recently retired so looking for something to so do dragged it out the garage and was going to do it up.
Only thing now is that cylinders 3 and 4 don't seem to be performing. In that when pull leads off 3 and 4 it hardly splutters.
Hmm must be the carbs so set about tuning them up. Runs better but still not happy.
Today did a compression test and cylinders 1 to 3 read 175psi but cyl 4 only 75. Don't sound optimistic does it!!
Poured oil into cylinder, tried it again and the reading nearly went full scale.
In the absence of a leak test I'm guessing rings in 4.
What are the chances of pulling the head off, bearing in mind the head has been on there for 40 years. Advice from my local garage is the studs are likely to be seized and no chance.
Is there any chance of removing piston out the bottom end?
I am not 100% sure it didn't have this problem when I put it away.
Another problem I have is the thermostat housing has almost been eaten away and the narrow pipe up to the header tank was blocked and I would like to replace it as it's leaking. Can't get one from Rimmers anyone know where I can get one?
Would welcome any comments good or bad.
Cheers Al
I have a Robin Hood based on the 2l Dolomite Sprint the slant 4 engine.
Bought it some years ago and in that time it's only done maybe a 100m. Wasn't completely happy with the build quality so put it in the garage where it was used by the wife as a shelf.
Anyway recently retired so looking for something to so do dragged it out the garage and was going to do it up.
Only thing now is that cylinders 3 and 4 don't seem to be performing. In that when pull leads off 3 and 4 it hardly splutters.
Hmm must be the carbs so set about tuning them up. Runs better but still not happy.
Today did a compression test and cylinders 1 to 3 read 175psi but cyl 4 only 75. Don't sound optimistic does it!!
Poured oil into cylinder, tried it again and the reading nearly went full scale.
In the absence of a leak test I'm guessing rings in 4.
What are the chances of pulling the head off, bearing in mind the head has been on there for 40 years. Advice from my local garage is the studs are likely to be seized and no chance.
Is there any chance of removing piston out the bottom end?
I am not 100% sure it didn't have this problem when I put it away.
Another problem I have is the thermostat housing has almost been eaten away and the narrow pipe up to the header tank was blocked and I would like to replace it as it's leaking. Can't get one from Rimmers anyone know where I can get one?
Would welcome any comments good or bad.
Cheers Al
- xvivalve
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Re: Dolomite based Robin Hood Kit Car
Welcome, you have come to a good place.
Your garage has done the Sprint engine a disservice; many do! All 10 head studs and bolts on the Sprint are protected under the rocker cover, so there shouldn't be a problem. The 1850 and Stag are a different matter as one bank of fixings on each head on those cars are exposed and yes they can seize. I've only known one stubborn Sprint head and that had been critically overheated.
Your diagnosis sounds correct to me.
I can supply you with a good second hand thermostat housing; is your's early, ie with the outlet to the expansion tank arcing over other unions, or late, having a horizontal spigot to connect the expansion tank hose to?
Your garage has done the Sprint engine a disservice; many do! All 10 head studs and bolts on the Sprint are protected under the rocker cover, so there shouldn't be a problem. The 1850 and Stag are a different matter as one bank of fixings on each head on those cars are exposed and yes they can seize. I've only known one stubborn Sprint head and that had been critically overheated.
Your diagnosis sounds correct to me.
I can supply you with a good second hand thermostat housing; is your's early, ie with the outlet to the expansion tank arcing over other unions, or late, having a horizontal spigot to connect the expansion tank hose to?
- Mad Mart
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Re: Dolomite based Robin Hood Kit Car
Ditto what Alun said. I have stripped dozens of Sprint engines, some have been sitting for 20+ years. Never had a problem removing the head. No chance removing the pistons from below.
Sprintless for the first time in 35+ years.
... Still Sprintless.
Engines, Gearboxes, Overdrives etc. rebuilt. PM me.
2012 Porsche Boxster 981 S


Engines, Gearboxes, Overdrives etc. rebuilt. PM me.
2012 Porsche Boxster 981 S

- Toledo Man
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Re: Dolomite based Robin Hood Kit Car
Welcome to the forum. You have indeed come to the right place. There's a wealth of knowledge and experience on here. Get the head off first and then you will know better what the problem could be. It could just be the head gasket that has gone. It might be possible to remove the pistons with the block in situ but they would have to come out from the top. Whereabouts are you from? Maybe there's somebody local to you who can help.
Let us know how you get on.
Let us know how you get on.
Toledo Man
West Yorkshire Area Organiser
Meetings take place on the first Wednesday of the month at 8.00pm at The Railway, 1 Birstall Lane, Drighlington, Bradford, BD11 1JJ
2003 Volvo XC90 D5 SE (PX53 OVZ - The daily driver)
2009 Mercedes-Benz W204 C200 CDI Sport (BJ58 NCV - The 2nd car)
1991 Toyota Celica GT (J481 ONB - a project car)
Former stable of SAY 414M (1974 Toledo), GRH 244D (1966 1300fwd), CDB 324L (1973 1500fwd), GGN 573J (1971 1500fwd), DCP 625S (1977 Dolomite 1300) & LCG 367N (1975 Dolomite Sprint), NYE 751L (1972 Dolomite 1850 auto) plus 5 Acclaims and that's just the Triumphs!
Check my blog at http://triumphtoledo.blogspot.com
My YouTube Channel with a bit of Dolomite content.
"There is only one way to avoid criticsm: Do nothing, say nothing and BE nothing." Aristotle
West Yorkshire Area Organiser
Meetings take place on the first Wednesday of the month at 8.00pm at The Railway, 1 Birstall Lane, Drighlington, Bradford, BD11 1JJ
2003 Volvo XC90 D5 SE (PX53 OVZ - The daily driver)
2009 Mercedes-Benz W204 C200 CDI Sport (BJ58 NCV - The 2nd car)
1991 Toyota Celica GT (J481 ONB - a project car)
Former stable of SAY 414M (1974 Toledo), GRH 244D (1966 1300fwd), CDB 324L (1973 1500fwd), GGN 573J (1971 1500fwd), DCP 625S (1977 Dolomite 1300) & LCG 367N (1975 Dolomite Sprint), NYE 751L (1972 Dolomite 1850 auto) plus 5 Acclaims and that's just the Triumphs!
Check my blog at http://triumphtoledo.blogspot.com
My YouTube Channel with a bit of Dolomite content.
"There is only one way to avoid criticsm: Do nothing, say nothing and BE nothing." Aristotle
Re: Dolomite based Robin Hood Kit Car
Hi Guys
Thanks for the quick replies.
Great advice and given me the confidence to pull the head off for a look. Was a bit nervous as the thermostat housing bolts sheared like carrots.
Also thinking of changing the valve seats as she still runs on lead additive. Any idea what money might be looking at?
Xvivalve thanks for the offer the pipe up to the header tank is horizontal. If you have one to spare let me know how much and I will be glad to take it off your hands.
Was a bit shocked to find the header tank was full but the engine was almost empty.
The lads round at the garage are x BL and know them from the days when I had a Metro.
Thanks again for the help will keep you up dated as work progresses.
Cheers Al
Thanks for the quick replies.
Great advice and given me the confidence to pull the head off for a look. Was a bit nervous as the thermostat housing bolts sheared like carrots.
Also thinking of changing the valve seats as she still runs on lead additive. Any idea what money might be looking at?
Xvivalve thanks for the offer the pipe up to the header tank is horizontal. If you have one to spare let me know how much and I will be glad to take it off your hands.
Was a bit shocked to find the header tank was full but the engine was almost empty.
The lads round at the garage are x BL and know them from the days when I had a Metro.

Thanks again for the help will keep you up dated as work progresses.
Cheers Al
- Attachments
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- Thermostat Housing. The stub has rotted away
- thermostat housing.jpg (277.84 KiB) Viewed 3066 times
Last edited by Toledo Man on Sat Sep 12, 2015 12:59 pm, edited 1 time in total.
Reason: Resized the photo.
Reason: Resized the photo.
- xvivalve
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Re: Dolomite based Robin Hood Kit Car
You do not need to touch the valve seats, it is an aluminium head therefore already has hardened inserts. Just use unleaded with, if you choose, an octane booster.
Your thermostat housing doesn't look too bad? I have sent you a PM nevertheless...
Your thermostat housing doesn't look too bad? I have sent you a PM nevertheless...
- Toledo Man
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Re: Dolomite based Robin Hood Kit Car
Alun, I was going to say the same. You can use 98 RON unleaded which is the nearest modern equivalent to 4-star as an alternative to octane booster. It sounds like the guys at the garage knew these cars back in the day if they were ex-BL. Have you considered starting a thread in the resto section documenting your progress?
Let us know how you get on.
Let us know how you get on.
Toledo Man
West Yorkshire Area Organiser
Meetings take place on the first Wednesday of the month at 8.00pm at The Railway, 1 Birstall Lane, Drighlington, Bradford, BD11 1JJ
2003 Volvo XC90 D5 SE (PX53 OVZ - The daily driver)
2009 Mercedes-Benz W204 C200 CDI Sport (BJ58 NCV - The 2nd car)
1991 Toyota Celica GT (J481 ONB - a project car)
Former stable of SAY 414M (1974 Toledo), GRH 244D (1966 1300fwd), CDB 324L (1973 1500fwd), GGN 573J (1971 1500fwd), DCP 625S (1977 Dolomite 1300) & LCG 367N (1975 Dolomite Sprint), NYE 751L (1972 Dolomite 1850 auto) plus 5 Acclaims and that's just the Triumphs!
Check my blog at http://triumphtoledo.blogspot.com
My YouTube Channel with a bit of Dolomite content.
"There is only one way to avoid criticsm: Do nothing, say nothing and BE nothing." Aristotle
West Yorkshire Area Organiser
Meetings take place on the first Wednesday of the month at 8.00pm at The Railway, 1 Birstall Lane, Drighlington, Bradford, BD11 1JJ
2003 Volvo XC90 D5 SE (PX53 OVZ - The daily driver)
2009 Mercedes-Benz W204 C200 CDI Sport (BJ58 NCV - The 2nd car)
1991 Toyota Celica GT (J481 ONB - a project car)
Former stable of SAY 414M (1974 Toledo), GRH 244D (1966 1300fwd), CDB 324L (1973 1500fwd), GGN 573J (1971 1500fwd), DCP 625S (1977 Dolomite 1300) & LCG 367N (1975 Dolomite Sprint), NYE 751L (1972 Dolomite 1850 auto) plus 5 Acclaims and that's just the Triumphs!
Check my blog at http://triumphtoledo.blogspot.com
My YouTube Channel with a bit of Dolomite content.
"There is only one way to avoid criticsm: Do nothing, say nothing and BE nothing." Aristotle
Re: Dolomite based Robin Hood Kit Car
Thanks for the info about the fuel. Leaded was still being sold when I got the car and never raised the question.
Ok today rigged an airline to no4 plug hole and blew air down with the piston at top and could clearly hear air coming out the oil filler.
So that kinda confirms a problem with the rings.
Have left it with the exhaust manifold studs soaking in penetrating oil.
Also filled No4 with oil to let it soak the rings just in case it's a stuck ring.
Will post further as it develops.
Cheers Al
Ok today rigged an airline to no4 plug hole and blew air down with the piston at top and could clearly hear air coming out the oil filler.
So that kinda confirms a problem with the rings.
Have left it with the exhaust manifold studs soaking in penetrating oil.
Also filled No4 with oil to let it soak the rings just in case it's a stuck ring.
Will post further as it develops.
Cheers Al
- GrahamFountain
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Re: Dolomite based Robin Hood Kit Car
I've bust the rings in a couple of Sprint engines. Both times it was because of pinking: once the timing slipped badly going over Kidstone pass into Bishopdale; once I put ordinary unleaded in and though I'd get away wi' it, but didn't. In both cases the lands between the piston rings had also gone, so it was a set of four pistons and rings - not cheap, well not in Yorkshire any road. I think, in one case at least, there was a piston or two that wasn't obviously bust, but I slung 'em anyway - if they'd been strained that badly, they wouldn't be worth keeping.
If you can get the sump off (no idea what subframe/chassis the Robin Hood has), the pistons and rods will obviously come out through the top. However, in both cases, the garage that did mine fitted new shells without re-grinding the crank. And in both cases the bearings failed fairly soon thereafter - one a big end, the other a main bearing.
I've since been told that fitting new shells on an old crank, however carefully measured, etc., is really, really bad idea. somthing to do with "ovality" was one suggestion. I've also been told that if you put the old ones back exactly as they came out, that's ok. But I have never tested that theory.
I also agree that they're fine on super unleaded. I have run several of these engines for tens of thousands of miles on super unleaded, much of it from ASDA, and never seen any problems with valve seat resession. Had the valve springs go once, but I think that was to do with an over heavy right boot (I wear what my eldest daughter [14] calls "old man's shoes" these days, and the problem's never re-occured).
Graham
If you can get the sump off (no idea what subframe/chassis the Robin Hood has), the pistons and rods will obviously come out through the top. However, in both cases, the garage that did mine fitted new shells without re-grinding the crank. And in both cases the bearings failed fairly soon thereafter - one a big end, the other a main bearing.
I've since been told that fitting new shells on an old crank, however carefully measured, etc., is really, really bad idea. somthing to do with "ovality" was one suggestion. I've also been told that if you put the old ones back exactly as they came out, that's ok. But I have never tested that theory.
I also agree that they're fine on super unleaded. I have run several of these engines for tens of thousands of miles on super unleaded, much of it from ASDA, and never seen any problems with valve seat resession. Had the valve springs go once, but I think that was to do with an over heavy right boot (I wear what my eldest daughter [14] calls "old man's shoes" these days, and the problem's never re-occured).
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).
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).
Re: Dolomite based Robin Hood Kit Car
Well after a lot of swearing, bruised knuckles and copious amounts of tea got No,4 piston out.
Found the scraper ring had broken into 3 pieces and a chunk of the ring as well.
Had a look on a well known web site local to me and nearly had grabbing pains in the credit card area.
Anyone know where I can obtain piston and rings at a reasonable price?
Cheers Allan
Found the scraper ring had broken into 3 pieces and a chunk of the ring as well.
Had a look on a well known web site local to me and nearly had grabbing pains in the credit card area.
Anyone know where I can obtain piston and rings at a reasonable price?
Cheers Allan
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- piston and rings.jpg (234.85 KiB) Viewed 2953 times
Last edited by Toledo Man on Thu Sep 17, 2015 8:22 pm, edited 1 time in total.
Reason: Resized the photo.
Reason: Resized the photo.
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Re: Dolomite based Robin Hood Kit Car
When I've had a problem like this in the past I have gone down to the local engine re-con place with the pistons / crank and asked what they can do. They often have NOS bits in their stores or know where they can get them. They then grind the crank / supply bearings /fit rings to suit. I have some contacts in Berkshire if that helps; Near Reading. Is that local to you ?
Tony.
Tony.
- GrahamFountain
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Re: Dolomite based Robin Hood Kit Car
This thread may help: viewtopic.php?f=4&t=29390
But that's probably only the case if your replacing the set: I would consider replacing the set of Sprint pistons with a set of TR7 ones (with modified valve cut-outs for sure, if I was starting with new) - I have a history with Sprint pistons (there's a long sob-story about it somewhere), and have been worrying about this issue for a while. But even I wouldn't put one TR7 piston in with three sprint ones.
As to the question of whether you should replace just the one that's showing low compression or do the lot anyway: That, I think, depends on the cause.
If it was pinking, I would certainly think damned hard about the risk some or all of the other pistons are damaged, waiting for the lands to give and break the rings, about the effort in putting it all back together, and about then having to take it all apart to do the rest vs. the cost of three other pistons and doing them all while they're accessible. Indeed, if it was any cause other than a weak component, they've all been stressed nearly the same, or should have been. So I would worry, lots, that they are all suspect. Still, if you've more time and knuckle skin than cash, it may be worth the risk.
You could pull the others and look, though I don't know how reassuring a visual inspection that showed nowt would be. And their being out - or there being owt (to see) - would only make me feel more like putting new ones back.
Graham
But that's probably only the case if your replacing the set: I would consider replacing the set of Sprint pistons with a set of TR7 ones (with modified valve cut-outs for sure, if I was starting with new) - I have a history with Sprint pistons (there's a long sob-story about it somewhere), and have been worrying about this issue for a while. But even I wouldn't put one TR7 piston in with three sprint ones.
As to the question of whether you should replace just the one that's showing low compression or do the lot anyway: That, I think, depends on the cause.
If it was pinking, I would certainly think damned hard about the risk some or all of the other pistons are damaged, waiting for the lands to give and break the rings, about the effort in putting it all back together, and about then having to take it all apart to do the rest vs. the cost of three other pistons and doing them all while they're accessible. Indeed, if it was any cause other than a weak component, they've all been stressed nearly the same, or should have been. So I would worry, lots, that they are all suspect. Still, if you've more time and knuckle skin than cash, it may be worth the risk.
You could pull the others and look, though I don't know how reassuring a visual inspection that showed nowt would be. And their being out - or there being owt (to see) - would only make me feel more like putting new ones back.
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).
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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Re: Dolomite based Robin Hood Kit Car
I agree with Graham and would suggest that this is detonation related and the consequent imminent failure
of other pistons is pretty likely.
I certainly would be having them all out and VERY closely inspected at the very least.
Jonners
of other pistons is pretty likely.
I certainly would be having them all out and VERY closely inspected at the very least.
Jonners
Note from Admin: sadly Jon passed away in February 2018 but his humour and wealth of knowledge will be fondly remembered by all. RIP Jonners.
Re: Dolomite based Robin Hood Kit Car
Hi again
Now the part no. on the piston face is 1D19 S29A+.508. is this oversize?
Thanks for the advice. Will have the others out for a look but might struggle with replacements.
Cheers and thanks again for your help.
Now the part no. on the piston face is 1D19 S29A+.508. is this oversize?
Thanks for the advice. Will have the others out for a look but might struggle with replacements.
Cheers and thanks again for your help.
- xvivalve
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Re: Dolomite based Robin Hood Kit Car
It is 20 thou over sized.
I have known folk suffer detonation previously and replace just the damaged piston, and that is on regularly used cars too. You just need to match the weight and type. If you look up the skirt, you should see the maker's name...
I have a few odd s/h spare pistons, I'll see if I can match it for you...
I have known folk suffer detonation previously and replace just the damaged piston, and that is on regularly used cars too. You just need to match the weight and type. If you look up the skirt, you should see the maker's name...
I have a few odd s/h spare pistons, I'll see if I can match it for you...