Im currently midway through the restoration of my 1978 sprint and whilst the engine is out am seriously contemplating having it rebuilt and having some cylinder head work done. Before the restoration I carried out a compression test to see what the general condition of the engine was, All readings were between 162-165 psi.
Is it worth having the engine rebuilt with compression test figures like this?
What would a rough estimate be for the cost of an engine rebuild with some cylinder head work (to accompany a piper ultimate road cam) be?
While its out I would maybe whip off the sump, clean it out and do the timing chain and tensioner and rear crank oil seal and maybe look at the
oil pump.
Otherwise it ain't broke so dont fix it. Standard cams are best for a road car and perfectly quick enough for modern use and economical too.
I stuck a trick cam in mine years ago and while its pretty quick its not that nice to drive in town traffic being a bit lumpy of idle and the cam does
make the head more noisy somehow. I only did it cos my cam had worn lobes.
If your engine ran nicely on a standard cam I'd leave well alone.
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.
I used Oselli some years ago for my Sprint cylinder head and later for a complete machining and balancing job on the MGB.
The best bit was the balancing . It made a BIG difference.
Try the link above for an idea of pricing. They are always busy so it may be sometime before you get your bits back though. You will get a very good job done though.
As Jonners says, the compression figures look O.K. but there is nothing like a complete dismantle and inspection on a restoration project for peace of mind.
HTH,
Tony.
No doubt someone would be delighted to take your money and rebuild it for you, but why go to the expense and bother?
Couple that with the poor quality parts currently on the market (search for threads about timing chain tensioner) and you could end up with a less reliable engine than you have now!
Nothing more annoying than have to take the engine out again after a resto. Take it apart, see what it is. Fresh new gaskets incl. head gasket. Do your waterpump.
There is a famous "Jeroen's half years" rule in Holland. From ALL the parts during a resto you have to think about for five minutes or more if it is ok, replace!! Whitin a half year after the resto these parts do break or leak or wathever and you still have to replace them. And most of the time replacing it was much easier and cheaper during the resto than afterwards. You are warned but don't live in Holland so i'm not sure this rule applies to you. But you can try....
The compression figures do tell there are indeed pistons and valves in the engine. Unfortunately nothing more.
It depends how far you want to go with your restoration, do you just want it back on the road so you can tinker with it after or are you going as far as me?
My Sprint engine rebuild has cost me around £2500 so far.
Thats for the parts (pistons, vandervell bearings, rings etc...), cleaning and vapour blasting the head, rebore, bottom end balance, rod balance (jig and scales), the head overhaul inc pressure test etc... water pump timing chain. The whole shebang! But I'll be assembling it, so I would imagine if you have someone else doing the work it would be more like £5k.
Add the carbs onto that and we are up close to £3k.
I got a quote from robsport about the cost of rebuilding my engine. To have a straight rebuild was £3,000. They showed me a rebuilt one and it looked fantastic. If you count up the man hours to get the engine looking as good as they have its probably worth it plus it would have guarantee with it. If you wanted it balanced they can do that for you as well but I didn't ask how much that was. I stopped him when he said 3 grand
I compression tested my engine and 1and 2 cylinders were 160 and the 3rd was absolute zero and 4 was 45 so may just get the head pressure tested first
The dolly sprint ,,it's a test of resilience and bank account
Mine's standard and we are expecting around 135 with standard carbs and cams on a well built unit.
170? Hmmm, I don't know what Marts one produces but I would have thought that's getting close to race or 'rally' territory. A few people on here will have a good opinion on this.
Off the top of my head though I'd budget rebuilding the carbs and jetting them properly, then electronic ignition and a rebuilt dizzy with new bushings. Most people forget about refurbishing and uprating the ancillaries as well.
Hot cam and pressure test and port match the head, new stems and machined valve faces. May need a skim but at the very least get it faced.
Bottom end, strip it, clean everything (cold carbon) if you don't need a rebore then a hone and balance, check the jackshaft bearing wear. Balance the rods using my method (thanks to Mart there! A lot of uk engine builders don't tend to do this), new bearings, rings, ARP Bolt set, maybe uprated oil pump and modified sump, timing chain and the correct Jag tensioner from Robsport, I'd say you'd be getting close to £5k.
Where are you based? I have used Roe Engineering for my machining and balancing work, they are based in Fleet, Hampshire, I'll be assembling though. There is Retro Engineering Ltd, but both Mark at Jigsaw and Simon at Robsport do know what they are doing.
