rebuild costs

[Raymond]

Thanks Geoff. I have bookmarked that link. A picture paints a thousand words.!

Sorry, but I won't be taking on another Range Rover. I have a 4.6 P38 as my daily driver. I run it on LPG (despite the warnings) and it is still nice but it's just one thing after another!

I used to have a 3 1/2 litre but it knew how to rust!

[David C]

Raymond - the easiest answer to your question about the cost of rebuilding a Bristol engine is economy of scale. It costs disproportionally more to produce small numbers of parts.

It is possible to rebuild a Bristol engine yourself on a budget. Parts such as pistons, bearing shells, cam followers, timing chain etc. are available from mass produced engines. These are not necessarily up to the original spec but would do good duty if the car isn't driven too hard. However, if you pay an engine builder they would not unreasonably expect to use the best parts to put together an engine they are proud to "own" as their work.

In some cases it may be possible to refresh an engine at modest cost but there is quite a lot of work involved in stripping the engine and assessing and testing all parts before starting a rebuild. This will have to be factored in to the rebuild price.

[Raymond]

Thank you for that David. It is useful to know that a time served fettler like me would be able to build a budget engine. I understand these had Brivadium (Brico alloy 30) dry liners; in which case they should be able to withstand very high mileages even if the pistons/rings need replacement. I presume (don't know for sure) if such a hard surface can even be rebored, or do new liners need to be pressed in? - and what about the problem of bedding in. I have seen some of these bores and they go smooth as glass !

I have read (somewhere in the distant past) that there is a tendency for the block to suffer from frost damage... but I don't know if they are any more susceptible than any other.?

I recently rebuilt a 1926 Dodge Brothers 3.5 litre side valve engine which had suffered from cracking across the valve seat. This was repaired by cast iron stitching. Very impressive. I repaired a frost crack in the water jacket with Belzona...any one here used either method?

[David C]

I need to qualify that there is a fair chance you could do a reasonably priced rebuild but you never know what you might find.
One of my engines had a broken rocker shaft, badly worn pistons and bores, pitted cam followers and a head that needed some welding. Some will advocate that all rocker shaft studs should be replaced with longer ones and the holes tapped full depth to reduce likelihood of the top of the castings breaking - which is what caused my rocker shaft to break.
Any significant corrosion on head studs and those affected should be replaced. Ensure all head nuts have good, thick, washers under them.
Another engine had a crack in one of the bearing caps. I was glad i had the block tested. I found a second hand replacement and had it line bored.
Another one had a crack in the water jacket where the oil /water heat exchanger ran on earlier engines. I had this stitched for a reasonable sum.
If your crank needs to be ground it will need re nitriding.

In short, you need to put in a few hours and get the parts thoroughly inspected before you know just how costly or not your rebuild will be.

Best of luck!

[Raymond]

Good morning David. I would be interested to know what you did about the worn bores in that engine.

NOT a Bristol... but I have found on more than one engine the previous owner had replaced the pistons with new STD but failed to attend to badly worn bores. I found it cheaper to install new liners and bore out to take the pistons. In the worst case the engine would start and tick over but lacked power. The guy had even tried to hide this by removing the clutch pedal and so prevent the car from being test driven!

[David C]

I went for bust on that engine and fitted new liners and Mahle pistons. By no means the cheapest option but I sorted it in the early eighties and it's still going strong now.

Oversize liners can be fitted with the Brivadium liners. Dependent upon the state of your head and how much it has been skimmed you will have to choose a suitable piston to correct compression ratio. One of the options discussed years ago was from MG TD but there must be a few options at 66MM. Slight variation in gudgeon pin diameter can be accommodated by fitting new small end bearings.

[Raymond]

David. I think new liners are the way to go. I don't have access to anything which will even look at Brivadium!

Regards the MG engine; I have recently done an XPAG engine with liners + 0.060". The (idiot) p.o. on that one had been running it without even changing the original pre1960 oil filter. The consequences were all too inevitable...