Turbell
Well-Known Member
Right, I'm at the end of my tether with a British built 750 ( 4CV ) engine build, type 662 Ventoux
Collective input required,
This has been ongoing for a year, partly because of getting stuff from France ( which I wish I hadn't ) Covid and my engineer is a bit.....well hit and miss.
Story starts last summer when I finally agreed to rebuild this engine after we fetched it back from Renaults care nearly ten years ago after a long lone when it was used a promotional tool, I followed the owner back from Silverstone where the car was stored and it boiled all the way, absolute nightmare stopping and filling it with water every few miles, owner was gutted and we just wanted it back to Nottinghamshire and pull it apart, there were other issues with car that Renault paid to rectify with no quibble but it was obvious a full build was now required as it had only ever had a quick gasket rebuild sometime in the past.
I pulled it out last year and stripped it all finding sunk liners, wrecked bores, valves, guides mains and B/e's, the head was too far gone so I used a another from stock skimmed, new guides valves, springs rockers, block decked, crank ground, another flywheel and all balanced.....the idea being to build the best I could and this is when the fun started.
The owner bought new repro pistons and liner from France but only 1mm base seals are available, these are copper, not paper as used on later Renaults.
I struggled getting the liner protrusion with the max 0.15mm protrusion across the block, having to dig some old stock ones out slightly thinner and use these in pots 1 and 2, it was still touch and go depending where i measured, but was stuck between a rock and a hard place so went with it.
I used an old stock copper/asbestos gasket and directed by engineer as he rated them higher than modern.......I had other issues with the repro french stuff such as waterpump sandwich plates that were made to fit two versions that leaked due to slotted holes etc, each trip to the owners house putting things right, I was losing interest fast.
When I finally got it holding water and started it mayo'd up straight away, shut it down and pulled the head, gasket not sealing on block face, liners hadn't crushed down, meaning oil and waterways had made friends.
Pulled the lump and stripped it back home, OE liners have a raised pip around the base so they can crush into the copper base seal, new repro liners have a reduced base and a taper on whats left, meaning they aren't as forthcoming when it comes to biting into the copper base seal, it was obvious the heights being borderline high would not do.
So.....i took the block and liners back to my engineer, we agreed the best after some measurements to recut the liner seats in the block and deck it to get the heights to the 0.15mm max height using some 0.95mm base seals I found on Ebay.FR.........months past till i got it all back, everything else in my home workshop on hold, new bathroom nightmare fitted, what a job..
So a couple of weeks ago I built the minimum I could back up ( with a modern gen Renault HG fibre gasket ) to pressure test the assembly, blanked everything of, fitted a valve and put a bar of air in it, took about ten mins to go flat, found a leak, sorted that and now it held for about an hour, WD40 showed it leaking air by foaming on the HG seal head to block on exhaust side.
Tried it with water in and after four days it was weeping on joint.....all apart again.....liners had sat down to 0.10mm, so compressed 00.5mm, I had some 0.90mm seals when from same Ebay.FR source so decided to drop heights to 0.10mm ( which is only 0.02mm above min) and used a copper gasket again with some Stag well seal on faces, filled with water......FFS after four days it's weeping
I'm at the end of my tether with this fecker, lost all interest with this and anything else with wheels, garage is strewn with an engine in bits, a part stripped GS1000 I bought to keep me occupied i can't get started on ......
Sooooo........what do think?
The liners differ in design, and I'm well versed in over seas sellers ditching stuff on me cos I can't walk back into their shop and scream at them, but surely if the new set up with the heights at 0.10mm, and allowing for 0.05 of crush a 0.05mm liner height should work, otherwise I'm losing fire ring seal?
Should I run it up and hope it seals ?, engineer has offered a drum of seal you put in, run it and drain, or he says we can modify liners to OE spec one Saturday morning ( months pass if I leave stuff with him....) but then I'm into re-strip and another HG, and what height do I aim for then?, plus more new base seals.
I've left the sump off with a piece of white hardboard under it and no coolant drops down into it's guts.
I've built a few of these little Ventoux type engines without this drama, this is the most expensive, no expense spared build and it's the worst, to say I hate it, is an understatement, i haven't made a bean on this build, all I have had is broken dates and sleepless nights.
Any thoughts?
Please before I swing....
Collective input required,
This has been ongoing for a year, partly because of getting stuff from France ( which I wish I hadn't ) Covid and my engineer is a bit.....well hit and miss.
Story starts last summer when I finally agreed to rebuild this engine after we fetched it back from Renaults care nearly ten years ago after a long lone when it was used a promotional tool, I followed the owner back from Silverstone where the car was stored and it boiled all the way, absolute nightmare stopping and filling it with water every few miles, owner was gutted and we just wanted it back to Nottinghamshire and pull it apart, there were other issues with car that Renault paid to rectify with no quibble but it was obvious a full build was now required as it had only ever had a quick gasket rebuild sometime in the past.
I pulled it out last year and stripped it all finding sunk liners, wrecked bores, valves, guides mains and B/e's, the head was too far gone so I used a another from stock skimmed, new guides valves, springs rockers, block decked, crank ground, another flywheel and all balanced.....the idea being to build the best I could and this is when the fun started.
The owner bought new repro pistons and liner from France but only 1mm base seals are available, these are copper, not paper as used on later Renaults.
I struggled getting the liner protrusion with the max 0.15mm protrusion across the block, having to dig some old stock ones out slightly thinner and use these in pots 1 and 2, it was still touch and go depending where i measured, but was stuck between a rock and a hard place so went with it.
I used an old stock copper/asbestos gasket and directed by engineer as he rated them higher than modern.......I had other issues with the repro french stuff such as waterpump sandwich plates that were made to fit two versions that leaked due to slotted holes etc, each trip to the owners house putting things right, I was losing interest fast.
When I finally got it holding water and started it mayo'd up straight away, shut it down and pulled the head, gasket not sealing on block face, liners hadn't crushed down, meaning oil and waterways had made friends.
Pulled the lump and stripped it back home, OE liners have a raised pip around the base so they can crush into the copper base seal, new repro liners have a reduced base and a taper on whats left, meaning they aren't as forthcoming when it comes to biting into the copper base seal, it was obvious the heights being borderline high would not do.
So.....i took the block and liners back to my engineer, we agreed the best after some measurements to recut the liner seats in the block and deck it to get the heights to the 0.15mm max height using some 0.95mm base seals I found on Ebay.FR.........months past till i got it all back, everything else in my home workshop on hold, new bathroom nightmare fitted, what a job..
So a couple of weeks ago I built the minimum I could back up ( with a modern gen Renault HG fibre gasket ) to pressure test the assembly, blanked everything of, fitted a valve and put a bar of air in it, took about ten mins to go flat, found a leak, sorted that and now it held for about an hour, WD40 showed it leaking air by foaming on the HG seal head to block on exhaust side.
Tried it with water in and after four days it was weeping on joint.....all apart again.....liners had sat down to 0.10mm, so compressed 00.5mm, I had some 0.90mm seals when from same Ebay.FR source so decided to drop heights to 0.10mm ( which is only 0.02mm above min) and used a copper gasket again with some Stag well seal on faces, filled with water......FFS after four days it's weeping
I'm at the end of my tether with this fecker, lost all interest with this and anything else with wheels, garage is strewn with an engine in bits, a part stripped GS1000 I bought to keep me occupied i can't get started on ......
Sooooo........what do think?
The liners differ in design, and I'm well versed in over seas sellers ditching stuff on me cos I can't walk back into their shop and scream at them, but surely if the new set up with the heights at 0.10mm, and allowing for 0.05 of crush a 0.05mm liner height should work, otherwise I'm losing fire ring seal?
Should I run it up and hope it seals ?, engineer has offered a drum of seal you put in, run it and drain, or he says we can modify liners to OE spec one Saturday morning ( months pass if I leave stuff with him....) but then I'm into re-strip and another HG, and what height do I aim for then?, plus more new base seals.
I've left the sump off with a piece of white hardboard under it and no coolant drops down into it's guts.
I've built a few of these little Ventoux type engines without this drama, this is the most expensive, no expense spared build and it's the worst, to say I hate it, is an understatement, i haven't made a bean on this build, all I have had is broken dates and sleepless nights.
Any thoughts?
Please before I swing....
