Ford Pre crossflow 1700cc ?
Discussion
I bought a 1500gt motor for my 105e, it had been rebuilt but never fitted, then sold to another guy, never fitted and he had it years until I bought it. So no known history.
My old school mechanic tested compression, very low, soaked in diesel and it came up on two but not on the other two, pulled the head and gasket had failed probably to be expected.
But he is telling me it is bored 90 thou and is 1700cc ? Is that possible?
My old school mechanic tested compression, very low, soaked in diesel and it came up on two but not on the other two, pulled the head and gasket had failed probably to be expected.
But he is telling me it is bored 90 thou and is 1700cc ? Is that possible?
anyoldcardave said:
I bought a 1500gt motor for my 105e, it had been rebuilt but never fitted, then sold to another guy, never fitted and he had it years until I bought it. So no known history.
My old school mechanic tested compression, very low, soaked in diesel and it came up on two but not on the other two, pulled the head and gasket had failed probably to be expected.
But he is telling me it is bored 90 thou and is 1700cc ? Is that possible?
If I understand this correctly, you bought a Mk.I Cortina 1500GT motor for your Ford Anglia 105e and it's down two pistons, so pulled the head off, and your mechanic is telling you that 90 thou overbore makes it into a 1700cc motor?My old school mechanic tested compression, very low, soaked in diesel and it came up on two but not on the other two, pulled the head and gasket had failed probably to be expected.
But he is telling me it is bored 90 thou and is 1700cc ? Is that possible?
No.
For it to be stretched out to 1700cc by boring it, the cylinders would have to be bored out to 86.27mm swept volume from the factory standard 80.96.
That's an overbore of 5.31mm to the cylinder.
90 thou is 2.286mm which would give a capacity of around 1583cc if that was really the overbore.
I would believe the latter capacity as it's more or less what Lotus took the Kent motor out to for the Lotus cortina (1580cc, twin-cam).
Not an expert though!
CraigyMc said:
If I understand this correctly, you bought a Mk.I Cortina 1500GT motor for your Ford Anglia 105e and it's down two pistons, so pulled the head off, and your mechanic is telling you that 90 thou overbore makes it into a 1700cc motor?
No.
For it to be stretched out to 1700cc by boring it, the cylinders would have to be bored out to 86.27mm swept volume from the factory standard 80.96.
That's an overbore of 5.31mm to the cylinder.
90 thou is 2.286mm which would give a capacity of around 1583cc if that was really the overbore.
I would believe the latter capacity as it's more or less what Lotus took the Kent motor out to for the Lotus cortina (1580cc, twin-cam).
Not an expert though!
That does seem excessive, which is why I asked the question, he is no techy, and neither am I, but he said he found the info on the net, but I cannot find it, No.
For it to be stretched out to 1700cc by boring it, the cylinders would have to be bored out to 86.27mm swept volume from the factory standard 80.96.
That's an overbore of 5.31mm to the cylinder.
90 thou is 2.286mm which would give a capacity of around 1583cc if that was really the overbore.
I would believe the latter capacity as it's more or less what Lotus took the Kent motor out to for the Lotus cortina (1580cc, twin-cam).
Not an expert though!
Makes little difference, it runs fine with a new head gasket, and revs well on the webber that was fitted to it, it could have been built 30 years ago, the guy I bought it from had it 15 years, and he bought it the same way as me, blind lol.
The only thing I can find is this, https://hpemotorsport.co.uk/kent-pre-xflow/, so 1700cc can be done, and 90thou is max rebore on a standard block.
Who knows, I am no expert either lol, but as I just wanted a 1500 I am happy.
Lotobear said:
The Lotus TC is a 1500 GT (pre crossflow) block bored out to 82.55mm to achieve 1558.
To achieve 1700 you will need the later 711m crossflow 'tall block'
That I have discovered is not true, 1700 can be achieved on a standard 1500 block, https://hpemotorsport.co.uk/kent-pre-xflow/.To achieve 1700 you will need the later 711m crossflow 'tall block'
This could be one of those for all I know lol, it has a big valve head, but he put a copper head gasket on it, and put it back together and it runs fine, but def is not standard. Not taking apart again.
anyoldcardave said:
Lotobear said:
The Lotus TC is a 1500 GT (pre crossflow) block bored out to 82.55mm to achieve 1558.
To achieve 1700 you will need the later 711m crossflow 'tall block'
That I have discovered is not true, 1700 can be achieved on a standard 1500 block, https://hpemotorsport.co.uk/kent-pre-xflow/.To achieve 1700 you will need the later 711m crossflow 'tall block'
This could be one of those for all I know lol, it has a big valve head, but he put a copper head gasket on it, and put it back together and it runs fine, but def is not standard. Not taking apart again.
CraigyMc said:
That'll be bored and stroked though, not just bored, surely?
Probably yes, the mechanic is old school ford and a MK1 Cortina nut, why he was given the job, he took the head off, measured things and said it was 1700, never heard of such a thing so did some research and only came up with the HPE link and asked the question here. It was bought as a rebuilt 1500gt, with some other parts, that the guy bought years ago, from another guy in South London, that had it built and never used it, apparently he had it some years before selling it, I think we are talking over 20 years since it was built.
It came fitted with a webber twin choke, 38dgas I think from memory, will have to check, runs fine on it. I prefer to leave it rather than run twins, it was only supposed to be a yard van, runaround and a bit of fun.
It is an estate, on all original panels, sills, floors, inner wings, strut tops, rear arches and spring hangers, had a bit on one out rigger and one seat belt mount, and a fillet on the sill centre under drivers door.
One strange thing with it though, it had obviously not been used once the head was off, all the valves were new, except one exhaust that was pitted, now replaced with new, strange but true lol.
guess will never know what exactly the engine is without stripping it down, and it is sorted and running now, happy with that when you buy one you cannot hear running.
anyoldcardave said:
CraigyMc said:
That'll be bored and stroked though, not just bored, surely?
Probably yes, the mechanic is old school ford and a MK1 Cortina nut, why he was given the job, he took the head off, measured things and said it was 1700, never heard of such a thing so did some research and only came up with the HPE link and asked the question here. It was bought as a rebuilt 1500gt, with some other parts, that the guy bought years ago, from another guy in South London, that had it built and never used it, apparently he had it some years before selling it, I think we are talking over 20 years since it was built.
It came fitted with a webber twin choke, 38dgas I think from memory, will have to check, runs fine on it. I prefer to leave it rather than run twins, it was only supposed to be a yard van, runaround and a bit of fun.
It is an estate, on all original panels, sills, floors, inner wings, strut tops, rear arches and spring hangers, had a bit on one out rigger and one seat belt mount, and a fillet on the sill centre under drivers door.
One strange thing with it though, it had obviously not been used once the head was off, all the valves were new, except one exhaust that was pitted, now replaced with new, strange but true lol.
guess will never know what exactly the engine is without stripping it down, and it is sorted and running now, happy with that when you buy one you cannot hear running.
From memory I recall his reputation as being somewhere around God level, so if you're looking for info he's probably authoritative.
DVA: are you still doing Robin Hoods?
CraigyMc said:
The guy who posted just above (DVA) probably doesn't remember me, but he did work for me on a Rover K-series head (for an elise) nearly 20 years ago.
From memory I recall his reputation as being somewhere around God level, so if you're looking for info he's probably authoritative.
DVA: are you still doing Robin Hoods?
He's a top man is Dave Andrews, he did a 1.4ss to 1.8ss conversion on my Caterham around 20 years ago too - and he won't remember me either!From memory I recall his reputation as being somewhere around God level, so if you're looking for info he's probably authoritative.
DVA: are you still doing Robin Hoods?
DVandrews said:
Hello Chaps,
Haven’t worked on a RH for some time, my own Cosworth powered one went a good few years ago. Still doing a lot of K series engines though. If your full names were in the postings it might have jogged my memory a little
.
Dave
You'd not remember me personally anyway as we didn't interact directly -- you'd have been dealing with Steve Butts; I was terrified of mistiming my engine through total incompetence so asked/begged him to do it on my car, which he did for not much money. Nice chap.Haven’t worked on a RH for some time, my own Cosworth powered one went a good few years ago. Still doing a lot of K series engines though. If your full names were in the postings it might have jogged my memory a little
.Dave
For my motor, you did what was asked for: a rough port on a standard K head that had suffered an HGF, so it was coming off anyway.
Steve fitted piper 270 camshafts and vernier cams to get it timed and kept it on the MEMs ECU.
From memory, I think the head was porous on the first install, we ended up taking it off again and having it sealed in Swindon then refitting it.
It worked fine afterwards, although with a slighty lumpy idle (I should have put an Emerald ECU on it to solve that).
I swore off having a road car with a Rover K when it didn't work initially after the rebuild, and didn't have another Lotus for 15 years (I now have one with the 3.5 V6 supercharged toyota motor). I wish I'd kept the rover K car now; I'd have rebuilt it as a track toy with a scholar-block 1.9 like Steve was using for Gurston at the time -- that car was fantastic.
All of this is from memory so forgive me if something doesn't make sense in there.
Also sorry for the thread drift chaps.
Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff