Xflow forged piston advice

[Painter an]

Hi guys. Right i have just got some second hand forged pistons the correct size to replace the 1300 ones i have in my 1700 they already have machined cut outs for a 244 cam i want to know what else i would need to swap over.my engine as only done few hundred miles since rebuilt last year.spec is 1700 polished ballanced crank.lightened flywheel.244 cam new big end and main bearings.new rings stage 4 race head with biggest valves possible twin duplex chain.steal rocker gear.will i need steal rods or just arp bolts.im aiming to fit twin 45s as running twin 40s at min so i am looking to get 150+ bhp any advice please.cheers

[HonkyWhiteTrash]

Are you sure the pistons are a straight swap? Forged pistons for 1700cc's are 83.5mm, cast crossflow pistons that most people refer to as 1700 are +090" which is actually 83.26mm and gives approx 1690cc's depending on accuracy of piston size and crank stroke. This difference in piston skirt size will give around 0.010" or 0.236mm difference in bore sizes.

[Painter an]

Are you sure the pistons are a straight swap? Forged pistons for 1700cc's are 83.5mm, cast crossflow pistons that most people refer to as 1700 are +090" which is actually 83.26mm and gives approx 1690cc's depending on accuracy of piston size and crank stroke. This difference in piston skirt size will give around 0.010" or 0.236mm difference in bore sizes.

Yes these are 83.5 so on that info looks like il need to get bit extra bored? Cheers

[Graham]

bore clearance is different between forged and cast anyway, so even if the bore size was the same, they would need honing out slightly bigger to suit the forged

[Painter an]

Thanks what other items will be needed/advised

[Graham]

can i ask, what the car is and what your using it for?

[Painter an]

can i ask, what the car is and what your using it for?

Show winning mk2 escort mexico rd use only but you know what its like never satisfied.

[Graham]

the thing is if its for road use only tuning it further will make it a pretty poor thing to use on the road, x/f's dont make much torque at the best of times ones which make 150 plus bhp make NO torque below about 5000rpm, unless you got a 4.1 or 4.4 diff and close ratio gearbox on the road it will actually be SLOWER unless your right at the top of the rev range. if you want more grunt, find an AX block and build an 1800, or better still AX block and a stroker crank

[Painter an]

Thanks thats fair enough but wouldnt it be a better engine with forged rather than cheaper option of 1300 pistons.

[carlos77744]

Thanks thats fair enough but wouldnt it be a better engine with forged rather than cheaper option of 1300 pistons.

A mk2 mex had a pinto installed they where flat as a fart but with a decent cam and carbs they go for ever and drive decent
I have a crossflow in my mk1 mex only reason I'd go forged pistons if I could afford them to get decent top rings mine go after 5000 miles on the 1300 pistons .

Sent from my SM-G900F using Tapatalk

[mk2 13sport]

Show winning mk2 escort mexico rd use only but you know what its like never satisfied.

16 pinto in a Mk2 mex not a 16 xflow ?

[Painter an]

16 pinto in a Mk2 mex not a 16 xflow ?

When i say show winning i mran condition/finish. Not originality for concours etc as i know should have pinto

[Graham]

Thanks thats fair enough but wouldnt it be a better engine with forged rather than cheaper option of 1300 pistons.

yes and no, stronger yes, if you keep the same cam you would defiantly want to machine them to drop the compression down a bit

[racing escort]

Forged pistons : OK (new rings off course) , the cam ... I would go for KC 234 for street use (just my opinion)

[Graham]

thing is he says he has 150bhp and is using a 244, but wants more

[fatboy slim]

thing is he says he has 150bhp and is using a 244, but wants more

i have some magic beans for sale, i have seen these used before to make 135hp with a bcf2 and 160+ with a 244. my 1660 only had 150 with a 254 on 45's. could have done with some of them magic beans but IIRC i think i ate em instead

[Painter an]

i have some magic beans for sale, i have seen these used before to make 135hp with a bcf2 and 160+ with a 244. my 1660 only had 150 with a 254 on 45's. could have done with some of them magic beans but IIRC i think i ate em instead

Did not say i had 150 bhp i said i would like to get 150 i currently have 141bhp with 1700 and 1300 pistons 244 cam full race head twin 40s i mearly asked if forged pistons would help i also asked in another thred if 45s would be better.graham answers alot of my questions which im gratefull for as he is very informative.but if ever you find any more of those magic beans can you let me know.cheers

[fatboy slim]

i know you don't have 150 bhp, you said so in your post. you also probably don't have 141bhp neither but that is irrelevant. at the moment you have a cam that will produce power up tp 8.5k.your existing pistons won't like going that high so obviously forged ones are better as they are stronger and lighter and will take the revs easily.you need to ask a few questions first, are they ok condition wise?,how much are replacement rings?, i would be asking my engine builder or the bloke who's machining the block these questions first rather than a forum. if everyones happy get them fitted,run in and take the car back to the same dyno/RR that it was on previously and see if it produces more poke and see if it drives,pulls,revs better. you will have your answer. if you are going to be using all those revs often then yes,45's will be better, but not on the road going down to the shops for the paper. to answer your other question std rods are fine as long as they are lightened and balanced and fitted with arp bolts. i will ask the age old question what are you using the car for?

[fatboy slim]

also find out what type of valves are fitted to your head ,if its a full race head they should be decent quality, REC for example, with an ID number on them as size isn't everything or so our lass tells me,as some valves will take the abuse and others lose their heads, literally

[Painter an]

Hi thanks for that the rolling rd figures i have showed max power at 6300 rpm and max torque was 127 at 4300 rpm it did 137 bhp on a diff rolling rd before since then i had changed the exhaust manifold from 4.1 to 4.2.1 which im guessing made the 4 extra bhp im happy with 244 cam it still drives nice when not on cam and idles ok i spose i ought to leave as is instead of chasing numbers.i dont know what valves are in it just the biggest you can fit.the engine was an ex rd rally engine i bought. Thanks for taking time to advise few things

[fatboy slim]

no problem. just going on my experience of over 30 years. good to see people keeping faith with the good old pushrod and not being tempted by the dark side of a pinto or one of those modern contraptions. as long as it drives good for you alls well. if you decide on any changes keep us all informed and good luck

[racing escort]

I guess the compression ration will rise from 10.3/1 to 11 or even 12/1 with forged pistons ? This should add more horsepower but would also mean a new setup of the carbs, the 244 will work even better I think.
If you're happy with the "on cam rev range" of the 244, stick with it

[Painter an]

Thanks for all the info guys does peak bhp at 6300 rpm and tprque at 4200 rpm sound about right for spec of engine etc
Cheers

[Forest_rallying]

I would n't want to be wasting spending £600 on a set of forged pistons for a fast Road engine.

I would also leave the forties on if you are going to continue using the 244 cam. By fitting 45's you would increase in loosing the engines drive ability. I found this out on a Road Rally Twink engine back in the 80's.

[Forest_rallying]

I would n't want to be wasting spending £600 on a set of forged pistons for a fast Road engine.

I would also leave the forties on if you are going to continue using the 244 cam. By fitting 45's you would increase in loosing the engines drive ability. I found this out on a Road Rally Twink engine back in the 80's.

[fatboy slim]

all he needs then is a 5.3 diff,rocket 5 speed and ear plugs and move next door to a filling station. job done