competition pinto build advice

[Tpau]

The exhaust valves were in the stock hardened seats while I cut the intakes in taking care to take out as little material as possible.
I must admit to being slightly to greedy with the first cut, was aiming for 44 cc chambers, on top of me being slightly greedy I asked for 1,65 cut and got 1,7.
So I think Grahams advise of taking it in several goes is sound.

One wild idea for checking how much to take of might be to make a filler bit of transparent plastic the thickness you are considering and stick that to the plexi while doing the cc-ing.

/T

[onecamohv]

i cut the absolute barest minimum to give the valves something to seat on, the new seats will be further into the chamber than the old. thats a good thing for getting valve lift on spec or even slightly more than specified

Yep and Luckily the valves from rec now are exactly 110mm, so worrying about every extra tenth the valves are going into the head is not as problematic as it was with longer valves.

In other news all my valve springs are under the the specified length of 37mm, but again the seats are going to take from that. They all range between 35.9mm and 36.7mm.
Il probably get a mm taken off the seat and shim to spec

[onecamohv]

The exhaust valves were in the stock hardened seats while I cut the intakes in taking care to take out as little material as possible.
I must admit to being slightly to greedy with the first cut, was aiming for 44 cc chambers, on top of me being slightly greedy I asked for 1,65 cut and got 1,7.
So I think Grahams advise of taking it in several goes is sound.

One wild idea for checking how much to take of might be to make a filler bit of transparent plastic the thickness you are considering and stick that to the plexi while doing the cc-ing.

/T

That's actually a great idea. I might try find a bit of 1.5mm plexi and try it! But I think you are both right, I think il take 1.5, do the chamber work and get a final cut

[katana]

Adding 'Fairy Liquid' (other brands are available) to your measuring fluid should help to reduce the meniscus effect by reducing surface tension . . . . . . in theory ! It should work similar to using 'water wetter' in cooling systems.

[alladdin]

Adding 'Fairy Liquid' (other brands are available) to your measuring fluid should help to reduce the meniscus effect by reducing surface tension . . . . . . in theory ! It should work similar to using 'water wetter' in cooling systems.

beat me too it. wont want much tho or it will end upin a bubble bath

[onecamohv]

i normally use meths, as its basically alcohol that you dont need to put a die in. il try put a drop of fairy in it and see the reaction

[rallyrob]

I have no idea if this works as I've never done it. But somewhere I read that Red Wine works.

[alladdin]

I have no idea if this works as I've never done it. But somewhere I read that Red Wine works.

i would strongly advise against this.
its far too valuable to waste

[katana]

i would strongly advise against this.
its far too valuable to waste

Not the stuff I was drinking last nite with Dinner - meths would have been preferable LOL!

[Graham]

i normally use meths, as its basically alcohol that you dont need to put a die in. il try put a drop of fairy in it and see the reaction

meths evaporates very quickly so perhaps not an ideal substance. i quite often use screen wash, some times anti freeze, sometimes degreaser out the parts washer

[onecamohv]

meths evaporates very quickly so perhaps not an ideal substance. i quite often use screen wash, some times anti freeze, sometimes degreaser out the parts washer

Yeah Wiped onto a surface for sure, but any decent qty like what's in a combustion chamber on a freezing cold head I think would be negligible. Although, its use doesn't seem to be giving me much of an advantage over other stuff. Il take a photo of the meniscus in the burette tomorrow. What's antifreeze like? That's interesting...is it not a bit 'sticky'?

[alladdin]

meths / alcohol will mix with water if that helps.

[alladdin]

Yeah

either i have the wrong person or an update is due

[onecamohv]

only picked up the bits from the machinist this morning so updates coming quick and fast going forward.

in the mean time ive been doing boring stuff like switching the wiring over from one side to the other, fuel line same etc. and also doing the cosmetics.
got the rocker cover vapour blasted, then i painted in 2k gloss, came out fantastic. also made a big wing sump in the mean time.

the machining all went well, head was crack free thanks be to jesus and the valves etc cut in no problem. only unforseen issue was a ring of rust pitting that didnt bore out of Cylinder 1 where water had been sitting on top of the piston half way down the bore, so had to put a liner in cylinder 1.
mains needed a grind, big ends survived with a polish.

crank, crank pulley, flywheel and clutch cover all dynamically balanced.

over the next few days, il be setting the deck height, balancing the rods, and CC'ing the chambers again and will probably need another skim off the head but im closer to where i want to be. Seats were cut on a new CNC serdi machine, its a beautiful piece of kit

some random pics to keep the thread going

[onecamohv]

[onecamohv]

also stripped to deburr and measure the pump, needed a good clean and a bit of deburr, but seems pretty good

[alladdin]

i have the wrong person someone on t/s page on FB having a dyno session and i made 2+2 = 6

nice to see progress tho

[katana]

Not sure using 'seedless raspberry jam' will achieve much LOL!

[onecamohv]

i have some nice updates to post in this thread later today on the progress of this build, i just have to upload the pics shortly.

while working on the head setting up and checking valve geometry, i was playing around with valve clearances.

i had heard from some pretty successful pinto hot rod/rally engine builders that they set the valve clearances at the stem rather than between the cam and lifter.

doing this there is about 4thou difference, so setting the clearance at the stem to 10 thou will leave only 6 thou at the cam.
obviously then setting the clearance to 10thou at the cam, leads to about 14/15thou at the valve stem. personally, id be concerened about having only 6 thou between pad and cam, and it does move the wipe area quite a bit on the pad

What say thee??

[Graham]

to be honest ive never done it, and cant see any good reason to do so, if you want to try tighter valve clearances just set them tighter in the normal fashion. what they are actually doing is increasing overlap at TDC and extending duration a fraction

[onecamohv]

to be honest ive never done it, and cant see any good reason to do so, if you want to try tighter valve clearances just set them tighter in the normal fashion. what they are actually doing is increasing overlap at TDC and extending duration a fraction

but i was thinking hardly to any useful effect ? the increase in actual measured valve lift was about 8 thou. once you get over .485 lift, is another 7/8 thou going to make any measurable difference? head is not on yet, so i can measure any change in duration.
On an RL31 would you just go with 10/12 at the cam normally Graham?

Also with wilder cams it would pull the lifter even further off the stem a fraction... at the same time, i understand where they are coming from setting the valve clearance at the VALVE...

[Graham]

the effect on timing and lift is minimal, but lift at TDC will be biggest change making the cam appear hotter.

a long long time ago i did experiment with valve clearances on something, after a lot of faffing around i came to the conclusion that it was basically a waste of time but slightly bigger was best!

[onecamohv]

the performance element was actually secondary in my mind, my main thought was getting it as close to perfect as it wants to be from a mechanical stand point for correct geometry and valve train happiness!! cheers Graham

[onecamohv]

The engine took a little longer to return due to machine shop being particularly busy, so I got it back last week.
Block was rebored to the new forged pistons, decked, and line honed.
Crank was ground on the mains and polished – flywheel lightened and then the whole lot dynamically balanced with the pressure plate. I also doweled the crack to the flywheel for that added bit of safety.
Head was skimmed on all sides to get me closer to the desired CR, we took about 50 thou off to start with.
Seats were CNC cut to accept the new bigger valves and seat height set. Spring seats were machined to accept double springs close to where I want them and then I can shim them to achieve the desired spring pressures.






While the big bits were away, I balanced the cosworth rods – the were pretty close to be fair on overall weight, but end to end were a decent bit out. So each end was balanced on rod balancing jig I made.
This takes ages, and can be a very frustrating process to get repeatable results.



After the seats have been cut, as previously mentioned, I then had to finish the porting job by blending the throat into the seat. Couple of hours at that had it nice






After working out the CR, I was super close and luckily on the good side of close, so the head went back for a dusting of about 9-10 thou.



After hours of cleaning, block was masked up and coated in 2k etch. Then I painted it in 2k grey, turned out great.




Also painted the not machined parts of the head

Installed new core plugs






Popped the crank in to confirm the bearing clearances, and then put in a piston with no rings on it so I could determine how much I need to skim off the pistons. As previously mentioned I'm using cossie rods which are 60thou longer than pinto rods, and with all said and done the piston is sticking out 57 thou. I'm using a 50thou head gasket, so this obviously is going to end in a intimate relationship between the piston and the head.

I set up the pistons in the lathe and skimmed them to the desired dimensions.




I also made up a dizzy blank setup from an old dizzy as I'm running mapped ignition. Cut down the dizzy body, counterbored it and put a sealed roller bearing top and bottom. I modified the shaft and set it back up with the Factory end float. Turned out great.



Bearings set and finally starting to go together




Unfortunately I was left short 2 circlips by Accralite, which I didn’t notice until assembly time, so I'm waiting to put pistons 3 and 4 in the block






While waiting for the circlips I started to build up the head and check geometry.
To recap I'm using 110mm REC valves with a KENT RL31. With the recommended valve clearances from KENT set, I checked how close we were to the ever evasive ‘book values’ of camshafts.
I'm getting nearly bang on exhaust value, book value is .4948 and I'm getting an average of .493 on the exhausts.
Inlet lift is down a bit on kents quoted specs, .508 quoted, I'm getting an average of .488 +/- a thou or 2. Pretty good I think.

The lifter is also quite close to parallel (or 90deg with the machined gasket face) I can fit a around 14thou feeler between the lifter and square, again pretty good.

Thanks for looking!

[Forest_rallying]

Any news on the progress of this build OHV?

[onecamohv]

yep just Haven’t had any time to update this lately – bit of a condensed version!

Finally got the missing circlips after a saga lasting a number of weeks, so I set about setting the piston heights for the final built.

i also had a bit of an issue where i build the engine initially with the Kent valve stem oil seals which i then learned were sh!te, so ended up stripping the head in the car to put the Reinz ones on.

Waste of head bolts and a gasket, but better to be safe than sorry at this point.

Checked out all ok, so it was time for a final build and dial in the cam. I set the cam lightly advanced to get a wider torque spread, but we’ll dial this in on the rollers.

engine is in the car now and running well, so it will be going to the rollers to be set up next week




As I'm running the ignition system on megajolt, I had to make a crank trigger bracket, which was a bit of a nightmare on this engine not many options but worked out well in the end.



Mocked up the engine mounts with the engine sitting where I wanted it. The factory angle of the engine is 4 degrees to allow oil to flow quickly enough to the return in the back of the head and I had no reason to change this. But I did sit the engine as far back as I could to help distribute the weight of this brute as far back as possible. Unfortunately this meant I had to shorten the prop by 25mm.




As the exhaust is now on the drivers side compared to the XE, I had to make up a simple transfer pipe from one side to the other under the gearbox.





Engine now in, wired and plumbed. Built up oil pressure via an external drive, and then thankfully she fired on the first go. Sounds really well. While I was bedding in the cam, I balanced the carbs and tuned the idle mixture but I expect a few jet changes on the rolling road.
Ran very well though, and sounds the nuts.

[mariors2000]

Hi onecamohv what engine power are you aiming for looks like your don't a great job on the engine all the best cheers mario.

[Forest_rallying]

Thanks for taking the time to reply with your updates, your work looks very impressive OHV!

I’ll look forward to the Rolling Road results, have you any ideas what figures to expect?

[Forest_rallying]

Thanks for taking the time to reply with your updates, your work looks very impressive OHV!

I’ll look forward to the Rolling Road results, have you any ideas what figures to expect?

[onecamohv]

Cheers! The build is nothing unorthodox, it's been done millions of times to this spec and the head is self ported without a flow bench, so I can't expect miracles. I've just tried to do everything the very best I can, spending time balancing everything, dialling in the exact cr, squish, etc. So I suppose I have to just go with what others are making as a yard stick, would it see 170? I've advanced the cam which will cost a couple of bhp and it's not even hit the road yet, only bedded in the cam so power will creep up as rings seat.
the RR operator I go to is no bullshit artist, and calls it as it is. No fiddled figures, so it always reads lower in most cases than other places.

Sent from my SM-G980F using Tapatalk

[alladdin]

As I'm running the ignition system on megajolt, I had to make a crank trigger bracket, which was a bit of a nightmare on this engine not many options but worked out well in the end.

any chance of a write up on making this setup ?

[onecamohv]

The bracket or the whole ignition setup ?

Sent from my SM-G980F using Tapatalk

[alladdin]

mainly the hardware but im sure there would be interest in the whole setup - as you say , pinto kits seem thin on ground

[dt36]

The bracket or the whole ignition setup ?

Sent from my SM-G980F using Tapatalk

I'd also be interested in the bracket.
I have a trigger wheel fitted to my Pinto in preparation to go throttle bodies in the future, but no bracket as of yet. Car is currently running on Bestek Distributor and carbs.

[Graham]

Cheers! The build is nothing unorthodox, it's been done millions of times to this spec and the head is self ported without a flow bench, so I can't expect miracles. I've just tried to do everything the very best I can, spending time balancing everything, dialling in the exact cr, squish, etc. So I suppose I have to just go with what others are making as a yard stick, would it see 170? I've advanced the cam which will cost a couple of bhp and it's not even hit the road yet, only bedded in the cam so power will creep up as rings seat.
the RR operator I go to is no bullshit artist, and calls it as it is. No fiddled figures, so it always reads lower in most cases than other places.

Sent from my SM-G980F using Tapatalk

it takes very little time to actually bed in rings, but the time the RR operators done some part throttle running and a couple of pulls the rings should be bedded.

power wise It all depends on how well the head works, i would expect you would see 170bhp, if the heads working well you will see a fair bit more.

re cam timing the old adage of advance for low end retard for top doesn't always work. Now i have the dyno i don't even time the cams, i just eyeball equal lift TDC and swing the cam timing on the dyno once i have the AFR and timing in the "window"

[onecamohv]

power wise It all depends on how well the head works, i would expect you would see 170bhp, if the heads working well you will see a fair bit more.

re cam timing the old adage of advance for low end retard for top doesn't always work. Now i have the dyno i don't even time the cams, i just eyeball equal lift TDC and swing the cam timing on the dyno once i have the AFR and timing in the "window"

Its the first pinto head ive done, so i think ive probably been too conservative in around the the upper part of the throat probably and everywhere else too. I really didnt want to blow through a stock rusty injection head i had to pay 200 quid for to start with.
I spent alot of time on the head finessing everything and getting the shapes and finish just right, but i just dont think i went mad enough on the throats. i didnt go bananas on the exhaust port walls either for the same reasons. time will tell i guess !
im also sticking to 36 chokes too given the sport im in

[onecamohv]

so, after quite a few hours playing on the dyno, the jury is in on this build

I have to say I'm both absolutely chuffed, and quite a bit surprised I managed to get these results from this build – all the painstaking hours and hours of work has finally paid off.

I really think I left a bit on the table with regards to the head, not wanting to break through anywhere and ruin a rare head I think I was a bit conservative in places.

Either way, really really happy with the results, dyno operator said it pulled like a train mid-range which is what I was hoping for, and it was one of those that just all came together and worked well
I was going to be happy with anything over 170bhp, quietly hoping for between 175-180, but in the end we made a whopping 190bhp, and 169lb.ft. with the timing dialled back to a safe zone.

Not bad for a cast iron 8v boat anchor! i must have excelled myself and done a pretty good job on the head

[alladdin]

[mariors2000]

Great power what chokes sizes did you end up with for 190 hp cheers mario

[Forest_rallying]

so, after quite a few hours playing on the dyno, the jury is in on this build

I have to say I'm both absolutely chuffed, and quite a bit surprised I managed to get these results from this build – all the painstaking hours and hours of work has finally paid off.

I really think I left a bit on the table with regards to the head, not wanting to break through anywhere and ruin a rare head I think I was a bit conservative in places.

Either way, really really happy with the results, dyno operator said it pulled like a train mid-range which is what I was hoping for, and it was one of those that just all came together and worked well
I was going to be happy with anything over 170bhp, quietly hoping for between 175-180, but in the end we made a whopping 190bhp, and 169lb.ft. with the timing dialled back to a safe zone.

Not bad for a cast iron 8v boat anchor! i must have excelled myself and done a pretty good job on the head

Great results there OMV, 169lb.ft out of a 2.0 Pinto’s really strong to torque by any ones standard. I admire your high standard of detail and it proves you were correct in not getting too greedy by grinding to much material out of the head, a hole in it makes nothing.

If time ever permits my next job’s to get mine with the Down Draught head onto the Rollers, if I could get what your engine’s got I would be more than happy. Incidentally what was the HP at the wheels?Once again well done.