Cletus' 68 Plymouth Valiant

[cletus]

On 20/06/2022 at 10:47, cletus said:

 

I think it has more boost than it should do

 

 

Fuckin dick, no wonder it did surprise wheelspins  

 

[cletus]

Thanks to the replies in the tech spam thread which basically reinforced what I was thinking, which is it doesn't have enough air flow and needs a better fan

I thought I'll live with the fan noise if that means I can actually drive it 

So I embarked on the mission of finding an engine driven fan that fits

Found the one I wanted on an NZ website , sweet, ordered it. 

Nope, " no stock sorry"

Bugger.

 

Found a different supplier who had one, ordered off their website

"Sorry, no stock, they might be here in 3 weeks? " 

 

Poos. 

 

 

Local guy had a plastic flex fan , I didn't want one of those as they are a lot deeper but meh I'll give it a shot , chucked it on, needed a bigger spacer so the blade cleared the alternator. 

spent ages rummaging around for some bolts

Started it, ran for a bit, moves heaps of air, good 

Gave it a rev to about 2500, the inch or so clearance at the bottom became 0 clearance and the fan hit the tank and broke the tip off one blade 

 

Ah yes that's why I hate these fans 

Luckily no damage to the radiator apart from some dinged fins 

 

 

 

 

Found a stock 245 steel fan I had in a box under the house, chucked that on, it will do for now and I'll find the one I want 

I think with a shroud on it should be OK,  the mechanical fans move heaps more air. It still creeps up at idle in the shed but no shroud and a slower fan speed than stock due to pulley sizes are the reasons I think

[cletus]

an update to my cooling system woes

I was convinced a fan shroud would fix my problems so I came up with an idea of what I wanted, and @RX FORD made me a nice tidy shroud and overflow bottle combo 

It made it better, thermostat opened at 180, I drove it around for 25min and it went up to 210 and stayed there. When I got home i opened the garage and left it idling for a minute to adjust idle, and it got hot and boiled 

 

I resisted the barry urge to remove the thermostat completely , I'd bought a 160f tstat so I put that in, and put a restriction in the bypass hose in case that was making the coolant do laps of the engine instead of the radiator 

 

Better again, tstat opens at 160, it went to 180 and stayed there for 10min driving around, I pulled over and it slowly crept up to 195 

 

So it's better, but not fixed. Bearing in mind this is a cool night and just tootling around slowly, it's still too borderline

 

I've got a stock 318 fan which has more aggressive angle on the blades which I might be able to fit if I remake the lower mounts on the radiator. 

 

Otherwise I'm running low on ideas. Maybe a small auxiliary radiator with an electric fan on it, or maybe I need to give the intercooler the heave ho as it's not helping airflow 

[cletus]

Under maximum jandal it squats more than the big bum girls in the fembot thread, and despite having about 80mm of clearance at ride height, the driveshaft would rub on the back of the tunnel which was not ideal 

 

so I made a pinion snubber bracket, it needed a reasonable amount of offset to make contact in the middle of the bit of floor that is designed for such activities 

Now it can have full power applied in the  forward direction which results in rapid transitions from one area to the next which is most satisfactory 

 

 

Did more mucking around with the overheating issue as well. Tried restricting water flow, it didn't make any noticeable difference 

Checked temps of top vs bottom tanks, I'm not sure how accurate the temp gun is or how much of an area it measures but it seemed accurate ish on everything except the radiator, ie it said the top tank was 28deg and I couldn't hold my hand on it  

It did suggest that the bottom tank was very hot at the same time, over 100deg, which is next to the exhaust , so maybe air temp affects the reading? Coolant temp was less than this at the time.

Next plan is the V8 spec fan, improve sealing around the shrouding, and something to keep exhaust heat away from the radiator  

 

[cletus]

OK

V8 fan and sealing around the edges of the shrouds made it better

Good enough that I drove it in total over 100 miles over a couple of days and it was pretty good, doesnt go over 180, at open road speed it's mint  

Today I made a heat shield thing between the exhaust and radiator  

Still gets hot and boils at idle though. 

 

So I'm pretty sure air flow is the problem 

So next will be try it minus the intercooler, I'm picking that will make the radiator work better, plus then there's space for a big electric fan on the front 

That will mean I'll have to redo the piping and swap the rad hose to the other side of the top tank. Dumb. 

 

Anyway, have some pics. 

 

[cletus]

 so I can keep track of what I've done:

Things that did not work or made negligible differences

10" elec fansx2

Plastic flexalite fan

245 fan no shroud

245 fan with shroud 

318 fan with shroud (probably most successful fan so far)

Derale 6 blade stainless flex fan

180deg thermostat

160deg thermostat 

No thermostat 

Restrict flow through hoses 

Seal edges of fan shroud 

Make fan shroud 360deg

Heat reflective stuff on rad tank, bottom of shroud 

Heat shield exhaust from bottom rad tank

Bigger bottom pulley to speed up fan and pump 

 

Im getting tired of working on it tbh. 

 

 

Only options left are- auxilary radiator and fan mounted somewhere . Probably under left front guard. I think this will be the most practical /cost effective option to try

Or

Remove intercooler so it doesn't block rad and allows a fan on the front . I want to have/need some sort of intercooler though, so would need to redo piping and buy intercooler and heat exchanger for water to air ($$) or buy water meth system (also $$)

 

 

 

[cletus]

Can also add to the list of "probably slowed the overheating but did not stop it" 

Heater core auxiliary cooler, this showed an 18degree difference in hose temps between hot and cold side 

 

Removal of intercooler.  

 

Side note at idle there is a warm breeze of 54 degrees coming out of the turbo

[cletus]

Alrighty then 

I think it's good enough for now. I'll see what it's like when summer comes but at the moment I can drive it all day and it hangs around 170-195 depending on what I'm doing

So final stuff done= 

Flowkooler pump (I'd forgotten but it already had a high flow pump but I think the flowkooler one is better)

Wrapped the crossover pipe in itchywrap 

No thermostat  (barry)

Bypass restricted to 6mm 

Two 11" spal fans on a shroud- originally I sealed it around the whole radiator and put holes in the bottom and made rubber flaps like an oem type shroud, I put a gopro in the engine bay to see what the flaps did at motorway speed and they only opened a little bit. So I put a seal just under the fans and removed the rubber flap, so the fans cover the top 2/3rds and cool that bit 

 

Also made a lip spoiler thing to direct air up to the bottom 1/3rd of the radiator which in my theory helps cooling at speed. This is a tester and I'll probably try to make a better looking one  

 

 

 

 

[cletus]

Next thing to sort out was tuning. I wanted to get this and the cooling sorted before I get it certed, because I didn't want to have to redo cert if the carb was going to be too hard to get right and I end up swapping to efi  

I rebuilt the carb when I swapped the motor in. When I had the whole setup in my VG I had a guy in Australia modify the carb to work better . From memory it was pretty good apart from a little flat spot at one point 

It's taken me a while to re learn about carbs and turbos again as there's a bit of mucking around getting them to work right 

 

I had some issues with lean backfires where it would pop back thru the carb at light throttle which was a lot worse than it was before . I swapped the old adjustable blow off valve back onto it as the one I put on it this time was a bit weak and would blow off early, with a carb turbo it's quite easy to have boost above the carb and vacuum below it, so the valve would open and leak boost which I think was doing wierd stuff to the carb 

So that made it a lot better 

Also put bowl vent extensions back on 

And had a fiddle with the boost referenced power valve. This seems to be where the solution is if I can adjust this a bit more finely  

 

 

 

[cletus]

Front shocks out again to swap to a 14kg spring instead of 10. I wasn't happy with how much coil clearance it had  

[cletus]

Don't forget, oldschooldotcodotenzed drag day is in December 

 

[cletus]

Ready for cert . Did a bit more fiddling around with tuning , removed bowl vent extensions again and swapped to a 3.5 power valve  

Getting the PV to open at the right point is a knife edge balance of too lean backfires and black smoke chooch

 

[cletus]

wof reg and cert done. 

 

[cletus]

Oldschool drag day '22 edition 

Did 8 passes 

Interestingly, every single one was 115mph. 

Did a few 12.4, 12.3 etc then 3x  12.0 in a row 

Last pass was near the end of racing so not much time to cool down,  I ignored the green and let it build boost with the brake pedal pushed as hard as I could , when I let the brake go it left harder than any other pass today, 

11.90

massively stoked with that.

 

I've never paid much attention to 60ft times but it appears that I should, as mentioned all passes were the same mph but the quickest was 1.87 vs 2.3something for the slowest 

[cletus]

I think the key to making this go better, is to build more boost at the start so it leaves harder, as that was the difference between 12.3 and 11.9 

 

I had a yarn to the guy that built the trans about the possibility of putting a transbrake in it , as torqueflites are generally strong, but have a weak point that can lead to catastrophic failure 

In first gear, under certain conditions, (and I'm not sure exactly why, I'm not a transmission expert ) the sprag clutch can be damaged easily . Usually from things like 

A burnout in first gear, where the tyre gets traction suddenly 

Downshifting to first gear when moving 

On and off the throttle in first gear 

Breakages in first gear like an axle, diff etc 

 

If the sprag (a one way clutch, that works with rollers and ramps) gets damaged and doesn't work, the forward clutch drum gets to spin 3x engine rpm. They are made of cast iron and don't like that, and they explode . 727s have a bigger drum than 904s so they are more prone to it  

 

So anyway, trans guy said you can put a transbrake in a 727, but to get the benefit from it I'd need a looser converter as well which would likely be a custom built thing to suit my combo. 

For those who are interested,  a transbrake works by putting the trans in first and reverse at the same time when you hold a button down- this allows rpm and boost to build by loading the engine against the converter.

Turbo cars can also use a thing called a bump box which momentarily releases the transbrake to 'bump in' to the staging lights- this allows you to stay out of the beams until you build boost 

 

I dunno if I'll get that serious about it, as it's mostly a road car, and it drives well with the converter it has in it  

 

 

 A easy thing to try is a 2 step rev limiter so I got one of those and an adjustable low rpm chip so I can see if that can build more boost mashing the brake pedal as hard as possible 

[cletus]

Fitted 2 step, had a tutu around with different rpm settings , non drag strip testing is impossible, as as soon as you let the button go it just draws 11s. But it will make 7psi on the footbrake and not creep forward 

[cletus]

Well that worked better than i expected. 

Went to night drags. 

Cold night air and the 2 step worked great 

Forward until the first staging lights come on , hit the button and the brakes hard, floor it, creep it into the second beam, by the time the green comes on theres a good amount of boost,wheeee

 

Result!  (534)

[cletus]

[cletus]

Ive had these wheels for a while, to sort of match the rear wheels for drag use, 15x3.5 

 

they didnt fit due to the calipers . Found some adapters that i had in stock, bolted them on. 

Doesnt look right ,tyres are too short and wheels stick out too much 

 

 

 

[cletus]

Went to Chrome at Hampton downs , gave it beans all day, used about $200 in fuel, took a few randoms then wife and kid out for some skids and everyone had fun.