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Is my engine getting too hot?

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psimitar Son of Jim - Creator of Good

2,506 posts · joined Jan 2009 ·

#910241
Hello all,

SO after putting the 1200 back together with re-ground crank, new bearings, new piston rings, reconned heads and new 31PICT-3 I drove the old girl about 20k from storage place to mine and towards the last 3-5k she started to get a bit jerky and not driving smooth on the accelerator at any speed.
When I had parked her up I felt the exhaust and the pea shooter was too hot to touch but she didn't smell particularly hot.
I left her for an hour and then drove her up our steep driveway and she pulled well up there with no jerkiness.

So, overheating or not? I put the jets from the old 28PIC into the new 31PICT so jetting should be fine and the timing was set with a light and was spot on.

I did notice that a brand new oil cooler has a foam seal around it and mine did not when all put back together.

Your thoughts please 🙂
madness is in the eye of the beholder 👍

bajachris88 The international telephone dialing code for Antarctica is 6

6,661 posts · joined Apr 2005 ·

#910246
Easiest way to test if an vw engine is overheating... When its reached running temperature, see if you can touch the dip stick. If its too hot to handle, your engine is overheating. 👍

not running lean when the choke fully opens?
(ô_!_/ô) (ô_!_/ô)
69' baja: kombi box, thing spindles, irs, disc front, type 3 rear drums, 2 inch lift kit, 31x10 rears. 👍
New engine in process: 94mm p&bs, 74mm C/w chomol Crank, 35.5x39 SP heads, turbo. Wierd combo, hopeful torque monsta!

68AutoBug Beetle Restorer - Experience over 138\% - YIKES --

11,654 posts · joined Aug 2002 ·

#910247
Hi
The exhausts are always very hot..
if one falls off never go back and oick it up... lol
Chrome holds the heat..
the foam may not make much difference...
I saw a TV show {UK TV] where the so called VW mechanic pulled all the foam off a new doghouse oil cooler before fitting it
it just seals the oil cooler so ALL the air goes thru the oil cooler..
I use a lot of foam on My oil coolers to really seal them but its probably overkill..

When a VW engine gets too hot, You can usually smell it..

when the oil is thick and cold it doesn't go thru the oil cooler until the oil is [hot] and thin, then the oil pressure valve lets it go thru the oil cooler.. Have You checked the oil pressure valve to see if it can move up & down easily..?

Maybe something is getting tight because of heat, not necessarily because the engine is too hot...

cheers

Lee

PS: the old telltale is to pull out the dipstick and see if You can hold it in Your hand.. If You can't , the oil is too HOT.
- Helping keep Air Cooled VWs on the road - location: SCONE in the Upper Hunter Valley - Northern NSW 320 kms NNW of SYDNEY---

psimitar Son of Jim - Creator of Good

2,506 posts · joined Jan 2009 ·

#910253
I'd forgotten that test. Hmm, will have to run her round the neighbourhood unregistered to try that test now. Bummer 🤪
madness is in the eye of the beholder 👍

grumble Son of Jim - Creator of Good

2,672 posts · joined Jun 2008 ·

#910260
You should also make allowance for the engine having new rings etc with the drag,as the rings bed in things will free up. I am assuming of course that the engine turned freely on assembly and the dowels havent been pinched.

matberry Moderator Go hard or go home

8,114 posts · joined Mar 2006 ·

#910265
psimitar wrote:I put the jets from the old 28PIC into the new 31PICT so jetting should be fine
This statement concerns me, since the jets are different between a 28 and a 31 PICT.
The spec from the VW publication Without Guesswork states

28 PICT 1.2 30bhp 22.5 vent, 122.5 main , 130 Air corrector 55 idle
28 PICT 1.5 42bhp 22.5 vent, 115 main, 145 OR 150 Air corrector, 45 idle
31 PICT 1.3 40bhp 24 vent, 125 main, 125 Air corrector, 55 idle


As you can see they are not the same, from your description of running rough when hotter, usually this indicates too rich but that doesn't look likely looking at the factory jet options. Assuming it's carb related, remembering it's a total package that makes the jetting correct, that is carb, ignition timing, manifold preheat, air filter, exhaust system,even wear of the carby....all effect the actual jet requirements.

Sus out exactly what jets are in it, also chect for manifold leaks at the carb base and heads.
Matt Berry Motorsports...air cooled advice, repairs and mods Ph 0408 704 662
OFF-ROAD,CIRCUIT,DRAG,STREET,ENDURANCE

psimitar Son of Jim - Creator of Good

2,506 posts · joined Jan 2009 ·

#910274
grumble wrote:You should also make allowance for the engine having new rings etc with the drag,as the rings bed in things will free up. I am assuming of course that the engine turned freely on assembly and the dowels havent been pinched.
Engine turned freely after new rings were installed and nothing was pinched/tight.
madness is in the eye of the beholder 👍

psimitar Son of Jim - Creator of Good

2,506 posts · joined Jan 2009 ·

#910275
matberry wrote:
psimitar wrote:I put the jets from the old 28PIC into the new 31PICT so jetting should be fine
This statement concerns me, since the jets are different between a 28 and a 31 PICT.
The spec from the VW publication Without Guesswork states

28 PICT 1.2 30bhp 22.5 vent, 122.5 main , 130 Air corrector 55 idle
28 PICT 1.5 42bhp 22.5 vent, 115 main, 145 OR 150 Air corrector, 45 idle
31 PICT 1.3 40bhp 24 vent, 125 main, 125 Air corrector, 55 idle


As you can see they are not the same, from your description of running rough when hotter, usually this indicates too rich but that doesn't look likely looking at the factory jet options. Assuming it's carb related, remembering it's a total package that makes the jetting correct, that is carb, ignition timing, manifold preheat, air filter, exhaust system,even wear of the carby....all effect the actual jet requirements.

Sus out exactly what jets are in it, also chect for manifold leaks at the carb base and heads.
Hiya Matt,

Correct if I'm wrong but the jets relate to the size of the venturi as well as the engine size?

Um, my old 28PICT had the jets you've stated for the 1.2 engine and the 31PICT had the jets stated for the 1.3 engine. So I thought changing to the 28PICT jets would be the right thing to do for my 1.2.
Do you think I need to put the original 31PICT jets back in? Been a while since I've played with carb jetting so may have got it wrong.

Ta
madness is in the eye of the beholder 👍

matberry Moderator Go hard or go home

8,114 posts · joined Mar 2006 ·

#910277
Put the jets back that were originally there.

There's way more to it, but basically a carb is there to mix the right amount of fuel into the air that passes through it. The combustion process is most efficient at 14 parts of air to every 1 part fuel 14:1 air to fuel ratio. (altho we like a richer mixture in our aircoolers)
So as a bigger engine draws more air, the carb should deliver more fuel.
Matt Berry Motorsports...air cooled advice, repairs and mods Ph 0408 704 662
OFF-ROAD,CIRCUIT,DRAG,STREET,ENDURANCE

psimitar Son of Jim - Creator of Good

2,506 posts · joined Jan 2009 ·

#910279
matberry wrote:Put the jets back that were originally there.

There's way more to it, but basically a carb is there to mix the right amount of fuel into the air that passes through it. The combustion process is most efficient at 14 parts of air to every 1 part fuel 14:1 air to fuel ratio. (altho we like a richer mixture in our aircoolers)
So as a bigger engine draws more air, the carb should deliver more fuel.
Cheers Matt 🙂 I know the 14:1 ratio but just so we are on the same page here.

I have a rebuilt 1.2 that the original 28PICT needs a re-bushing so I bought a 31PICT until I've time for that. So I swapped the original 1.2 28PICT jets into the new 31PICT thinking this would keep the correct jetting for the 1.2

So do you still think I need to place the original jets that came with the 31PICT back inplace of the jets I swapped from the 28PICT?

Just want to check so we are on the same page 🙂

Cheers,
Mike
madness is in the eye of the beholder 👍

matberry Moderator Go hard or go home

8,114 posts · joined Mar 2006 ·

#910282
Same page, put in the jets that came with the carb. Don't worry about yours being a 1200
Matt Berry Motorsports...air cooled advice, repairs and mods Ph 0408 704 662
OFF-ROAD,CIRCUIT,DRAG,STREET,ENDURANCE

psimitar Son of Jim - Creator of Good

2,506 posts · joined Jan 2009 ·

#910284
cool. I'll do that. I did wonder as reminded me a bit of my old 1600 1303 with twin ICT's. Would get all jerky going up the motorway but only after 140 miles at 70mph. Dipstick was too hot to handle so upped the mains by 5 points and never happened again 🙂
madness is in the eye of the beholder 👍

68AutoBug Beetle Restorer - Experience over 138\% - YIKES --

11,654 posts · joined Aug 2002 ·

#910285
psimitar wrote:Hello all,

SO after putting the 1200 back together with re-ground crank, new bearings, new piston rings, reconned heads and new 31PICT-3 I drove the old girl about 20k from storage place to mine and towards the last 3-5k she started to get a bit jerky and not driving smooth on the accelerator at any speed.
When I had parked her up I felt the exhaust and the pea shooter was too hot to touch but she didn't smell particularly hot.
I left her for an hour and then drove her up our steep driveway and she pulled well up there with no jerkiness.

So, overheating or not? I put the jets from the old 28PIC into the new 31PICT so jetting should be fine and the timing was set with a light and was spot on.

Your thoughts please 🙂
You have mismatched the jets
put the original jets back in for that carburetor as You have altered up the air/fuel ratio for that carby.

Not sure if that has anything to do with Your car slowing down??
fuel blockage?? loose spark plug lead?? bad condensor..??

LEE
- Helping keep Air Cooled VWs on the road - location: SCONE in the Upper Hunter Valley - Northern NSW 320 kms NNW of SYDNEY---

psimitar Son of Jim - Creator of Good

2,506 posts · joined Jan 2009 ·

#910287
68AutoBug wrote:
psimitar wrote:Hello all,

SO after putting the 1200 back together with re-ground crank, new bearings, new piston rings, reconned heads and new 31PICT-3 I drove the old girl about 20k from storage place to mine and towards the last 3-5k she started to get a bit jerky and not driving smooth on the accelerator at any speed.
When I had parked her up I felt the exhaust and the pea shooter was too hot to touch but she didn't smell particularly hot.
I left her for an hour and then drove her up our steep driveway and she pulled well up there with no jerkiness.

So, overheating or not? I put the jets from the old 28PIC into the new 31PICT so jetting should be fine and the timing was set with a light and was spot on.

Your thoughts please 🙂
You have mismatched the jets
put the original jets back in for that carburetor as You have altered up the air/fuel ratio for that carby.

Not sure if that has anything to do with Your car slowing down??
fuel blockage?? loose spark plug lead?? bad condensor..??

LEE
Yea, I'll pop the other jets back in. See how we go with that. Everything else is brand new and think this is first port of call before looking elsewhere.

Ta
madness is in the eye of the beholder 👍

66deluxe Custom Title Time!

1,593 posts · joined Aug 2005 ·

#910301
68AutoBug wrote:
psimitar wrote:Hello all,

SO after putting the 1200 back together with re-ground crank, new bearings, new piston rings, reconned heads and new 31PICT-3 I drove the old girl about 20k from storage place to mine and towards the last 3-5k she started to get a bit jerky and not driving smooth on the accelerator at any speed.
When I had parked her up I felt the exhaust and the pea shooter was too hot to touch but she didn't smell particularly hot.
I left her for an hour and then drove her up our steep driveway and she pulled well up there with no jerkiness.

So, overheating or not? I put the jets from the old 28PIC into the new 31PICT so jetting should be fine and the timing was set with a light and was spot on.

Your thoughts please 🙂
You have mismatched the jets
put the original jets back in for that carburetor as You have altered up the air/fuel ratio for that carby.

Not sure if that has anything to do with Your car slowing down??
fuel blockage?? loose spark plug lead?? bad condensor..??

LEE
Your a broken record again Lee.
This is my Volkswagen, there are many like it, but this one is mine. Without me my Volkswagen is useless, without my Volkswagen, I am useless.

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