Loosing power uphill or under load any ideas?

[Worby876]

Hi Fellas,

Hope you are all havin a great Easter long week end.

I took the old Bedford Motorhome for a spin today and it went Ok for about 10 15 KMs then when coming back
home I noticed it started to miss and lose power off the lights and nearly stalled at one point.

She coughed and spluttered and did some small back fires and really started to loose power even in low gear.
I tried her on petrol and still no good.

So I left here to cool down a bit and finally drove her home on dusk when the air was cooler and after I removed the air intake filter
she only just managed to crawl up our steep hill where I live and at a few points I thought she wouldn't make it.

Some back ground.
Its a 202 straight 6 donk running on dual fuel. 4 speed manual aussie box.

New spark plugs after I recently changed the head gasket over (she was loosing coolant out the exhaust and over heating)
Now she starts straight away on LPG and idles fine, doesn't get hot and seems OK but when she gets a bit warm looses power
and starts to miss and splutter and generally no real confidence in power.

I read about a similar thing here and it turned out to be bent valve rods when the head was reconned.
In my situation nothing was done to head or rods only a new head gasket fitted.

I dont think anything was changed or moved when i did that but Im not as mechanically savvy as my late father.
Some of you know his website Jacks Shed on old holden http://gallery.oldholden.com/Jack_s/
so you can see what she is fitted out with etc.

Its fitted with a flash lube set up so the valves should be OK ...they seemed fine to me when I did the head gasket
change over a few weeks ago. She backfired so bad coming up the hill that it blew the exhaust muffler box apart and
I had to get a new one fitted.

Drove home from the muffler shop up the hill no probs...but it was raining and cool so maybe that was a factor.

Anyways Im not sure where to start looking..dont want to pull the head off again unless I have too,
Maybe its a timing thing? could it have gotten out of timing when i pulled the head off?
I didn't mover the motor or anything ...just took the head off scraped the block clean, new head gasket spray on goo' a new repco head gasket and put the head back on and retentioned all the head bolts in order using tension wrench as per Holden manual.

Once i finished I filled the radiator and added techtyl additive hit the keys and Vroom she started first go on LPG and purred like a kitten.

Like i said before Im not as mechanically minded as Dad, but happy to have a go..have basic tools, and not much $$$ so really need to fix it myself if possible.

Any clues or pointers appreciated.

cheers

[restoreid]

Hey Worby I know this may sound stupid but check the oil levil in the sump if it is low &you are going uphill the oil flows away from the pickup & without oil pressure the lifters dont pump up & ittle develope a miss mine done that on my last outing & I thought id blown it up but after I let it cool down & the oil all drained back into ths sump it ran fine again topped the oil up again & its fine now Just a thought

[John Abbott]

Worby....Before i found this site i was a regular poster on the old holden site and talked to your dad once or twice when trying to get my bedford running better. I found him a wealth of information and just loved the way he put his ideas to work in a simple and practical way. He thought "outside the square " to solve any problems he had with his camper. It was very saddening to hear of his passing mate, but no doubt he is watching out for you and the bedford upstairs... cheers...Johnno.  P.S I am wondering wether your problem might be ignition (plugs ,leads.distributor?)

[Worby876]

Thanks for your kind words John,

we sure do miss him, Ive been reading his old threads trying to get an idea of what I should
do to get the Old girl to pull up the hill without dying in the rear end.

http://oldholden.com/node/27503#comment-110045

I will check the Oil levels and the leads, coil etc to see if I can find any obvious
tell tails signs of whats causing the problem.

like i said its got new plugs, and she starts and idles fine...like a proverbial sewing machine.
So unless the coil or leads or dizzy breaks down under load Im not sure what it could be.

I might need to invest in a timing strobe light and a pressure gauge to measure the cylinders
to ensure I haven't dropped a valve or something. Dad had all the gear but my step mum
sold or gave a lot of it away  :'(

My hope is to get her back to her former glory and do a trip to the Alice and back.

Or down to Victoria to do the great Ocean Road....just for the heck of it 

cheers

[LS120]

have just had the same problem with my red 202 & standard (single thrught) carb...

i managed to fix it enough to get us home this easter & about 120km to home but only at 60k max but up hill at 45km in second was fine..
i is the carb.. i found thius with the simptons you had.. i broke down on the side of the road 15km from our start of poiun back...
took it off.. stripped it down. but didnt have anythis small enough to clear out the jets...
put it back together & could start & idle fine could even rev it up over 3k & ok... but no power under load...
limped tp a frends place about 30km away & luck they were there.. played around with it most of the day with coils.. wires etc... but the only thig that made it any better was pulling the choke on to get a better less lumpy running speed... thats how i got home.. using the choke to get it to run better.. I'm going to strip & re-build it this week & yes i had the same problem with exhuse also blew the manifold -exhust ring to bits.. sounds like a tractor..
 hope this helps..

David

[restoreid]

Could be fuel pump too

[Rothu]

I think you might have read my post about the bent push rods.
 
I've had to change my head gaskets numerous times for various reasons, but this sounds like exactly the same problem I had on one change-over. The hydraulic lifters. If they are not bled properly, they will fill up and not empty when under load. It will idle fine, but any load will cause it to backfire as some of the valves are open all over the shop. So if you just change the head gasket and put the head back on and just bolt all the rockers back in without bleeding them ,you'll have this problem.

What I had to do is go back and take the spark plugs out, take the rocker cover and all rockers off, set cylinder 1 at TDC (take the cover off the dizzy and see it at 1, and use a long screw driver in the spark plug hole to check it's all the way up), see that the push rods on 1 were completely down and level, THEN torque the rockers down. this will bleed the lifters for that cylinder. Then turn the engine until the next set of rods (on 5) are completely down and level and did the same thing. The firing order is 1 5 3 6 2 4. This solved the problem I had which had the same symptoms as yours.

hope this helps!

[JOE RYAN]

I had a similar problem on a Toyota 15 years ago checking carby, ignition, I had that carby apart 20 odd times turned out to be an air leak on the inlet manifold, run some water from a hose or oil from oiling can over manifold casket and if there is a leak you will see it being sucked in. Alternatively just recheck nuts for tightness

Cheers

Joe

[Worby876]

Hi fellas...Thanks for all your suggestions...wow...there a lot of possible things to cause this problem eh?

Well I had a look at the Oil level this morning and she is full and a nice honey colour, as she has hardly
done any miles since the last oil change..less than 100 I figure.

I tried to start her on LPG and she struggled to start..and wouldn't idle...kept on dying.
I gave her some revs and kept the idle up hoping she would come good when it got a bit warm
but was very lumpy and rough and finally died.

I tried again with a little adjustment on Dads advance device that moves the dizzy around a bit for
better performance on ULP and LPG see here if your interested.

http://gallery.oldholden.com/Jack_s/Adjustable+Distributor+Settings+whist+on+the+move/

and this thread here     

http://oldholden.com/node/27503#comment-110284

I noticed the fan belt was squealing a bit when I gunned the revs so i will retention the fan belt at the alternator,
but doubt this is a factor of the probs...(everything happens in 3's so Im told)

Also I noticed the flashlube reservoir was empty ...so I bought a new bottle from Super-cheap Auto along with a new timing strobe light
& cylinder pressure meter kit oh my aching wallet ...credit card actually  :'(

So after I refilled the Flashlube bottle I restarted her but still wouldn't idle...rough as guts...

I tried her on ULP and after pumping the gas peddle finally she coughed to life and hey presto...shes purring
away ever so nicely on ULP (petrol) I reset the lever on Dads gismo for ULP and the idle was nice and smooth.

So I drove her back in the drive way (not risking a run just yet in case i can make it back up the Hill where I live..
very steep (I reckon 16% grade or more...Its a bugger to walk up if your not fit ...like me  )
 Anyway I stopped her, and flicked back to LPG and she stated but still rough and lumpy and dies..What the @#$..

Back inside for a cup of tea and a lie down and try to figure what is going on...most strange...

It could be the valve rods not set right as per one of the posts..I didn't know they where hydraulic lifters
I just thought they rod up and down on the cam and the "T" pieces and rocker covers tensioned down
kept them all nice and snug...Are all 202 fitted with Hydraulic lifters?...I didn't recall the workshop manual
say anything about resetting them one by one after the headgasket removal change over?

I will experment with the timing light to see if its all synced OK with the dizzy etc and to see if the mechanism dad made
does advance the light about and inch or or so back and forth which according to his notes equals 6 to 12 degrees.

Im in uncharterd territory here fellas..so bear with me   

Then I guess I will take the engine cover off and test the compression of all the pots to rule out any possible damage
or enset of Valve seat Recession (VSR) ..boy I hope not...

Hey will this also tell me if I need to reset the valve push rods ? Or do I have to take the rocker cover off to do that?

Thanks again for all your suggestions and interest....I should be out enjoying the holiday eh..the joys of motoring and all that.

but sounds like i'm in good company eh?

Cheers

Ian

[rossie]

if shes running good on petrol, and goes to crap when you turn it to gas, when cold and not when hot. Try the gas system, sounds like it migh be jelling up and needs a clean