Phil Bennett

Wonder if anyone can help (or suggest someone who might know the answer) with my injection pump ?

1970 Mack with the ENDT864 engine (am aware not one of Mack’s finest engines..)

 

AMBAC Rotary PSM pump (I know, not a brilliant pump as well…)

 

Problem: When cranking engine, it goes from ‘not firing’ to ‘running away’ at 1400rpm with the lightest of throttle movement.

 

Recent work done:

1) Pump is overhauled (in the UK by person familiar with the PSM pump), is refitted and all works fine.

 

2) Engine then just stops running after about 15 mins of running on tickover.

However, the injection pump’s ‘lift pump’ was a known problem as not able to find overhaul parts and the one fitted was the ‘best of two’, so suspected that as the issue.

 

3) Bypassed lift pump with electrical and all running again straight away, just fine.

 

4) Found overhaul parts in the States for lift pump and had one of them overhauled and tested here in the UK.

 

5) Refitted lift pump (now works fine) and, at same time, overhauled the throttle linkages / bushings and also ‘reworked’ the throttle rod to avoid a new fuel line fitting.

 

6) Have removed the governor cover to checked that the throttle linkage ‘movement’ is in sync with the governor, and all appears correct.

NB: Mack used to have a PTO, so we have a dash ‘fast idle’ pull lever which allows me to fine tune the tickover.  This pull lever is NOT at issue here – indeed it is useful to incrementally adjust the tickover

 

My questions are;

 

1) Could I have refitted the lift pump incorrectly that would cause the engine to ‘race’ ?

(or inadvertently moved something)

 

2) Viewing inside the pump once the governor cover is removed, I can see the movement inside the pump actuated by the throttle lever – which looks fine.

But can I view / check  this with movement with engine running and the governor cover removed ?

Or will I get oil squirting out ?

 

3) Or could it just be coincidence that something else in the pump may have failed to make it ‘race’ ?

 

Any thoughts / comment welcome.

 

Thanks

 

Phil

Hello to all,

Update on trying to improve on low engine power output on 1970 R719  ENDT864 V8.

Thanks for the many replies and suggestions.

So far;

New filters, fuel lines and fresh diesel.

As advised, I've adjusted the pump stud by 1/4 turn clockwise (screwed 'in'), but no change.

**Even after reading manual, I'm really not quite sure what this 'stud' adjustment does (see image) - any advice ? **

Fuel pump readings (no load) are from 15psi @ 600rpm to 31psi @ 2000rpm.

Might go back to basic checks such as re-torque head nuts (weak point) rechecking cylinder compressions, valve clearances and injector spray.

Plus check fuel pressure 'under load'.

Other comments welcomed.

Thanks

Phil

Hello Larry,

Thanks for comment.

In answer to your suggestion, "No", I do believe the linkage is working just fine.  But I will double check tomorrow.  Ironically I did have an issue with the linkage in that it was 'catching' on one of the exhaust clamps, but that was easily solved by loosening clamp and swivelling round.  I am aware that the external  'arm linkage' (which is connected to the throttle rods) on the side of the pump is kinda 'spring loaded' (looks by design) to avoid overstraining said arm when throttle at full stretch.

General consensus seems to be that the engine is running too lean (and that the turbos may be a little 'tired', though the lean fuels seems to be the first place to start.

Understand I need to slightly adjust the stud (slacken lock nut first) by winding 'in' 1/4 of a turn...  See image enclosed.

Thanks

Phil

 

Hello,

Wonder if anyone out there can offer any views / comments on my 'problem' ?

I have a 1970 R719 with the ENDT864 twin turbo V8 fitted, all pretty original.

Understand that engine should deliver around 300hp, but was not Macks finest and had 'issues'...

My Problem: Thought not used for everyday haulage (just shows), if I pull a ballasted 20' container (32 tons), I struggle to get much 'get up and go' over 35mph.

As if the 300 hp is just not there.

On a slight downhill road, it can (and will) do 50 mph.  But a slight incline, not really.

Compression fine.  Injectors fine (clean exhaust), fresh diesel, filters and replaced fuel lines.  Fuel pump pressure as per Mack manual.

Checking the Turbo boost pressures (no gauges fitted, but have added aftermarket to be able to check) only give (under load pulling 32 ton)

 

Mack Max RPM = 2300

 

1600rpm – 1800rpm = 2 to 4 psi.

 

Best PSI reading is just about 5psi when accelerating up to 2000rpm.

Am I expecting too much in the way of 'performance' from a truck of this age / era / horsepower ?

Thanks

Phil

 

 

 

 

Mike,

Thanks for comments. 

I suppose whether the poster sees my comments might depend if he has a copy automatically sent to his email address and how often it's checked.  or they might regularly check the BMT website for replies.... ?

You are probably right about the '719' being the ENDT864.

I made an error on the last paragraph by referring to '712' instead of '719' (I keep getting them mixed up - must be an age thing....)

It sure seems that the ENDT864 (of which not a huge number were ever made) is quite thin on the ground these days.  There is mine (in England), another in the States (NEK, Holliston) from the same batch as mine sent to Campanella of Warwick, Rhode Island, the two axle R series of Dan Thomas, plus your CF and, I believe, one or two other Fire Appliance versions.  Plus might be one or two in Australia left ?   Maybe a B series or two still about with the ENDT864.

Mine is kinda running OK - bit dribbly now, but always starts on the button no matter how long it is left standing.  Don't think it is knocking out 300ish hp though...  220,000 on the clock, which is prob correct considering it's use as short haul sand and gravel in its working days.  Complete truck still passes the UK VOSA test for trucks each year- same test as modern Volvo, Scani, Mercs etc

How is your doing ?

Phil

Hello

Bit behind with seeing this post, and not sure if I can help you, but... I to have the ENDT864 engine in my R719LS

If you google 'american bosch V8 diesel', then this website comes up.

www.nestimmobiliare.com/american-bosch-psb4a-fuel-injection-pump-manual.pdf

I've no idea if this is any good or not as I've never tried to open it....you have to 'sign up', and I did not want nor need to.

There was also somebody selling some PSM rotary Bosch pumps in eBay.  Item 321248648864.  But do pay $600 !  Offer less than $200 and they may well sell at that......

Would you be able to tell me if you do have a R712LS as opposed to the R700 ?  Thought the ENDT864 (twin turbo V8) was only fitted to the R712LS - maybe 272 of them made ?  Not a brilliant engine, it seems...

Phil

 

 

Hello,

I tried this ages ago, but thought I'd try again.

Looking for some 1100R x 22" (NOT 22.5") tyres for R719LS.

I know they are not very common now (still for sale in South America though, and, of course, the Chinese make 'em), AND I'm the wrong country too (UK).

Open to ideas / Suggestions.

Phil

Are you still interested in photos of R719LS ?

If so, I have one over here in England, so let me know.

Phil

Hello.

Wonder if anyone can help or advise ? (Have also placed this in the General Discussion)

Am over in England and my R719LS has the 1100R x 22" tyres fitted. (NOT 22.5")

Managed to buy x6 Firestone T575 highway tyres about 6 years ago, but could do with a final x4.

Firestones to match would be great, but other brands are fine (availablity seems limited these days).

Anyone any experience in procurring these 1100R x 22" ??

I can container them from Apopka, Florida.

Thank You !!

Hello.

Wonder if anyone can help or advise ? (Have also placed this in the General Discussion)

Am over in England and my R719LS has the 1100R x 22" tyres fitted. (NOT 22.5")

Managed to buy x6 Firestone T575 highway tyres about 6 years ago, but could do with a final x4.

Firestones to match would be great, but other brands are fine (availablity seems limited these days).

Anyone any experience in procurring these 1100R x 22" ??

I can container them from Apopka, Florida.

Thank You !!

Hello. Wonder if anyone out there can help ? Am based in England (UK) and have a R719LS (1970).

It's has the quadreplex gearbox set up (5spd + 4 spd) and is fitted with a PTO located on the passengers side of gearbox.

I'd like to remove said PTO and 'blank off', but has anyone any advice before I just go undoing bolts etc. Will oil flow out ? Will internal parts fall out ?

I'm sure I can have made up a suitable 'blanking off' plate securely affixed and sealed.

Any suggestions welcome.

Thanks

Phil