Top End Refresh....

Just been given the OK by the other half to look into a Top End Refresh of the P38A

If y'all been following my previous threads and my trials with low oil pressure etc....you'll know I have refreshed the bottom end with new bearing on the Crank and Big Ends.

Oil pressure is 1000% better, but still flickering light at idle for longer than a couple of minutes....blip the throttle and it will recover!

Anywho, spoken with the other half and she says I can go for a refresh of the top side! I said I would like to do the camshaft, followers, push rods, rockers, and rocker shafts....but mostly the rockers and shafts!

She said, while its apart you may as well go a bit further and do the lot!

Love her.......

OK, now the question.....when it comes to the Rockers etc....do I just change the Rockers and Shafts....or should I change the rockers, shafts and pedestals or the whole assembly including the springs and washers...etc??

Whilst she has given me the go ahead, I would still like to not spend for the sake of it!

Not looking for power as the motor has done 178K and I am not a racer so I will be going for a standard profile Cam.....only thing for the 4.0 V8 Island 4x4 only list a Britpart shaft....any comments on this or a supplier of a better quality shaft if the Britpart one is a bit poo...!!!

Rockers and shafts renew and also cam followers if you are replacing the crank Pedestals should be OK springs should be ok so you dont have to take the head off

St.

I don't think your bottom end is sound enough to invest any money on the top end.

I was always told to avoid oil pressure warning light at all cost.

A long long time ago, I ran a car with an oil pressure gauge.

The gauge was on 5pis and oil light was out. After lots of talking around, if oil light is on then you are 'breaking; the engine..

I think you may have gained some time but it sounds broken or raise your engine tick-over maybe to get it away from oil light on region.

best of luck

Cheers for the advice Don, the oil light only flickers on then off a couple of times at idle, it is not on permanently...

Appreciate what you are saying about the bottom end not being sound enough...but with new bearings on the mains and big ends....then there is every possibility that the pressure loss could be through the rocker shafts due to wear.

So the bottom end could be sound and the next weakest point could be the top end of the engine!

Even if it doesn't solve the issue....at least the forum will get a 'How To' out of it for changing the cam, followers, rods, rockers, shafts and pedestals!

Hi ,dont know if its any use ,but just seen genuine L/R camshaft on E bay in P38 Rangerover

Products - Piper Cams - Europe’s leading manufacturer of performance camshafts

RPi Engineering - V8 Engine and Component List

V8 Tuner - Rover/Chevy/Ford V8 - Camshafts

( i keep thinking about a cam for the 4.6 and the 3.9)

Even if it doesn't solve the issue....at least the forum will get a 'How To' out of it for changing the cam, followers, rods, rockers, shafts and pedestals!

With this attitude and your willingness to get stuck in and do the job, you deserve success!

I'm with you - now you've done the bottom end it must be worth doing the top?
Good luck Saint

tarphenry said:

Hi ,dont know if its any use ,but just seen genuine L/R camshaft on E bay in P38 Rangerover

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mmmmm,i bought a "genuine" l/r camshaft of the bay of e about a year ago,it lasted 3000 miles and it was f££ked.i did the job a second time with a kent h180 cam from turner engineering just to guarantee the quality of the parts.

donp38 said:

St.

I don't think your bottom end is sound enough to invest any money on the top end.

I was always told to avoid oil pressure warning light at all cost.

best of luck

Click to expand...

+1 also ant I would wait a short while more for the shells to bed/mate the crank as you could be back at the start line again in a matter of weeks,imo needs a crank grind, o/s shells & brand new oil pump atleast m8

Thanks for all the advice guys, I understand what you are all saying about the bottom end, but when I bought the car, there was no oil pressure issues....just a leak.

I cured the leak with a replacement front cover, but the oil pressure kept running low with this front cover, so after putting up with it for a while I replaced the oil pump, which made no difference, so i went to out the original pump in the second cover...and bust the front cover....so I replaced the original cover with the new pump, and found the source of the leak and solved it, but I struggled to get any pressure with this....

So I replaced the mains and big end bearings and I now have pressure back. If she idles for longer than 2 minutes then the light flickers on and off....raise revs to around 1000 and the stays off, go back to idle and 2 minutes later the lamp flickers a couple of times!

So who's to say that the period run a while a go with dubious oil pressure knackered the main bearings etc...so they have been done, and also during this period it knackered the rocker shafts too!!

Replace the cam, followers, shaft, rockers etc....may plug the pressure drop!!

Got to be worth a punt!!

As I said the engine was fine until i changed the front cover!!

Saint.V8 said:

Thanks for all the advice guys, I understand what you are all saying about the bottom end, but when I bought the car, there was no oil pressure issues....just a leak.

I cured the leak with a replacement front cover, but the oil pressure kept running low with this front cover, so after putting up with it for a while I replaced the oil pump, which made no difference, so i went to out the original pump in the second cover...and bust the front cover....so I replaced the original cover with the new pump, and found the source of the leak and solved it, but I struggled to get any pressure with this....

So I replaced the mains and big end bearings and I now have pressure back. If she idles for longer than 2 minutes then the light flickers on and off....raise revs to around 1000 and the stays off, go back to idle and 2 minutes later the lamp flickers a couple of times!

So who's to say that the period run a while a go with dubious oil pressure knackered the main bearings etc...so they have been done, and also during this period it knackered the rocker shafts too!!

Replace the cam, followers, shaft, rockers etc....may plug the pressure drop!!

Got to be worth a punt!!

As I said the engine was fine until i changed the front cover!!

Click to expand...

The rockers would be the last thing to receive oil if the mains had gone. Which they had. So if the mains were that bad the rockers should be a lot more worn. Cam shaft bearings maybe knackered as well you have opened Pandoras box.

personally ant id run the thinnest oil possible not adding any addatives at all so oil can circulate get to the top end & back to sump asap ,mobil 1

wil2813 said:

personally ant id run the thinnest oil possible not adding any addatives at all so oil can circulate get to the top end & back to sump asap ,mobil 1

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:crazy::crazy::doh::doh:

wammers said:

:crazy::crazy::doh::doh:

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so why not never hurt any v8 p38 ive owned

wil2813 said:

so why not never hurt any v8 p38 ive owned

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Running thinner oil won't do much good at all for oil pressure issues.

:5bwilly_nilly:

wil2813 said:

so why not never hurt any v8 p38 ive owned

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Stick some 3 in 1 in it and see what happens.

Just a passing thought - I don't know if I missed it in this or the previous threads on the oil pump replacement and new bearings, but have you connected a gauge to check the actual oil pressure, i.e. could the pressure switch for the warning light be faulty?

Alastair

I've always run 20/50 changed every 3K miles in the TVR, but a good one like Valvoline VR1, however they have the older oil pump (pre serp) design.

These old buick V8's weren't designed for thin oil IMHO.

Will you need to set the preload on the rockers?

donp38 said:

St.

I don't think your bottom end is sound enough to invest any money on the top end.

I was always told to avoid oil pressure warning light at all cost.

A long long time ago, I ran a car with an oil pressure gauge.

The gauge was on 5pis and oil light was out. After lots of talking around, if oil light is on then you are 'breaking; the engine..

I think you may have gained some time but it sounds broken or raise your engine tick-over maybe to get it away from oil light on region.

best of luck

Click to expand...

Tend to agree - shells that have worn down to the backing metal usually means crank journals have suffered. Even if the oil light is extinguished, it doesn't neccessarily mean everythings OK. 10 psi at 2500 rpm is a no-no. The engine has suffered from low oil pressure before your rebuild, so what other bearings/surfaces have taken a hit?

Try to hook up a gauge if you can and go from there. I'd be a bit worried if I had changed the shells and the light still came on at idle - somethings still amiss.

A thought - when you fire it up from cold, how long 'til the light goes out?