Very good explanation

I've just taken the tappets out of the gf's d2, rebuilt engine but rockers were over shimmed for some reason, tappets were topped out to the point a few rods were loose enough to make a racket. Many thanks for your content, gave me enough motivation to just do it myself and save myself for outsourcing idiocy.

@churchhouseclassics

2 жыл бұрын

That is the #1 reason for my videos. It started long ago when I found that nobody could tune carbs any more and to be frank that is a piece of cake if you know how. 👍🍻

THANK YOU... I did not know about this, too late now car long gone, this could well have explained a few things.. I figured the hydraulic tappets took care of it. Thanks again to Haynes for no mention on this, can't see anything myself in the RAVE manual either in response to previous comment.

@andyrbush

3 жыл бұрын

I have found the Haynes manuals to be a complete waste of time. I invest in the OEM manuals and have found so many details that Haynes never mention. A good example was with a Camaro 3rd gen, where the OEM manual said that the car would over heat if left in drive when not moving, because the radiator was originally sized for a manual transmission.

Having too much preload will not cause the valves to be held open, the lifter just fills up with oil but the oil pressure is not anywhere near high enough to lift the valve, once the lifter is full of oil it effectively becomes 'solid' once the lifter is off the base circle of the cam, this is because the oil port in the lifter tunnel no longer lines up with the recess in the lifter. The only way the valve could be held open is if the lifter was 'bottomed out, it would need a few hundred thou of preload to cause that! Having a lot of preload is not a good idea for another reason which is that Rover use the fact that the lifters start to pump up at around 5400 rpm, this is because the standard valve train will start to float at this rpm. When a lifter is pumped up it will hold the valve off the seat until the lifter can bleed down whilst it is on the base circle, this causes a mis-fire which acts as a crude rev limiter. (It can only be filled with oil or bleed down whilst its more or less on the base circle). The big issue is that at around 20 degrees BTDC to 10 degrees ATDC a lifter that has pumped up will be holding the valve at a higher lift than 'normal', this could be critical at the end of the exhaust stroke when using a long duration cam because the piston could end up hitting the exhaust valve, at no point should the exhaust valve be closer than 2mm away from the piston. I've built loads of Rover engines where 'eye browse' need to be cut into the pistons in order to have enough clearance. (Easily checked with weak checker springs at 5 degree intervals from 20 BTDC to 10 ATDC). Bear in mind that if the lifter has a preload of 40 thou (1mm) then it could hold the valve open 1.6mm more than it is supposed to be open at any given time if it has pumped up . Skimming heads and decking the block also brings the valves closer to the pistons. Shimming the pedestals is not the best way of setting the preload, the valve train geometry on a Rover engine is already quite poor, just look at the wear on any of the rocker pads (the part that contacts the tip of the valve), you can see that the pad contact gets very close to the edge of the valve stem, it can become a point contact rather than a line contact, high lift cams make this worse, as does shimming the pedestals, in fact I machine about 1.4mm off the pedestals when using any form of 'high lift' cam, this greatly improves the valve train geometry. I then use adjustable push rods which normally need to be shortened several mm (approx 5mm). It is then very easy to setup the preload, all that needs to be done is to adjust the pushrod so all of the play is removed, then wind on 5 'flats' on the adjuster, this will put about 23 thou of pre-load into the lifter. Having said all that if you are just re-building a bog stock old snotter then I understand that people might not go to all the trouble that I have mentioned above but if you are building a 'hot' V8 you need to go the extra mile and get everything spot on!

@churchhouseclassics

3 жыл бұрын

Superb advise from an engineer, many thanks indeed for taking the time to share this info 👍

@sidecarbod1441

3 жыл бұрын

@@churchhouseclassics Thanks for the complement, I've built quite a few Rover V8's and I am also learning more and more 'stuff' whenever I can.

@richardmarkham8369

2 жыл бұрын

Sidecarbod, ever done any videos of Rover V8 rebuilding?

@sidecarbod1441

7 ай бұрын

@@richardmarkham8369 No I've not, I must admit that I just comment on other peoples videos! I have done a load of work on Edelbrock carbs which I use on Rover engines, I actually have made my own needles and primary boosters for these carbs, (The Edelbrock annular boosters are pretty crap!) I've also done a load of work on ignitions systems for the V8. I lock out the dizzy after replacing the internals of it and then use it to trigger a programable MSD system. I was thinking about doing some videos on this stuff. The last engine I built was a 4.6, running an Edelbrock 500 carb and MSD system, it knocked out 315 BHP on the rollers which isn't too bad! I actually have an engine in my Cobra 427 kit car which is built to the same spec as the 315 BHP engine but I run it with a 115 BHP nitrous oxide shot, so I guess it makes about 430 BHP....I don't use the car in the wet! LOL

Very interesting, I think I would need to see how to measure the clip clearance really close up for myself as I couldn't be sure I was seeing it correctly.

Very interesting there has been a lot of crap talked about the preload I get it now .Have you any more video on the cam change I would like to change the cam in my 4.6 when the weather gets better, any more information would be very gratefully received.

Очень показательные видео спасибо

@churchhouseclassics

Жыл бұрын

My pleasure

Thank you so much for this video. I am going to have to make another attempt as I have either bad rockers or my preload is wrong. I am not sure which but it needs to be done. Do you have any advice as to when to know if your camshaft is on its way out?

@churchhouseclassics

4 ай бұрын

camshafts usually need replacing at anything after about 65k miles, they still work, indeed mine was still ok at nearly 200k but I definitely noticed this improvement fitting a new unit. shadows across the tip of the lobe is the usual sign that it is worn out. If you have built yours up and it is ticking, there are some very very cheap and nasty hydraulic followers available with a horrific fail rate. kzread.info/dash/bejne/k2t8qamjo5nKpJc.htmlfeature=shared is a good one that explains the issue. drop me an email if you need help

Скиньте пожалуйста распечатку листа которую показывали. Спасибо

@churchhouseclassics

Жыл бұрын

send me an email address and I will to churchhouseclassics @ gmail . com

Why would it hold the valve open when the valve spring is many times stronger than the tappet spring? Also when shimming the pedestals it would be fatal not only to block the oil galleries but also to fail to check they were adequately sealed once assembled in order to prevent a loss of oil pressure?

@churchhouseclassics

4 жыл бұрын

Tappet spring may be weaker than valve spring but when it is bottomed out it is metal on metal... Plus you need to include oil pressure which adds to the tappet spring strength. Also shims are flat and true, in fact probably seal the issues that will exist between the head face and the rocker pedestal. only really needed for skimmed heads, else possibly not needed

@juancornetto8243

4 жыл бұрын

@@churchhouseclassics I get what you're stabbing at. The only way extra oil is getting in though is if the pushrod is not pressing on the tappet. So as you say, so long as the tappet isn't bottomed out to begin with it should be good. appreicate that the official shims are tailor made for the job, but for the benefit of anyone else watching don''t just smoke up some shims using aluminium cans as you might knacker your oil feed/pressure. cheers.

@moienghafari6629

3 жыл бұрын

could you pleese explain how lifter work in the system, my mean is how hydraulik lifter work when the v/v is open and close. thanks

How much the camshaft bolt torque.

@churchhouseclassics

3 жыл бұрын

Hello, 58nm is what the manual says, I also use a dab of threadlock

Did you ever realise that the spacer behind the cam gear was on the wrong way round?.....

@churchhouseclassics

5 жыл бұрын

I must have but couldn't remember so I invested 40 minutes yesterday. The Haynes WM is not clear on it but the parts and official WM are.

If these tappets are self adjusting then why would you have to use shims?

@churchhouseclassics

2 жыл бұрын

Because the hydraulic tappets have a limit to how far they move and are built to a tolerance. Perfect until you skim 20thou off the head or deck the block and all of a sudden the pushrods are too long. so then you get into adjustable pushrods which to be honest is the solution, or shim the rocker gear pedestal which is fine for most scenarios.

Why doesn't someone make adjustable rocker arms??

@churchhouseclassics

Жыл бұрын

with hydraulic tappets? you can get adjustable pushrods but doing this will save you a shed load

Does anyone make solid lifters and adjustable tappets instead of this complicated setup?

@churchhouseclassics

10 ай бұрын

Yes indeed, they are available but pricey. Up until recently a good supply of reliable hydraulic lifters was available from a US supplier. I note that Britpart now supply an OEM tappet at near 3 times the cost of the unreliable unit that they also sell

@sidecarbod1441

7 ай бұрын

@@churchhouseclassics BritPart....really they should be called ShitPart! There are loads of lifters that can be used because basically a Chevvy lifter will fit. BUT the ball-socket size of these lifters is smaller so you cannot use a standard pushrod with them, RealSteel supply both ball sizes when you buy there adjustable pushrods, you then just tap in the correct size ones. (don't mess this up, they are hard to get out!)

That's Rover V8 and not range Rover right?

@churchhouseclassics

2 жыл бұрын

Not sure I understand your question, it is indeed a Rover v8 3.5 and was installed into a Range Rover

@stuarthart3370

Жыл бұрын

I think you're asking whether that's a Rover V8 engine, or a Range Rover engine. Since Rover fitted the heavily, or really that should be lightly, modified Buick V8 engine to a range of cars and other vehicles for: Rover; Land Rover; and Range Rover, as well as cars like the TVR, the Morgan, and a range of other sports cars for smaller manufacturers, then the answer is it could probably fit in a Land Rover a Rover SD1 etc. it's worth reading the history of the engine and how Rover made a very impressive engine out of a cast off from Buick. Casting was the key :-)