Piston Slap??

[sumo]

Hi All, My 100s Tojo 4.7L V8 Petrol suffers piston slap, It was supposingly

Rebored and oversize pistons fitted. ,about 18mths ago, Ihave had it to a reputable engine builder who had a camera down no6 bore and could see some chaffing , I.m under the impression now that it was honed and standard pistons fitted, It goes well no oil issues does everything right its just this rattle on start up and sometimes under load, It reacts different to temperature as well after a run it seems to get to a certain temp and will sit there idling quite as a church mouse, and sometimes if you push it along and get it hot the rattle will appear again. I'm running Penrite 20/50 with a lucas additive in it, could not get a oil more slippery than this mix i tell you. My question is has anyone had experience with the brass band playing in their donk, Thought i would ask the knowledge bank here as the

toyo boys won't admitt to any probs they think nothing can go wrong.:mad:

Is this thing going to explode:eek: Some have said no, others have said yes,


Cheers Sumo:)

[Tank]

Well if was honed and standard pistons fitted, then unless the piston to bore clearance was correct, I would be taking it back to the engine builder, oversize pistons are stamped on the top of the piston, get the bloke with the camera to have a look see. Standard bore size pistons have no marking on top. If for instance the engine was bored 20 thou. (") OS then the piston will have .020 stamped on the top, also if they honed it out and used standard pistons and rings then the ring gaps may not be correct, Regards Frank.

[Blknight.aus]

I'll back what tank said and to answer your question.

yes, drive it hard enough long enough like it is and it will eat a piston then chuck a rod..

[scarry]

yes, drive it hard enough long enough like it is and it will eat a piston then chuck a rod..


Yer,but isn't that normal for any Tojo.................






:wasntme:

[Ace]

How long ago was the work done and im assuming it was done before you bought it?

[rovercare]

I'll back what tank said and to answer your question.

yes, drive it hard enough long enough like it is and it will eat a piston then chuck a rod..

Its how you build high horsepower engines, loooose;)

but a 3UZ-fe should be deadly quite

[sumo]

How long ago was the work done and im assuming it was done before you bought it?

G/Day Mate, It was done after i bought it, by dealer, as i picked up on piston slap a day after i bought it.I did roughly a 80k test drive and there was not a noise in it, so you can imagine the fight i had with the dealer. Anyway they pulled the sump off as they reckoned it was a bottom end noise,and yes there was wear there,(175000ks???????), so they said they where obliged to fix the knock,The crank was ground and all new bearings went in, LOand Behold they never looked at the rest of the motor,so on the day they rang and said all fixed,i was actually getting excited,got there started it up and would you believe the thing was knocking its head off. How the hell any sort of dealer or mechanic could stand there and say it was fine has still got me stuffed:mad::mad::mad:, After the biggest showdown,of all time they kept it and pulled the top end down, it was then you could see evidents of piston slap on 4&6 cyls, So out the motor came again:mad: and thats when i was told a rebore was to be done and new pistons fitted, TWO MTHS THIS WAS GOING ON FOR:mad:, Any way
It was all done put back together, and of course the phone call again come and get it, Took the keys off the salesman and went over jumped in and started it up, NO I"M NOT JOKING!!!! IT SOUNDED LIKE THE LOCAL BAND UNDER THE BONNET,:confused::confused:,They stuffed up with the shims up top, But once again why say its all good? Anyway i could go on &on, but finally they got it right, and it was good for about twelve mths, then a ever so slight rattle appeared but not to concerning, But two yrs on its noisy on start up and until it gets a fair bit of heat in it.Smooth, no oil issue, plenty of grunt. My guess is they put standard pistons back in and a couple of bores have been more worn than the others hence the return of the rattle. I've decided to drive it till it drops then source another motor........Well have you ever heard a story like that, and thats only about half of it:mad::mad::mad::mad::mad::mad::mad:

Cheers Sumo:D

[Tank]

Sounds very dodgy to me, the engine would have to have been taken out to remove the crank and the head would have been taken off to remove the pistons, so you're saying they removed the engine, removed the crank, had it reground without taking off the head, Dodgy Bros. Inc. and what are these "shims" they stuffed up "up top".
What you should have done if you have no tools or mechanical knowledge would be to go to a competent mechanic, have him remove the engine, then take it to a Reputable well known engine reconditioner and have them rebuild it, at least you would get a warranty, Regards Frank.

[clubagreenie]

The shims they stuffed up would be the cam bucket shims. They run over bucket shims (sit ontop of the valve buckets), ok for std use but at high rpms they can flick out. So you can convert to shim under of shimless (the whole bucket is available in different sizes or you grind the tip of the valve)

I can say with certainty that these are a bomb proof engine as long as you keep the oil changed reasonably regularly and nothing interrupts the oil supply, especially at the front pair of big end bearings.

How? How's 14000rpm and 800+hp at the wheels, naturally aspirated std crank, destroked and oversized back to 4.7.

Only issue I had was oil supply at the front big ends. The gauge showed better than expected pressure, that turned out to be due to despite opening up the crank ports and block galleries and asking for the bearings to be supplied drilled and chamferred one wasn't (didn't inspect all of them as it turned out). The reduction in flow backed up the pressure and thus showed better pressure, the gauge sender takes pressure from between the first and second galleries (from the front) but oil flows from back to front. The oil wedge on one side of the bearing was reduced and it had a cycling knock sound as well as scuffing on the associated bores. After a new crank as it pick up and spun half the bearing over the other, opening the oil ports more (& progressively back to front) oil pressure stabilised back to a more normal level as well just being smoother and quieter.

Getting back to your issue. I'd try a lighter oil (on the cold side, still 50 on the hot), we used to run 50 mono but pre heated oil and water. Getting the oil up to all the moving parts (and there's hundreds) is key. Also have them check the oil return paths down to the sump. They are just a straight drop to the sump but can sludge up and stop oil getting back to the sump quick enough. If it was only honed then std pistons should be fine but if it was scuffed enough for that I'd expect a oversize and new pistons.

On the whole, it'll need a complete rebuild. Could be made very reliable, improve the oil flow and running temps with very little mods and few extra's apart from what you'd need anyway. Everything can be found on ebay or from the US.

[Ace]

G/Day Mate, It was done after i bought it, by dealer, as i picked up on piston slap a day after i bought it.I did roughly a 80k test drive and there was not a noise in it, so you can imagine the fight i had with the dealer. Anyway they pulled the sump off as they reckoned it was a bottom end noise,and yes there was wear there,(175000ks???????), so they said they where obliged to fix the knock,The crank was ground and all new bearings went in, LOand Behold they never looked at the rest of the motor,so on the day they rang and said all fixed,i was actually getting excited,got there started it up and would you believe the thing was knocking its head off. How the hell any sort of dealer or mechanic could stand there and say it was fine has still got me stuffed:mad::mad::mad:, After the biggest showdown,of all time they kept it and pulled the top end down, it was then you could see evidents of piston slap on 4&6 cyls, So out the motor came again:mad: and thats when i was told a rebore was to be done and new pistons fitted, TWO MTHS THIS WAS GOING ON FOR:mad:, Any way
It was all done put back together, and of course the phone call again come and get it, Took the keys off the salesman and went over jumped in and started it up, NO I"M NOT JOKING!!!! IT SOUNDED LIKE THE LOCAL BAND UNDER THE BONNET,:confused::confused:,They stuffed up with the shims up top, But once again why say its all good? Anyway i could go on &on, but finally they got it right, and it was good for about twelve mths, then a ever so slight rattle appeared but not to concerning, But two yrs on its noisy on start up and until it gets a fair bit of heat in it.Smooth, no oil issue, plenty of grunt. My guess is they put standard pistons back in and a couple of bores have been more worn than the others hence the return of the rattle. I've decided to drive it till it drops then source another motor........Well have you ever heard a story like that, and thats only about half of it:mad::mad::mad::mad::mad::mad::mad:

Cheers Sumo:D

Not good at all mate, I'd be getting them to chip in pay for some of the replacement engine to be done by someone else. Thats just not good enough, especially when it would appear that their idea of "right" is not the same as yours. Are they all deaf mechanics?