Supra is at Hyper sr for single turbo

[j80leo]

Just going off what the mechanic said he was going to do not sure why he is doing this my head is not warped the engine has only got 58k on it so in very good condition

[dunk shaw]

58K on the engine is good so the bottom end ie shells and crank journals shouldnt be an issue, i still cant see any point in skimming the head if its not warped.

[Martin F]

Originally Posted by dunk shaw

i still cant see any point in skimming the head if its not warped.

Me neither

[Angry Koala]

I've always been told you never split an engine unless there's a need to do so....

I may therefore be showing my ignorance but why would you have the head off an engine with only 58k on it? I wouldn't have thought the valve stems would need doing that early would they and even if they did I was under the impression that this doesn't require the head coming off anyway?

And why are you having the valves cut back (what does that even mean? I've heard of fitting larger valves for increased performance but never cutting them back and just interested in the reasons/benefits)?

[dunk shaw]

Originally Posted by Angry Koala

I've always been told you never split an engine unless there's a need to do so....

I may therefore be showing my ignorance but why would you have the head off an engine with only 58k on it? I wouldn't have thought the valve stems would need doing that early would they and even if they did I was under the impression that this doesn't require the head coming off anyway?

And why are you having the valves cut back (what does that even mean? I've heard of fitting larger valves for increased performance but never cutting them back and just interested in the reasons/benefits)?

Im in the same school of thought and if it aint broke dont fix it lol, it does seem a little strange taking it off to do jobs that at 58k shouldnt need doing, if its playing safe then you might as well pull the motor out and do the whole lot !

I can see cutting the valves in being a good idea but i'd have had it leakdown tested 1st which would have showed if it needed anything doing.

All the best Adam and hope you dont think im getting on your case, just dont want you wasting your hard earnt dosh.

[j80leo]

Originally Posted by dunk shaw

Im in the same school of thought and if it aint broke dont fix it lol, it does seem a little strange taking it off to do jobs that at 58k shouldnt need doing, if its playing safe then you might as well pull the motor out and do the whole lot !

I can see cutting the valves in being a good idea but i'd have had it leakdown tested 1st which would have showed if it needed anything doing.

All the best Adam and hope you dont think im getting on your case, just dont want you wasting your hard earnt dosh.

Just having the uprated headgasket to prevent it going in the future paul told me when you remove the head it twists slightly so thats the reason you have to skim the head thats what i have been told and the thicker headgasket ends up only been around .5mm thicker than stock headgasket so not a major difference, he has also done the leak test before removing the head and all is fine i trust his judgement on this and Dunk i do not think your getting on my case your like my older brother much older lol

[UltraFlynn]

Originally Posted by j80leo

...much older lol

ROFL

[j80leo]

Originally Posted by Flynn

ROFL

You liked that one Matt

[Martin F]

Originally Posted by j80leo

Just having the uprated headgasket to prevent it going in the future paul told me when you remove the head it twists slightly so thats the reason you have to skim the head thats what i have been told and the thicker headgasket ends up only been around .5mm thicker than stock headgasket so not a major difference, he has also done the leak test before removing the head and all is fine i trust his judgement on this and Dunk i do not think your getting on my case your like my older brother much older lol

OK, just to clarify something, i'm purely trying to give advice here to try and assist, because something is not ringing true with either the advice your mechanic is giving or what you are posting here.


As the other guys have said, it's generally accepted not to remove the head unless you have good reason to. I thought your mechanics reason for removing the head was to do the stem seals, which can be done without removing the head but some mechanics preference may be to remove the head. If he is removing the head on a 58k good condition engine just to have a look i'd walk away now before he inflates your bill further.

As for upgrading the stock headgasket, what a 'croc of shit' that is. Have you ever heard of problems with the stock headgasket? (unlike MKIII's) A lot of guys in the states running big power continually use the Toyota gasket for good reasons, it's a good quality part.

The heads can warp when they are removed, but it's not necessarily the case and there is a good procedure in the Toyota manual for checking the head once it is removed to see if it needs skimming.

By my (very) crude calculations by fitting a headgasket 0.5mm thicker than stock, your compression ratio will go from 8.5:1 to 8.1:1 (may want to get somebody else to double check these calcs, like your mechanic) which will result in a slight decrease in performance off boost, but may allow slightly higher boost. Are you sure that is your desired result?

[j80leo]

Originally Posted by Martin F

OK, just to clarify something, i'm purely trying to give advice here to try and assist, because something is not ringing true with either the advice your mechanic is giving or what you are posting here.


As the other guys have said, it's generally accepted not to remove the head unless you have good reason to. I thought your mechanics reason for removing the head was to do the stem seals, which can be done without removing the head but some mechanics preference may be to remove the head. If he is removing the head on a 58k good condition engine just to have a look i'd walk away now before he inflates your bill further.

As for upgrading the stock headgasket, what a 'croc of shit' that is. Have you ever heard of problems with the stock headgasket? (unlike MKIII's) A lot of guys in the states running big power continually use the Toyota gasket for good reasons, it's a good quality part.

The heads can warp when they are removed, but it's not necessarily the case and there is a good procedure in the Toyota manual for checking the head once it is removed to see if it needs skimming.

By my (very) crude calculations by fitting a headgasket 0.5mm thicker than stock, your compression ratio will go from 8.5:1 to 8.1:1 (may want to get somebody else to double check these calcs, like your mechanic) which will result in a slight decrease in performance off boost, but may allow slightly higher boost. Are you sure that is your desired result?

When the mechanic did the leak test one cylinder was a tad low hence removing the head but he then found that it was something else causing the slight low compression (i think it was the head gasket that caused it) as for the lower compression ratio then i would like it to be as standard but if thats what i have to go with then thats what i will do i trust his judgement over myself as he has been tuning supra's a lot longer than me thats why i take it somewhere that is skilled in this area, you can't take your car somewhere and then keep ringing them up telling them how you want your car tuning as you might aswel do it yourself my understanding about lowering the compression ratio is you lower the chance of the engine causing detination but the down sind is tad more lag because the burn front of the fuel has changed.

One question has anybody who is saying this is the wrong way of doing this, have you been out in a car that has had this done this way over the other way and noticed that much lag it was noticeable??