Jump to content

BlownCoronas 1971 Toyota Corona


BlownCorona

Recommended Posts

On 20/06/2019 at 14:10, BlownCorona said:

ive got a lead on an old school reconditioner that 2 of my work mates have worked with (one even did his apprenticeship with him) and a third work mate has been a customer. he sounds experienced and well priced. im unsure what sort of a bill to expect though. 

i can buy 1mm over pistons but im not all that sure thatll be enough 1.5mm (90mm) would be preferable if i can find something thatll cross over. 

ive not looked at the valve seats, its another thing i didnt really worry about because of the good comp test ect. will have a look once i grab a valve compressor. hopefully they arnt fucked too. 

 

it genuinely did go well. im very surprised to say the least. 

 

Factory 2ARFE pistons might work as they are 90mm

Factory compression ratio is 10.4:1

2ARFE

 

Head 50cc

Pins 22mm

Rods 157.5mm

Comp height 34.8mm

 

Think the dome is -10cc from memory and can't remember the pin height (also no idea what 18r pistons pin height is)

Would need to see how they compare but heaps of wrecks around with them so can be found cheap and stock 2ARFE seem to handle 350whp

Wouldn't be hard to work out what comp you would get in the 18R if you know the headgasket thickness and combustion chamber size of the head, if the rods are shorter then youll lose some compression but that wouldn't be a bad thing anyway :p

Not sure if this is helpful or not

  • Like 1
Link to comment
Share on other sites

  • Replies 250
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

I'm a little worried that the source of my leak into the cooling issue could be related to this, and there's a crack somewhere in there. 

Any ideas on how to check for this, or would it be rather obvious? 

 

The machining isn't something you can do @NickJ? Though I think your shop does cnc stuff primarily yeah? 

Edited cause of wrong Nick taged lol. though i think NickM is actually someone who works in the motorsport industry 

Link to comment
Share on other sites

8 minutes ago, Valiant said:

@bean.101 will know what to do.

Have a look over the other end of this thread and see what you think.

I'd be tempted to find some local pistons for a different engine that could be substituted. 

Water marks are gay. But not the end of the world. I had a 3ct estima that had bore rust from someone removing the head and leaving coolant (water) in the bores.  I rerung it and didn't smoke at all. But the corrosion hadn't eaten into the bore. It was more surface rust leaving a stain once honed. You really need to get the comp height of your original piston and go from there. We use the Wiseco website a lot for Piston info. They may have 18r info.

 

  • Like 1
Link to comment
Share on other sites

thoughts on the condition of 3 and 4? where the bore has deteriorated? 

a simple case of bore it out, or are there other factors?

 

i read your escort thread, looks like expensive (rightfully) processes which kinda bums me out right now. im not a particularly rich man, but the thought of shelving the project is even worse.

  • Like 1
Link to comment
Share on other sites

1 minute ago, BlownCorona said:

thoughts on the condition of 3 and 4? where the bore has deteriorated? 

a simple case of bore it out, or are there other factors?

 

i read your escort thread, looks like expensive (rightfully) processes which kinda bums me out right now. im not a particularly rich man, but the thought of shelving the project is even worse.

To look at via a picture they look similar. But its pretty hard to gage. Your welcome to swing past work with it. We have people come past regularly for info on bits and pieces. We wont charge anything to look at it and its far easier to get a better idea. Boring to the next oversize and living with some water mark staining would possibly be a best case scenario. Yes I understand the money side of things. Parts and Labour make it pricey.  

Link to comment
Share on other sites

3 and 4 are substantially worse. 1 and 2 are only stained and i cant feel anything with a fingernail. initially i thought all 4 were like that and i was happy to give a quick hone and carry on. 

where abouts do you work? i may be money poor but boy am im also time poor on another level... still keen to try get it in somewhere for a look. 

Link to comment
Share on other sites

2 minutes ago, BlownCorona said:

3 and 4 are substantially worse. 1 and 2 are only stained and i cant feel anything with a fingernail. initially i thought all 4 were like that and i was happy to give a quick hone and carry on. 

where abouts do you work? i may be money poor but boy am im also time poor on another level... still keen to try get it in somewhere for a look. 

Caraid 32 Duke st.  Ha ha cars will destroy both time and money.

  • Like 1
Link to comment
Share on other sites

Don't fall into the trap of thinking you need perfection if you know it ran well before.
Some engines builders scoff at me for saying this but... There have been many people who build engines with pitting in the bore.
One guy bored 90 thou' oversize and still had some pitting. He calls those pits "oil retention dimples" now.

1 mm oversize should cure the worst of it.

(This is only my advice and i cannot recommend pistons to fit as i know nothing of the pin height ect of said engine)

  • Like 3
Link to comment
Share on other sites

i know what your saying. 

put it this way, i had a thin rag wiping down the bores and felt 'dents' as i moved up and down, they are probably half a mil deep at an absolute guess. 1mil over would probably cure it, but if i can get something thatll do 1.5mil it would be sweet as.  one of the dents is weirdly smooth, not corrosion like at all. not sure about that one. 

 

im also exploring a couple of leads for other blocks. so will see how those pan out too. im not going to get a chance to grab a battery for my calipers today, but will go roughly measure them with a ruler today and make a start on seeing if anything will be in the ball park of fitting. 

 

it ran bizzarly well for the state of the bores. it had some issues with poor idle and flat spots, but i still am pretty confident those are tune and ecu trigger related. it only had about 2 hours total of road and track tuning in it. 

feeling slightly better today, but still pretty sad. anyone want to sell me a $500 shitbox so i can get the crown panel and painted and not have it deteriorate.

 

Link to comment
Share on other sites

4 hours ago, BlownCorona said:

feeling slightly better today, but still pretty sad. anyone want to sell me a $500 shitbox so i can get the crown panel and painted and not have it deteriorate.

 

My flatmate is looking to pawn off his 1995 Corona for probably $800-$900. Fresh wof a week ago (brand new brake hoses all around), oil and filter changed earlier this week.

Link to comment
Share on other sites

rough piston measurements are

Diameter - 88.5 mm (stock)

Comp height - 42.5 mm

Pin diameter - 22.0 mm

these measurements were taken by measuring with my dead electric verniers, locking them and then measuring the verniers with a steel ruler. so by absolutely no means definite. but for anyone interested there they are. ill take proper measurements later on and post them here

Link to comment
Share on other sites

20 hours ago, BlownCorona said:

I'm a little worried that the source of my leak into the cooling issue could be related to this, and there's a crack somewhere in there. 

Any ideas on how to check for this, or would it be rather obvious? 

 

The machining isn't something you can do @NickJ? Though I think your shop does cnc stuff primarily yeah? 

Edited cause of wrong Nick taged lol. though i think NickM is actually someone who works in the motorsport industry 

Yeah we're mainly large CNC machines, yes they could do it, but its not the kind of work we do daily, even then a top level motorsport machinist would be cheaper!

I have a bore gauge at home that could measure into the pockets if you want to look that close?

Link to comment
Share on other sites

3 hours ago, BlownCorona said:

rough piston measurements are

Diameter - 88.5 mm (stock)

Comp height - 42.5 mm

Pin diameter - 22.0 mm

these measurements were taken by measuring with my dead electric verniers, locking them and then measuring the verniers with a steel ruler. so by absolutely no means definite. but for anyone interested there they are. ill take proper measurements later on and post them here

 

Whats the pin height?

Link to comment
Share on other sites

1 minute ago, BlownCorona said:

is pin height not compression height? none of the piston dimension drawing listed anything else? but i can measure anything your interested in tomorrow. and in more detail/accurate next week

It could be maybe I am getting my terminology out of wack ;) its Friday and I am a couple of beers in

Just curious and hoping that something off the shelf will work for you as 1500 for forged pistons isn't cheap

Link to comment
Share on other sites

5 hours ago, ajg193 said:

My flatmate is looking to pawn off his 1995 Corona for probably $800-$900. Fresh wof a week ago (brand new brake hoses all around), oil and filter changed earlier this week.

just found out my sister may not be using her car for 6 months, so might be able to nab that and get to work on the crown! 

cheers though

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...