7a 83mm bore

[v33sonata]

Hey guys this is my 1st post. I am working on converting my old 7a turbo project into a 7age 20v. I need to re-bore the block but its currently at 82mm has anyone ever bored a 7a to 83mm? and did it last?

Thanks in advanced

 

[mh wong]

i was searching n asking around bout 7a, no one tell me 7a is reliable, theres 1 mech in kajang told me if u want turboing later, its better to bore 82mm only, unless, u want to play na, then, u can actually bore it to 83mm.

ok, when i ask him how is the reliability,
he answer me, u cant abuse it the way u drive 4age, if u always hirevving, it tend to break, bcoz, water "hole" r too close to the piston wall.
2. 7a will tend to burn the engine oil slightly higher compare 4a.
3. without hicam, it cant rev >8.5k, the power lost after 7k+ rpm.
4. with 7a, the timing will slightly not accurate.
5. save fuel compare 4a
6. 7a flywheel is weak compare 4a flywheel, another drifter told me, they had experienced flywheel broken while drifting. unless you have stroker kit, the crank can use 4a flywheel.
7. in zth, theres a old timer share his experience, saying that, if u have same performance parts on 4age, it can eat 7age within 400m.
8. 7afe block is not like 4age, if you r not lucky enough, when you bore it to 83mm, sometime, the block surface have small hole, so, you have to use another block.

after gather all the information, im not dare to convert to 7a. just share

 

[v33sonata]

I have already done a 7agte. I never heard that about the coolant jackets being close to the cyl walls. interesting. My plan now is to do a 20v bt 7a none turbo so I guess the 83mm should be ok? I'll have to put some extra time into the coolant system just in case. I already have rods so it should be pretty stout and I know of a company that does rekeying the timing belt sprocekt to get the timing back on. So hopefully all will be good :) if not I still have a 4a block in the garage lol! But I appreciate EVERYONES input as this is something different from the norm.

 

[mh wong]

I have already done a 7agte. I never heard that about the coolant jackets being close to the cyl walls. interesting. My plan now is to do a 20v bt 7a none turbo so I guess the 83mm should be ok? I'll have to put some extra time into the coolant system just in case. I already have rods so it should be pretty stout and I know of a company that does rekeying the timing belt sprocekt to get the timing back on. So hopefully all will be good :) if not I still have a 4a block in the garage lol! But I appreciate EVERYONES input as this is something different from the norm.

do u ever think want to stroker ur 4a to bcom 1.8cc instead of playing with 7a.

4a with stroker still can hi rev, but dunno bout 7a, i heard 4a can rev happy till 11k rpm, 7a only roungly 9k rpm plus, with the extra rpm revving, people said it can eat 7a. u have any idea ?

 

[v33sonata]

The 7a's will rev just as high if you get better internals. (as I do) but no stroking a 4a never crossed my mind.....

 

[D7zul]

i've contacted a company selling an 82 & 83mm stroker kit in australia..

he said if u using for daily use.. better go for 82mm..

83mm is for racing only.. or if u willing to do an overhaul every month

 

[v33sonata]

i've contacted a company selling an 82 & 83mm stroker kit in australia..

he said if u using for daily use.. better go for 82mm..

83mm is for racing only.. or if u willing to do an overhaul every month

So why would anyone do a race motor that's going to pop every weekend....? LOL was this the 4a or 7a motor?

has anyone actually done an 83mm bore?

 

[mh wong]

So why would anyone do a race motor that's going to pop every weekend....? LOL was this the 4a or 7a motor?

has anyone actually done an 83mm bore?

1 mech in Kajang did it few times, he told me no problem, he do said last time the 7a-ge that he did got problem, now, he oledi manage to do it properly. its only u cant abuse it like 4age, means 1 in a while can, but not long distance continuous drive hard, he explain, affraid the cylinder wall will crack.

 

[D7zul]

So why would anyone do a race motor that's going to pop every weekend....? LOL was this the 4a or 7a motor?

has anyone actually done an 83mm bore?

they will rebuild the engine after every race..

and it's 7a motor..

 

[KenDiriwan]

i was searching n asking around bout 7a, no one tell me 7a is reliable, theres 1 mech in kajang told me if u want turboing later, its better to bore 82mm only, unless, u want to play na, then, u can actually bore it to 83mm.

Isit Ah Nga from Power Speed?

 

[mh wong]

Isit Ah Nga from Power Speed?

yeah bro.

---------- Post added at 08:46 PM ---------- 6 hour anti-bump limit - Previous post was at 08:07 PM ----------

he quo me rm5k,

 

[D7zul]

v33sonata, hv u done 83mm bore on ur 7age?

Did u put oil squiter in it?