7A rod compatibility?

[sam-131]

so a ca18 rod with a ca18 bearing would have the right clearances to be used in a 7a ?

whats max overbore on a 7a block? could it be possible to use the ca18 piston?

[DX20VT]

For what it's worth,

I did a lot of research into rods also, honda and mazda and nissan's

all required something to be modified and then something else would have to be changed and then pistons heights etc etc,

In the end I got a set of proper 7A aftermarket rods brand new for around $750 in Australian currency,
which meant that I could run standard crank, standrad 4AGZE pistons etc.

The few dollar extra spent on the rods were more than saved in other area's.

Pays to price around though as for the same rod I got priced from that up to 2.5X the price for the same brand from another supplier.

[Mooro]

Wise words and definitely a consideration. I came to the same conclusion as you when I was looking at the nissan rods, but if the mazda rods can be used with minimal machinging and the length is correct then they maybe a cheaper alternative for a budget build.

Any updates turbo4agte?

[nick.parker]

In the end I got a set of proper 7A aftermarket rods brand new for around $750 in Australian currency

Wow thats cheap. From whom did you buy the rods?

Cheers, Nick.

[Mooro]

The was a group buy on club4age recently for 7age rods at $350 US, so with shipping and conversion rate that would end up pretty cheap.

[DX20VT]

Got them from ARGO through a race team we sort of deal with in Aussie, apparantly they just happened to be on special at the time I needeed them, lol

Matt

[turbo4agte]

I was wrong!

Got my 7A block and BP rod together and tried it, and you guessed it... doesn't fit.

I dont know why, but the Haynes manual for the Mazda Protege lists the 1.8L engine with a crank pin (rod journal diameter) of 48mm when in fact its only 45mm. Thus the big end on the BP rod is only 48mm. Now that I look back at the Crower listing it also lists it at 48mm, and its the 2.0L rod thats the same as a 7A.

Haynes listed the specs wrong and led me to waste my time pulling it out of a block.

Well I guess we still have to wait on a cheaper rod to come out. I still have no intention of using a stock 7A rod, so I'll have to wait it out or fork out the money like the rest of the guys who have gone this route.

[jezza323]

you could always have the crank offset ground and gain some capacity in the process

[Mooro]

Damn...thats a shame but I suspected that would be the outcome.

I wonder how much it would cost to lighten the 7a crank significantly and do an offset grind on it.

[turbo4agte]

you could always have the crank offset ground and gain some capacity in the process

Well talking with an old race engine builder about it he said not to do it. Its a 48mm journal vs 45mm, so in all its a 3mm difference, so you have to cut 1.5mm off all around. Although the crank is forged, cutting 1.5mm off is a very bad idea. At that point your getting past or leaving very little case hardening. The most he would ever go on a crank is 0.75mm (0.030").

So we'll have to wait on Eagle or Belfab to make a rod in the $300-$400 range.

[jezza323]

ive just organised a rod group buy for a 5efe engine from www.spoolimports.com. he can do any rods for $550 for a 4 cyl set. just need 6 ppl. or if he already has a listing for it it will be $490 with 5 ppl

pretty cheap

[turbo4agte]

Thought of that. Yeah, well I got another company already that I contacted about 3 months ago, James Belfiore at Belfab racing. He is now ready to go for only $340 with 12 buyers.

[Cameron_Datto]

Thought of that. Yeah, well I got another company already that I contacted about 3 months ago, James Belfiore at Belfab racing. He is now ready to go for only $340 with 12 buyers.

Is $ 340 for a set of 4 or Per Rod ?

[DX20VT]

Is $ 340 for a set of 4 or Per Rod ?

would have to be a set as otherwise they are way to expensive,

$340 a set is quite cheap, but you have to remember,
that is quoted on a batch of almost 50 made at once,
so could be about right. ( 12 sets of 4 = 48 rods)

[turbo4agte]

Of course its $340 for the full set... were not millionaires here who can afford $1300 rods.

The owner of the shop actually said he's going to run 50 sets. He at first wanted us to get half of the run with 25 buyers, but I've asked him to lower it and said he'd atleast take the 12 for now, and I guess he'll have the extra 38 sets in stock. But he wont start anything until we have atleast the 12 people to pay.