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Re: engine combination possibilities
Posted: Fri May 08, 2015 11:12 pm
by rabidrabbit001
4JG1 PISTON DIMENSIONS
http://morida-taiwan.com/product-detail.php?pid=14&sid=17&id=954JG2T PISTON DIMENSIONS
http://morida-taiwan.com/product-detail.php?pid=14&sid=17&id=97For a larger height difference of .3 mm for the 4jg1 pistons.
That's like two hairs thick.
Can this height not be resolved by the use of a 4jg1 head gasket?
Re: engine combination possibilities
Posted: Sat May 09, 2015 2:40 am
by geeves
If its really an issue it would be possible to skim that much off the top but I would just pick the thickest gasket as well. Remember its a different head
Re: engine combination possibilities
Posted: Sat Jan 16, 2016 3:53 am
by rabidrabbit001
Ok here is an update. I am driving my 4jg2t to 4jg1t conversion. First thing is the damage found in the 4jg2t head when removed. All cylinder chambers had cracks of varying sizes. All has chamber cracks and all had cracks between valves.
Re: engine combination possibilities
Posted: Sat Jan 16, 2016 4:10 am
by rabidrabbit001
Here are the new pistons chamber and top polished. Before:
After polish:
Re: engine combination possibilities
Posted: Sat Jan 16, 2016 4:13 am
by rabidrabbit001
New liners...dry ice method used and works like a charm.
Re: engine combination possibilities
Posted: Sat Jan 16, 2016 4:20 am
by rabidrabbit001
New main and rod bearings. Head chamber polished. Complete match ported and polished. (4JB1 head)
Re: engine combination possibilities
Posted: Sat Jan 16, 2016 4:35 am
by rabidrabbit001
3 notch head gasket
Re: engine combination possibilities
Posted: Sat Jan 16, 2016 4:44 am
by rabidrabbit001
Also did a complete belt timing to gear timing swap. (4jb1 rear and front cover/gears) oiler tube not shown. Yes I installed it after photo. 2 parts needed to complete swap: cam thrust plate and remove plug behind idler gear (A) from block for oil galley to allow oil flow to idler gear and oiler tube.
After running the 4jb1 gears for 2 weeks I decided to use the 4jg1 gears that I had also purchased. They are alot quieter. Less chatter and the motor seemed to tune better after 4jg1 gears installed. Idle also seems smoother.
Re: engine combination possibilities
Posted: Sat Jan 16, 2016 5:12 am
by geeves
Its coming along well
That 4jg2 head wasnt going to be going much further.
Are those steel or chrome liners? (remember rings and bores must be one of each not the same)
Any dyno figures?
Re: engine combination possibilities
Posted: Sat Jan 16, 2016 9:44 am
by Roderunner
Nice!..... Did you do a piston to valve clearance check with the various gear drives? I ask because the 4jg2 has 50 degrees of valve overlap according to my workshop manual, I haven't got any duration figures for the 4jb1 engine to compare that figure with.
While you have your hands greasy could you please measure the valves on the 4jg2 head as I want to know if the belt drive engine has the same valve sizes as the gear driven 4jg2. Thanks, if you could keep us posted on your progress it would be appreciated. cool build by the way.