WRX Forged Rebuild
29 August 2009, 04:18 PM
#151
well i had 4 pistons for my rebuild but two got damaged, and ruined block.
bought new block and ordered two new pistons.
The two new pistons i had where different machining and weights to the two original pistons.
so i checked the part numbers to the years the pistons belong too and found out the original two were for 98 on and the new two i bought were for pre 98.
now my original block was pre 98, so id fitted the wrong pistons in my block, which caused all my problems.
so iv now got 2 pistons on order too match the 2nd lot of pistons i ordered to replace that which were damaged.
so il now have 4 new pistons for a pre 98 block which i have.
the other differences in the pistons are stroke height. the new pistons have a longer stroke so more compression than the original pistons i had. explaining why i only had 110psi per cylinder.
cdf raciing who supplied the pistons has been a top bloke through my nightmare and i recomment the company to anyone looking to buy parts.
The problem we faced is my impreza is on the cross over year, which must have caused confusion.
but cdf has rectified all my issues, no argument whatsoever. mistake made and rectified and im very happy now awaiting the arrival of my two new pistons.
chris is a top man, so thanks chris.
also spoke to wiseco technical to clear the matter and make sure everything this tiem will be ok.
with such a low compression and fuel set up wiseco said it was possible the fuel wasnt being compressed in the chamber enough and getting the explosion in the chamber i should have had leaving residual fuel behind which eventually would wash bores and create the issues i had.
mmmm, maybe, who knows, just glad i bought from a company that cares about its customers. cdf racing
bought new block and ordered two new pistons.
The two new pistons i had where different machining and weights to the two original pistons.
so i checked the part numbers to the years the pistons belong too and found out the original two were for 98 on and the new two i bought were for pre 98.
now my original block was pre 98, so id fitted the wrong pistons in my block, which caused all my problems.
so iv now got 2 pistons on order too match the 2nd lot of pistons i ordered to replace that which were damaged.
so il now have 4 new pistons for a pre 98 block which i have.
the other differences in the pistons are stroke height. the new pistons have a longer stroke so more compression than the original pistons i had. explaining why i only had 110psi per cylinder.
cdf raciing who supplied the pistons has been a top bloke through my nightmare and i recomment the company to anyone looking to buy parts.
The problem we faced is my impreza is on the cross over year, which must have caused confusion.
but cdf has rectified all my issues, no argument whatsoever. mistake made and rectified and im very happy now awaiting the arrival of my two new pistons.
chris is a top man, so thanks chris.
also spoke to wiseco technical to clear the matter and make sure everything this tiem will be ok.
with such a low compression and fuel set up wiseco said it was possible the fuel wasnt being compressed in the chamber enough and getting the explosion in the chamber i should have had leaving residual fuel behind which eventually would wash bores and create the issues i had.
mmmm, maybe, who knows, just glad i bought from a company that cares about its customers. cdf racing
Chris
17 October 2009, 01:25 PM
#153
update, iv now got all my bits, bearings, rings and pistons thanks to chris at cdf. due to the nightmare iv had the first time around iv asked a engine builder to lend a hand in this building of the short block.
now being the guy he is, my workshop foreman, he still wants me to do all the calculations myself and he will check them all before anything gets touched. so its a learning curve for me and il know its all done right.
so next step is to gap my pistons rings, iv been reading up on wiseco and they recommend for my build a top ring gap of .0045 per inch of bore and 0.0055 for 2nd compression ring. which is high performance street / strip.
so for example
my bore is 92.5mm which when divided by 25.4 to convert to inches is 3.64 inches
so its 3.64 x .0045 for my top gap, which is 0.016
same aplied for 2nd ring but x .0055 which is 0.020
now thats just a example as even tho my pistons and bores have been done to 92.5mm
im still gonna measure each bore to make sure every calculation and ring gap is correct.
wiseco stated the oil rings do not need to be gapped but a minium space of 0.10 inches is recommended, so while im there, thats also gonna be checked over.
so its on with the maths and horrid jobs before is a nice straight forward assembly.
now being the guy he is, my workshop foreman, he still wants me to do all the calculations myself and he will check them all before anything gets touched. so its a learning curve for me and il know its all done right.
so next step is to gap my pistons rings, iv been reading up on wiseco and they recommend for my build a top ring gap of .0045 per inch of bore and 0.0055 for 2nd compression ring. which is high performance street / strip.
so for example
my bore is 92.5mm which when divided by 25.4 to convert to inches is 3.64 inches
so its 3.64 x .0045 for my top gap, which is 0.016
same aplied for 2nd ring but x .0055 which is 0.020
now thats just a example as even tho my pistons and bores have been done to 92.5mm
im still gonna measure each bore to make sure every calculation and ring gap is correct.
wiseco stated the oil rings do not need to be gapped but a minium space of 0.10 inches is recommended, so while im there, thats also gonna be checked over.
so its on with the maths and horrid jobs before is a nice straight forward assembly.
21 October 2009, 07:19 PM
#154
fitted pistons today, gapped topped rings to 0.16 and bottom ring 0.20. very easy process, took approx 1 hr to do all rings and refit pistons. i put ring in bore and used piston upside down to push ring down into bore slightly keeping it level and in same place everytime i checked for gap. i also checked oil rings. minimum clearance was 0.10 which all rings were above.
28 October 2009, 11:03 PM
#156
had day off work today, so hit garage early, fitted heads, water pump, oil pump, sump, new fuel rails, sorted wiring and injectors, cam pulleys all on. need to order a few bits now and make my mind on few ideas in my head and il be away. couldnt fit clutch as i need a spigot bearing. turbo, power steering are all simple to fit, so hoping to get friday off to do my running around for parts and have engine full assembled ready to fit sunday. which should be nice and easy :-S providing i can get all necessary parts.
13 December 2009, 12:21 PM
#157
scooby is finally a runner as of 10.30 last night. got all bits i needed from awesome imports down in bristol. fitting engine friday night anf fisnished up last night, only let the engine idle for 10 mins and then shut it off. i kno i got a air lock so that will be sorted today and all the finishing up bit. then its ready for insurance and tax and to hit the road for a running in.
16 December 2009, 11:10 AM
#159
had a disaster after trying to sort clutch, small snap ring that sits in pressure plate had come off inside bell housing. the clutch release bearing wud not lock into pressure plate. so it was engine back out and back in, took hour and 45 mins, i was ruinned, but all worked. so took it out last night for its first 15 min drive, all felt nice and really happy so far. next up to clean car up, bit of tlc and wait for jgm to come plug it in, make sure fueling etc is all correct. 
16 December 2009, 11:25 PM
#161
iv yet to meet simon, but looking forward to it, car is bit embarrassing the state its in now, but has been off rd for months and looks a bit tired. but being a panel beater painter, if simon gives me the thumbs up il treat it to a nice respray in april
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