jspinn13

hey all, my 93 prelude with h22a1 swap has some baaad compression.

i just tested it this morning and 1&2 were perfect with 155 comp. but when 3 came around i got 145 and 4 got about 87...

i was wondering what it might be that causing this. i am slightly leaking oil, and the spark plugs have small amounts of oil in the slots too.
i was told it was either piston rings, valves, or the head gaskets were bad (i really hope its just gaskets).

but what do you think it is? and what is it most likely to be?

preluder1989

Do a cylinder leakage test, this test will pinpoint whats causing the bad compression. How many miles on the engine?

jspinn13

its low miles, between 20-40k. (its a swap so i dont know)

indylude18

You're lucky it runs at all like that. Do a leakdown test to determine where the problem is. If you are lucky it's in the head, if your unlucky it's the piston rings and you will need a rebuild/swap.

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preluder1989

Thats low mileage for it to have bad compression, take it to a shop or someone that can perform a leak down test. are you sure you did the compression test correctly?

jspinn13

yeah i did it right, the last two cylinders were sticking too when we did it. but how much is it to do a leak down test? and how do you do it?



and as of this morning i have been stalling in the middle of third gear and at times when it shouldnt be stalling.

doc-vtec

u need a tool with a spark plug end and an air line male the other end,u can make 1 out of a long hollow bar and a bit of oxie-aset welding,get a treaded part of an old spark plug and weld it to 1 end and a male air line juntion on to the other end,if u wana do it urself i can send u on the proceedure,its pretty easy

jspinn13

well i have a friend who is a mechanic and he's charging me 100 to do it (he has all the tools already). does that sound like a good price? or do you think it could be cheaper for another garage to do?

preluder1989

Before you pay 100$, make sure its not your piston rings. you have already done the first compression test and got your numbers (155, 145, and 87). now do a compression test again, but before you do, drop a couple squirts of oil in the cylinder you are testing. (the oil will create a temporary seal around the piston rings) if your compression numbers go up, then your piston rings are starting to fail.

jspinn13

oh ok cool thanks ill do that today and come back with da numbahs lol

doc-vtec

100 is ok but he not doing u any favers,the cylender leak test will also test ur pistion rings,u just have to know wat u are doing,but do use the oil trick first and see if it makes a difference,when u are doing the compression test make sure all the plugs are out and u have ur foot on the trottle all the way open

TheJGB-2KTypeSH

And don't forget to pull the fuel pump fuse

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AJHS2011

uhhh i had this on my 91 prelude, except i was getting no compression from any 4 cylinders. ripped the block apart and found a blown exhaust or intake valve(cant remember) that was blown. so i went ahead and replaced all 16 valves. took a while but its worth it.

My advise: start taking the cylinder head off but make sure you know where everything goes when you get ready to put it back together. ps: dont leave any parts laying around out in the weather, a lot of mine rusted in a couple days