stagefumer11 Posted February 21, 2006 Share Posted February 21, 2006 Im at the point of needing to do another head gasket. (lucky for me) The idea of shaving the head has come into play so i can bring the compression up. Now this is a l20et which is 7:3 Compression? Correct me if im wrong. Now my goal is to get it in to the low 8's which will help with the lack of low end torque. What would be the required amount to take off the head that doesnt require me to shim... ect the cam towers ect ? Quote Link to comment Share on other sites More sharing options...
AK-Z Posted February 21, 2006 Share Posted February 21, 2006 Sorry that I can't answer your question but I have a question to add to that. If you were to use a thinner gasket would you have to shim it as well? Quote Link to comment Share on other sites More sharing options...
Clifton Posted February 21, 2006 Share Posted February 21, 2006 Another 800cc's (L28) would help your low end torque alot more. I have cut .070" off a head and not shimmed it. It will retard your cam timing, favoring the top end but you can move the sprocket to get it back or just leave it. I don't think you will notice much from such a small increase though. I didn't when I went from a 1.4mm to a 3mm headgasket. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted February 21, 2006 Share Posted February 21, 2006 Doesn't retarded timing favour the bottom end as the valve opens later so the air has less time to get in before the piston is all the way at the bottom of the bore and stops sucking? Dave Quote Link to comment Share on other sites More sharing options...
JMortensen Posted February 21, 2006 Share Posted February 21, 2006 No, retarded cam = higher end power. Clifton, did you have trouble with the timing chain when you did that? How long did you run it after you did that? Because I've seen a few L engines chew the crap out of the slack side guide because of the chain tensioner being too loose when the head was shaved and the cam towers not shimmed. You're introducing .140" slack in the chain that way. Too much IME to be ignored. Quote Link to comment Share on other sites More sharing options...
Tony D Posted February 21, 2006 Share Posted February 21, 2006 A better response to compression would be to put the dished N/A or even the flat-topped pistons from a norma L20E in there, and be done with it. The amount you will get from cutting the head will be nil, and cause all sorts of timing issues as stated above. As far as the L28, if you can't get em, you can't get em, right! Tax class, and insurance regulation in NZ are a bit different than in the USA where engine swaps can usually be carried out willy-nilly. So to sum it up, find an L20E and swap those pistons in there. Get a late enough EFI engine (post-1975), and they will have a dished top that is in the 8.0 8.2 range. My 75 L20A with dual SU's had pistons with a slight dome to them. Damndest thing! Quote Link to comment Share on other sites More sharing options...
Clifton Posted February 21, 2006 Share Posted February 21, 2006 No' date=' retarded cam = higher end power. Clifton, did you have trouble with the timing chain when you did that? How long did you run it after you did that? Because I've seen a few L engines chew the crap out of the slack side guide because of the chain tensioner being too loose when the head was shaved and the cam towers not shimmed. You're introducing .140" slack in the chain that way. Too much IME to be ignored.[/quote'] It was a friends car. Don't know what happened with it long term. We adjusted the slack side rail over as far as it would go. Don't know how anyone would know if it was an L28 or L20 from the outside. The stamp on the block can be easily changed. People ship JDM front cuts all the time. An old L28 can't be too much to ship. Quote Link to comment Share on other sites More sharing options...
stagefumer11 Posted February 22, 2006 Author Share Posted February 22, 2006 Id love to go the l28 route. but the cost isnt worth it. $750 seems to be the normal price for a Early l28e these days. Swapping over can be done but needs to be certed wich is another 350 on top of the motor purchase. IF i work out the pro's and con's A rb20det would be a more cost effective swap. (i dont want to loose the L motor tho) Quote Link to comment Share on other sites More sharing options...
stagefumer11 Posted February 22, 2006 Author Share Posted February 22, 2006 Here is some intresting information. Got the head off today. No visiable markings on the head gakset. No blow outs ect. Piston number 1. Full of water. (to the top of the dish) What else could be the problem. We also came across that the front set of head bolts were torqued alot less that the rear; Which makes me think that it wasnt done the best last time. Also there seamed to be excess crap on the block. Which looked old compared to the newish head gasket on it. SO maybe the last head gasket job on this motor wasnt done right ( it did cost me 1200bucks tho) Or could there be another problem with water getting into the number one piston ? Head problems ? Quote Link to comment Share on other sites More sharing options...
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