Modifying 1.7L heads

Michel J · 02-21-2004, 04:31 AM

Can 1.7L heads be modified with larger valves such as 44/36 sizes? Are the ports size different than the 1.8 and 2L heads?

thanks,

Michel

SteveStromberg · 02-21-2004, 05:54 AM

They can be moded and the port are different. Steve

Bleyseng · Bleyseng's Garage

Just go to the 42x36 sizes like the 2.0l. The 1.7 head has a good shape to the chamber but too large of valves and you will have problems. You could have them relocate the spark plug too but have the ports enlarged so the intake can flow with the larger valve.

Geoff

Michel J · 02-21-2004, 08:24 AM

I see people out there that install large valves in bus type heads. Does it matter to these folks that do the machine work what core head they start out with such as a 1.7 or 1.8 or 2.0 bus head? It seems to me that there is a bunch of work to do anyway, so it may not matter what core they start out with.
The engine I am building is a 96 bore by 78 stroke. I have a set of 1.7 heards that have been opened up to accept the 96mm cylinders but have the stock valve setup.
Thanks for your help.

Michel

Dave at Pelican Parts · Dave at Pelican Parts's Garage

Depends on how much work you're doing. If you are putting a whole lot of time/money/effort into a set of heads, then it matters less which ones you start with--most of the differences are things you'll already be dealing with anyway. If you are doing very little to the heads, then which one you start with is very important.

Stock 1.7 valves are definitely on the small size for a 2250cc motor. Going to 2.0 valve sizes (42/36) would be a real gain in power for that, and going larger might not be a bad idea.

--DD

Alfred1 · 02-21-2004, 10:18 AM

Michel J · 02-21-2004, 12:31 PM

Thanks for the info Alfred. Dave, I was thinking of going to 48 38 valve sizes. The are a couple of people I was thinking of sending my 1.7 heads to. The first being Westside core in Palmdale,CA and the other a place called "Tuttles" in LA. Anyone have anything to say about these places or any other suggestions would be appreciated. TIA

MXMARK · 02-21-2004, 01:08 PM

Micheal, I am running 1.7 heads with 48mm and 38mm valves. I really like it. Great pull from 2000 to 6500, best power 3000 to 5500. I have heard that if I had the same $ into some 2.0l heads then the motor would pull to 7000 or more instead of 6500. 103x76 with 44mm webers Web 86a cam. Good luck with the new motor. Mark

Michel J · 02-21-2004, 02:22 PM

Michael,

That was great info. Who did your heads?

Michel

MXMARK · 02-21-2004, 02:56 PM

Michel, Sorry I spelled your name wrong. I had Fat performance do the whole motor. I have another motor that I would like to have Jake put together. I would call Greg at www.fatperformance.com and Jake at www.aircooledtechnology.com and see what each of them think you should do. I have respect for both of them and I know they are competitors that both do good work. I like that Jake is into setting up the ignition to go with all of the other mods. Jake is also very helpful on this forum. Thanks Mark

Michel J · 02-21-2004, 04:01 PM

Michael,

Yes, thanks. I know about those type 4 places you mentioned. I am trying to build my engine on a very low budget so those guys really don't want anything to do with me. I tried emailing directly to Jake a couple of times, but, did not get a reply. Can't blame him as he is trying to run a business and make $. He does have a very good website and I am thankful for it.
The fat people want $5k plus for an engine also. I am tring to build mine for under $2k
doing the rebuild myself.

Michel